[Federal Register Volume 63, Number 14 (Thursday, January 22, 1998)]
[Proposed Rules]
[Pages 3267-3270]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-1427]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-14-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-10-10, -30, 
and -40 Series 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 Model 
DC-10-10, -30, and -40 series airplanes. This proposal would require 
replacement of certain taper-lok attachments and forward trunnion bolts 
with new components that attach the left and right main landing gear 
(MLG) to each wing. This proposal is prompted by a report indicating 
that, due to overstrength of the forward trunnion bolt, an MLG broke 
away and ruptured a wing fuel tank while an airplane was being operated 
off the runway. The actions specified by the proposed AD are intended 
to ensure that the MLG separates from the wing when it is subjected to 
unpredictable overloads during abnormal operations, and to prevent 
consequent primary structural damage to the airplane.

DATES: Comments must be received by March 9, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-14-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: Ronald Atmur, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone 
(562) 627-5224; fax (562) 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

[[Page 3268]]

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 97-NM-14-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-114, Attention: Rules 
Docket No. 97-NM-14-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report indicating that, while a McDonnell 
Douglas Model DC-10-10 series airplane was being operated off the 
runway, a main landing gear (MLG) broke away and ruptured the wing fuel 
tank. The results of analysis and testing conducted by the manufacturer 
revealed that certain fasteners (e.g., the forward trunnion bolt and 
the bolts for the attach fitting), which attach the MLG to the rear 
spar of the wing, are overstrength. Consequently, the MLG may not 
separate from the airplane, as designed, when unpredictable overloads 
are placed on the MLG during abnormal operations. This condition, if 
not corrected, could result in primary structural damage to the 
airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas DC-10 Service 
Bulletin 57-78, Revision 1, dated August 26, 1986 (for Model DC-10-10 
series airplanes), which describes procedures for replacing 24 TL 
taper-lok attachments that attach the left and right MLG attach fitting 
assemblies on each wing with heat-treat TLH taper-lok attachments. This 
service bulletin also describes procedures for replacing the forward 
trunnion bolts on the left and right MLG of each wing with ``zero 
margin'' trunnion bolts.
    The FAA also has reviewed and approved McDonnell Douglas DC-10 
Service Bulletin 57-79, Revision 1, dated September 21, 1979, as 
revised by McDonnell Douglas DC-10 Service Bulletin 57-79, Service 
Bulletin Change Notification, dated January 23, 1980 (for Model DC-10-
10 series airplanes). This service bulletin describes procedures for 
replacing the 1\1/2\-inch-diameter bolts that attach the left and right 
MLG attach fitting and rear spar of each wing with 1\1/4\-inch-diameter 
bolts and bushings, and installing bolt retainers.
    In addition, the FAA has reviewed and approved McDonnell Douglas 
DC-10 Service Bulletin 57-82, dated February 19, 1980 (for Model DC-10-
30 and -40 series airplanes). This service bulletin describes 
procedures for replacing the forward trunnion bolts of the left and 
right MLG of each wing with ``zero margin'' trunnion bolts. For certain 
groups of airplanes, the service bulletin also describes procedures for 
replacing the 1\1/2\-inch-diameter bolts that attach the left and right 
MLG attach fitting and rear spar of each wing with 1\1/4\-inch-diameter 
bolts and bushings, and installing bolt retainers.
    Accomplishment of the replacement of all of these fasteners will 
allow the MLG to separate from the wing. This separation is intended to 
minimize the possibility of primary structural damage to the airplane 
when the MLG is subjected to unpredictable overloads during abnormal 
operations.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type of design, the 
proposed AD would require accomplishment of the actions specified in 
the service bulletins described previously in accordance with the 
procedures specified in those service bulletins.

Cost Impact

For McDonnell Douglas Model DC-10-10 Series Airplanes

    There are approximately 119 Model DC-10-10 series airplanes of the 
affected design in the worldwide fleet, and 108 airplanes of U.S. 
registry that would be affected by the proposed requirements for 
replacement of taper-lok attachments and forward trunnion bolts. The 
FAA estimates that it would take approximately 462 work hours per 
airplane to accomplish these proposed actions, and that the average 
labor rate is $60 per work hour. Required parts would cost 
approximately $47,000 per airplane. Based on these figures, the cost 
impact of these proposed actions on U.S. operators is estimated to be 
$8,069,760, or $74,720 per airplane.
    There are approximately 111 Model DC-10-10 series airplanes of the 
affected design in the worldwide fleet, and 82 airplanes of U.S. 
registry that would be affected by the proposed requirements for 
replacement of larger attach bolts and installation of bolt retainers. 
The FAA estimates that it would take approximately 500 work hours per 
airplane to accomplish these proposed actions, and that the average 
labor rate is $60 per work hour. Required parts would cost 
approximately $11,734 per airplane. Based on these figures, the cost 
impact of these proposed actions on U.S. operators is estimated to be 
$3,422,188, or $41,734 per airplane.

For McDonnell Douglas Model DC-10-30 and DC-10-40 Series Airplanes

    There are approximately 168 Model DC-10-30 and DC-10-40 series 
airplanes of the affected design in the worldwide fleet, and 82 
airplanes of U.S. registry that are identified as Groups I and II 
airplanes in the relevant service bulletins and that would be affected 
by the proposed requirements for replacement of larger attach bolts, 
installation of bolt retainers, and replacement of forward trunnion 
bolts. The FAA estimates that it would take approximately 576 work 
hours per airplane to accomplish these proposed actions, and that the 
average labor rate is $60 per work hour. Required parts would cost 
approximately $20,000 per airplane. Based on these figures, the cost 
impact of these proposed actions on U.S. operators is estimated to be 
$4,473,920, or $54,560 per airplane.
    There are approximately 20 Model DC-10-30 and DC-10-40 series 
airplanes of the affected design in the worldwide fleet, and 6 
airplanes of U.S. registry that are identified as Group III airplanes 
in the relevant service bulletins and that would be affected by the 
proposed requirements for replacement of forward trunnion bolts. The 
FAA estimates that it would take approximately 76 work hours per 
airplane to accomplish this proposed action, and that the average labor 
rate is $60 per work hour. Required parts would cost approximately 
$15,800 per airplane. Based on these figures, the cost impact of this 
proposed action on U.S. operators is estimated to be $122,160, or 
$20,360 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no

[[Page 3269]]

operator has yet accomplished the proposed action, and that no operator 
would accomplish that action in the future if this AD were not adopted.
    However, the FAA has been advised that the following actions have 
been accomplished on Model DC-10-10 series airplanes in accordance with 
the requirements of this proposed AD:
    <bullet> Taper-lok attachments and forward trunnion bolts have been 
replaced on 77 U.S.-registered airplanes. Therefore, the future 
economic cost impact of those proposed actions on U.S. operators is now 
only $2,316,320.
    <bullet> Larger attach bolts have been replaced and bolt retainers 
have been installed on 77 U.S.-registered airplanes. Therefore, the 
future economic cost impact of those proposed actions on U.S. operators 
is now only $208,670.
    <bullet> The FAA also has been advised that the following actions 
have been accomplished on Model DC-10-30 and DC-10-40 series airplanes 
in accordance with the requirements of this proposed AD:
    <bullet> Forward trunnion bolts and larger attach bolts have been 
replaced and bolt retainers have been installed on 40 U.S.-registered 
airplanes identified as Groups I and II airplanes in the relevant 
service bulletins. Therefore, the future economic cost impact of those 
proposed actions on U.S. operators is now only $2,291,520.
    <bullet> Forward trunnion bolts have been replaced on 3 U.S.-
registered airplanes identified as Group III airplanes in the relevant 
service bulletins. Therefore, the future economic cost impact of this 
proposed action on U.S. operators is now only $61,080.

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 97-NM-14-AD.

    Applicability: Model DC-10-10, DC-10-30, and DC-10-40 series 
airplanes; certificated in any category; as listed in the following 
McDonnell Douglas service bulletins:
    <bullet> McDonnell Douglas DC-10 Service Bulletin 57-78, 
Revision 1, dated August 26, 1986;
    <bullet> McDonnell Douglas DC-10 Service Bulletin 57-79, 
Revision 1, dated September 21, 1979, as revised by McDonnell 
Douglas DC-10 Service Bulletin Change Notification 57-79, dated 
January 23, 1980; and
    <bullet> McDonnell Douglas DC-10 Service Bulletin 57-82, dated 
February 19, 1980.

    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 request approval for an 
alternative method of compliance in accordance with paragraph (e) 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 ensure that the main landing gear (MLG) separates from the 
wing when it is subjected to unpredictable overloads during abnormal 
operations, and to prevent consequent primary structural damage to 
the airplane, accomplish the following:
    (a) For Model DC-10-10 series airplanes, as listed in McDonnell 
Douglas DC-10 Service Bulletin 57-78, Revision 1, dated August 26, 
1986: Within 5 years after the effective date of this AD, accomplish 
the requirements of paragraphs (a)(1) and (a)(2) of this AD, in 
accordance with the service bulletin.
    (1) Replace 24 TL taper-lok attachments that attach the left and 
right MLG attach fitting assemblies on each wing with heat-treat TLH 
taper-lok attachments in accordance with the service bulletin. And
    (2) Replace each forward trunnion bolt on the left and right MLG 
of each wing with a ``zero margin'' trunnion bolt in accordance with 
the service bulletin.

    Note 2: Replacement of taper-lok attachments and forward 
trunnion bolts accomplished prior to the effective date of this AD 
in accordance with McDonnell Douglas DC-10 Service Bulletin 57-78, 
dated February 19, 1980, is considered acceptable for compliance 
with the requirements of paragraphs (a)(1) and (a)(2) of this AD.

    (b) For Model DC-10-10 series airplanes, as listed in McDonnell 
Douglas DC-10 Service Bulletin 57-79, Revision 1, dated September 
21, 1979, as revised by McDonnell Douglas DC-10 Service Bulletin 
Change Notification 57-79, dated January 23, 1980: Within 5 years 
after the effective date of this AD, replace each 1\1/2\-inch-
diameter bolt and bushing that attach the left and right MLG attach 
fitting and rear spar of each wing with a 1\1/4\-inch-diameter bolt, 
and install bolt retainers, in accordance with the service bulletin 
and service bulletin change notification.

    Note 3: Replacement of 1\1/2\-inch-diameter bolts and 
installation of bolt retainers prior to the effective date of this 
AD in accordance with McDonnell Douglas DC-10 Service Bulletin 57-
79, dated June 5, 1979, are considered acceptable for compliance 
with the requirements of paragraph (b) of this AD.

    (c) For Model DC-10-30 and DC-10-40 series airplanes: Except as 
provided by paragraph (d) of this AD, within 5 years after the 
effective date of this AD, accomplish the requirements of paragraph 
(c)(1) or (c)(2) of this AD, as applicable, in accordance with 
McDonnell Douglas DC-10 Service Bulletin 57-82, dated February 19, 
1980.
    (1) For airplanes identified as Groups I and II in the service 
bulletin: Replace each forward trunnion bolt on the left and right 
MLG of each wing with a ``zero margin'' forward trunnion bolt; 
replace each 1\1/2\-inch-diameter bolt and bushing that attach the 
left and right MLG attach fitting and rear spar of each wing with a 
1\1/4\-inch-diameter bolt, and install bolt retainers, in accordance 
with the service bulletin.
    (2) For airplanes identified as Group III in the service 
bulletin: Replace each forward trunnion bolt on the left and right 
MLG of each wing with a ``zero margin'' trunnion bolt in accordance 
with the service bulletin.
    (d) For Model DC-10-30 and DC-10-40 airplanes: Installation of a 
trunnion bolt having part number (P/N) ARG7558-501 or P/N ARG7558-
507 on the MLG, in accordance with AD 96-03-05, amendment 39-9502, 
constitutes terminating action for the requirement to replace the 
trunnion bolts for that landing gear, as required in paragraph 
(c)(1) or (c)(2) of this AD.

[[Page 3270]]

    (e) 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 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (f) 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 14, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-1427 Filed 1-21-98; 8:45 am]
BILLING CODE 4910-13-U