[Federal Register Volume 61, Number 225 (Wednesday, November 20, 1996)]
[Proposed Rules]
[Pages 59036-59038]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-29607]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-NM-218-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model MD-11 and MD-
11F Series 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 McDonnell Douglas
Model MD-11 and MD-11F series airplanes, that currently requires, among
other things, repetitive visual inspections to detect discrepancies of
the fuel pipe of the fuel transfer system of the tail tank and
associated mounting bracket located in the aft fuselage compartment.
That AD was prompted by reports of cracking or bending of the fuel pipe
mounting support and/or attaching bracket in the aft fuselage
compartment due to a fuel pressure surge that caused repetitive loading
of this area. This action would add a requirement to install a
restraint on the tail tank fuel pipe, which would terminate the
repetitive visual inspections. The actions specified by the proposed AD
are intended to prevent such cracking/bending, which could expose the
fuel pipe coupling O-ring. An exposed O-ring could lose its sealing
effect and could allow a fuel leak in the aft fuselage compartment,
which would present a fire hazard.
DATES: Comments must be received by December 30, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-218-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except
Federal holidays.
The service information referenced in the proposed rule may be
obtained from McDonnell Douglas Corporation, 3855 Lakewood Boulevard,
Long Beach, California 90846, Attention: Technical Publications
Business Administration, Department C1-L51 (2-60). This information may
be examined at the FAA, Transport Airplane Directorate, 1601 Lind
Avenue, SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Ray Vakili, Aerospace Engineer,
Propulsion Branch, ANM-140L, FAA, Los Angeles Aircraft Certification
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone
(310) 627-5262; fax (310) 627-5210.
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 notice may be changed in
light of the comments received.
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 notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 96-NM-218-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
[[Page 59037]]
FAA, Transport Airplane Directorate, ANM-103, Attention: Rules Docket
No. 96-NM-218-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
Discussion
On July 1, 1996, the FAA issued AD 96-14-07, amendment 39-9691 (61
FR 35946, July 9, 1996), applicable to certain McDonnell Douglas Model
MD-11 and MD-11F series airplanes. That AD requires:
1. repetitive visual inspections to detect discrepancies (i.e.,
cracks or deformation) of the fuel pipe of the fuel transfer system of
the tail tank and associated mounting bracket located in the aft
fuselage compartment; and
2. repetitive inspections to verify the correct position of the
fuel pipe flange, and various follow-on actions.
That action was prompted by reports of cracking or bending of the
fuel pipe mounting support and/or attaching bracket in the aft fuselage
compartment due to a fuel pressure surge that caused repetitive loading
of this area. The requirements of that AD are intended to prevent such
cracking/bending, which could expose the fuel pipe coupling O-ring. An
exposed O-ring could lose its sealing effect and could allow a fuel
leak in the aft fuselage compartment, which may result in a possible
in-flight or ground fire.
In the preamble to AD 96-14-07, the FAA specified that the actions
required by that AD were considered ``interim action'' and that the
manufacturer was developing a modification to positively address the
unsafe condition. The FAA indicated that it may consider further
rulemaking action once the modification was developed, approved, and
available. The manufacturer now has developed such a modification, and
the FAA has determined that further rulemaking action is indeed
necessary; this proposed AD follows from that determination.
Explanation of Relevant Service Information
The FAA has reviewed and approved McDonnell Douglas Service
Bulletin MD11-28-082, dated July 29, 1996, which describes procedures
for installation of a restraint on the tail tank fuel pipe. The
restraint will minimize the migration of the fuel pipe and reduce the
possibility of fuel leaks. Accomplishment of the installation would
eliminate the need for the repetitive visual inspections.
The FAA finds that accomplishment of the installation described in
McDonnell Douglas Service Bulletin MD11-28-082 will positively address
the unsafe condition identified as possible in-flight or ground fire
due to fuel leaking from the fuel pipe coupling.
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 96-14-07 to continue to require
repetitive visual inspections to detect discrepancies (i.e., cracks or
deformation) of the fuel pipe of the fuel transfer system of the tail
tank and associated mounting bracket located in the aft fuselage
compartment and to verify the correct position of the fuel pipe flange,
and various follow-on actions. The proposed AD also would require
installation of a restraint on the tail tank fuel pipe, which would
constitute terminating action for the repetitive visual inspections
requirements. The actions would be required to be accomplished in
accordance with the service bulletin described previously.
The FAA has determined that long term continued operational safety
will be better assured by modifications or design changes to remove the
source of the problem, rather than by repetitive inspection. Long term
inspections may not be providing 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 terminating modification requirement of this AD action is in
consonance with these considerations.
Cost Impact
There are approximately 152 McDonnell Douglas Model MD-11 and MD-
11F series airplanes of the affected design in the worldwide fleet. The
FAA estimates that 42 airplanes of U.S. registry would be affected by
this proposed AD.
The actions that are currently required by AD 96-14-07, and
retained in this proposed AD, take approximately 6 work hours per
airplane to accomplish, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the currently required
actions on U.S. operators is estimated to be $15,120, or $360 per
airplane, per inspection cycle.
The new actions that are proposed in this AD action would take
approximately 3 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Required parts would be supplied by
the manufacturer at no cost to the operators. Based on these figures,
the cost impact of the proposed requirements of this AD on U.S.
operators is estimated to be $7,560, or $180 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.
Regulatory Impact
The regulations proposed herein would 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
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
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.
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 39-9691 (61 FR
35946, July 9, 1996), and by adding a
[[Page 59038]]
new airworthiness directive (AD), to read as follows:
McDonnell Douglas: Docket 96-NM-218-AD. Supersedes AD 96-14-07,
Amendment 39-9691.
Applicability: Model MD-11 and MD-11F series airplanes,
manufacturer's fuselage numbers 0447 through 0599 inclusive;
certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 (f) 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 the possibility of an in-flight or ground fire due to
fuel leaking from the fuel pipe coupling, accomplish the following:
Restatement of Requirements of AD 96-14-07, Amendment 39-9691
(a) Perform a visual inspection to detect discrepancies (i.e.,
cracks or deformation) of the fuel pipe of the fuel transfer system
of the tail tank and associated mounting bracket located in the aft
fuselage compartment; and to verify the correct position of the fuel
pipe flange, in accordance with McDonnell Douglas Alert Service
Bulletin MD11-28A082, dated May 14, 1996; at the time specified in
paragraph (a)(1) or (a)(2) of this AD, as applicable.
(1) For airplanes on which the modification specified in
McDonnell Douglas Service Bulletin 28-22, dated September 24, 1991,
has been accomplished; or that have been repaired in accordance with
an FAA-approved repair procedure, as specified in paragraph (a)(3)
of AD 91-24-09, amendment 39-8095; or on which the shroud assembly
has been replaced with a serviceable part: Prior to the accumulation
of 600 flight hours, or within 60 days after July 24, 1996 (the
effective date AD 96-14-07, amendment 39-9691), whichever occurs
later.
(2) For airplanes on which the modification specified in
McDonnell Douglas Service Bulletin 28-22, dated September 24, 1991,
has not been accomplished: Prior to the accumulation of 600 flight
hours, or within 60 days since accomplishment of the last visual
inspection in accordance with AD 91-24-09, amendment 39-8095;
whichever occurs first.
(b) Condition 1. No Discrepancy Found. If no discrepancy is
detected during any visual inspection required by paragraph (a) of
this AD, accomplish either paragraph (b)(1) or (b)(2) of this AD.
(1) Condition 1. Option 1. Repeat the visual inspection required
by paragraph (a) of this AD thereafter at intervals not to exceed
600 flight hours or 60 days, whichever occurs later. Or
(2) Condition 1. Option 2. Prior to further flight, install a
temporary phenolic support block assembly, shim, clamp, and bracket
between the tail tank fuel pipe and station Y=2033.750 bulkhead, in
accordance with Condition 1, Option 2, of McDonnell Douglas Alert
Service Bulletin MD11-28A082, dated May 14, 1996. Within 6 months
after accomplishment of this installation, perform a one-time
inspection to verify the correct position of the temporary support
block assembly installation in accordance with Figure 2 (Sheet 2 of
3) of the alert service bulletin.
(i) If the assembly is found to be positioned properly, repeat
the verification of the correct position of the fuel pipe flange, as
specified in paragraph (a) of this AD, thereafter at intervals not
to exceed 15 months.
(ii) If the assembly is found to be improperly positioned, prior
to further flight, reposition the fuel pipe in accordance with
Figure 2 (Sheet 2 of 3) of the alert service bulletin. Repeat the
verification of the correct position of the fuel pipe flange, as
specified in paragraph (a) of this AD, thereafter at intervals not
to exceed 15 months.
(c) Condition 2. Discrepancy Found; O-Ring Not Exposed. If any
discrepancy is detected, and the fuel pipe is found to be improperly
positioned, but the O-ring is not exposed, during any visual
inspection required by paragraph (a) of this AD, prior to further
flight, accomplish either paragraph (c)(1) or (c)(2) of this AD.
(1) Condition 2. Option 1. Repeat the visual inspection in
paragraph (a) of this AD thereafter at intervals not to exceed 600
flight hours or 60 days, whichever occurs later. Or
(2) Condition 2. Option 2. Prior to further flight, install a
temporary phenolic support block assembly, shim, clamp, and bracket
between the tail tank fuel pipe and station Y=2033.750 bulkhead; and
reposition the fuel pipe assembly, as applicable; in accordance with
Condition 2, Option 2, of McDonnell Douglas Alert Service Bulletin
MD11-28A082, dated May 14, 1996. Within 6 months after
accomplishment of this installation, perform a one-time inspection
to verify the correct position of the temporary support block
assembly installation in accordance with Figure 2 (Sheet 2 of 3) of
the alert service bulletin.
(i) If the assembly is found to be positioned properly, repeat
the verification of the correct position of the fuel pipe flange, as
specified in paragraph (a) of this AD, thereafter at intervals not
to exceed 15 months.
(ii) If the assembly is found to be improperly positioned, prior
to further flight, reposition the fuel pipe in accordance with
Figure 2 (Sheet 2 of 3) of the alert service bulletin. Repeat the
verification of the correct position of the fuel pipe flange, as
specified in paragraph (a) of this AD, thereafter at intervals not
to exceed 15 months.
(d) Condition 3. Discrepancy Found; O-Ring Exposed. If any
discrepancy is detected, and the fuel pipe is found to be improperly
positioned, and the O-ring is exposed, during any visual inspection
required by paragraph (a) of this AD, prior to further flight,
replace the O-ring with a new O-ring, and install a temporary
phenolic support block assembly, shim, clamp, and bracket between
the tail tank fuel pipe and station Y=2033.750 bulkhead, in
accordance with McDonnell Douglas Alert Service Bulletin MD11-
28A082, dated May 14, 1996. Within 6 months after accomplishment of
the replacement and installation, perform a one-time inspection to
verify the correct position of the temporary support block assembly
installation in accordance with Figure 2 (Sheet 2 of 3) of the alert
service bulletin.
(1) If the assembly is found to be positioned properly, repeat
the verification of the correct position of the fuel pipe flange, as
specified in paragraph (a) of this AD, thereafter at intervals not
to exceed 15 months.
(2) If the assembly is found to be improperly positioned, prior
to further flight, reposition the fuel pipe in accordance with
Figure 2 (Sheet 2 of 3) of the alert service bulletin. Repeat the
verification of the correct position of the fuel pipe flange, as
specified in paragraph (a) of this AD, thereafter at intervals not
to exceed 15 months.
New Requirements of This AD
(e) Within 24 months after the effective date of this AD,
install a restraint on the tail tank fuel pipe in accordance with
McDonnell Douglas Service Bulletin MD11-28-082, dated July 29, 1996.
Accomplishment of the installation constitutes terminating action
for the repetitive inspection requirements of this AD.
(f) 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, Los Angeles Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate. Operators shall
submit their requests through an appropriate FAA Principal
Maintenance Inspector, who may add comments and then send it to the
Manager, Los Angeles ACO.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles ACO.
(g) 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.
Issued in Renton, Washington, on November 13, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-29607 Filed 11-19-96; 8:45 am]
BILLING CODE 4910-13-U
