[Federal Register Volume 60, Number 187 (Wednesday, September 27, 1995)]
[Proposed Rules]
[Pages 49808-49811]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-23913]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-108-AD]


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain McDonnell Douglas DC-10-
10, -15, and -30 series airplanes and Model KC-10A (military) 
airplanes. This proposal would require inspections to detect cracks of 
the upper aft mating bolt hole of the wing pylon truss fittings, and 
various follow-on actions. This proposal is prompted by reports of 
cracks found in the upper aft mating bolt hole of the wing pylon truss 
fitting located near the engine forward mount on Model DC-10-30 series 
airplanes, which were caused by fatigue-related stress. The actions 
specified by the proposed AD are intended to prevent fatigue-related 
cracking, which could lead to failure of the fitting, separation of a 
portion of the engine forward mount truss from the pylon, and 
consequent separation of the engine from the airplane.

DATES: Comments must be received by November 6, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-108-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; or at the FAA, Transport Airplane 
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: Maureen Moreland, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 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 95-NM-108-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. 95-NM-108-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports of four cracks found in the upper aft 
mating bolt hole of the wing pylon truss fitting located near the 
engine forward mount on Model DC-10-30 series airplanes. Three of the 
four cracks were found on the No. 1 pylon truss fittings; the fourth 
crack was found on the No. 3 pylon truss fitting. Two of these cracks 
emanated toward the upper surface of the inboard fitting; the other two 
cracks emanated toward the upper surface of the outboard fitting. This 
cracking occurred on airplanes that had accumulated between 66,959 and 
85,067 total flight hours and between 14,538 and 19,889 total landings. 
The cause of such cracking has been attributed to fatigue-related 
stress. The effects of such fatigue-related cracking could lead to 
failure of the fitting and separation of a portion of the engine 
forward mount truss from the pylon. This condition, if not corrected, 
could result in separation of the engine from the airplane.
    The area where the cracking was found on the Model DC-10-30 series 
airplanes is identical to that of Model DC-10-10, -15, and KC-10A 
(military) series airplanes (regardless of the configuration of the 
truss fittings installed in the wing pylons). Therefore, Model DC-10-
10, -15, and KC-10A (military) series airplanes may be subject to the 
same cracking problems.
    The FAA has reviewed and approved McDonnell Douglas DC-10 Service 
Bulletin 54-108, dated February 9, 1995, which describes procedures for 
performing an ultrasonic or eddy current inspection to detect cracks of 
the upper aft mating bolt hole of the engine pylon truss fittings. It 
also describes various follow-on actions to perform (i.e., repair, 
various inspections, replacement, coldwork), depending on the results 
of the inspection. For cases where no cracks are detected during 
inspection, the service bulletin describes procedures for either 
conducting repetitive inspections, or installing a preventative 
modification and performing follow-on ultrasonic inspections. The 
preventative modification entails enlarging, cold working, and 
installing bushings in the upper aft and middle mating bolt holes. 
Repair or replacement of the affected truss fittings will ensure 
structural integrity of the forward mount assembly of the engine.
    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 ultrasonic or eddy current 
inspections to detect cracks of the upper aft mating bolt hole of the 
wing pylon truss fittings, and various follow-on actions. The actions 
would be required to be accomplished in accordance with the service 
bulletin described previously.
    Operators should note that, although the service bulletin specifies 
that the operators should contact the manufacturer for disposition of 
certain conditions found, this proposal would require repair of those 
conditions to be accomplished in accordance with a method approved by 
the Manager, Los Angeles Aircraft Certification Office, FAA, Transport 
Airplane Directorate. 

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    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 long-standing requirement.
    There are approximately 376 Model DC-10-10, -15, and -30 series 
airplanes and Model KC-10 (military) airplanes of the affected design 
in the worldwide fleet. The FAA estimates that 228 airplanes of U.S. 
registry would be affected by this proposed AD. It would take 
approximately 5 work hours per airplane to accomplish the proposed 
inspections, at an average labor rate of $60 per work hour. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $68,400, or $300 per airplane, per 
inspection.
    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.
    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), 40101, 40113, 44701.


Sec. 39.13  [Amended]

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

McDonnell Douglas: Docket 95-NM-108-AD.

    Applicability: Model DC-10-10, -15, and -30 series airplanes and 
Model KC-10A (military) airplanes; as listed in McDonnell Douglas 
DC-10 Service Bulletin 54-108, dated February 9, 1995; 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 use the authority 
provided in paragraph (c) of this AD 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 fatigue-related cracking, which could lead to failure 
of the pylon truss fitting, separation of a portion of the engine 
forward mount truss from the pylon, and consequent separation of the 
engine from the airplane, accomplish the following:
    (a) For Model DC-10-15, and -30 series airplanes and Model KC-
10A (military) airplanes: Prior to the accumulation of 10,000 total 
landings on the pylon truss fitting or within 1,000 landings on the 
pylon truss fitting after the effective date of this AD, whichever 
occurs later, perform either an ultrasonic inspection or an eddy 
current inspection to detect cracks of the upper aft mating bolt 
hole of the wing pylon truss fittings, in accordance with McDonnell 
Douglas DC-10 Service Bulletin 54-108, dated February 9, 1995.
    (1) If no cracks are detected, repeat the inspections as 
follows:
    (i) If the immediately preceding inspection was conducted using 
ultrasonic techniques, conduct the next inspection within 5,000 
landings.
    (ii) If the immediately preceding inspection was conducted using 
eddy current techniques, conduct the next inspection within 8,000 
landings.
    (2) Terminating action for the repetitive inspections required 
by paragraph (a)(1) of this AD is as follows:
    (i) Accomplish the preventative modification in accordance with 
Condition 1 (bushing not installed), Option III, or Condition 2 
(bushing installed), Option II, of the service bulletin, as 
applicable. And
    (ii) Prior to the accumulation of 10,000 total landings on the 
pylon truss fitting following accomplishment of the modification, 
perform an ultrasonic inspection to detect cracks of the upper aft 
mating bolt hole of the wing pylon truss fittings, in accordance 
with the service bulletin. And
    (iii) Thereafter, repeat the ultrasonic inspection at intervals 
not to exceed 5,000 landings on the pylon truss fitting.
    (3) If any crack is found in the pylon truss fitting during any 
inspection required by this paragraph, prior to further flight, 
repair it in accordance with the service bulletin. At the times 
specified in the service bulletin, perform follow-on actions in 
accordance with the service bulletin. In all cases, where the 
service bulletin indicates ``contact Douglas for disposition,'' the 
repair must be accomplished in accordance with a method approved by 
the Manager, Los Angeles ACO, FAA, Transport Airplane Directorate.
    (b) For Model DC-10-10 series airplanes: Prior to the 
accumulation of 17,000 total landings on the pylon truss fitting or 
within 1,500 landings on the pylon truss fitting after the effective 
date of this AD, whichever occurs later, perform either an 
ultrasonic inspection or an eddy current inspection to detect cracks 
of the upper aft mating bolt hole of the wing pylon truss fittings, 
in accordance with McDonnell Douglas DC-10 Service Bulletin 54-108, 
dated February 9, 1995.
    (1) If no cracks are detected, repeat the inspections as 
follows:
    (i) If the immediately preceding inspection was conducted using 
ultrasonic techniques, conduct the next inspection within 10,000 
landings.
    (ii) If the immediately preceding inspection was conducted using 
eddy current techniques, conduct the next inspection within 15,000 
landings.
    (2) Terminating action for the repetitive inspections required 
by paragraph (b)(1) of this AD is as follows:
    (i) Accomplish the preventative modification in accordance with 
Condition 1 

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(bushing not installed), Option III, or Condition 2 (bushing 
installed), Option II, of the service bulletin, as applicable. And
    (ii) Prior to the accumulation of 18,000 total landings on the 
pylon truss fitting following accomplishment of the modification, 
perform an ultrasonic inspection to detect cracks of the upper aft 
mating bolt hole of the wing pylon truss fittings, in accordance 
with the service bulletin. And
    (iii) Thereafter, repeat the ultrasonic inspection at intervals 
not to exceed 10,000 landings on the pylon truss fitting.
    (3) If any crack is found in the pylon truss fitting during any 
inspection required by this paragraph, prior to further flight, 
repair it in accordance with the service bulletin. At the times 
specified in the service bulletin, perform follow-on actions in 
accordance with the service bulletin. In all cases, where the 
service bulletin indicates ``contact Douglas for disposition,'' the 
repair must be accomplished in accordance with a method approved by 
the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, 
Transport Airplane Directorate.
    (c) 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.

    (d) 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 September 21, 1995.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-23913 Filed 9-26-95; 8:45 am]
BILLING CODE 4910-13-U