[Federal Register Volume 68, Number 117 (Wednesday, June 18, 2003)]
[Proposed Rules]
[Pages 36502-36504]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-15339]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2000-NM-408-AD]
RIN 2120-AA64
Airworthiness Directives; Learjet Model 60 Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the supersedure of an existing
airworthiness directive (AD), applicable to certain Learjet Model 60
airplanes, that currently requires inspection to detect bends in or
damage to the fuel crossflow tube; inspection to determine clearance
between the fuel crossflow tube and the flight control cables; and
replacement or repair of the tube, if necessary. This action would
require a review of airplane maintenance records or an inspection to
determine if a fuel crossflow tube having a certain part number is
installed; and follow-on/corrective actions, as applicable. This action
also would expand the applicability of the existing AD to include
additional airplanes. The actions specified by the proposed AD are
intended to prevent chafing and consequent failure of the fuel
crossflow tube due to inadequate clearance between the tube and the
flight control cables, which could result in loss of fuel from one fuel
tank during normal operating conditions or loss of fuel from both main
fuel tanks during fuel cross-feeding operations. This action is
intended to address the identified unsafe condition.
DATES: Comments must be received by August 4, 2003.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 2000-NM-408-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:
[email protected]. Comments sent via fax or the Internet must
contain ``Docket No. 2000-NM-408-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 Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-
2942. This information may be examined at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Jeffrey Janusz, Aerospace Engineer,
Systems and Propulsion Branch, ACE-116W, FAA, Wichita Aircraft
Certification Office, 1801 Airport Road, Room 100, Mid-Continent
Airport, Wichita, Kansas 67209; telephone (316) 946-4148; fax (316)
946-4407.
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 2000-NM-408-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. 2000-NM-408-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On June 28, 1995, the FAA issued airworthiness directive (AD) 95-
14-09, amendment 39-9303 (60 FR 36984, July 19, 1995), applicable to
certain Learjet 60 airplanes, to require inspection to detect bends in
or damage to the fuel crossflow tube; inspection to determine clearance
between the fuel crossflow tube and the flight control cables; and
replacement or repair of the tube, if necessary. That action was
prompted by reports of chafing of the fuel crossflow tube by flight
control cables. The requirements of that AD are intended to prevent
chafing and consequent failure of the fuel crossflow tube due to
inadequate clearance between the tube and the flight control cables,
which could result in loss of fuel from one fuel tank during normal
operating conditions or loss of fuel from both main fuel tanks during
fuel cross-feeding operations.
Actions Since Issuance of Previous Rule
Since the issuance of that AD, the manufacturer has implemented a
design change to adequately preclude chafing or bending of the fuel
crossflow tube. Although the minimum clearance required by AD 95-14-09
was adequate, there was a possibility that the fuel crossflow tube
could be installed incorrectly due to installation variables, including
rotation of the fuel crossflow tube. The design change calls for an
increased minimum clearance and the installation of a specific part
number for the fuel crossflow tube, which can be installed in only one
way.
Explanation of New Service Information
The FAA has reviewed and approved Bombardier Learjet 60 Alert
Service Bulletin SB A60-28-3, Revision 2, dated October 26, 1998. This
service bulletin describes procedures for inspecting the fuel crossflow
tube for damage (e.g., chafing and/or bends), measuring the clearance
between the
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crossflow tube and flight control cables, and correcting incorrect
clearance. For certain airplanes, this service bulletin also describes
procedures for replacing existing fuel crossflow tubes with new fuel
crossflow tubes. This service bulletin also adds certain airplanes to
the effectivity listing.
We also have reviewed and approved Bombardier Learjet 60 Service
Bulletin SB 60-28-4, Revision 2, dated August 22, 2001. For certain
airplanes, this service bulletin describes procedures for replacing
existing fuel crossflow tubes with new fuel crossflow tubes, and
measuring the clearance between the crossflow tube and flight control
cables.
Accomplishment of the actions specified in these service bulletins
is intended to adequately address the identified unsafe condition.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed AD would supersede AD 95-14-09 to require a review of
maintenance records or an inspection to determine if a fuel crossflow
tube having a certain part number is installed; and follow-on/
corrective actions, as applicable. Certain actions would be required to
be accomplished in accordance with the service bulletins described
previously, except as discussed below.
Differences Between Proposed Rule and Service Bulletins
Operators should note the following differences between the
proposed AD and the service bulletins:
[sbull] Bombardier Learjet 60 Alert Service Bulletin SB A60-28-3,
Revision 2, recommends that the fuel crossflow tube be inspected for
bends and evidence of damage (e.g., contact with the flight control
cables). It also recommends that the clearance between the fuel
crossflow tube and flight control cables be measured to ensure that it
is at least 0.150 inch. This proposed AD would not require those
inspections because they pertain to the previous airplane design. In
lieu of the previously described inspections for bends and evidence of
damage, this proposed AD would require a review of the airplane
maintenance records or an inspection to determine if a certain part
number for the fuel crossflow tube is installed. In addition, the
proposed AD would require measurement of the clearance between the fuel
crossflow tube and flight control cables to ensure that it is at least
0.35 inch. We have determined that an interval of 25 flight hours
(after the effective date of this proposed AD) for accomplishment of
the review of the airplane maintenance records/inspection would address
the identified unsafe condition in a timely manner.
[sbull] Alert Service Bulletin A60-28-3, Revision 2, also
recommends a compliance time of 600 flight hours to replace the fuel
crossflow tube, if necessary. This proposed AD would extend the
compliance time to require replacement of any fuel crossflow tube not
having the correct part number, with a new tube having the correct part
number, within 90 days after the proposed inspection. In developing an
appropriate compliance time for this proposed AD, we considered not
only the manufacturer's recommendation, but the degree of urgency
associated with addressing the subject unsafe condition, the average
utilization of the affected fleet, and the time necessary to perform
the inspection. In light of all of these factors, the FAA finds a
longer compliance time for completing the proposed actions to be
warranted, in that it represents an appropriate interval of time
allowable for affected airplanes to continue to operate without
compromising safety.
[sbull] Bombardier Learjet 60 Service Bulletins SB A60-28-3,
Revision 2, and SB 60-28-4, Revision 2, specify that if the correct
fuel crossflow tube part number is installed and if the specified
minimum clearance does not exist between the fuel crossflow tube and
the flight control cables, the manufacturer may be contacted for
disposition. This proposed AD would require that correction of any
incorrect clearances be accomplished per a method approved by the FAA.
Clarification of Part Number for Installation
Operators should note that, in Bombardier Learjet 60 Alert Service
Bulletin SB A60-28-3, Revision 2, the fuel crossflow tube to be
installed in the airplane is incorrectly identified as part number (P/
N) 6026020-001 in Figure 1, detail D; the correct P/N is 6026020-005.
The FAA has been advised that the manufacturer will issue a revision to
this alert service bulletin to correct the error.
Changes to the Applicability of the Existing AD
This proposed AD would expand the applicability to include affected
airplanes having serial numbers 60-056 through 60-145 inclusive, in
addition to serial numbers 60-001 through 60-055 inclusive identified
in the existing AD. All of these airplanes are subject to the
identified unsafe condition of this AD.
Changes to 14 CFR Part 39/Effect on the Proposed 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
directive system. The regulation now includes material that relates to
altered products, special flight permits, and alternative methods of
compliance (AMOC). Because we have now included this material in part
39, only the office authorized to approve AMOCs is identified in each
individual AD. Therefore paragraph (d) and Note 1 of AD 95-14-09 have
not been included in this proposed AD. Paragraph (c) of AD 95-14-09 has
been revised to only identify the office authorized to approve AMOCs,
and is identified as paragraph (f) in this proposed AD.
Cost Impact
There are approximately 145 Model 60 airplanes of the affected
design in the worldwide fleet. The FAA estimates that 109 airplanes of
U.S. registry would be affected by this proposed AD.
It would take approximately 2 work hours per airplane to accomplish
the review of airplane maintenance records/inspection proposed in this
AD action, at an average labor rate of $60 per work hour. Based on
these figures, the cost impact of the proposed requirements of this AD
on U.S. operators is estimated to be $13,080, or $120 per airplane.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the current or 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
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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.
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 removing amendment 39-9303 (60 FR
36984, July 19, 1995), and by adding a new airworthiness directive
(AD), to read as follows:
Learjet: Docket 2000-NM-408-AD. Supersedes AD 95-14-09, Amendment
39-9303.
Applicability: Model 60 airplanes, serial numbers 60-001 through
60-145 inclusive, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent chafing and consequent failure of the fuel crossflow
tube due to inadequate clearance between the tube and the flight
control cables, which could result in loss of fuel from one fuel
tank during normal operating conditions or loss of fuel from both
main fuel tanks during fuel cross-feeding operations, accomplish the
following:
Part Identification
(a) Within 25 flight hours after the effective date of this AD,
inspect the fuel crossflow tube to determine whether part number (P/
N) 5026020-005 is installed. Instead of inspecting the tube, a
review of airplane maintenance records is acceptable if the P/N of
the tube can be positively determined from that review.
Clearance Measurement and Corrective Action
(b) For all airplanes: If P/N 6026020-005 is found installed
during the review or inspection required by paragraph (a) of this
AD, before further flight, measure the clearance between the fuel
crossflow tube and the flight control cables to determine if it is
at least 0.35 inch, per paragraph 2.B.(8) of the Accomplishment
Instructions of Bombardier Learjet 60 Alert Service Bulletin SB A60-
28-3, Revision 2, dated October 26, 1998.
(1) If the clearance is 0.35 inch or more, no further action is
required by this paragraph.
(2) If the clearance is less than 0.35 inch, before further
flight, repair per a method approved by the Manager, Wichita
Aircraft Certification Office (ACO), FAA.
Part Replacement, Measurement, and Repair
(c) For airplanes having serial numbers 60-001 through 60-055:
If P/N 6026020-005 is not found installed during the review or
inspection required by paragraph (a) of this AD, within 90 days
after accomplishing the review or inspection, replace the existing
fuel crossflow tube with a new fuel crossflow tube having P/N
6026020-005, and measure the clearance between the newly installed
fuel crossflow tube and the flight control cables, per paragraph
2.A. of the Accomplishment Instructions of Bombardier Learjet 60
Service Bulletin SB 60-28-4, Revision 2, dated August 22, 2001.
(1) If the clearance is 0.35 inch or more, no further action is
required by this paragraph.
(2) If the clearance is less than 0.35 inch, before further
flight, repair per a method approved by the Manager, Wichita ACO,
FAA.
(d) For airplanes having serial numbers 60-056 through 60-145:
If P/N 6026020-005 is not found installed during the review or
inspection required by paragraph (a) of this AD, within 90 days
after accomplishing the review or inspection, replace the existing
fuel crossflow tube with a new fuel crossflow tube having P/N
6026020-005, and measure the clearance between the newly installed
fuel crossflow tube and the flight control cables to determine if
the clearance is at least 0.35 inch, per paragraph 2.B. of the
Accomplishment Instructions of Bombardier Learjet 60 Alert Service
Bulletin SB 60-28-3, Revision 2, dated October 26, 1998.
(1) If the clearance is 0.35 inch or more, no further action is
required by this paragraph.
(2) If the clearance is less than 0.35 inch, before further
flight, repair per a method approved by the Manager, Wichita ACO,
FAA.
Note 1: Alert Service Bulletin SB A60-28-3, Revision 2, Figure
1, detail D., incorrectly identifies the fuel crossflow tube to be
installed as P/N 6026020-001. The manufacturer is aware of this
error and plans to correct the part number in the next revision of
the alert service bulletin.
Part Installation
(e) As of the effective date of this AD, only fuel crossflow
tubes having P/N 6026020-005 shall be installed on any airplane.
Alternative Methods of Compliance
(f) In accordance with 14 CFR 39.19, the Manager, Wichita ACO,
FAA, is authorized to approve alternative methods of compliance for
this AD.
Issued in Renton, Washington, on June 12, 2003.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 03-15339 Filed 6-17-03; 8:45 am]
BILLING CODE 4910-13-P