Airworthiness Directives; McDonnell Douglas Model DC-10-30 and - 30F Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-NM-62-AD]

Airworthiness Directives; McDonnell Douglas Model DC-10-30 and -

30F 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-10-30 and -30F series airplanes. This proposal would require

replacement of cargo door latch spool fitting attach bolts fabricated

from H-11 steel with Inconel bolts. This proposal is prompted by a

report of a broken latch spool fitting attach bolt found on a cargo

door on a Model DC-9 series freighter airplane. The actions specified

by the proposed AD are intended to prevent inadvertent opening of a

cargo door while the airplane is in flight, and subsequent loss of

pressurization and reduced controllability of the airplane.

DATES: Comments must be received by October 10, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 94-NM-62-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. LS1, 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, 3229 East Spring Street,

Long Beach, California.

FOR FURTHER INFORMATION CONTACT: Maureen Moreland, Aerospace Engineer,

Airframe Branch, ANM-121L, FAA, Transport Airplane Directorate, Los

Angeles Aircraft Certification Office, 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-62-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-62-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

On April 26, 1991, the FAA issued AD 91-10-07, amendment 39-6991

(56 FR 21268), applicable to McDonnell Douglas Model DC-10 series

airplanes, manufacturer's fuselage numbers 1 through 379 inclusive.

That AD requires inspection of the cargo door latch spool fitting

attach bolts fabricated from H-11 steel and replacement of those bolts

with Inconel bolts. That action was prompted by a report of a broken

latch spool fitting attach bolt found on a cargo door on a Model DC-9

series freighter airplane. Broken bolts could jeopardize the integrity

of the door locking capability. The requirements of AD 91-10-07 are

intended to prevent loss of pressurization and reduced controllability

of the aircraft due to inadvertent opening of a cargo door while the

airplane is in flight.

Since the issuance of AD 91-10-07, the manufacturer has informed

the FAA that cargo door latch spool fitting attach bolts fabricated

from H-11 steel also were installed on 8 additional Model DC-10

production airplanes. Therefore, these 8 airplanes are subject to the

same unsafe condition as addressed by that AD.

The FAA has reviewed and approved McDonnell Douglas DC-10 Alert

Service Bulletin A52-212, Revision 4, dated November 3, 1993, that

describes procedures for replacement of the H-11 cargo door latch spool

fitting attach bolts and associated hardware with Inconel bolts and

associated hardware. Replacing the existing H-11 material bolts and

associated hardware with new bolts made from Inconel material and

associated hardware will eliminate the possibility of stress corrosion

failures.

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 replacement of H-11 cargo door latch spool

fitting attach bolts with Inconel bolts on 8 Model DC-10-30 and -30F

series airplanes. The actions would be required to be accomplished in

accordance with the alert service bulletin described previously.

Note: The FAA's normal policy is that, when an AD requires a

substantive change, such as a change in its applicability, the

``old'' AD is superseded by being removed from the system and a new

AD added. In the case of this AD action, the FAA normally would have

proposed superseding AD 91-10-07 to expand its applicability to

include the 8 additional airplanes. However, in reconsideration of

the entire fleet size that would be affected by such a supersedure

action, and the consequent workload associated with revising

maintenance record entries, the FAA has determined that a less

burdensome approach is to issue a separate AD applicable only to the

8 airplanes. This AD does not supersede AD 91-10-07; airplanes

listed in the applicability of AD 91-10-07 continue to be required

to comply with the requirements of that AD. This proposed AD is a

separate AD action, and would be applicable only to eight airplanes

listed in the alert service bulletin described above.

There are 8 Model DC-10 series airplanes of the affected design in

the worldwide fleet. The FAA estimates that 6 airplanes of U.S.

registry would be affected by this proposed AD, that it would take

approximately 86 work hours per airplane to accomplish the proposed

actions, and that the average labor rate is $55 per work hour. Required

parts would cost approximately $10,682 per airplane. Based on these

figures, the total cost impact of the proposed AD on U.S. operators is

estimated to be $92,472, or $15,412 per airplane.

The total 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.

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 adding the following new

airworthiness directive:

McDonnell Douglas: 94-NM-62-AD.

Applicability: Model DC-10-30 and -30F series airplanes having

fuselage numbers 409, 412, 416, 419, 422, 433, 434, and 435;

certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent inadvertent opening of a cargo door while the

airplane is in flight, and subsequent loss of pressurization and

reduced controllability of the airplane, accomplish the following:

(a) Within 2 years after the effective date of this AD, replace

all H-11 cargo door latch spool fitting attach bolts with Inconel

bolts, in accordance with McDonnell Douglas DC-10 Alert Service

Bulletin A52-212, Revision 4, dated November 3, 1993.

(b) 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.

(c) 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 15, 1994.

S.R. Miller,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-17765 Filed 7-20-94; 8:45 am]

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