[Federal Register: September 19, 2003 (Volume 68, Number 182)]
[Proposed Rules]
[Page 54869-54872]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19se03-31]
[[Page 54869]]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2001-NM-88-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-300, -400, and -500
Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Supplemental notice of proposed rulemaking; reopening of
comment period.
-----------------------------------------------------------------------
SUMMARY: This document revises an earlier proposed airworthiness
directive (AD), applicable to certain Boeing Model 737-300, -400, and -
500 series airplanes, that would have required replacement of the hinge
assemblies on certain escape slide compartments of the forward doors
with new, stronger hinge assemblies. This new action revises the
proposed rule by adding an inspection for incorrectly crimped hinge
assemblies, and corrective action if necessary, for certain airplanes.
The actions specified by this new proposed AD are intended to prevent
forward door escape slides from falling out of their compartments into
the airplane interior and inflating, which could impede an evacuation
in the event of an emergency. This action is intended to address the
identified unsafe condition.
DATES: Comments must be received by October 14, 2003.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 2001-NM-88-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9 a.m. and 3 p.m., Monday through Friday, except
Federal holidays. Comments may be submitted via fax to (425) 227-1232.
Comments may also be sent via the Internet using the following address:
9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must
contain ``Docket No. 2001-NM-88-AD'' in the subject line and need not
be submitted in triplicate. Comments sent via the Internet as attached
electronic files must be formatted in Microsoft Word 97 or 2000 or
ASCII text.
The service information referenced in the proposed rule may be
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,
Washington 98124-2207. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: Keith Ladderud, Aerospace Engineer,
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 917-6435; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Communications shall identify the Rules Docket number
and be submitted in triplicate to the address specified above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this action may be changed in
light of the comments received.
Submit comments using the following format:
[sbull] Organize comments issue-by-issue. For example, discuss a
request to change the compliance time and a request to change the
service bulletin reference as two separate issues.
[sbull] For each issue, state what specific change to the proposed
AD is being requested.
[sbull] Include justification (e.g., reasons or data) for each
request.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed rule. All
comments submitted will be available, both before and after the closing
date for comments, in the Rules Docket for examination by interested
persons. A report summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this action must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 2001-NM-88-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules
Docket No. 2001-NM-88-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) to add an airworthiness directive (AD), applicable to
certain Boeing Model 737-300, -400, and -500 series airplanes, was
published as a notice of proposed rulemaking (NPRM) in the Federal
Register on July 9, 2002 (67 FR 45412). That NPRM (the ``original
NPRM'') would have required replacement of the hinge assemblies on
certain escape slide compartments of the forward doors with new,
stronger hinge assemblies. The original NPRM was prompted by an
investigation that revealed that the soft aluminum hinge assemblies on
the escape slide compartments on affected airplanes are susceptible to
deformation. That condition, if not corrected, could result in forward
door escape slides falling out of their compartments into the airplane
interior and inflating, which could impede an evacuation in the event
of an emergency.
Comments
Due consideration has been given to the comments received in
response to the original NPRM.
Support for the Original NPRM
Several commenters support the original NPRM. One commenter adds
that accomplishment of the proposed actions will help eliminate
unintended slide deployments on affected airplanes.
Request To Cite Revised Service Bulletin
The manufacturer states that Boeing Service Bulletin 737-25-1430,
dated February 22, 2001, misidentifies certain part numbers in the
Existing Parts Accountability table. (That service bulletin was cited
as the appropriate source of service information for the actions
specified in the original NPRM.) The manufacturer advises of the
revision of that service bulletin to correct the part number
discrepancy, and requests that the original NPRM be revised to cite the
revised service bulletin.
The FAA agrees with the request. Revision 1 of the service
bulletin, dated April 10, 2003, was issued to correct the part numbers
and to add an inspection for incorrectly crimped hinge assemblies for
airplanes already modified by the original issue of the service
bulletin, which may have not ensured that all hinge assemblies are
crimped at one or both ends. An incorrectly crimped hinge assembly may
not hold the hinge pin correctly. In this supplemental NPRM:
[[Page 54870]]
[sbull] Paragraph (a) has been revised to limit its applicability
to airplanes on which the original issue of the service bulletin has
not been done.
[sbull] Paragraph (a) has been revised to cite Revision 1 of the
service bulletin.
[sbull] New paragraph (b) has been added to require inspection of
airplanes on which the original service bulletin was done.
[sbull] Subsequent paragraphs have been reidentified accordingly.
Request To Withdraw the Proposed AD
One commenter requests withdrawal of the proposed AD as
unnecessary. The commenter suggests that the proposed AD was prompted
by an isolated incident during which multiple unfavorable conditions
existed. The commenter, an operator, reports that, since the early
1990s, its affected airplanes have flown over seven million miles
without an escape slide inflating inside the cabin.
The FAA does not agree with the request to withdraw the original
NPRM. While few slides have actually inflated inside an airplane, there
have been multiple incidents of escape slides dropping out of the
closed door-mounted stowage compartment into the passenger compartment.
An escape slide that drops out of its compartment could automatically
inflate inside the passenger compartment and impede an emergency
evacuation. This supplemental NPRM would mandate a design change that
will prevent the slide from dropping out of its closed compartment.
Request for Additional Information
One commenter, an operator, suggests that the manufacturer
investigate the prevalence of the incident that prompted this AD (i.e.,
an escape slide dropping out of its closed door-mounted stowage
compartment and inflating inside the passenger compartment). The
operator asserts its intent to ascertain the background of the unsafe
condition by requesting from Boeing all previous correspondence on this
issue between the manufacturer and operators.
The FAA acknowledges the comment, although the commenter requests
no specific change to the original NPRM. In light of the previous
comment and response, the FAA finds it necessary to proceed with this
AD action to address the identified unsafe condition.
Request To Extend the Compliance Time
Several commenters request that the proposed compliance time to
replace the hinge assemblies be extended from 24 months to 36 months to
enable operators to do the work during the normal overhaul schedule for
the escape slides.
The FAA agrees with this request. In revising this compliance time,
the FAA considered the safety implications, parts availability, and
typical maintenance schedules of affected operators. Extending the
compliance time to the suggested 36 months will not adversely affect
safety but will accommodate the time necessary for the operators to
obtain replacement parts and schedule the work. Paragraph (a) of the
original NPRM has been revised accordingly in this supplemental NPRM.
Request To Revise Compliance Time
Several commenters request revision of paragraph (b) of the
original NPRM (paragraph (c) in this supplemental NPRM), which
specifies that certain hinge assemblies may no longer be installed
after the effective date of the AD. The commenters request that this
compliance time be extended to coincide with the compliance time to
replace all hinge assemblies. The commenters state that this extension
would give operators more time to update airplane manuals and prevent
unforeseen delays if parts are not readily available.
The FAA does not agree. Once an unsafe condition has been
identified, the FAA generally prohibits that condition from being
introduced (or re-introduced) into the fleet. When it is determined
that replacement (safe) parts are immediately available to operators,
the FAA typically prohibits installation of the unsafe parts as of the
effective date of the AD. While this AD action was being developed, the
FAA carefully considered all relevant information including parts
availability and determined that sufficient parts would be available to
meet operator demand.
Further, the FAA considers the period of time between publication
of the final rule in the Federal Register and the effective date of the
AD (35 days) sufficient for operators to determine their immediate need
for parts and to obtain them. In individual cases where this is not
possible, this supplemental NPRM contains a provision (in paragraph
(d)) that would allow operators to request an extension of the
compliance time, based upon a specific showing of need. The FAA
considers that this provision ensures an adequate level of safety
without imposing any undue burden on operators.
No change to this supplemental NPRM is necessary regarding this
issue.
Request for Coinciding Compliance Times
One commenter questions the timing of this AD in connection with
the issuance of AD 2001-15-01, amendment 39-12335 (66 FR 38361, July
24, 2001). AD 2001-15-01 requires modification of the escape slides by
modifying the latch assembly and installing a cover assembly on the
trigger housing of the inflation cylinder. The commenter advises that
the two ADs will require closely associated work at different times.
The FAA infers that the commenter requests harmonization of the ADs'
compliance times.
The FAA does not agree. The compliance time for AD 2001-15-01 is 18
months for some actions and 36 months for the remaining actions,
effective from August 28, 2001. Therefore, a coordinated work schedule
for the two ADs would necessitate a shorter compliance time for the
proposed requirements in this supplemental NPRM. As stated previously,
the FAA finds the proposed compliance time'extended to 36 months as
requested'to be adequate. No further change to this supplemental NPRM
is necessary regarding the compliance time.
Request To Provide Alternative Actions
One commenter requests that the original NPRM be revised to provide
for the option of repetitively inspecting and testing the hinge
assemblies, instead of replacing them within the specified compliance
time. The commenter states that the alternative repetitive inspections
would prevent the unnecessary replacement of functional parts.
The FAA does not agree, based on the determination that the subject
hinge assemblies are weak and must be replaced within the proposed
compliance time. The FAA has determined that long-term continued
operational safety will be better ensured by modifications or design
changes to remove the source of the problem, rather than by repetitive
inspections. Long-term inspections may not provide the degree of safety
assurance necessary for the transport airplane fleet. This, coupled
with a better understanding of the human factors associated with
numerous repetitive inspections, has led the FAA to consider placing
less emphasis on special procedures and more emphasis on design
improvements. The proposed modification requirement is consistent with
these considerations. No further
[[Page 54871]]
change to this supplemental NPRM is necessary regarding this issue.
Request To Allow Alternative Finishes
One commenter prefers that the service bulletin avoid specifying
the finish (for the primer or topcoat) to be used to conceal the flush
rivets. Because some operators may have already painted the container
assemblies with an unspecified finish, the operator suggests that the
original NPRM be revised to specifically allow use of an ``equivalent''
finish.
The FAA does not agree. An ``operator's equivalent procedure'' may
be used only if approved as an alternative method of compliance (AMOC)
in accordance with paragraph (d) of this supplemental NPRM. No change
to this supplemental NPRM is necessary regarding this issue.
Request To Revise Reference to Service Bulletin Figure
One operator suggests that Boeing Service Bulletin 737-25-1430
depicts the latch assembly in use before AD 2001-15-01 was issued. This
latch assembly, part number 65C19901-20, is depicted in Figure 2, Sheet
2 of 6, of that service bulletin. The commenter suggests this was an
oversight, but expresses concern about the potential confusion it may
raise for other operators. The FAA infers that the commenter requests
that reference to this figure be revised or removed from the proposed
AD.
The FAA agrees. As stated earlier, this supplemental NPRM has been
revised to cite Revision 1 of the service bulletin, which includes the
commenter's suggested change.
Request To Revise Part Reidentification Method
One commenter requests a revision of the method of reidentification
(reidentifying the part number) specified in the original NPRM. The
commenter doubts that the existing part number would be present on all
affected escape slide covers, which may have been subject to prior
maintenance, repair, or repainting. The commenter suggests
reidentifying the reworked escape slide compartment by adding ``SB 737-
25-1430 Compliant'' adjacent to any existing part numbers.
The FAA does not agree with the request. Reidentification with the
new part number, as proposed in this supplemental NPRM, would ensure
that the correct part number is installed. However, the FAA may
consider requests for AMOCs if submitted with detailed procedures that
would ensure an acceptable level of safety, under the provisions of
paragraph (d) of this supplemental NPRM.
Request To Revise Description of Unsafe Condition
The manufacturer states that an escape slide released from its
compartment into the airplane interior would not always automatically
inflate. The commenter requests that the original NPRM be revised to
imply only the potential for the slide to inflate--the slide ``could,''
rather than ``would,'' automatically inflate. The original NPRM refers
to one incident of the escape slide inflating inside the airplane; in
that instance, the commenter suggests that the severe swerving motion
of the airplane likely caused the escape slide to move across the floor
and inflate. The FAA infers that the commenter requests that the
discussion of the unsafe condition identified in the original NPRM be
reworded accordingly.
The FAA agrees that the commenter's suggested wording is clearer
than the wording in the Discussion section of the original NPRM.
Although this supplemental NPRM does not repeat that section, the
events associated with the identified unsafe condition are clarified in
the discussion under ``Request to Withdraw the Proposed AD.''
Request To Revise Cost Estimate
Several commenters report that the price of the replacement parts
has increased since the original NPRM was issued. The manufacturer has
confirmed that the current parts cost is $1,569. The Cost Impact
section has been revised accordingly in this supplemental NPRM.
Additional Changes to the Original NPRM
In the original NPRM, the heading for paragraph (b) is ``Spare
Parts.'' In this supplemental NPRM, the heading for that paragraph
(reidentified as paragraph (c)) has been renamed ``Part Installation''
to more accurately define the proposed requirement.
Conclusion
Since certain changes expand the scope of the original NPRM, the
FAA has determined that it is necessary to reopen the comment period to
provide additional opportunity for public comment.
Cost Impact
There are approximately 1,974 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 793 airplanes of U.S.
registry would be affected by this supplemental NPRM.
Replacement of the hinge assemblies, if necessary, would take
approximately 5 work hours per airplane, at an average labor rate of
$65 per work hour. Required parts would cost approximately $1,569 per
airplane. Based on these figures, the cost impact of the proposed hinge
replacement is estimated to be $1,894 per airplane.
The inspection, if necessary, would take approximately 1 to 3 work
hours per airplane, at an average labor rate of $65 per work hour.
Based on these figures, the cost impact of the proposed inspection is
estimated to be $65 to $195 per airplane.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the proposed 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 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.
Regulatory Impact
The regulations proposed herein would not have a substantial direct
effect 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, it
is determined that this proposal would not have federalism implications
under Executive Order 13132.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, 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 copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting 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.
[[Page 54872]]
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
part 39 of the Federal Aviation Regulations (14 CFR part 39) as
follows:
PART 39--AIRWORTHINESS DIRECTIVES
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]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
Boeing: Docket 2001-NM-88-AD.
Applicability: Model 737-300, -400, and -500 series airplanes;
certificated in any category; as listed in Boeing Special Attention
Service Bulletin 737-25-1430, Revision 1, dated April 10, 2003.
Compliance: Required as indicated, unless accomplished
previously.
To prevent forward door escape slides from falling out of their
compartments into the airplane interior and inflating, which could
impede an evacuation in the event of emergency, accomplish the
following:
Hinge Assembly Replacement
(a) For airplanes on which the hinge assemblies have not been
replaced as of the effective date of this AD in accordance with
Boeing Special Attention Service Bulletin 737-25-1430, dated
February 22, 2001: Within 36 months after the effective date of this
AD, replace the hinge assemblies on the escape slide stowage
compartments of the forward doors with new, stronger hinge
assemblies, in accordance with Part 1 of the Accomplishment
Instructions of Boeing Special Attention Service Bulletin 737-25-
1430, Revision 1, dated April 10, 2003.
Hinge Assembly Inspection
(b) For airplanes on which the hinge assemblies were replaced
before the effective date of this AD in accordance with Boeing
Special Attention Service Bulletin 737-25-1430, dated February 22,
2001: Within 36 months after the effective date of this AD, perform
a general visual inspection for incorrectly crimped hinge
assemblies, in accordance with Part 2 of the Accomplishment
Instructions of Boeing Special Attention Service Bulletin 737-25-
1430, Revision 1, dated April 10, 2003. If any hinge assembly is not
correctly crimped, perform corrective action before further flight
in accordance with Revision 1 of the service bulletin.
Note 1: 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.''
Part Installation
(c) As of the effective date of this AD, no person may install a
hinge assembly P/N 65C30431-6 or 65C30431-7 on any airplane.
Alternative Methods of Compliance
(d) In accordance with 14 CFR 39.19, the Manager, Seattle
Aircraft Certification Office, FAA, is authorized to approve
alternative methods of compliance for this AD.
Issued in Renton, Washington, on September 15, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 03-23936 Filed 9-18-03; 8:45 am]
BILLING CODE 4910-13-U