[Federal Register Volume 61, Number 132 (Tuesday, July 9, 1996)]
[Rules and Regulations]
[Pages 35946-35949]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-17217]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-NM-133-AD; Amendment 39-9691; AD 96-14-07]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model MD-11 and MD-
11F Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to certain McDonnell Douglas Model MD-11 and MD-11F
series airplanes, that currently requires repetitive inspections of the
tail tank fuel pipe assembly and the associated mounting brackets in
the aft fuselage compartment, and follow-on actions, if necessary. That
AD also provides for an optional terminating modification for the
repetitive inspections. This amendment deletes the optional terminating
modification, and expands the applicability of the existing AD to
include additional airplanes. This amendment is 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 actions specified in
this 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.
DATES: Effective July 24, 1996.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 24, 1996.
Comments for inclusion in the Rules Docket must be received on or
before September 9, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-133-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056.
The service information referenced in this AD 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; or at the FAA, Los Angeles Aircraft
Certification Office, Transport Airplane Directorate, 3960 Paramount
Boulevard, Lakewood, California; or at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Raymond 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: On November 4, 1991, the FAA issued AD 91-
24-09, amendment 39-8095 (56 FR 61364, December 3, 1991), applicable to
certain McDonnell Douglas Model MD-11 and MD-11F series airplanes. That
AD requires repetitive visual inspections of the tail tank fuel pipe
assembly and the associated mounting brackets located in the aft
fuselage compartment to verify the correct position of the pipe flange
and to detect damaged brackets. It also requires various follow-on
actions, if any discrepancy is detected. That AD also provides for an
optional terminating modification for the repetitive inspections. That
action was prompted by a report of an uncontained fuel leak in the aft
fuselage compartment on an in-service airplane, which was the result of
migration of the tail tank fuel pipe assembly, and consequent exposure
of the O-ring that provides the seal between the pipe assembly and the
coupling shroud assembly. The actions required by that AD are intended
to prevent a fuel leak in the aft fuselage compartment area, and the
possibility of an in-flight or ground fire.
Actions Since Issuance of Previous Rule
Since the issuance of that AD, the FAA has received several reports
of cracking or bending of the fuel pipe mounting support and/or
attaching bracket at station Y=2033.750 in the aft
[[Page 35947]]
fuselage compartment on McDonnell Douglas Model MD-11 series airplanes.
A section of the fuel pipe assembly and support bracket of some of
these airplanes had been replaced in accordance with the optional
terminating modification specified in AD 91-24-09. Additionally, this
replacement had been accomplished during production on certain other
airplanes on which these incidents occurred.
Investigation revealed that a fuel pressure surge during transfer
of the tail tank fuel caused repetitive loading of the fuel pipe
mounting support and/or attaching bracket, which resulted in the
subject cracking/bending. Although none of the reported events have
resulted in a fuel leak in the aft fuselage compartment, the FAA has
determined that severe deformation of the bracket could allow the pipe
to migrate, which could also expose the O-ring that provides the seal
between the fuel pipe and coupling. If the O-ring is exposed, it could
lose its sealing effect, and allow a fuel leak in the aft fuselage
compartment, which could result in a possible in-flight or ground fire.
In light of these recent incidents, which are similar to the
incident that prompted the issuance of AD 91-24-09, the FAA finds that
the optional and on-condition terminating modifications (i.e.,
replacement of a section of the fuel pipe assembly and support bracket,
an FAA-approved repair procedure, and replacement of the shroud
assembly) specified in AD 91-24-09 do not adequately preclude the
addressed unsafe condition identified as in-flight or ground fire.
Therefore, the FAA finds that 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 are necessary. These actions will
ensure that the unsafe condition presented by fuel surge during
transfer of tail tank fuel is corrected, and provide an acceptable
level of safety.
Explanation of Relevant Service Information
The FAA has reviewed and approved McDonnell Douglas Alert Service
Bulletin MD11-28A082, dated May 14, 1996. The alert service bulletin
describes procedures for 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. These
follow-on actions include replacing the O-ring, repositioning the tail
tank fuel pipe, and installing a temporary phenolic support block
assembly. Installation of a phenolic support block assembly between the
tail tank fuel pipe and adjoining structure as a temporary restraint
will minimize the possibility of migration of the tail tank fuel pipe.
In addition, the visual inspections and certain of the follow-on
actions of Alert Service Bulletin MD11-28A082 are essentially identical
to those described in McDonnell Douglas MD-11 Alert Service Bulletin
A28-22, Revision 4, dated September 16, 1991 (which was referenced in
AD 91-24-09). However, the effectivity listing of Alert Service
Bulletin MD11-28A082 includes additional airplanes that were not
included in the effectivity listing of Alert Service Bulletin A28-22.
These additional airplanes have been found to be subject to the
addressed unsafe condition.
Explanation of Requirements of Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other airplanes of this same type design, this AD
supersedes AD 91-24-09 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. This AD also expands the applicability of the existing AD to
include additional airplanes.
This is considered to be interim action. The manufacturer has
advised that it currently is developing a modification that will
positively address the unsafe condition addressed by this AD. Once this
modification is developed, approved, and available, the FAA may
consider additional rulemaking.
Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the 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 that
summarizes each FAA-public contact concerned with the substance of this
AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this rule must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 96-NM-133-AD.'' The postcard will be date stamped and
returned to the commenter.
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.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and that it is not a ``significant regulatory
action'' under Executive Order 12866. It has been determined further
that this action involves an emergency regulation under DOT Regulatory
Policies and Procedures (44 FR 11034, February 26, 1979). If it is
determined that this emergency regulation otherwise would be
significant under DOT Regulatory
[[Page 35948]]
Policies and Procedures, a final regulatory evaluation will be prepared
and placed in the Rules Docket. A copy of it, if filed, 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, Incorporation by
reference, Safety.
Adoption of the Amendment
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
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 39-8095 (56 FR
61364, December 3, 1991), and by adding a new airworthiness directive
(AD), amendment 39-9691, to read as follows:
96-14-07 McDonnell Douglas: Amendment 39-9691, Docket 96-NM-133-AD.
Supersedes AD 91-24-09, Amendment 39-8095.
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
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 (e) 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:
(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 the effective date of
this AD, 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, whichever occurs first.
(b) CONDITION 1. 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) 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) 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. 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) 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) 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. 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.
(e) 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.
(f) 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.
(g) The actions shall be done in accordance with McDonnell
Douglas Alert Service
[[Page 35949]]
Bulletin MD11-28A082, dated May 14, 1996. This incorporation by
reference was approved by the Director of the Federal Register in
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be
obtained from McDonnell Douglas Corporation, 3855 Lakewood
Boulevard, Long Beach, California 90846, Attention: Technical
Publications Business Administration, Department C1-L51 (2-60).
Copies may be inspected at the FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los
Angeles Aircraft Certification Office, Transport Airplane
Directorate, 3960 Paramount Boulevard, Lakewood, California; or at
the Office of the Federal Register, 800 North Capitol Street, NW.,
suite 700, Washington, DC.
(h) This amendment becomes effective on July 24, 1996.
Issued in Renton, Washington, on July 1, 1996.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-17217 Filed 7-8-96; 8:45 am]
BILLING CODE 4910-13-P
