[Federal Register: March 25, 2004 (Volume 69, Number 58)]
[Rules and Regulations]
[Page 15238-15248]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr25mr04-5]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-NM-111-AD; Amendment 39-13544; AD 2004-06-18]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-100, -200, -300, -400,
and -500 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to certain Boeing Model 737-300 and -400 series
airplanes, that currently requires either repetitive leak checks on the
forward lavatory service system and repair, as necessary, or draining
of the system and placarding the lavatory inoperative. This amendment
also requires periodic changing of the seals of certain lavatory drain
systems; replacing ``donut valves'' with other FAA-approved valves;
revising certain leak test intervals; and revising the pressurization
and fluid level requirements for testing. The actions specified by this
AD are intended to prevent damage to engines, airframes, and property
on the ground that is associated with the problems of ``blue ice'' that
forms from leaking lavatory drain systems on transport category
airplanes and subsequently dislodges from the airplane fuselage.
DATES: Effective April 29, 2004.
ADDRESSES: Information pertaining to this amendment may be examined at
the Federal Aviation Administration (FAA), Transport Airplane
Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Don Eiford, Aerospace Engineer, Cabin
Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington; telephone (425) 917-6465; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 89-11-03,
amendment 39-6223 (54 FR 21933, May 22, 1989), which is applicable to
certain Boeing Model 737-300 and -400 series airplanes, was published
as a supplemental notice of proposed rulemaking (NPRM) in the Federal
Register on November 26, 1997 (62 FR 62708). That action proposed to
continue to require either repetitive leak checks on the forward
lavatory service system and repair, as necessary, or draining of the
system and placarding the lavatory inoperative. In addition, that
action proposed to add a requirement to perform leak checks of other
lavatory drain systems; require the installation of a cap or vacuum
break on the flush/fill line; and require either a periodic replacement
of the seal for the cap and tank anti-siphon valve or periodic
maintenance of the vacuum break in the flush/fill line. Further, that
action proposed to require a periodic changing of the seals of certain
lavatory drain systems; and replacing ``donut valves'' with other FAA-
approved valves.
Comments Received
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Comments That Resulted in a Change To the Final Rule
Requests To Extend Leak Test Interval
One commenter requests that paragraph (a)(4) of the supplemental
NPRM be revised to extend the leak test intervals of certain service
panel drain valves (also known as and referred to in the supplemental
NPRM as waste drain valves) from 1,000 flight hours to 2,000 flight
hours. The commenter also requests that Table 1 of paragraph (a) of the
supplemental NPRM be updated to reflect the appropriate valves approved
for the 1,000-flight hour interval. In addition, the commenter requests
that paragraph (a)(5) of the supplemental NPRM be revised to extend the
leak test intervals from 600 flight hours to 1,000 flight hours. The
commenter advises that more than 7,000 Shaw valves have accumulated in
excess of 50 million flight hours during the past 10 years. The
commenter states that it is aware of less than five blue ice events
that could have been attributed to a Shaw Aero service panel valve and
suggests that this is ample evidence to support the extensions of the
leak test intervals. The commenter further states that service
experience clearly indicates that the main problems regarding blue ice
occur
[[Page 15239]]
after a period of two years of residue build-up on the sealing surfaces
of the valve design. Therefore, the commenter concludes that the
performance of the Shaw valves in real life maintenance environments
will, if approved for an interval of 2,000 flight hours for the leak
test, continue to operate with no blue ice events.
Another commenter requests that the improved Shaw valves specified
in Table 1 of paragraph (a) of the supplemental NPRM be approved for
the 2,000 flight hour interval that is specified in paragraph (b) of
the supplemental NPRM. The commenter states that the improved valves
specified in Table 1 of paragraph (a) of the supplemental NPRM, coupled
with the incorporation of the maintenance program specified in
paragraph (b) of the supplemental NPRM, justify increasing the leak
test intervals.
The FAA agrees that the interval for the leak test of the waste
drain valves specified in Table 1 of paragraph (a) of the supplemental
NPRM should be extended. Since the issuance of the supplemental NPRM,
requests for alternative methods of compliance (AMOCs) have been
approved to extend the leak test interval to 4,000 flight hours for
certain valves. We have determined that, if those valves are maintained
properly, the valves are capable of leak-free operation. To simplify
and clarify the requirements of this AD, we have consolidated the leak
test intervals for certain valves specified in the supplemental NPRM
for -4,500, -2,000, and -1,000 flight hour intervals into one group
with a leak test interval of 4,500 flight hours. Therefore, we have
revised this final rule to specify that the valves listed in Table 1 of
this AD are approved for a leak test interval of 4,500 flight hours.
For certain other valves, we have consolidated the leak test interval
to 1,000 flight hours. Consequently, after the removal of ``donut''
type valves as required by this AD, there will be only two leak test
intervals specified in the AD. To accommodate this change in the final
rule, we have consolidated the requirements of paragraphs (a)(2),
(a)(3), and (a)(4) of the supplemental NPRM into paragraph (a)(2) of
this AD. We consider that the requirement of this AD to repair any
leaking valves before further flight to be an additional safety factor
in this determination.
Request To Add a Panel Ball Valve With a 48-Month Seal Replacement
Interval
Two commenters request that the interval for the leak test for
Kaiser Electroprecision panel ball valve, part number (P/N) 2651-357,
be extended to 2,000 flight hours. Both commenters request that the
seal replacement interval be every 48 months. The commenters explain
that ample testing with airlines has been accomplished to justify the
2,000 flight hour interval.
We agree with the commenters' request. Since the issuance of the
supplemental NPRM, additional flight data has been submitted to the FAA
justifying an extension of the leak check interval. Additionally, the
valve manufacturer has recommended that the seal change interval be
revised to every 48 months. We have revised paragraphs (a) and (d) of
the final rule to reflect these changes.
Requests Regarding Use of Certain Leak Test Tools
Three commenters request that use of a vacuum leak test tool be
approved for performing the requirements of paragraph (b)(3)(ii)(A) of
the supplemental NPRM, just as it is specified in paragraph
(a)(8)(ii)(A) of the supplemental NPRM. The commenters note that use of
a vacuum leak test tool does not require the airplane to be
pressurized, and is, therefore, valid for performing the requirements
of both paragraphs.
We agree with the commenters' request. We have redesignated
paragraph (b) of the supplemental NPRM to paragraph (d) of the final
rule and revised it from, ``Pressurize the airplane to 3 PSID * * *''
to ``Apply 3 PSID across the valve in the same direction as occurs in
flight.''
Another commenter requests the FAA to specify that it is
unnecessary to completely cover the upstream end of the valve being
tested with fluid when a vacuum leak test tool is used to test the
inner seal of the service panel valves. The commenter notes that
leakage will be detected by a loss of applied vacuum, not by fluid
leaking past the inner seal.
We agree and have added new paragraphs (b) and (c) of this AD that
specify procedures to perform vacuum leak tests.
Requests To Provide an Additional Option for Paragraph (d) of the
Supplemental NPRM
Several commenters request that installation of an FAA-approved
liquid level sensor and motorized shut-off valve (also known as and
specified as an automatic shut-off valve in the supplemental NPRM) be
accepted as another option for compliance with the requirements of
paragraph (d) of the supplemental NPRM. That paragraph specifies
installation of an FAA-approved lever/lock cap, vacuum break, or flush/
fill ball valve for all lavatories. Additionally, the commenters
request that this system also be provided in paragraphs (a)(8) and
(b)(3) of the supplemental NPRM. One commenter points out that the
automatic shut-off valve system is similar to other systems currently
installed in another airplane model, and it has proven effective in
preventing ``blue ice'' incidents.
We agree with the commenters' request and have revised those
paragraphs of the final rule to add the automatic shut-off valve as an
additional method of compliance. Also, we have redesignated paragraph
(d) of the supplemental NPRM as paragraph (f) of the final rule, and
paragraphs (a)(8) and (b)(3) of the supplemental NPRM as paragraphs
(a)(5)(iv) and (d)(3)(iv) of the final rule.
Request To Specify Terminating Action
One commenter requests that the actions required by the
supplemental NPRM and incorporation of an FAA-approved maintenance
program be considered as terminating action for the requirements of the
supplemental NPRM. The commenter states that the proposed actions, such
as donut valve removal, seal replacement, and rinse system upgrade,
will reduce the incidence of ``blue ice'' significantly, and in
conjunction with the FAA-approved maintenance program, justify
providing accomplishment of those actions as terminating action.
We agree with the commenter's request. A review of reports
indicates that, since the issuance of several blue ice ADs, the number
of reported events of blue ice has decreased markedly. We consider the
decrease as an indication that the existing blue ice ADs are effective.
Therefore, we have revised paragraph (d) of the final rule to allow
terminating action by incorporation of the requirements of paragraphs
(d), (f), and (g) of the AD into the operator's FAA-approved
maintenance program.
Request To Extend Intervals for Seal Replacement
One commenter requests that paragraphs (a)(1) and (b)(1) of the
supplemental NPRM be revised to provide that, for waste drain systems
that incorporate more than one type of valve, the seal replacement
interval of all affected valves in the system would be that of the
valve with the longest seal replacement interval. For example, if an
in-line drain valve were installed with a service panel valve,
replacement of the service panel valve seal would coincide with
replacement of the in-line drain valve seal. The commenter suggests
that it be specified that the secondary valve would not be a means of
continuing
[[Page 15240]]
operations if the seal of the valve with the longest replacement
interval were malfunctioning.
We partially agree with the commenter. We have revised paragraphs
(a)(1) and (d)(1) of the AD to permit extension of the interval for
replacement of the seals. However, we do not consider it necessary to
specify that the secondary valve would not be a means of continuing
operations if the seal of the valve with the longest replacement
interval is malfunctioning, since the final rule requires any worn or
damaged seal or any seal leakage to be repaired before further flight.
Request To Revise Paragraph (b) To Clarify Leak Test Interval
One commenter requests that certain language used in paragraph (a)
of the supplemental NPRM be added to paragraph (b) of the supplemental
NPRM. The language states, ``If the waste drain system incorporates
more than one type of valve, only one of the waste drain system leak
test procedures (the one that applies to the equipment with the longest
leak test interval) must be conducted at each service panel location.''
We agree that clarification is needed and have revised the final
rule accordingly. Paragraph (b) of the supplemental NPRM also has been
redesignated as paragraph (d) of the final rule.
Request To Add Appropriate Leak Tests for Auxiliary Waste Tanks
One commenter states that the flush/fill line valve tests specified
in paragraphs (a) and (b) of the supplemental NPRM cannot be
accomplished as specified for airplanes that have auxiliary waste tanks
installed. The commenter explains that auxiliary waste tanks cannot be
half-filled because the bowl is installed only on the primary waste
tank. Additionally, the primary waste tank cannot be tested by this
procedure without filling the auxiliary tank, because the standpipe
installation in the primary tank precludes filling the bowl half-full.
Therefore, the commenter requests that an appropriate leak test be
specified for those airplanes with auxiliary waste tanks installed. The
commenter did not suggest any specific leak test.
We agree with the commenter's request. Since using a vacuum test
does not require filling the tanks with fluid, we have determined that
such use of a vacuum test in accordance with applicable airplane and
component maintenance manuals will provide an acceptable method to
comply with the leak test requirements for airplanes with auxiliary
waste tanks installed. We have clarified paragraphs (a)(5) and (d)(3)
of the final rule to specify that vacuum test equipment (rigs) may be
used for those airplanes for the flush/fill line leak tests.
Request To Allow Certain Leak Test Extensions
One commenter states that, although paragraph (c) of the
supplemental NPRM provides for revision of the leak test intervals
required by paragraph (b) of the supplemental NPRM, no similar
provision is made for operators who comply with the requirements of
paragraph (a) of the supplemental NPRM. The commenter explains that it
is implementing a maintenance program that complies with the
requirements of paragraph (a) of the supplemental NPRM for certain
airplanes in its fleet, and that it complies with the requirements of
paragraph (b) of the supplemental NPRM for certain other airplanes in
its fleet. The commenter requests that paragraph (c) of the
supplemental NPRM be revised to permit extension of the leak test
intervals for airplanes that are in compliance with either paragraph
(a) or (b) of the supplemental NPRM.
We agree. The provision to extend the leak test intervals provided
in paragraph (c) of the supplemental NPRM has been revised accordingly.
Paragraph (c) of the supplemental NPRM has also been redesignated as
paragraph (e) in the final rule.
Request To Clarify Use of ``Dump Valve''
One commenter requests that the FAA revise the term ``dump valve''
as used in the supplemental NPRM to read ``toilet tank dump valve.'' We
agree with the commenter's request and have changed the final rule
accordingly.
Request To Specify ``FAA-Approved Vacuum Breaks''
One commenter requests that, rather than requiring the use of two
particular vacuum breaks as specified in paragraph (a) of the
supplemental NPRM, the FAA require the use of any FAA-approved vacuum
breaks. We agree with the commenter's request and have changed the
final rule accordingly.
Request To Revise a Part Number for the Vacuum Breaker Check Valve
One operator requests that reference to the P/N series for the Shaw
vacuum breaker check valves by changed from ``301-0009-01'' to ``309-
0009.'' We agree with the commenter's request and have corrected the
references to those P/Ns in the final ru;e accordingly.
Comments Received That Did Not Result in a Change to the Final Rule
Request To Approve Terminating Action
One commenter requests that a certain in-line drain valve be
approved as a terminating action for the requirements of paragraph (b)
of the supplemental NPRM. The commenter states that it is not aware of
any reports of leakage on the particular valve.
We do not agree with the commenter's request. Since in-line drain
valves may be damaged, fouled, and worn, we have determined that it is
not appropriate to approve those valves as a terminating action for the
requirements of paragraph (b) of the supplemental NPRM (redesignated as
paragraph (d) in the final rule). However, we have also provided for
terminating action by allowing incorporation of the requirements of
paragraphs (d), (f), and (g) of the final rule into the operator's FAA-
approved maintenance program.
Request To Revise Replacement Intervals
One commenter states that the FAA should not extend replacement
intervals for certain valve seals based on the success of certain other
in-line ball valve seals. The commenter specifies that the two
different types of valves are not similar, and therefore, extending the
replacement intervals should not be approved on that basis.
We do not agree that certain valve seals should not have the
replacement interval extended. We did not approve the extension of the
replacement interval of the seals based on similarity with another type
of valve. We based that approval on the manufacturer's recommended seal
change interval and on the successful operating experience with an
extended interval for the seal change. No change is necessary to the
final rule in this regard.
Request To Require Both a Vacuum Break Check Valve and a Lever Lock Cap
Two commenters request that the FAA require both a vacuum break
check valve and a lever lock cap on the lavatory fill/rinse line. One
commenter states that a large portion of blue ice leakage propagates
from the lavatory fill/rinse line and check valve designs are
inherently vulnerable to this waste system environment. Also, a single
vacuum breaker check valve provides no positive mechanical means of
closure as required for all other critical leak path valves with the
waste system.
We do not agree with the commenter's request. As we explained in
the ``Comments Received'' section of the
[[Page 15241]]
supplemental NPRM, we acknowledge that redundant systems generally
provide a higher level of safety; however, in this case, the vacuum
breaker provides redundancy to the check valve function. In the case of
a check valve alone, the lever lock cap provides redundancy to the
check valve. There are insufficient data to show which combination is
more reliable. No change is necessary to the final rule in this regard.
Request To Revise Replacement Intervals of Certain Seals
Two commenters request that the seal replacement intervals
specified in paragraphs (a)(1)(ii) and (b)(1)(ii) of the supplemental
NPRM be revised from ``Thereafter, repeat the replacement of the seals
at intervals not to exceed 18 months or 6,000 flight hours, whichever
occurs later'' to read ``Thereafter, repeat the replacement of the
seals at intervals not to exceed 18 months.'' One commenter did not
provide any justification for the requested change. The other commenter
states that the seal in a ball-type or half-ball type valve (especially
when used at the service panel) is subjected to significantly greater
dynamic action than the seal in a flapper-type valve. The distance that
the ball or half-ball drags across the seal subjects the seal to
considerably more wear than that experienced by an o-ring seal in a
flapper-type valve as it moves from a sealed to an unsealed position.
Also, the plastic seals used in the ball or half-ball type valves are
much less forgiving and less compressible than elastomer-type seals
used in flapper-type valves and thus are more susceptible to being
damaged by foreign objects and allowing leakage. The potential for ice,
hardened debris, and black tar buildup on the ball at the service panel
makes the seals much more susceptible to damage as the ball is dragged
across the seals. The commenter concludes that the location of the
service panel valve relative to the in-line valve makes damage more
susceptible to the seals or mating surfaces as a result of service and
maintenance processes.
We do not agree with the commenters' request. The proposed
replacement intervals for those seals specified in the supplemental
NPRM were based on the manufacturer's recommended seal change interval
and on successful operational experience with a longer seal change
interval. We consider that, if leakage does occur before the specified
replacement interval, the requirement to repair any leaks or placard
the lavatory inoperative before further flight will ensure that the
valve does not continue to leak. No change is necessary to the final
rule in this regard.
Request To Require the Same Proof for Approval
One commenter requests that other valve suppliers be required to
complete the same or similar number of flight test hours as the
PneuDraulics valve before extended leak test intervals are granted, and
that credit for similarity be disallowed. The commenter states that the
25,000 flight hours and use of similarity to approve extended leak
check intervals for valves as proposed in Notes 9 and 11 of the
supplemental NPRM are inadequate. The commenter states that the FAA
required it to complete 13 million flight hours over a 3-year period
before an extension to 4,000 flight hours was considered. The commenter
asserts that other applicants for extended leak test intervals should
be required to have a similar service history, and that service history
should be based upon in-flight experience with the exact design in the
exact location of use. The commenter states that the FAA cannot act as
a judge of equality in the marketplace, and that it must maintain its
role of acting in the best interest of airline passenger safety. The
commenter recommends that the FAA judge engineering data equally and
fairly, and that all requests for approval of an extended leak test
extension be determined by the same set of criteria.
We do not agree that ``credit'' for similarity should be
disallowed. We have allowed use of similarity for partial credit in
lieu of service experience, but a considerable amount of successful
service history was required before an extended interval was approved.
In granting such approvals, we primarily consider service history
obtained by operators using a program to gather data similar to that
outlined in paragraph (b) of the supplemental NPRM. For instance in the
case of a certain valve, operators reported approximately 936,000
flight hours and one leak. In another case, operators reported
approximately 848,000 flight hours and 2 leaks. In a third case,
operators reported approximately 480,000 flight hours and no leaks,
plus similarity to another valve manufactured by the same company.
These data indicate that any of these valves can be effective in
service. The requirement to repair any leak or placard the lavatory
inoperative before further flight is intended to motivate operators to
select and maintain the most reliable valves in order to avoid leaking.
No change is necessary to the final rule in this regard.
Request To Reduce Time of the Leak Test
One commenter requests that the duration of the five-minute leak
test be reduced to one minute for the leak tests that are performed
with a vacuum leak check tool. The commenter states that any leak path
will be readily detected within one minute when a three pounds per
square inch differential pressure is generated. If the pressure gauge
remains stationary, the inner seal is leak-tight.
We do not agree with the commenter's request. The commenter did not
provide any data to substantiate that a one-minute leak test is as
sensitive to low leakage rates as a five-minute leak test. No change is
necessary to the final rule in this regard. However, under the
provisions of paragraph (h) of the final rule, the FAA may approve
requests for alternative method of compliance (AMOC) if data are
submitted to substantiate that such an AMOC would provide an acceptable
level of safety.
Request To Revise the Economic Impact Section
One commenter requests that the FAA add information to the Economic
Impact section to advise operators that the leak check tool (the hand-
held vacuum pump) provides a more economic method of performing the
leak test. The commenter states that without the leak check tool, the
engine or auxiliary power unit (APU) must be started and the leak test
will take four work hours for each lavatory drain valve. The commenter
points out that, with the leak check tool, there is no need to power up
the airplane and the leak test takes only five or 10 minutes to perform
for each lavatory drain.
We do agree that it is necessary to add the additional information
concerning the costs of performing a leak test with the leak check
tool. As explained in the Economic Impact section of the supplemental
NPRM and in this final rule, the costs discussed are estimates based on
the fact that certain airplanes may be required to be leak tested as
many as 15 times each year, while certain other valve configurations
may be required to be leak tested as few as three times each year.
Additionally, some airplanes that have various combinations of drain
valves installed would require approximately two leak tests of one
drain valve and three leak tests of the other drain valve each year.
Because of the varied costs that may be incurred by different
operators, we have provided estimated costs of the leak tests that
range from between $1,170 and $5,850 per airplane per year. No
[[Page 15242]]
change is necessary to the final rule in this regard.
Request To Limit Leak Test Extensions Specified in Paragraph (b)
The commenter states that, in the recent past, the FAA provided
rationale for not granting an across-the-board leak check extension for
a manufacturer when the FAA stated that, ``it recognizes that varying
aspects of each airlines operational environment and the human factors
associated with maintenance procedures means that equal results for all
airlines would not necessarily result.'' Therefore, the commenter
states that the FAA encouraged operators who had proven and effective
maintenance programs to individually obtain approval for increased leak
check intervals. The commenter agrees with that approach and requests
that any extensions of the leak test intervals specified in paragraph
(b) of the supplemental NPRM be granted only on an airline-by-airline
basis, rather than across-the-board leak check extensions for certain
service panel valves.
We do not agree with the commenter's request. Since the time that
we granted extension of leak test intervals on an operator-by-operator
basis, sufficient data has been submitted to justify the conclusion
that certain service panel valves, if properly maintained, can perform
satisfactorily under different operating conditions and maintenance
programs. Further, to ensure that leakage does not become a problem in
conditions that may not be foreseen, the requirement to repair any leak
or to placard the lavatory inoperative before further flight should
ensure the operational safety of the fleet. No change to the final rule
is necessary in this regard.
Conclusion
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the changes previously
described. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
Changes to 14 CFR Part 39/Effect on the AD
On July 10, 2002, the FAA issued a new version of 14 CFR part 39
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness
directives system. The regulation now includes material that relates to
altered products, special flight permits, and alternative methods of
compliance. However, for clarity and consistency in this final rule, we
have retained the language of the supplemental NPRM regarding that
material.
Change to Labor Rate Increase
After the supplemental NPRM was issued, we reviewed the figures we
use to calculate the labor rate to do the required actions. To account
for various inflationary costs in the airline industry, we find it
appropriate to increase the labor rate used in these calculations from
$60 per work hour to $65 per work hour. The economic impact
information, below, has been revised to reflect this increase in the
specified hourly labor rate.
Cost Impact
There are approximately 2,410 Model 737 series airplanes of the
affected design in the worldwide fleet. The FAA estimates that 1,031
airplanes of U.S. registry and 110 U.S. operators will be affected by
this AD.
The required waste drain system leak test and outer cap inspection
will take approximately 6 work hours per airplane to accomplish, at an
average labor rate of $65 per work hour. Based on these figures, the
cost impact on U.S. operators of these requirements of this AD is
estimated to be $402,090, or $390 per airplane, per test/inspection.
Certain airplanes (i.e., those that have ``donut'' type drain
valves installed) may be required to be leak tested as many as 15 times
each year. Certain other airplanes having other valve configurations
will be required to be leak tested as few as 3 times each year. Some
airplanes that have various combinations of drain valves installed will
require approximately 2 leak tests of 1 drain valve and 3 leak tests of
the other drain valve each year. Based on these figures, the annual
(recurring) cost impact of the required repetitive leak tests on U.S.
operators is estimated to be between $1,170 and $5,850, per airplane
per year.
With regard to replacement of ``donut'' type drain valves, the cost
of a new valve is approximately $1,200. However, the number of leak
tests for an airplane that is flown an average of 3,000 flight hours a
year is thereby reduced from 15 tests to 3 tests. The cost reduction
because of the number of tests required is approximately equal to the
cost of the replacement valve. Therefore, no additional cost is
incurred because of this change.
We estimate that it will take approximately 1 work hour per
airplane lavatory drain to accomplish a visual inspection of the
service panel drain valve cap/door seal and seal mating surfaces, at an
average labor cost of $65 per work hour. As with leak tests, certain
airplanes will be required to be visually inspected as many as 15 times
or as few as 3 times each year. Based on these figures, the annual
(recurring) cost impact of the required repetitive visual inspections
on U.S. operators is estimated to be between $195 and $975 per
airplane, per year.
The required installation of the flush/fill line cap will take
approximately 1 work hour per cap to accomplish, at an average labor
rate of $65 per work hour. The cost of required parts will be $275 per
cap. There is an average of 2.5 caps per airplane. Based on these
figures, the cost impact on U.S. operators of these requirements of
this AD is estimated to be $875,500, or $850 per airplane.
The addition of the seal change requirement to paragraph (a) of
this AD will require approximately 2 work hours to accomplish, at an
average labor cost of $65 per hour. The cost of required parts will be
$200 per each seal change. Based on these figures, the cost impact on
U.S. operators of these requirements of this AD is estimated to be
$340,230, or approximately $330 per airplane per year.
The number of required work hours, as indicated above, is presented
as if the accomplishment of the actions required in this AD were to be
conducted as ``stand alone'' actions. However, in actual practice,
these actions could be accomplished coincidentally or in combination
with normally scheduled airplane inspections and other maintenance
program tasks. Therefore, the actual number of necessary ``additional''
work hours will be minimal in many instances. Additionally, any costs
associated with special airplane scheduling should be minimal.
In addition to the costs discussed above, for those operators who
elect to comply with paragraph (d) of this AD, we estimate that it will
take approximately 40 work hours per operator to incorporate the
lavatory drain system leak test procedures into the maintenance
programs, at an average labor cost of $65 per work hour. Based on these
figures, the cost impact of the maintenance revision requirement of
this AD action on the 110 U.S. operators is estimated to be $286,000,
or $2,600 per operator.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the requirements of this
AD action, and that no operator would accomplish those actions in the
future if this AD were not adopted. The cost impact figures discussed
in AD rulemaking
[[Page 15243]]
actions represent only the time necessary to perform the specific
actions actually required by the AD. These figures typically do not
include incidental costs, such as the time required to gain access and
close up, planning time, or time necessitated by other administrative
actions.
We recognize that the obligation to maintain aircraft in an
airworthy condition is vital, but sometimes expensive. Because ADs
require specific actions to address specific unsafe conditions, they
appear to impose costs that would not otherwise be borne by operators.
However, because of the general obligation of operators to maintain
aircraft in an airworthy condition, this appearance is deceptive.
Attributing those costs solely to the issuance of this AD is
unrealistic because, in the interest of maintaining safe aircraft,
prudent operators would accomplish the required actions even if they
were not required to do so by the AD.
A full cost-benefit analysis has not been accomplished for this AD.
As a matter of law, in order to be airworthy, an aircraft must conform
to its type design and be in a condition for safe operation. The type
design is approved only after the FAA makes a determination that it
complies with all applicable airworthiness requirements. In adopting
and maintaining those requirements, the FAA has already made the
determination that they establish a level of safety that is cost-
beneficial. When the FAA, as in this AD, makes a finding of an unsafe
condition, this means that the original cost-beneficial level of safety
is no longer being achieved and that the required actions are necessary
to restore that level of safety. Because this level of safety has
already been determined to be cost-beneficial, a full cost-benefit
analysis for this AD would be redundant and unnecessary.
Regulatory Impact
The regulations adopted herein will not have substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government. Therefore, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a
significant economic impact, positive or negative, on a substantial
number of small entities under the criteria of the Regulatory
Flexibility Act. A final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
Adoption of the Amendment
0
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends part 39 of
the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
0
2. Section 39.13 is amended by removing amendment 39-6223 (54 FR 21933,
May 22, 1989), and by adding a new airworthiness directive (AD),
amendment 39-13544, to read as follows:
2004-06-18 Boeing: Amendment 39-13544. Docket 95-NM-111-AD.
Supersedes AD 89-11-03, Amendment 39-6223.
Applicability: All Model 737-100, -200, -300, -400 and -500
series airplanes, certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must request approval for an
alternative method of compliance in accordance with paragraph (h) of
this AD. The request should include an assessment of the effect of
the modification, alteration, or repair on the unsafe condition
addressed by this AD; and, if the unsafe condition has not been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required as indicated, unless accomplished
previously.
To prevent engine damage, airframe damage, and/or hazard to
persons or property on the ground as a result of ``blue ice'' that
has formed from leakage of the lavatory drain system or flush/fill
systems and dislodged from the airplane, accomplish the following:
Replacing Valve Seals and Performing Leak Tests
(a) Except as provided by paragraph (d) of this AD, accomplish
the applicable requirements of paragraphs (a)(1) through (a)(6) of
this AD at the time specified in each paragraph. If the waste drain
system incorporates more than one type of valve, only one of the
waste drain system leak test procedures (the one that applies to the
equipment with the longest leak test interval) must be conducted at
each service panel location. Except as provided in paragraphs (b)
and (c) of this AD, the waste drain system valve leak tests
specified in this AD shall be performed in accordance with the
following requirements: fluid shall completely cover the upstream
end of the valve being tested; the direction of the 3 pounds per
square inch differential pressure (PSID) shall be applied across the
valve in the same direction as occurs in flight; the other waste
drain system valves shall be open; and the minimum time to maintain
the differential pressure shall be 5 minutes.
(1) Replace the valve seals in accordance with the applicable
schedule specified in paragraph (a)(1)(i), (a)(1)(ii), or
(a)(1)(iii) of this AD. If an in-line drain valve as specified in
paragraph (a)(1)(i) of this AD is installed in the same lavatory
drain line as the valves specified per paragraph (a)(1)(ii) or
(a)(1)(iii) of this AD, seal replacement for the valves specified in
paragraph (a)(1)(ii) or (a)(1)(iii) of this AD may be performed at
the seal replacement interval for the in-line drain valve.
Note 2: The seals and o-rings in the service panel drain valve
that are to be replaced in accordance with paragraph (a)(1) or
(d)(1) of this AD are the seals and o-rings that seal against the
valve door, lid, cap, or ball, which is opened to allow flow through
the service panel drain valve or in-line drain valve. The seals and
o-rings in the lavatory flush/fill line valve or cap that are to be
replaced in accordance with paragraph (a)(5) or (d)(3) of this AD
are the seals and o-rings that seal against a surface and prevent
backflow from the lavatory waste tank through the flush/fill line.
(i) For each lavatory drain system that has an in-line drain
valve installed, Kaiser Electroprecision part number (P/N) series
2651-278 or service panel ball valve, Kaiser Electroprecision P/N
series 2651-357: Replace the seals within 5,000 flight hours after
the effective date of this AD, or within 48 months after the last
documented seal change, whichever occurs later. Thereafter, repeat
the replacement of the seals at intervals not to exceed 48 months.
(ii) For each lavatory drain system that has a Pneudraulics P/N
series 9527 valve: Replace the seals within 5,000 flight hours after
the effective date of this AD, or within 18 months of the last
documented seal change, whichever occurs later. Thereafter, repeat
the replacement of the seals at intervals not to exceed 18 months or
6,000 flight hours, whichever occurs later.
(iii) For each lavatory drain system that has any other type of
drain valve: Replace the seals within 5,000 flight hours after the
effective date of this AD, or within 18 months
[[Page 15244]]
after the last documented seal change, whichever occurs later.
Thereafter, repeat the replacement of the seals at intervals not to
exceed 18 months.
(2) For each lavatory drain system that has an in-line drain
valve installed having Kaiser Electroprecision P/N series 2651-278,
or service panel drain valve installed having Kaiser
Electroprecision P/N series 2651-357, or Pneudraulics P/N series
9527, or Shaw Aero valve having a P/N or serial number (S/N) as
listed in Table 1 of this AD: Within 4,500 flight hours after the
effective date of this AD, or within 4,500 hours after the last
documented leak test, whichever occurs later, accomplish the
procedures specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this
AD. Thereafter, repeat the procedures at intervals not to exceed 18
months or 4,500 flight hours, whichever occurs later.
(i) Conduct a leak test of the toilet tank dump valve (in-tank
valve that is spring loaded closed and operable by a T-handle at the
service panel) and the in-line drain valve (Kaiser Electroprecision
P/N series 2651-278) or service panel drain valve (Kaiser
Electroprecision P/N series 2651-357, or Pneudraulics P/N series
9527, or Shaw Aero valve having a P/N or serial number (S/N) as
listed in Table 1 of this AD). The toilet tank dump valve leak test
must be performed by filling the toilet tank with a minimum of 10
gallons of water/rinsing fluid and, after a period of 5 minutes,
testing for leakage. Take precautions to avoid overfilling the tank
and spilling fluid into the airplane. Except as provided by
paragraphs (b) and (c) of this AD, the in-line drain valve or
service panel drain valve leak test must be performed with a minimum
of 3 PSID applied across the valve in the same direction as occurs
in flight.
(ii) If a service panel valve or cap is installed, perform a
general visual inspection of the service panel drain valve outer
cap/door seal and the inner seal (if the valve has an inner door
with a second positive seal), and the seal mating surfaces for wear
or damage that may allow leakage.
Note 3: For the purposes of this AD, a general visual inspection
is defined as: ``A visual examination of an interior or exterior
area, installation, or assembly to detect obvious damage, failure,
or irregularity. This level of inspection is made from within
touching distance unless otherwise specified. A mirror may be
necessary to enhance visual access to all exposed surfaces in the
inspection area. This level of inspection is made under normally
available lighting conditions such as daylight, hangar lighting,
flashlight, or droplight and may require removal or opening of
access panels or doors. Stands, ladders, or platforms may be
required to gain proximity to the area being checked.''
Table 1.--Shaw Aero Valves Approved for 4,500 Flight Hour Leak Test
Interval
------------------------------------------------------------------------
Serial numbers of part number
Shaw waste drain valve part number valve approved for 4,500
flight hour leak test interval
------------------------------------------------------------------------
331 Series............................. All.
10101000B-A-1.......................... 0207-0212, 0219, 0226 and
higher.
10101000B-A-1.......................... 0001-0206, 0213-0218, and 0220-
0225 that are marked ``SBB38-1-
58,'' and that incorporate the
improvements outlined in Shaw
Service Bulletin 10101000B-38-
1, dated October 7, 1994.
10101000BA2............................ 0130 and higher.
10101000BA2............................ 0001-0129 that are marked
``SBB38-1-58,'' and that
incorporate the improvements
outlined in Shaw Service
Bulletin 10101000B-38-1, dated
October 7, 1994.
10101000C-A-1.......................... 0277 and higher.
10101000C-A-1.......................... 0001-0276 that are marked
``SBC38-2-58,'' and that
incorporate the improvements
outlined in Shaw Service
Bulletin 10101000C-38-2, dated
October 7, 1994.
10101000CN OR 10101000C-N.............. 3649 and higher.
10101000CN OR 10101000C-N.............. 0001-3648 that is marked
``SBC38-2-58,'' and that
incorporate the improvements
outlined in Shaw Service
Bulletin 10101000C-38-2, dated
October 7, 1994.
------------------------------------------------------------------------
(3) For each lavatory drain system with a lavatory drain system
valve that incorporates either ``donut'' plug, Kaiser
Electroprecision P/N 4259-20 or 4259-31; Kaiser Roylyn/Kaiser
Electroprecision cap/flange P/N 2651-194C, 2651-197C, 2651-216,
2651-219, 2651-235, 2651-256, 2651-258, 2651-259, 2651-260, 2651-
275, 2651-282, 2651-286; or other FAA-approved equivalent parts;
accomplish the requirements at the specified times of paragraphs
(a)(3)(i), (a)(3)(ii), and (a)(3)(iii) of this AD. For the purposes
of paragraph (a)(3) of this AD, ``equivalent part'' means either a
``donut'' plug that mates with the cap/flange having part numbers
listed in this paragraph, or a cap/flange that mates with the
``donut'' plug having part numbers listed in this paragraph, such
that the cap/flange and ``donut'' plug are used together as an
assembled valve.
(i) Within 200 flight hours after the effective date of this AD,
and thereafter at intervals not to exceed 200 flight hours, conduct
leak tests of the toilet tank dump valve and the service panel drain
valve. The leak test of the toilet tank dump valve must be performed
by filling the toilet tank with a minimum of 10 gallons of water/
rinsing fluid and testing for leakage after a period of 5 minutes.
Take precautions to avoid overfilling the tank and spilling fluid on
the airplane. Except as provided by paragraphs (b) and (c) of this
AD, the service panel drain valve leak test must be performed with a
minimum 3 PSID applied across the valve in the same direction as
occurs in flight.
(ii) Perform a general visual inspection of the outer door/cap
and seal mating surface for wear or damage that may cause leakage.
This inspection shall be accomplished in conjunction with the leak
tests of paragraph (a)(3)(i) of this AD.
(iii) Within 5,000 flight hours after the effective date of this
AD, replace the donut valve (part numbers per paragraph (a)(3) of
this AD) with another type of FAA-approved valve. Following
installation of the replacement valve, perform the appropriate leak
tests and seal replacements at the intervals specified for that
replacement valve, as applicable.
(4) For each lavatory drain system not addressed in paragraph
(a)(2) or (a)(3) of this AD: Within 1,000 flight hours or 6 months
after the effective date of this AD, whichever occurs later,
accomplish the actions specified in paragraphs (a)(4)(i) and
(a)(4)(ii) of this AD. Thereafter, repeat those actions at intervals
not to exceed 1,000 flight hours or 6 months, whichever occurs
later.
(i) Conduct a leak test of the toilet tank dump valve and the
service panel drain valve. The toilet tank dump valve leak test must
be performed by filling the toilet tank with a minimum of 10 gallons
of water/rinsing fluid and, after a period of 5 minutes, testing for
leakage. Take precautions to avoid overfilling the tank and spilling
fluid on the airplane. Except as provided by paragraphs (b) and (c)
of this AD, the service panel drain valve leak test must be
performed with a minimum of 3 PSID applied across the valve inner
door/closure device.
(ii) Perform a general visual inspection of the outer cap/door
and seal mating surface for wear or damage that may cause leakage.
(5) For flush/fill lines: Within 5,000 flight hours after the
effective date of this AD, perform the requirements of paragraph
(a)(5)(i), (a)(5)(ii), (a)(5)(iii), or (a)(5)(iv) of this AD, as
applicable. Thereafter, repeat the requirements at intervals not to
exceed 5,000 flight hours, or 48 months after the last documented
seal change, whichever occurs later. For airplanes that contain
auxiliary waste tanks, the leak tests may be performed per one of
the leak test procedures in
[[Page 15245]]
paragraph (b) or (c) of this AD, or by using the leak test
procedures without filling the toilet tank bowl half-full of fluid
per the applicable airplane or component maintenance manual.
Note 4: The seals/o-rings in the service panel drain valve that
are to be replaced in accordance with paragraph (a)(1) or (d)(1) of
this AD are the seals/o-rings that seal against the valve door/lid/
cap/ball, which is opened to allow flow through the service panel
drain valve or in-line drain valve. The seals/o-rings in the
lavatory flush/fill line valve or cap that are to be replaced per
paragraph (a)(5) or (d)(3) of this AD are the seals/o-rings that
seal against a surface and prevent backflow from the lavatory waste
tank through the flush/fill line.
(i) If a lever lock cap is installed on the flush/fill line of
the subject lavatory, replace the seals on the toilet tank anti-
siphon (check) valve and the flush/fill line cap with new seals.
Perform a leak test of the toilet tank anti-siphon (check) valve
with a minimum of 3 PSID across the valve in the same direction as
occurs in flight, in accordance with paragraph (a)(5)(ii)(A) of this
AD, as applicable.
Note 5: The leak test procedure described in Boeing 737
Maintenance Manual, 38-32-00/501, may be referred to as guidance for
this test if the toilet tank is filled to the level specified in
paragraph (a)(5)(ii)(A) of this AD.
(ii) If a vacuum breaker check valve, Monogram P/N series 3765-
190, or Shaw Aero Devises P/N series 301-000, or other FAA-approved
vacuum break check valve is installed on the subject lavatory,
replace the seals/o-rings in the valve. Perform a leak test of the
vacuum breaker check valve and verify proper operation of the vent
line vacuum breaker in accordance with paragraphs (a)(5)(ii)(A) and
(a)(5)(ii)(B) of this AD.
(A) Leak test the toilet tank anti-siphon valve or the vacuum
breaker check valve by filling the toilet tank with water/rinsing
fluid to a level such that the bowl is approximately half full (at
least 2 inches above the flapper in the bowl.) Apply 3 PSID across
the valve in the same direction as occurs in flight. The vent line
vacuum breaker on vacuum breaker check valves must be pinched closed
or plugged for this leak test. If there is a cap/valve at the flush/
fill line port, the cap/valve must be removed/open during the test.
Check for leakage at the flush/fill line port for a period of 5
minutes.
(B) Verify proper operation of the vent line vacuum breaker by
filling the tank and testing at the fill line port for back drainage
after disconnecting the fluid source from the flush/fill line port.
If back drainage does not occur, replace the vent line vacuum
breaker or repair the vacuum breaker check valve in accordance with
the component maintenance manual to obtain proper back drainage. As
an alternative to the above test technique, verify proper operation
of the vent line vacuum breaker in accordance with the procedures of
the applicable component maintenance manual.
(iii) If a flush/fill ball valve, Kaiser Electroprecision P/N
series 0062-0009 is installed on the flush/fill line of the subject
lavatory, replace the seals in the flush/fill ball valve and the
toilet tank anti-siphon valve with new seals. Perform a leak test of
the toilet tank anti-siphon valve with a minimum of 3 PSID across
the valve in the same direction as occurs in flight, in accordance
with paragraph (a)(5)(ii)(A) of this AD.
(iv) If an FAA-approved shut-off valve that uses a mechanical or
electrical devise to prevent overfilling of the toilet tank is
installed, replace the seals/o-rings in the shut-off valve. Perform
the leak test of the shut-off valve per the applicable airplane or
component maintenance manual, or per the procedures specified in
paragraph (b) or (c) of this AD.
(6) As a result of the leak tests and inspections required by
paragraph (a) of this AD, or if evidence of leakage is found at any
other time, accomplish the requirements of paragraph (a)(6)(i),
(a)(6)(ii), or (a)(6)(iii), as applicable.
(i) If a leak is discovered, prior to further flight, repair the
leak. Prior to further flight after repair, perform the appropriate
leak test, as applicable. Additionally, prior to returning the
airplane to service, clean the surfaces adjacent to where the
leakage occurred to clear them of any horizontal fluid residue
streaks; such cleaning must be to the extent that any future
appearance of a horizontal fluid residue streak will be taken to
mean that the system is leaking again.
Note 6: For purposes of this AD, ``leakage'' is defined as any
visible leakage, if observed during a leak test. At any other time
(than during a leak test), ``leakage'' is defined as the presence of
ice in the service panel, or horizontal fluid residue streaks/ice
trails originating at the service panel. The fluid residue is
usually, but not necessarily, blue in color.
(ii) If any worn or damaged seal is found, or if any damaged
seal mating surface is found, prior to further flight, repair or
replace it with a new seal, in accordance with the valve
manufacturer's maintenance manual.
(iii) In lieu of performing the requirements of paragraph
(a)(6)(i) or (a)(6)(ii) of this AD: Before further fight, drain the
affected lavatory system and placard the lavatory inoperative until
repairs can be accomplished.
One Alternative to Accomplishing Test Procedures
(b) As an alternative to the test procedures for service panel
drain valves and in-line drain valves specified in paragraph (a) or
(d) of this AD, and flush/fill line valves as specified in paragraph
(a)(5) or (d)(3) of this AD, a vacuum leak test may be done in
accordance with ``Shaw Aero Devices Document ILS-193C (Operation
Instructions for the Waste Drain Valve Inner Flapper and Lavatory
Rinse/Fill Valve Leak Test Tool), Revision C, dated July 1999. The
tests shall be conducted with a minimum of 3 PSI differential
pressures across the valve seal being tested in the same direction
as occurs in flight. The duration of the test shall be 5 minutes.
The test may be conducted with fluid completely covering the seal to
be tested and checked for fluid leakage, or by subjecting the seal
to a vacuum without fluid present, and checking for loss of vacuum.
Any movement of the vacuum gauge needle indicates loss of vacuum and
constitutes failure of the test. Failure of the test also occurs if
fluid is behind the valve being tested and any leakage of fluid past
the valve occurs during the test. Operators should note that the
test rig may not work for all valve types. Confirm compatibility of
the test rig to the valve by verifying compatibility with the
manufacturer(s) of the test rig and valve. Other leak test tools may
be used for this test if approved per paragraph (h) of this AD.
Another Alternative to Accomplishing Test Procedures
(c) As an alternative to the test procedures for service panel
drain valves and in-line drain valves specified in paragraph (a) or
(d) of this AD, and flush/fill line valves as specified in paragraph
(a)(6) or (d)(3) of this AD, a vacuum test may be done in accordance
with ``Operating Instructions for Lavatory Waste Drain Valve and
Flush/Fill Valve Leak Test Tool,'' AAXICO Industries, Ltd., Document
AI 18, Issue 4, dated January 2002. The test shall be conducted with
a minimum of 3 PSI differential pressures across the valve seal
being tested in the same direction as occurs in flight. The duration
of the tests shall be 5 minutes. The test may be conducted with
fluid completely covering the seal to be tested and checked for
fluid leakage, or by subjecting the seal to a vacuum without fluid
present, and checking for loss of vacuum. Any movement of the vacuum
gauge needle indicates loss of vacuum and constitutes failure of the
test. Failure of the test also occurs if fluid is behind the valve
being tested and any leakage of fluid past the valve occurs during
the test. Operators should note that the test rig might not work for
all valve types. Confirm compatibility of the test rig to the valve
by verifying compatibility with the manufacturer(s) of the test rig
and valve. Other leak test tools may be used for this test if
approved per paragraph (h) of this AD.
Revising the FAA-Approved Maintenance Program
(d) As an alternative to the requirements of paragraph (a) of
this AD, operators may revise the FAA-approved maintenance program
to include the requirements specified in paragraphs (d), (f), and
(g) of this AD, which constitutes terminating action for the AD.
However, until the FAA-approved maintenance program is revised,
operators must accomplish the requirements of paragraph (a) of this
AD. If the waste drain system incorporates more than one type of
valve, only one of the waste drain system leak test procedures (the
one that applies to the equipment with the longest leak test
interval) must be conducted at each service panel location. The
waste drain system valve leak tests specified in paragraphs (a) and
(d) of this AD shall be performed in accordance with the following
requirements: Fluid shall completely cover the upstream end of the
valve being tested unless a vacuum test is being performed in
accordance with paragraph (b) or (c) of this AD; the direction of
the 3 PSID shall be applied across the valve in the same direction
as occurs in flight; the other waste drain system valves
[[Page 15246]]
shall be open; and the minimum time to maintain the differential
pressure shall be 5 minutes. A differential pressure greater than 3
psi may be used if specified by procedures referenced in paragraph
(b) or (c) of this AD.
(1) Replace the valve seals in accordance with the applicable
schedule specified in paragraph (d)(1)(i), (d)(1)(ii), or
(d)(1)(iii) of this AD. If an in-line drain valve as specified in
paragraph (d)(1)(i) of this AD is installed in the same lavatory
drain line as the valves specified in paragraph (d)(1)(ii) or
paragraph (d)(1)(iii) of this AD, seal replacement for the valves
specified in paragraphs (d)(1)(ii) and (d)(1)(iii) of this AD may be
performed at the seal replacement interval for the in-line drain
valve. (See Note 2 of this AD.)
(i) For each lavatory drain system that has an in-line drain
valve installed, Kaiser Electroprecision P/N series 2651-278 or
service panel ball valve installed, Kaiser Electroprecision P/N
series 2651-357: Replace the seals within 5,000 flight hours after
the effective date of this AD, or within 48 months of the last
documented seal change, whichever occurs later. Thereafter, repeat
the replacement of the seals at intervals not to exceed 48 months.
(ii) For each lavatory drain system that has a Pneudraulics P/N
series 9527 valve: Replace the seals within 5,000 flight hours after
the effective date of this AD, or within 18 months of the last
documented seal change, whichever occurs later. Thereafter, repeat
the replacement of the seals at intervals not to exceed 18 months or
6,000 flight hours, whichever occurs later.
(iii) For each lavatory drain system that has any other type of
drain valve: Replace the seals within 5,000 flight hours after the
effective date of this AD, or within 18 months of the last
documented seal change, whichever occurs later. Thereafter, repeat
the replacement of the seals at intervals not to exceed 18 months.
(2) Conduct periodic leak tests of the lavatory drain systems in
accordance with the applicable schedule specified in paragraph
(d)(2)(i), (d)(2)(ii), or (d)(2)(iii) of this AD. Only one of the
waste drain system leak test procedures (the one that applies to the
equipment with the longest leak test interval) must be conducted at
each service panel location.
(i) For each lavatory drain system that has an in-line drain
valve installed having Kaiser Electroprecision P/N series 2651-278;
service panel drain valve installed having Kaiser Electroprecision
P/N series 2651-357; Pneudraulics part number series 9527; or Shaw
Aero P/N/S/N as listed in Table 1 of this AD: Within 5,000 flight
hours after the effective date of this AD, or within 5,000 hours of
the last documented leak test, whichever occurs later, accomplish
the procedures specified in paragraphs (d)(2)(i)(A) and (d)(2)(i)(B)
of this AD. Thereafter repeat the procedures at intervals not to
exceed 18 months or 5,000 flight hours, whichever occurs later.
(A) Conduct a leak test of the toilet tank dump valve (in-tank
valve that is spring loaded closed and operable by a T-handle at the
service panel) and the in-line drain valve (Kaiser Electroprecision
P/N series 2651-278) or the service panel drain valve (Kaiser
Electroprecision P/N series 2651-357, Pneudraulics part number
series 9527, or Shaw Aero Part Number/Serial Number as listed in
Table 1 of this AD). The leak test of the toilet tank dump valve
must be performed by filling the toilet tank with a minimum of 10
gallons of water/rinsing fluid and testing for leakage after a
period of 5 minutes. Take precautions to avoid overfilling the tank
and spilling fluid on the airplane. Except as provided by paragraphs
(b) and (c) of this AD, the in-line drain valve or service panel
drain valve leak test must be performed with a minimum of 3 PSID
applied across the valve in the same direction as occurs in flight.
(B) If a service panel valve or cap is installed, perform a
general visual inspection of the service panel drain valve outer
cap/door seal and the inner seal (if the valve has an inner door
with a second positive seal), and the seal mating surfaces, for wear
or damage that may allow leakage.
(ii) For each lavatory drain system with a lavatory drain system
valve that incorporates either ``donut'' plugs Kaiser
Electroprecision P/N 4259-20 or 4259-31; Kaiser Roylyn/Kaiser
Electroprecision cap/flange part number 2651-194C, 2651-197C, 2651-
216, 2651-219, 2651-235, 2651-256, 2651-258, 2651-259, 2651-260,
2651-275, 2651-282, 2651-286; or other FAA-approved equivalent part;
accomplish the requirements at the times specified in paragraphs
(d)(2)(ii)(A), (d)(2)(ii)(B), and (d)(2)(ii)(C) of this AD. For the
purposes of this paragraph, (d)(2)(ii), ``FAA-approved equivalent
part'' means either a ``donut'' plug that mates with the cap/flange
having P/Ns listed in this paragraph, or a cap/flange that mates
with the ``donut'' plug having P/Ns listed in this paragraph, such
that the cap/flange and ``donut'' plug are used together as an
assembled valve.
(A) Within 200 flight hours after the effective date of this AD,
or within 200 flight hours after the last documented leak test,
whichever occurs later, conduct leak tests of the toilet tank dump
valve and the service panel drain valve. Thereafter, repeat the
tests at intervals not to exceed 200 flight hours. The toilet tank
dump valve leak test must be performed by filling the toilet tank
with a minimum of 10 gallons of water/rinsing fluid and, after a
period of 5 minutes, testing for leakage. Take precautions to avoid
overfilling the tank and spilling fluid on the airplane. Except as
provided in paragraphs (b) and (c) of this AD, the service panel
drain valve leak test must be performed with a minimum of 3 PSI
differential applied across the valve in the same direction as
occurs in flight.
(B) Perform a visual inspection of the outer door/cap and seal
mating surface for wear or damage that may cause leakage. Perform
this inspection in conjunction with the leak tests specified in
paragraph (d)(2)(ii)(A).
(C) Within 5,000 flight hours after the effective date of this
AD, replace the donut valve with another type of FAA-approved valve.
Following replacement of the valve, perform the subsequent leak
tests and seal replacements at the intervals specified for the new
valve.
(iii) For each lavatory drain system that incorporates any other
type of approved valves: Within 1,000 flight hours after the
effective date of this AD, or within 1,000 flight hours of the last
documented leak test, whichever occurs later, accomplish the
requirements of paragraphs (d)(2)(iii)(A) and (d)(2)(iii)(B) of this
AD. Thereafter, repeat the requirements at intervals not to exceed
1,000 flight hours.
(A) Conduct leak tests of the toilet tank dump valve and the
service panel drain valve. The toilet tank dump valve leak test must
be performed by filling the toilet tank with a minimum of 10 gallons
of water/rinsing fluid and, after a period of 5 minutes, testing for
leakage. Take precautions to avoid overfilling the tank and spilling
fluid on the airplane. The service panel drain valve leak test must
be performed with a minimum of 3 PSID applied across the valve in
the same direction as occurs in flight. If the service panel drain
valve has an inner door with a second positive seal, only the inner
door must be tested.
(B) Perform a general visual inspection of the outer cap/door
and seal mating surface for wear or damage that may cause leakage.
(3) For flush/fill lines: Within 5,000 flight hours after the
effective date of this AD, perform the requirements of paragraph
(d)(3)(i), (d)(3)(ii), (d)(3)(iii), or (d)(3)(iv), as applicable.
Thereafter, repeat the requirements at intervals not to exceed 5,000
flight hours, or 48 months after the last documented seal change,
whichever occurs later. For airplanes that contain auxiliary waste
tanks, the leak tests may be performed per one of the leak test
procedures in paragraph (b) or (c) of this AD, or by performing the
leak test procedures without filling the toilet tank bowl half-full
of fluid per the applicable airplane or component maintenance
manual.
(i) If a lever lock cap is installed on the flush/fill line of
the subject lavatory, replace the seals on the toilet tank anti-
siphon (check) valve and the flush/fill line cap. Perform a leak
test of the toilet tank anti-siphon (check) valve with a minimum of
3 PSID across the valve in the same direction as occurs in flight,
as specified in paragraph (d)(3)(ii)(A) of this AD.
(ii) If a vacuum breaker check valve having Monogram P/N series
3765-190; Shaw Aero Devices P/N series 301-0009-01; or other FAA-
approved vacuum breaker check valve is installed on the subject
lavatory; replace the seals/o-rings in the valve. Prior to further
flight, leak test the vacuum breaker check valve, and test for
proper operation of the vent line vacuum breaker as specified in
paragraphs (d)(3)(ii)(A) and (d)(3)(ii)(B) of this AD.
(A) Leak test the toilet tank anti-siphon valve or the vacuum
breaker check valve by filling the toilet tank with water/rinsing
fluid to a level such that the bowl is approximately half full (at
least 2 inches above the flapper in the bowl). Except as provided in
paragraphs (b) and (c) of this AD, apply 3 PSID across the valve in
the same direction as occurs in flight. The vent line vacuum breaker
on vacuum breaker check valves must be pinched closed or plugged for
this leak test. If there is a cap/valve at the flush/fill line port,
the cap/valve must be removed/opened during the test. Test for
leakage at the flush/fill line port for a period of 5 minutes.
[[Page 15247]]
Note 7: The leak test procedure in the appropriate section of
Boeing 737 Maintenance Manual 38-32-00 may be used as guidance for
this test if the toilet tank is filled approximately half full (at
least 2 inches above the flapper in the bowl).
(B) Verify proper operation of the vent line vacuum breaker by
filling the tank and testing at the fill line port for back drainage
after disconnecting the fluid source from the flush/fill line port.
If back drainage does not occur, replace the vent line vacuum
breaker or repair the vacuum breaker check valve in accordance with
the component maintenance manual as required to obtain proper back
drainage.
(iii) If a flush/fill ball valve, Kaiser Electroprecision P/N
series 0062-009 is installed on the flush/fill line of the subject
lavatory, replace the seals in the flush/fill ball valve and the
toilet tank anti-siphon valve. Perform a leak test of the toilet
tank anti-siphon valve in accordance with paragraph (d)(3)(ii)(A) of
this AD.
(iv) If an FAA-approved shut-off valve that uses a mechanical or
electrical device to prevent overfilling the toilet tank is
installed, replace the seals/o-rings in the shut-off valve. Perform
a leak test of the shut-off valve per the applicable airplane or
component maintenance manual, or per the procedures specified in
paragraph (b) or (c) of this AD.
(4) Provide procedures for accomplishing visual inspections to
detect leakage, to be conducted by maintenance personnel at
intervals not to exceed 4 calendar days or 45 flight hours, which
ever occurs later.
(5) Provide procedures for reporting leakage. These procedures
shall provide that any ``horizontal blue streak'' findings must be
reported to maintenance and that, prior to further flight, the
leaking system shall either be repaired, or be drained and placarded
inoperative.
(6) Provide training programs for maintenance and servicing
personnel that include information on ``blue ice awareness'' and the
hazards of ``blue ice.''
(7) If a leak is discovered during a leak test required by
paragraph (d) of this AD; or if evidence of leakage is found at any
other time; or if repair/replacement of a valve (or valve parts) is
required as a result of a visual inspection required in accordance
with this AD; prior to further flight, accomplish the requirements
of paragraph (d)(7)(i), (d)(7)(ii), or (d)(7)(iii) of this AD, as
applicable.
Note 8: For purposes of this AD, ``leakage'' is defined as any
visible leakage, if observed during a leak test. At any other time
(than during a leak test), ``leakage'' is defined as the presence of
ice in the service panel, or horizontal fluid residue streaks/ice
trails originating at the service panel. The fluid residue is
usually, but not necessarily, blue in color.
(i) Repair the leak and, prior to further flight after repair,
perform a leak test. Additionally, prior to returning the airplane
to service, clean the surfaces adjacent to where the leakage
occurred to clear them of any horizontal fluid residue streaks; such
cleaning must be to the extent that any future appearance of a
horizontal fluid residue streak will be taken to mean that the
system is leaking again.
(ii) Repair or replace the valve or valve parts.
(iii) In lieu of either paragraph (d)(7)(i) or (d)(7)(ii), drain
the affected lavatory system and placard the lavatory inoperative
until repairs can be accomplished.
Requesting Extension of Leak Test Intervals
(e) Requests for extensions of the leak test intervals required
by paragraph (a) or (d) of this AD must be approved by the Manager,
Seattle Aircraft Certification (ACO), FAA. Requests for such
revisions must be submitted to the Manager of the Seattle ACO
through the FAA Principal Maintenance Inspector (PMI), and must
include the following information:
(1) The operator's name;
(2) A statement verifying that all known cases/indications of
leakage or failed leak tests are included in the submitted material;
(3) The type of valve (make, model, manufacturer, vendor part
number, and serial number);
(4) The period of time covered by the data;
(5) The current FAA leak test interval;
(6) Whether or not seals have been replaced between the seal
replacement intervals required by this AD;
(7) Whether or not a service panel drain valve is installed
downstream of an in-line drain valve, Kaiser Electroprecision P/N
series 2651-278: Data on a service panel valve installed downstream
of an in-line drain valve will not be considered as an indicator of
the reliability of the service panel drain valve because the in-line
valve prevents potential leakage from reaching the service panel
drain valve.
(8) Whether or not leakage has been detected between leak test
intervals required by this AD, and the reason for leakage (i.e.,
worn seals, foreign materials on sealing surface, scratched or
damaged sealing surface on valve, etc.); and
(9) Whether or not any cleaning, repairs, or seal changes were
performed on the valve prior to conducting the leak test. (If such
activities have been accomplished prior to conducting the periodic
leak test, that leak test shall be recorded as a ``failure'' for
purposes of the data required for this request submission. The
exception to this is the normally-scheduled seal change in
accordance with paragraph (a)(1) and (d)(1) of this AD. Performing
this scheduled seal change prior to a leak test will not cause that
leak test to be recorded as a failure. Debris removal of major
blockages done as part of normal maintenance for previous flights is
also allowable and will not cause a leak test to be recorded as a
failure. Minor debris removal that is not commonly removed during
the normal ground maintenance test should not be removed prior to
the leak test).
Note 9: Requests for approval of revised leak test intervals may
be submitted in any format, provided the data give the same level of
assurance specified in paragraph (e) of this AD. Results of an
Environmental Quality Analysis (EQA) examination and leak test on a
randomly selected high-flight-hour valve, with seals that have not
been replaced during a period of use at least as long as the desired
interval, may be considered a valuable supplement to the service
history data, reducing the amount of service data that would
otherwise be required.
Note 10: For the purposes of expediting resolution of requests
for revisions to the leak test intervals, the FAA suggests that the
requester summarize the raw data; group the data gathered from
different airplanes (of the same model) and drain systems with the
same kind of valve; and provide a recommendation from pertinent
industry group(s) and/or the manufacturer specifying an appropriate
revised leak test interval.
Note 11: In cases where changes are made to a valve design
approved for an extended leak test interval such that a new valve
dash number or P/N is established for the valve, the FAA may not
require extensive service history data to approve the new valve to
the same leak test interval as the previous valve design. The FAA
will consider similarity of design, the nature of the design
changes, the nature and amount of testing, and like factors to
determine the appropriate data requirements and leak test interval
for a new or revised valve based upon an existing design.
Certain Installations
(f) For all airplanes: Unless already accomplished, within 5,000
flight hours after the effective date of this AD, perform the
actions specified in paragraph (f)(1), (f)(2), (f)(3), or (f)(4) of
this AD:
(1) Install an FAA-approved lever/lock cap on the flush/fill
lines for all lavatories; or
(2) Install a vacuum break check valve having Monogram P/N
series 3765-190, Shaw Aero Devises P/N series 301-0009, or other
FAA-approved vacuum break check valve in the flush/fill lines for
all lavatories; or
(3) Install a flush/fill ball valve Kaiser Electroprecision P/N
series 0062-0009 on the flush/fill lines for all lavatories; or
(4) Install an FAA-approved shut-off valve that uses a
mechanical or electrical device on the flush/fill lines for all
lavatories to prevent overfilling the toilet tank.
For Airplanes Acquired After the Effective Date of This AD
(g) For any affected airplane acquired after the effective date
of this AD: Before any operator places into service any airplane
subject to the requirements of this AD, a schedule for the
accomplishment of the leak tests required by this AD shall be
established in accordance with either paragraph (g)(1) or (g)(2) of
this AD, as applicable. After each leak test has been performed
once, each subsequent leak test must be performed in accordance with
the new operator's schedule, in accordance with either paragraph (a)
or (d) of this AD as applicable.
(1) For airplanes previously maintained in accordance with this
AD, the first leak test to be performed by the new operator must be
accomplished in accordance with the previous operator's schedule or
with the new operator's schedule, whichever would result in the
earlier accomplishment date for that leak test.
(2) For airplanes that have not been previously maintained in
accordance with this AD, the first leak test to be performed by
[[Page 15248]]
the new operator must be accomplished prior to further flight, or in
accordance with a schedule approved by the FAA PMI, but within a
period not to exceed 200 flight hours.
Alternative Method of Compliance
(h) Alternative method(s) of compliance with this AD:
(1) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Seattle ACO, FAA. Operators shall
submit their requests through an appropriate FAA PMI, who may add
comments and then send it to the Manager, Seattle ACO.
(2) All previously issued alternative methods of compliance
approved for AD 89-11-03 (54 FR 21933, May 22, 1989) are hereby
terminated as of the effective date of this AD and are no longer in
effect.
Note 12: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
Note 13: For any valve that is not eligible for the extended
leak test intervals of this AD: To be eligible for the extended leak
test intervals specified in paragraph (a) or (d) of this AD, the
service history data of the valve must be submitted to the Manager,
Seattle ACO, with a request for an alternative method of compliance.
The request should include an analysis of known failure modes for
the valve, if it is an existing design, and known failure modes of
similar valves, with an explanation of how design features will
preclude these failure modes, results of qualification tests, and
approximately 25,000 flight hours or 25,000 flight cycles of service
history data which include a winter season, collected in accordance
with the requirements of paragraph (e) of this AD, or a similar
program. One of the factors that the FAA will consider in approving
alternative valve designs is whether the valve meets Boeing
Specification S417T105 or 10-62213. However, meeting the Boeing
specification is not a prerequisite for approval of alternative
valve designs.
Special Flight Permits
(i) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished.
Effective Date of This AD
(j) This amendment becomes effective on April 29, 2004.
Issued in Renton, Washington, on March 19, 2004.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-6677 Filed 3-24-04; 8:45 am]
BILLING CODE 4910-13-P