Airworthiness Directives; McDonnell Douglas Model DC-10-10, -10F, -15, -30, -30F, -40, and -40F Series Airplanes, and Model KC-10A (Military) Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-134-AD; Amendment 39-8828; AD 94-04-08]

Airworthiness Directives; McDonnell Douglas Model DC-10-10, -10F,

-15, -30, -30F, -40, and -40F Series Airplanes, and Model KC-10A

(Military) Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD),

applicable to certain McDonnell Douglas Model DC-10 series airplanes

and Model KC-10A (military) airplanes, that requires inspections to

detect cracking in the No. 2 engine pylon lower spar forward mount and

thrust link fitting attach bolts, replacement of cracked bolts, and the

eventual replacement of all bolts made of H-11 material with bolts made

of Inconel. This amendment is prompted by reports of failures of these

attach bolts due to stress corrosion. The actions specified by this AD

are intended to prevent failure of the attach bolts, which could reduce

the fail-safe capability of the attachment assembly.

DATES: Effective March 24, 1994.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of March 24, 1994.

ADDRESSES: The service information referenced in this AD 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, Mail Code 2-98. This information may

be examined at the Federal Aviation Administration (FAA), Transport

Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton,

Washington; or at the FAA, Transport Airplane Directorate, Los Angeles

Aircraft Certification Office, 3229 East Spring Street, Long Beach,

California; or at the Office of the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: John Cecil, Aerospace Engineer,

Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los

Angeles Aircraft Certification Office, 3229 East Spring Street, Long

Beach, California 90806-2425; telephone (310) 988-5322; fax (310) 988-

5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations to include an airworthiness directive (AD) that is

applicable to certain McDonnell Douglas Model DC-10 series airplanes

and Model KC-10A (military) airplanes was published in the Federal

Register on October 26, 1993 (58 FR 57568). That action proposed to

require inspections to detect cracking in the No. 2 engine pylon lower

spar forward mount and thrust link fitting attach bolts, replacement of

cracked bolts, and the eventual replacement of all bolts made of H-11

material with bolts made of Inconel.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the comments received.

One commenter supports the proposal.

Two commenters request that the proposed compliance time for the

inspections be extended to coincide with normally scheduled maintenance

intervals. These commenters suggest that if the compliance times were

extended to 24 months, the confusion and expense of special scheduling

could be avoided. The FAA does not concur. In developing the proposed

compliance time, the FAA primarily considered analyses of the mode of

failure of the subject bolts due to stress corrosion, as well as the

service history of the fleet. Based on this data and the safety

implications presented by loss of fail-safe capability of the

attachment assembly should the bolts fail, the FAA has determined that

the proposed compliance times of 12 months for the initial inspection

and 18 months for the repetitive inspection interval are both

appropriate and warranted. Further, the FAA took into account the

average utilization rate of the affected fleet, the practical aspects

of an orderly inspection of the fleet during regular maintenance

periods, and the availability of required replacement parts. The

compliance times as proposed should allow ample time for the

inspections to be conducted concurrently with scheduled maintenance,

thereby minimizing the costs associated with special airplane

scheduling. In light of all of these factors, the FAA considers that

any extension of the compliance intervals to be unacceptable.

After careful review of the available data, including the comments

noted above, the FAA has determined that air safety and the public

interest require the adoption of the rule as proposed.

There are approximately 354 Model DC-10 series airplanes and Model

KC-10A airplanes of the affected design in the worldwide fleet. The FAA

estimates that 206 airplanes of U.S. registry will be affected by this

AD

The inspections required by this AD will 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

inspections requirements of this AD on U.S. operators is estimated to

be $90,640, or $440 per airplane, per inspection cycle.

The replacement actions required by this AD will take approximately

8 work hours per airplane to accomplish, at an average labor rate of

$55 per work hour. Required parts will cost approximately $2,700 per

airplane. Based on these figures, the total cost impact of the

replacement actions of this AD on U.S. operators is estimated to be

$646,840, or $3,140 per airplane.

The total cost impact figures discussed above are based on

assumptions that no operator has yet accomplished any of the

requirements of this AD action, and that no operator would accomplish

those actions in the future if this AD were not adopted.

The regulations adopted herein will 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 final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is

not a ``significant regulatory action'' under Executive Order 12866;

(2) is not a ``significant rule'' under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action

and it is contained in the Rules Docket. A copy of it may be obtained

from the Rules Docket at the location provided under the caption

ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends 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:

94-04-08 McDonnell Douglas: Amendment 39-8828. Docket 93-NM-134-AD.

Applicability: Model DC-10-10, -10F, -15, -30, -30F, -40, and -

40F series airplanes, and KC-10A (military) airplanes; having

fuselage numbers 1 though 374 inclusive; certificated in any

category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent failure of the No. 2 engine pylon lower spar forward

mount and thrust link fitting attach bolts, which could reduce the

fail-safe capability of the attachment assembly, accomplish the

following:

(a) Within 12 months after the effective date of this AD,

perform an ultrasonic inspection to detect cracking of the No. 2

engine pylon lower spar forward mount and thrust link fitting attach

bolts made of H-11 material, in accordance with McDonnell Douglas

DC-10 Service Bulletin 54-100, Revision 1, dated September 17, 1993.

(1) If no cracking is detected, repeat the ultrasonic inspection

thereafter at intervals not to exceed 18 months, until the

requirements of paragraph (b) of this AD are accomplished.

(2) If cracking is detected during any inspection required by

this paragraph, prior to further flight, accomplish either paragraph

(a)(2)(i) or (a)(2)(ii):

(i) Replace the cracked bolt with a new bolt made of H-11

material and continue to inspect in accordance with this paragraph

at intervals not to exceed 18 months, until the requirements of

paragraph (b) of this AD are accomplished. Or

(ii) Replace the cracked bolt with a bolt made of Inconel, and

replace the associated hardware, in accordance with the service

bulletin. Such replacement constitutes terminating action for

required ultrasonic inspections for that bolt.

(b) Within 5 years after the effective date of this AD, replace

all No.2 engine pylon lower spar forward mount and thrust link

fitting attach bolts made of H-11 material, with bolts made of

Inconel, and replace the associated hardware, in accordance with

McDonnell Douglas DC-10 Service Bulletin 54-100, Revision 1, dated

September 17, 1993. Such replacement constitutes terminating action

for the inspections required by 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). 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.

(d) 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.

(e) The inspections and replacement shall be done in accordance

with McDonnell Douglas DC-10 Service Bulletin 54-100, Revision 1,

dated September 17, 1993. This incorporation by reference was

approved by the Director of the Federal Register in accordance with

5 U.S.C. 552(a) and 1 CFR part 51. Copies 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, Mail Code 2-98. Copies may be

inspected at the FAA, Transport Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane

Directorate, Los Angeles Aircraft Certification Office, 3229 East

Spring Street, Long Beach, California; or at the Office of the

Federal Register, 800 North Capitol Street, NW., suite 700,

Washington, DC.

(f) This amendment becomes effective on March 24, 1994.

Issued in Renton, Washington, on February 14, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-3754 Filed 2-18-94; 8:45 am]

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