[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
