[Federal Register Volume 60, Number 11 (Wednesday, January 18, 1995)]
[Proposed Rules]
[Pages 3590-3592]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-1134]



-----------------------------------------------------------------------


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-176-AD]


Airworthiness Directives; McDonnell Douglas Model DC-10-10, -15, 
-30, -40, and KC-10 (Military) Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain McDonnell Douglas DC-10 
and KC-10 series airplanes. This proposal would require repetitive eddy 
current inspections to detect fatigue cracking of the pylon aft 
bulkhead flange, upper pylon box web, fitting radius, and adjacent 
tangent areas; and repair, if necessary. This proposal is prompted by 
fatigue cracking found in the wing pylon aft bulkheads on two 
airplanes. The actions specified by the proposed AD are intended to 
prevent failure of the wing pylon aft bulkhead due to fatigue cracking, 
which could lead to separation of the engine and pylon from the 
airplane.

DATES: Comments must be received by March 14, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-176-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, P.O. Box 1771, Long Beach, 
California 90801-1771, Attention: Business Unit Manager, Technical 
Administrative Support, Dept. L51, M.C. 2-98. 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.

FOR FURTHER INFORMATION CONTACT: Maureen Moreland, Aerospace Engineer, 
Airframe Branch, ANM-120L, Los Angeles Aircraft Certification Office, 
FAA, Transport Airplane Directorate, 3960 Paramount Boulevard, 
Lakewood, California 90712; telephone (310) 627-5238; 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 94-NM-176-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-103, Attention: Rules 
Docket No. 94-NM-176-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On July 24, 1992, the FAA issued AD 92-17-13, amendment 39-8342 (57 
FR 36894, August 17, 1992), which is applicable to McDonnell Douglas 
Model DC-10 series airplanes. That AD requires a one-time visual 
inspection to detect cracks of the wing pylon aft bulkheads and upper 
spar webs, and repair, if necessary; additionally, it requires that 
operators submit a report of their inspection findings to the FAA. That 
AD was prompted by reports of fatigue cracking that occurred in the 
wing pylon aft bulkheads on two airplanes. The fatigue cracking 
initiated at fastener holes and/or at the lower forward edge of the 
bulkhead flange. Such cracking, if not detected and corrected in a 
timely manner, could lead to failure of the wing pylon aft bulkhead 
[[Page 3591]] and subsequent separation of the engine and pylon from 
the airplane.
    One of the intended purposes of the one-time visual inspection and 
submission of reports required by that AD was to allow the FAA and the 
manufacturer to obtain data as to the general condition of the affected 
fleet relevant to the identified fatigue cracking. Based on this data, 
the manufacturer has conducted further investigation and analysis of 
the cracking found in the subject areas. This effort has revealed that 
the cracking was caused by fatigue that was accelerated by preload 
conditions. The manufacturer has developed inspection procedures that 
will ensure that this fatigue cracking is identified and corrected 
before it reaches critical lengths.
    The FAA has reviewed and approved McDonnell Douglas Alert Service 
Bulletin A54-106, Revision 2, dated November 3, 1994, which describes 
procedures for conducting repetitive eddy current inspections to detect 
fatigue cracking of the pylon aft bulkhead flange, upper pylon box web, 
fitting radius, and adjacent tangent areas.
    The service bulletin also describes procedures for performing a 
visual inspection for gaps between the pylon aft bulkhead flange, upper 
pylon box web, fitting radius, and adjacent tangent areas, and shimming 
any gaps found. Once this inspection is performed, the repetitive eddy 
current inspections of these areas are no longer necessary.
    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 require repetitive eddy current inspections to detect 
fatigue cracking of the pylon aft bulkhead flange, upper pylon box web, 
fitting radius, and adjacent tangent areas. If any cracks are found, 
they would be required to be repaired in accordance with a method 
approved by the FAA. The proposed AD would also provide for an optional 
terminating action consisting of a gap inspection of bulkhead 
components and necessary shimming. The actions would be required to be 
accomplished in accordance with the service bulletin described 
previously.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this notice to clarify this requirement.
    There are approximately 426 Model DC-10 and KC-10 series airplanes 
of the affected design in the worldwide fleet. The FAA estimates that 
269 airplanes of U.S. registry would be affected by this proposed AD, 
that it would take approximately 8 work hours per airplane to 
accomplish the proposed eddy current inspections, and that the average 
labor rate is $60 per work hour. Based on these figures, the total cost 
impact of the proposed AD on U.S. operators is estimated to be 
$129,120, or $480 per airplane, per inspection cycle.
    The total cost impact figure discussed above is 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.
    Should an operator elect to accomplish the optional terminating 
action that would be provided by this proposed rule, it would require 
approximately 2 work hours per airplane to accomplish the gap 
inspection, at an average labor rate of $60 per work hour. The cost and 
labor associated with any necessary shimming would vary, depending upon 
what was revealed by the gap inspection.
    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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

McDonnell Douglas: Docket 94-NM-176-AD.

    Applicability: Model DC-10-10, -15, -30, -40, and KC-10 
(military) series airplanes; as listed in McDonnell Douglas Alert 
Service Bulletin A54-106, Revision 2, dated November 3, 1994; 
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 use the authority 
provided in paragraph (d) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition; or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent failure of the wing pylon aft bulkhead due to fatigue 
cracking, which could lead to separation of the engine and pylon 
from the airplane, accomplish the following:
    (a) Prior to the accumulation of 1,800 landings after the 
effective date of this AD, conduct an eddy current inspection to 
detect fatigue cracks in the pylon aft bulkhead flange, upper pylon 
box web, fitting radius, and adjacent tangent areas, in accordance 
[[Page 3592]] with McDonnell Douglas Alert Service Bulletin A54-106, 
Revision 2, dated November 3, 1994. Repeat this inspection 
thereafter at intervals not to exceed 1,800 landings.
    (b) If any crack(s) is found during any inspection required by 
paragraph (a) of this AD, prior to further flight, repair in 
accordance with a method approved by the Manager, Los Angeles 
Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate.
    (c) Accomplishment of the gap inspection and necessary shimming 
in accordance with ``Phase III,'' as specified in McDonnell Douglas 
Alert Service Bulletin A54-106, Revision 2, dated November 3, 1994, 
constitutes terminating action for the inspections required by 
paragraph (a) of this AD.
    (d) 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 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.

    (e) 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 January 11, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-1134 Filed 1-17-95; 8:45 am]
BILLING CODE 4910-13-U