[Federal Register Volume 59, Number 140 (Friday, July 22, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-17860]


[[Page Unknown]]

[Federal Register: July 22, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-51-AD]

 

Airworthiness Directives; McDonnell Douglas Model DC-10 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain McDonnell Douglas 
Model DC-10 series airplanes, that currently requires inspection of the 
wing rear spar lower cap aft tang fastener and the wing trailing edge 
access door sill to detect fatigue cracking, and repair, if necessary. 
This action would require installation of a crack preventative 
modification of the wing rear spar lower cap, and follow-on 
inspections. This proposal is prompted by reports of additional 
cracking found in the current inspection area. The actions specified by 
the proposed AD are intended to prevent propagation of cracks in the 
subject area, which could compromise the structural integrity of the 
airplane.

DATES: Comments must be received by October 11, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-51-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, 3229 East Spring 
Street, Long Beach, California.

FOR FURTHER INFORMATION CONTACT: Maureen Moreland, Aerospace Engineer, 
Airframe Branch, ANM-120L, Los Angeles Aircraft Certification Office, 
FAA, Transport Airplane Directorate, 3229 East Spring Street, Long 
Beach, California 90806-2425; telephone (310) 988-5238; fax (310) 988-
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-51-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-51-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On September 25, 1991, the FAA issued AD 91-21-05, amendment 39-
8052 (56 FR 50650, October 8, 1991), which is applicable to certain 
McDonnell Douglas Model DC-10 series airplanes. That AD requires 
repetitive inspections to detect fatigue cracking of the wing rear spar 
lower cap aft tang and the wing trailing edge access door sill, and 
repair of any cracking found. That action was prompted by reports of 
fatigue cracks found in the wing rear spar lower cap aft tang on four 
Model DC-10 series airplanes. This cracking was found during an 
inspection conducted in accordance with the Supplemental Inspection 
Document (SID) program; that program was required to be implemented by 
AD 89-22-10, amendment 39-6330 (54 FR 42291, October 16, 1989). The 
requirements of AD 91-21-05 are intended to prevent fatigue cracking in 
the subject area. Such cracking, if not detected and corrected in a 
timely manner, could compromise the structural integrity of the 
airplane.
    Since the issuance of that AD, there have been 10 additional 
reports of fatigue cracks found in the wing rear spar lower cap aft 
tang. Such cracking presents the same unsafe condition as addressed by 
the existing AD 91-21-05.
    Additionally, since the issuance of that AD, the manufacturer has 
developed a crack preventative modification of the wing rear spar lower 
cap aft tang and wing trailing edge access door sill that is intended 
to minimize the possibility of cracking in these areas.
    The FAA has reviewed and approved McDonnell Douglas Alert Service 
Bulletin A57-123, Revision 1, dated June 8, 1993, which contains 
procedures for conducting various inspections to detect fatigue 
cracking of the wing rear spar lower cap aft tang fastener and the wing 
trailing edge access door sill, and procedures for repairing any 
cracking found. This revised service bulletin is essentially identical 
to the original version, which was referenced in AD 91-21-05 as the 
appropriate source of service information. The only relevant changes 
are a revised listing of current operators of affected airplanes, and 
the inclusion of additional repair options.
    The FAA has also reviewed and approved McDonnell Douglas Service 
Bulletin 57-123, dated June 8, 1993, that describes procedures for 
installing a crack preventative modification of the wing rear spar 
lower cap aft tang and wing trailing edge access door sill. This 
modification entails replacing Taper-Lok fasteners with straight 
titanium fasteners, and cold working the holes in the wing rear spar 
lower cap forward and aft tangs between stations Xors=430.000 and 
Xors=410.000. Accomplishment of this modification will minimize 
the possibility of fatigue cracking in the subject areas.
    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 supersede AD 91-21-05 to continue to require 
repetitive inspections of the wing rear spar lower cap aft tang 
fastener and the wing trailing edge access door sill to detect fatigue 
cracking, and repair of any cracking found. These actions would be 
required to be accomplished in accordance with either the original or 
revised version of McDonnell Douglas Alert Service Bulletin A57-123.
    This proposed AD would also require the eventual installation of 
the crack preventative modification. Once this modification is 
accomplished, repetitive post-modification inspections would be 
required after the accumulation of a certain number of landings. These 
actions would be required to be accomplished in accordance with 
McDonnell Douglas Service Bulletin 57-123.
    There are approximately 282 Model DC-10 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 175 
airplanes of U.S. registry would be affected by this proposed AD.
    The currently required inspections take approximately 8 work hours 
per airplane to accomplish, at an average labor rate of $55 per work 
hour. Based on these figures, the total cost impact of the current 
inspection requirements of this AD on U.S. operators is estimated to be 
$77,000, or $440 per airplane, per inspection.
    The proposed modification would take approximately 12 work hours to 
accomplish, at an average labor rate of $55 per work hour. Required 
parts would cost between $3,730 and $6,730 per airplane, depending upon 
the airplane model. Based on these figures, the total cost impact of 
the proposed modification requirement of this AD on U.S. operators is 
estimated to be between $4,390 and $7,390 per airplane.
    The proposed post-modification inspections would take approximately 
12 work hours per airplane to accomplish, at an average labor rate of 
$55 per work hour. Based on these figures, the total cost impact of the 
proposed post-modification inspection requirement of this AD on U.S. 
operators is estimated to be $115,500, or $660 per airplane, per 
inspection.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the current or 
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. 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 removing amendment 39-8052 (56 FR 
50650, October 8, 1991), and by adding a new airworthiness directive 
(AD), to read as follows:

McDonnell Douglas: Docket 94-NM-51-AD. Supersedes AD 91-21-05, 
Amendment 39-8052.

    Applicability: Model DC-10-10, -10F, and -15 series airplanes, 
fuselage numbers through 379, inclusive; and Model DC-10-30, -30F, 
and -40 series airplanes, fuselage numbers through 275, inclusive; 
certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To ensure the structural integrity of these airplanes, 
accomplish the following:
    (a) Except as provided in paragraphs (b) through (e) of this AD, 
prior to the accumulation of 7,000 landings or within 30 days after 
October 23, 1991 (the effective date of AD 91-21-05, amendment 39-
8051), which ever occurs later, conduct the initial inspections 
specified in either paragraph (a)(1), (a)(2), or (a)(3) of this AD.
    (1) Conduct an eddy current inspection of the wing rear spar 
lower cap aft tang, and a dye penetrant inspection of the wing 
trailing edge access door sill located between Xors=417.000 and 
Xors=424.000, in accordance with Option III of McDonnell 
Douglas Alert Service Bulletin A57-123, dated July 25, 1991, or 
Revision 1, dated June 8, 1993. In addition, within 1,500 landings 
after performing the eddy current and dye penetrant inspections, 
conduct the inspections specified in either paragraph (a)(2) or 
(a)(3) of this AD, and repeat them thereafter as indicated. Or
    (2) Conduct an ultrasonic inspection of the area around the six 
wing rear spar lower cap aft tang fastener holes, and a dye 
penetrant inspection of the wing trailing edge access door sill 
located between stations Xors=417.000 and Xors=424.000, in 
accordance with Option II of McDonnell Douglas Alert Service 
Bulletin A57-123, dated July 25, 1991, or Revision 1, dated June 8, 
1993. Repeat these inspections thereafter at intervals not to exceed 
1,900 landings until the modification required by paragraph (g) of 
this AD is accomplished. Or
    (3) Conduct an eddy current inspection of the six wing rear spar 
lower cap aft tang fastener holes, and a dye penetrant inspection of 
the wing trailing edge access door sill located between stations 
Xors=417.000 and Xors=424.000, in accordance with Option I 
of McDonnell Douglas Alert Service Bulletin A57-123, dated July 25, 
1991, or Revision 1, dated June 8, 1993. Repeat these inspections 
thereafter at intervals not to exceed 3,300 landings until the 
modification required by paragraph (g) of this AD is accomplished.
    (b) The requirements of paragraph (c) of this AD apply to 
airplanes on which both of the following actions have been 
accomplished:
    (1) A dye penetrant inspection of the wing trailing edge access 
door sill located between stations Xors=417.000 and 
Xors=422.000 has been accomplished prior to October 23, 1991, 
in accordance with McDonnell Douglas Service Bulletin 57-61, 
Revision 2, dated August 15, 1990; and
    (2) An eddy current inspection of the wing rear spar lower cap 
aft tang has been accomplished prior to October 23, 1991, per DC-10 
Supplemental Inspection Document, Principal Structural Element (PSE) 
57.10.007 and 57.10.008, in accordance with McDonnell Douglas 
Service Bulletin 57-61, Revision 2, dated August 15, 1990.
    (c) For airplanes specified in paragraph (b) of this AD: Conduct 
the initial inspections specified in either paragraph (c)(1) or 
(c)(2) of this AD within 1,500 landings after accomplishing the 
inspections (dye penetrant and eddy current) specified in paragraph 
(b) of this AD, or within 30 days after October 23, 1991, whichever 
occurs later.
    (1) Conduct an ultrasonic inspection of the area around the six 
wing rear spar lower cap aft tang fastener holes, and a dye 
penetrant inspection of the wing trailing edge access door sill 
located between stations Xors=417.000 and Xors=424.000, in 
accordance with Option II of McDonnell Douglas Alert Service 
Bulletin A57-123, dated July 25, 1991, or Revision 1, dated June 8, 
1993. Repeat these inspections thereafter at intervals not to exceed 
1,900 landings until the modification required by paragraph (g) of 
this AD is accomplished. Or
    (2) Conduct an eddy current inspection of the six wing rear spar 
lower cap aft tang fastener holes, and a dye penetrant inspection of 
the wing trailing edge access door sill located between stations 
Xors=417.000 and Xors=424.000, in accordance with Option I 
of McDonnell Douglas Alert Service Bulletin A57-123, dated July 25, 
1991, or Revision 1, dated June 8, 1993. Repeat these inspections 
thereafter at intervals not to exceed 3,300 landings until the 
modification required by paragraph (g) of this AD is accomplished.
    (d) The requirements of paragraph (e) of this AD apply to 
airplanes on which both of the following actions have been 
accomplished:
    (1) A dye penetrant inspection of the wing trailing edge access 
door sill located between stations Xors=417.000 and 
Xors=422.000 has been accomplished prior to October 23, 1991, 
in accordance with McDonnell Douglas Service Bulletin 57-61, 
Revision 2, dated August 15, 1990; and
    (2) An eddy current inspection of the wing rear spar lower cap 
aft tang fastener holes located between stations Xors=417.000 
and Xors=422.000 has been accomplished prior to October 23, 
1991, per DPS 4.735-9, in accordance with McDonnell Douglas Service 
Bulletin 57-61, Revision 2, dated August 15, 1990.
    (e) For airplanes specified in paragraph (d) of this AD: Conduct 
the initial inspections specified in either paragraph (e)(1) or 
(e)(2) of this AD within 3,300 landings after the accomplishment of 
the inspection specified in paragraph (d)(1) of this AD, or within 
30 days after October 23, 1991, whichever occurs later.
    (1) Conduct an ultrasonic inspection of the area around the six 
wing rear spar lower cap aft tang fastener holes, and a dye 
penetrant inspection of the wing trailing edge access door sill 
located between stations Xors=417.000 and Xors=424.000, in 
accordance with Option II of McDonnell Douglas Alert Service 
Bulletin A57-123, dated July 25, 1991, or Revision 1, dated June 8, 
1993. Repeat these inspections thereafter at intervals not to exceed 
1,900 landings until the modification required by paragraph (g) of 
this AD is accomplished. Or
    (2) Conduct an eddy current inspection of the six wing rear spar 
lower cap aft tang fastener holes, and a dye penetrant inspection of 
the wing trailing edge access door sill located between stations 
Xors=417.000 and Xors=424.000, in accordance with Option I 
of McDonnell Douglas Alert Service Bulletin A57-123, dated July 25, 
1991, or Revision 1, dated June 8, 1993. Repeat these inspections 
thereafter at intervals not to exceed 3,300 landings until the 
modification required by paragraph (g) of this AD is accomplished.
    (f) If any crack(s) is found during any inspection conducted in 
accordance with paragraphs (a) through (e) of this AD, prior to 
further flight, repair in a manner approved by the Manager, Los 
Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate.
    (g) Prior to the accumulation of 10,000 total landings, or 
within 5 years after the effective date of this AD, whichever occurs 
later, accomplish the crack preventative modification in accordance 
with McDonnell Douglas Service Bulletin 57-123, dated June 8, 1993. 
Accomplishment of this modification constitutes terminating action 
for the inspection requirements of paragraphs (a) through (e) of 
this AD.
    (h) Prior to the accumulation of 10,000 landings after the 
accomplishment of the crack preventative modification required by 
paragraph (g) of this AD, conduct an inspection of the wing rear 
spar lower cap in accordance with McDonnell Douglas Service Bulletin 
57-123, dated June 8, 1993. Repeat this inspection thereafter in 
accordance with the following schedule. Any crack(s) found during 
any inspection required by this paragraph must be repaired, prior to 
further flight, in accordance with a method approved by the Manager, 
Los Angeles ACO, FAA, Transport Airplane Directorate.
    (1) For Model DC-10-10, -10F, and -15 series airplanes: Repeat 
the inspection at intervals not to exceed 4,550 landings.
    (2) For Model DC-10-30 and -30F series airplanes: Repeat the 
inspection at intervals not to exceed 2,810 landings.
    (3) For Model DC-10-40 series airplanes: Repeat the inspection 
at intervals not to exceed 3,400 landings.
    (i) 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: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (j) 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 July 18, 1994.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-17860 Filed 7-21-94; 8:45 am]
BILLING CODE 4910-13-U