[Federal Register Volume 61, Number 77 (Friday, April 19, 1996)]
[Proposed Rules]
[Pages 17261-17263]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-9690]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-212-AD]


Airworthiness Directives; McDonnell Douglas Model DC-10 and MD-11 
Series Airplanes and KC-10A (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 all McDonnell Douglas Model DC-10 
and MD-11 series airplanes and KC-10A (military) airplanes. This 
proposal would require repetitive inspections to detect corrosion or 
failure of the steel Hi-Lok fasteners at the inboard flap inboard 
track, and replacement of corroded/failed steel Hi-Lok fasteners with 
inconel Hi-Lok fasteners. The proposed AD also provides for termination 
of the repetitive inspections by replacing all of the steel Hi-Lok 
fasteners with inconel Hi-Lok fasteners. This proposal is prompted by 
reports of failed and/or corroded steel fasteners found in the inboard 
flap inboard track due to stress corrosion. The actions specified by 
the proposed AD are intended to prevent such stress corrosion, which 
could result in binding of the flap and inability of the flap to extend 
or retract; this situation may lead to asymmetric flap deployment and 
subsequent reduced controllability of the airplane during flight.

DATES: Comments must be received by May 31, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-212-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: Ron Atmur, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone 
(310) 627-5224; 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-212-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-212-AD, 1601 Lind Avenue SW., Renton, Washington 
98055-4056.

Discussion of Service History

    The FAA has received several reports of failed and/or corroded 
fasteners found in the inboard flap inboard track on Model DC-10 series 
airplanes. The failed fasteners were found on two airplanes, which had 
accumulated 18,357 and 23,901 total landings, respectively. 
Investigation revealed that the fasteners on these airplanes are made 
of H-11 steel, which is susceptible to stress corrosion. Stress 
corrosion in the fasteners in the inboard flap inboard track could 
result in binding of the flap and inability of the flap to extend or 
retract. If the flap fails to extend or retract, the resultant 
asymmetric flap deployment could

[[Page 17262]]

result in reduced controllability of the airplane during flight.
    The fasteners in the flap tracks on the Model DC-10 series 
airplanes are identical to those installed on Model MD-11 series 
airplanes. Therefore, the FAA has determined that Model MD-11 series 
airplanes may be subject to the same failed/corroded fastener problem.
Discussion of Relevant Service Documents
    The FAA has reviewed and approved McDonnell Douglas Service 
Bulletin DC10-57-134, dated August 15, 1995 [for Model DC-10 series 
airplanes and KC-10 (military) airplanes], and McDonnell Douglas 
Service Bulletin MD11-57-031, dated August 15, 1995 (for Model MD-11 
series airplanes). These service bulletins describe procedures for 
repetitive visual inspections to detect corrosion or failure of the 
steel Hi-Lok fasteners at the inboard flap inboard track; and 
replacement of corroded/failed steel Hi-Lok fasteners with Hi-Lok 
fasteners made of inconel.
    These service bulletins also provide instructions for replacing all 
steel Hi-Lok fasteners with inconel Hi-Lok fasteners, which, if 
accomplished, eliminates the need for the repetitive inspections. 
Replacement of steel fasteners with corrosion-resistant inconel 
fasteners will minimize the possibility of fastener failure.
Discussion of the 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 require repetitive visual inspections to detect 
corrosion or failure of the steel Hi-Lok fasteners at the inboard flap 
inboard track. The proposed AD also would require replacement of 
corroded/failed steel Hi-Lok fasteners with inconel Hi-Lok fasteners. 
In addition, the proposed AD provides for an optional terminating 
action for the repetitive inspection requirements by replacing all the 
steel Hi-Lok fasteners with Hi-Lok fasteners made of inconel. The 
actions would be required to be accomplished in accordance with the 
service bulletins described previously.
    The FAA is not proposing to mandate the replacement of all steel 
Hi-Lok fasteners for several reasons:
    1. Accessing the inboard flap inboard track area for inspection is 
easily accomplished.
    2. The corroded/failed fasteners are easily detectable by means of 
a visual inspection.
    3. The failure of a fastener may adversely affect the 
controllability of the airplane; however, the visual inspections will 
preclude the potential occurrence of multiple failed fasteners, which 
could result in a catastrophic failure.

Differences Between the Proposed Rule and Relevant Service Documents

    Operators should note that the proposed compliance time of 18 
months for the initial and repetitive inspections differs from the 
compliance times recommended in both of the referenced McDonnell 
Douglas service bulletins:
     Service Bulletin DC10-57-134 (for Model DC-10 series 
airplanes) recommends a compliance time of 24 months.
     Service Bulletin MD11-57-031 (for Model MD-11 series 
airplanes) recommends a compliance time of 15 months. (The manufacturer 
advised the FAA that it inadvertently specified a 15-month compliance 
time in this service bulletin, and had intended that it be consistent 
with the 24-month compliance time recommended in Service Bulletin DC10-
57-134.)
    In developing an appropriate compliance time for this action, the 
FAA considered not only the degree of urgency associated with 
addressing the subject unsafe condition, but the susceptibility of the 
subject area to stress corrosion cracking. In addition, the FAA finds a 
compliance time of 18 months will allow the inspection to be performed 
at a base during regularly scheduled maintenance where special 
equipment and trained maintenance personnel will be available, if 
necessary. In consideration of these items, the FAA finds that the 
initial and repetitive visual inspections conducted at the proposed 
compliance time of 18 months will better ensure that any detrimental 
effect associated with stress corrosion will be identified and 
corrected prior to the time that it could adversely affect the 
fasteners in the inboard flap inboard track.

Cost Impact

    There are approximately 514 McDonnell Douglas Model DC-10 and Model 
MD-11 series airplanes, and KC-10A (military) airplanes of the affected 
design in the worldwide fleet. The FAA estimates that 276 airplanes of 
U.S. registry would be affected by the inspection requirements proposed 
in this AD, that it would take approximately 2 work hours per airplane 
to accomplish the proposed actions, and that the average labor rate is 
$60 per work hour. Based on these figures, the cost impact of the 
proposed inspection requirements on U.S. operators is estimated to be 
$33,120, or $120 per airplane, per inspection cycle.
    The 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.

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 adding the following new 
airworthiness directive:

McDonnell Douglas: Docket 95-NM-212-AD.
    Applicability: All Model DC-10 and MD-11 series airplanes, and 
KC-10A (military) airplanes, certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability

[[Page 17263]]

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 (c) 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 stress corrosion cracking in the fasteners in 
the inboard flap inboard track, which could result in binding of the 
flap and inability of the flap to extend or retract, accomplish the 
following:
    (a) For Model DC-10 series airplanes and KC-10A (military) 
airplanes: Within 18 months after the effective date of this AD, 
perform a visual inspection to detect corrosion or failure of the 
steel Hi-Lok fasteners at the inboard flap inboard track in 
accordance with McDonnell Douglas Service Bulletin DC-10-57-134, 
dated August 15, 1995.
    (1) If no corrosion or failure is detected, accomplish either 
paragraph (a)(1)(i) or (a)(1)(ii) of this AD.
    (i) Repeat the inspection required by paragraph (a) of this AD 
thereafter at intervals not to exceed 18 months until paragraph 
(a)(1)(ii) of this AD is accomplished.
    (ii) Replace all steel Hi-Lok fasteners with inconel Hi-Lok 
fasteners in accordance with McDonnell Douglas Service Bulletin DC-
10-57-134, dated August 15, 1995. Accomplishment of this replacement 
constitutes terminating action for the repetitive inspection 
requirements of paragraph (a)(1)(i) of this AD.
    (2) If any corrosion or failure is detected, prior to further 
flight, accomplish either paragraph (a)(2)(i) or (a)(2)(ii) of this 
AD, in accordance with McDonnell Douglas Service Bulletin DC-10-57-
134, dated August 15, 1995.
    (i) Replace all corroded/failed steel Hi-Lok fasteners with 
inconel Hi-Lok fasteners in accordance with the service bulletin. 
Repeat the visual inspection required by paragraph (a) of this AD 
thereafter at intervals not to exceed 18 months until paragraph 
(a)(2)(ii) of this AD is accomplished
    (ii) Replace all steel Hi-Lok fasteners with inconel Hi-Lok 
fasteners, in accordance with McDonnell Douglas Service Bulletin DC-
10-57-134, dated August 15, 1995. Accomplishment of this replacement 
constitutes terminating action for the repetitive inspection 
requirements of paragraph (a)(2)(i) of this AD.
    (b) For Model MD-11 series airplanes: Within 18 months after the 
effective date of this AD, perform a visual inspection to detect 
corrosion or failures of the steel Hi-Lok fasteners at the inboard 
flap inboard track in accordance with McDonnell Douglas Service 
Bulletin MD11-57-031, dated August 15, 1995.
    (1) If no corrosion or failures are detected, accomplish either 
paragraph (b)(1)(i) or (b)(2)(ii) of this AD.
    (i) Repeat the inspection required by paragraph (b) of this AD 
thereafter at intervals not to exceed 18 months until paragraph 
(b)(1)(ii) of this AD is accomplished.
    (ii) Replace all steel Hi-Lok fasteners with inconel Hi-Lok 
fasteners in accordance with McDonnell Douglas Service Bulletin 
MD11-57-031, dated August 15, 1995. Accomplishment of this 
replacement constitutes terminating action for the repetitive 
inspection requirements of paragraph (b)(1)(i) of this AD.
    (2) If any corrosion or failure is detected during the 
inspection required by paragraph (b) of this AD, prior to further 
flight, accomplish either paragraph (b)(2)(i) or (b)(2)(ii) of this 
AD, in accordance with McDonnell Douglas Service Bulletin MD11-57-
031, dated August 15, 1995.
    (i) Replace all corroded/failed steel Hi-Lok fasteners with 
inconel Hi-Lok fasteners in accordance with the service bulletin. 
Repeat the visual inspection required by paragraph (b) of this AD 
thereafter at intervals not to exceed 18 months until paragraph 
(b)(2)(ii) of this AD is accomplished.
    (ii) Replace all steel Hi-Lok fasteners with inconel Hi-Lok 
fasteners in accordance with McDonnell Douglas Service Bulletin 
MD11-57-031, dated August 15, 1995. Accomplishment of this 
replacement constitutes terminating action for the repetitive 
inspection requirements of paragraph (b)(2)(i) of this AD.
    (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 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.

    (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 April 15, 1996.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-9690 Filed 4-18-96; 8:45 am]
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