[Federal Register Volume 59, Number 61 (Wednesday, March 30, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-7493]


[[Page Unknown]]

[Federal Register: March 30, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-221-AD]

 

Airworthiness Directives; McDonnell Douglas Model DC-10-10, -15, 
-30, and -40 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 certain McDonnell Douglas Model 
DC-10-10, -15, -30, and -40 series airplanes and KC-10A (military) 
airplanes. This proposal would require inspections to detect fatigue-
related cracking in certain areas of the horizontal stabilizer; and 
repair of cracked parts. This proposal would also require installation 
of terminating modifications, which, when accomplished, would eliminate 
the repetitive inspections. This proposal is prompted by reports of 
fatigue-related cracks found on the horizontal stabilizer. The actions 
specified by the proposed AD are intended to prevent loss of the load 
carrying and fail safe capability of the horizontal stabilizer, damage 
to the adjacent structure, and subsequent reduced structural integrity 
of the airplane.

DATES: Comments must be received by May 23, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 93-NM-221-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 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, 
CA 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, Transport Airplane Directorate, 
Los Angeles Aircraft Certification Office (ACO), 3229 East Spring 
Street, Long Beach, California.

FOR FURTHER INFORMATION CONTACT: Wahib Mina, Aerospace Engineer, 
Airframe Branch, ANM-121L, FAA, Transport Airplane Directorate, Los 
Angeles ACO, 3229 East Spring Street, Long Beach, California 90806-
2425; telephone (310) 988-5324; 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 93-NM-221-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. 93-NM-221-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The manufacturer reports that fatigue-related cracks have been 
found on the horizontal stabilizer on several McDonnell Douglas Model 
DC-10-10, -15, -30, and -40 series airplanes and KC-10A (military) 
airplanes. One operator reported two instances of fatigue-related 
cracks on the forward spar upper cap near the closing rib on the 
horizontal stabilizer on airplanes that had accumulated approximately 
22,643 landings. Two operators reported three cases of fatigue-related 
cracks in the forward upper skin panel in the outboard section of the 
horizontal stabilizer on airplanes that had accumulated between 17,339 
and 19,627 total landings. This skin panel is located immediately aft 
of (and attaches to) the forward spar upper cap on the horizontal 
stabilizer. Investigation by the manufacturer has revealed that these 
cracks are the result of fatigue-related stress. Fatigue-related cracks 
in the outboard section of the horizontal stabilizer, if not detected 
and corrected in a timely manner, could result in loss of the load 
carrying and fail safe capability of the forward spar upper caps and 
the forward upper skin panels, damage to the adjacent structure, and 
subsequent reduced structural integrity of the airplane.
    The FAA has reviewed and approved McDonnell Douglas DC-10 Service 
Bulletin 55-24, dated October 25, 1993, that describes procedures for 
repetitive eddy current inspections to detect fatigue-related cracking 
in the forward spar upper cap of the horizontal stabilizer. The service 
bulletin also describes procedures for accomplishment of a preventative 
modification for the forward spar upper cap. The preventative 
modification entails rework of the fastener holes of the forward spar 
upper cap. Incorporation of this preventative modification would 
eliminate the need for repetitive inspections of the forward spar upper 
cap. Accomplishment of this preventative modification will restore the 
structural integrity of the forward spar upper cap.
    The FAA has also reviewed and approved McDonnell Douglas DC-10 
Service Bulletin 55-25, dated October 25, 1993, that describes 
procedures for performing repetitive eddy current inspections to detect 
fatigue-related cracking in the forward upper skin panel of the 
horizontal stabilizer. The service bulletin also describes procedures 
for accomplishment of a preventative modification for the forward upper 
skin panel. The preventative modification entails rework of the 
fastener holes of the forward upper skin panel. Incorporation of this 
preventative modification would eliminate the need for repetitive 
inspections of the forward upper skin panel. Accomplishment of this 
preventative modification will restore the structural integrity of the 
forward upper skin panel.
    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 eddy current inspections to detect 
fatigue-related cracking on the forward spar upper caps and the forward 
upper skin panels in the outboard section of the horizontal stabilizer. 
The proposed AD would also require that cracked parts be repaired in 
accordance with a method approved by the FAA. This proposal would also 
require accomplishment of preventative modifications, which, when 
accomplished, would terminate the repetitive inspections of the forward 
spar upper caps and the forward upper skin panels. The inspections and 
modifications would be required to be accomplished in accordance with 
the service bulletins described previously.
    There are approximately 427 Model DC-10-10, -15, -30, and -40 
series airplanes and KC-10A (military) airplanes of the affected design 
in the worldwide fleet. The FAA estimates that 241 airplanes of U.S. 
registry would be affected by this proposed AD.
    The accomplishment of the proposed inspection would take 
approximately 3 work hours per airplane, at an average labor charge of 
$55 per work hour. Based on these figures, the total cost impact of the 
proposed inspection actions on U.S. operators is estimated to be 
$39,765, or $165 per airplane, per inspection cycle.
    The accomplishment of the proposed modification of the forward spar 
upper cap would take approximately 248 work hours per airplane. 
Likewise, the accomplishment of the proposed modification of the 
forward upper skin panel would take approximately 248 work hours per 
airplane. The average labor rate is $55 per work hour. Required parts 
would cost approximately $10,600 per airplane. Based on these figures, 
the total cost impact of the proposed modification actions AD on U.S. 
operators is estimated to be $9,129,080, or $37,880 per airplane.
    The FAA recognizes that the proposed modifications would require a 
large number of work hours to accomplish. However, the 5-year 
compliance time specified in paragraph (d) of this proposed AD should 
allow ample time for the modifications to be accomplished 
coincidentally with scheduled major airplane inspection and maintenance 
activities, thereby minimizing the costs associated with special 
airplane scheduling.
    The total cost impact figures discussed above are 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 14 
CFR part 39 of the Federal Aviation Regulations 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 adding the following new 
airworthiness directive:

McDonnell Douglas: Docket 93-NM-221-AD.

    Applicability: Model DC-10-10, -15, -30, and -40 series 
airplanes and KC-10A (military) airplanes; as listed in McDonnell 
Douglas DC-10 Service Bulletins 55-24 and 55-25, both dated October 
25, 1993; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent reduced structural integrity of the airplane, 
accomplish the following:
    (a) For Model DC-10-10 and -15 series airplanes: Prior to the 
accumulation of 18,000 total landings, or within 90 days after the 
effective date of this AD, whichever occurs later, unless previously 
accomplished within the last 4,500 landings, perform an eddy current 
inspection to detect fatigue-related cracking of the forward spar 
upper caps on the horizontal stabilizer, in accordance with 
McDonnell Douglas Service Bulletin 55-24, dated October 25, 1993.
    (1) If any crack is detected, prior to further flight, repair 
the crack in accordance with a method approved by the Manager, Los 
Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate. After repair, repeat the inspection thereafter at 
intervals not to exceed 4,500 landings in accordance with the 
service bulletin.
    (2) If no crack is detected, repeat the inspection thereafter at 
intervals not to exceed 4,500 landings in accordance with the 
service bulletin.
    (b) For Model DC-10-10 and -15 series airplanes: Prior to the 
accumulation of 10,000 total landings, or within 120 days after the 
effective date of this AD, whichever occurs later, unless previously 
accomplished within the last 4,500 landings, perform an eddy current 
inspection to detect fatigue-related cracking of the forward upper 
skin panel of the horizontal stabilizer, in accordance with 
McDonnell Douglas Service Bulletin 55-25, dated October 25, 1993.
    (1) If any crack is detected, prior to further flight, repair 
the crack in accordance with a method approved by the Manager, Los 
Angeles ACO, FAA, Transport Airplane Directorate. After repair, 
repeat the inspection thereafter at intervals not to exceed 4,500 
landings in accordance with the service bulletin.
    (2) If no crack is detected, repeat the inspection thereafter at 
intervals not to exceed 4,500 landings in accordance with the 
service bulletin.
    (c) For Model DC-10-30 and -40 series airplanes: Prior to the 
accumulation of 17,500 total landings, or within 120 days after the 
effective date of this AD, whichever occurs later, unless previously 
accomplished within the last 4,500 landings, perform an eddy current 
inspection to detect fatigue-related cracking of the forward upper 
skin panel of the horizontal stabilizer, in accordance with 
McDonnell Douglas Service Bulletin 55-25, dated October 25, 1993.
    (1) If any crack is detected, prior to further flight, repair 
the crack in accordance with a method approved by the Manager, Los 
Angeles ACO, FAA, Transport Airplane Directorate. After repair, 
repeat the inspection thereafter at intervals not to exceed 4,500 
landings in accordance with the service bulletin.
    (2) If no crack is detected, repeat the inspection thereafter at 
intervals not to exceed 4,500 landings in accordance with the 
service bulletin.
    (d) For all airplanes: Within 5 years after the effective date 
of this AD, install the preventative modifications for the forward 
spar upper cap on the horizontal stabilizer, in accordance with 
McDonnell Douglas Service Bulletin 55-24, dated October 25, 1993; 
and for the forward upper skin panel on the horizontal stabilizer, 
in accordance with McDonnell Douglas Service Bulletin 55-25, dated 
October 25, 1993. Accomplishment of these preventative modifications 
in accordance with these service bulletins constitutes terminating 
action for the repetitive inspections required by this AD.
    (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 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.

    (f) Special flight permits may be issued in accordance with 
Federal Aviation Regulations (FAR) 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 March 24, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-7493 Filed 3-29-94; 8:45 am]
BILLING CODE 4910-13-U