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CFR Citation: 14 CFR Part 39

Docket ID: [Docket No. 2001-NM-125-AD]

RIN ID: RIN 2120-AA64

NOTICE: PROPOSED RULES

ACTION: Airworthiness directives:

DOCUMENT ACTION: Notice of proposed rulemaking (NPRM).

SUBJECT CATEGORY: Airworthiness Directives; McDonnell Douglas Model MD-90-30 Airplanes

DATES: Comments must be received by April 14, 2003.

DOCUMENT SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all McDonnell Douglas Model MD90 30 airplanes. This proposal would require replacing the lanyards on the pressure relief door for the thrust reverser with new, improved lanyards, and doing associated modifications. This action is necessary to ensure that the lanyards on the pressure relief door have adequate strength. Lanyards of inadequate strength could allow the pressure relief door to detach from the thrust reverser in the event that an engine bleed air duct bursts, which could result in the detached door striking and damaging the horizontal stabilizer, and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

SUMMARY: McDonnell Douglas,

SUPPLEMENTAL INFORMATION

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 action may be changed in light of the comments received.

Submit comments using the following format:
[sbull] Organize comments issuebyissue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
[sbull] For each issue, state what specific change to the proposed AD is being requested.
[sbull] Include justification (e.g., reasons or data) for each request.

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 FAApublic 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 action must submit a selfaddressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 2001NM125AD.'' 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, ANM114, Attention: Rules Docket No. 2001NM125AD, 1601 Lind Avenue, SW., Renton, Washington 980554056.

Discussion

The FAA has received a report indicating that, on all McDonnell Douglas Model MD9030 airplanes, the lanyards on the pressure relief door for the thrust reversers do not meet the certification requirements for strength. Lanyards of inadequate strength could allow the pressure relief door to detach from the thrust reverser in the event that an engine bleed air duct bursts, which could result in the detached door striking and damaging the horizontal stabilizer. Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin MD9078 048, including Evaluation Form, dated February 15, 2001, which describes procedures for replacing the lanyards on the pressure relief door for the thrust reverser with new, improved lanyards, and doing associated modifications.

Boeing Service Bulletin MD9078048 refers to International Aero Engines Service Bulletin V2500NAC780184, dated February 16, 2001, as the appropriate source of service information for replacing the door lanyards and doing the associated modifications. The procedures in that service bulletin include removing the pressure relief door, replacing the door lanyard assemblies with new, improved assemblies, modifying the pressure relief door (including replacing existing brackets with new brackets and reidentifying the door with a new part number), modifying the lower track beam (including removing terminals, replacing the aft quickrelease pin with a new pin, and reidentifying the beam with a new part number), modifying the heat shield on the lanyard assembly attach lugs, and reinstalling the pressure relief door.

Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe condition. 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 design, the proposed AD would require accomplishment of the actions specified in the service bulletins described previously, except as discussed below. Clarification of Applicability

Boeing Service Bulletin MD9078048 specifies an effectivity of Model MD9030 airplanes ``equipped with V2500D5 thrust reversers prior to serial number 0701001.'' All Model MD9030 airplanes are equipped with the subject thrust reversers; thus, all Model MD9030 airplanes are subject to this proposed AD.

Differences Between Proposed AD and Service Information

The service bulletins recommend replacing the door lanyards and doing associated modifications at the next scheduled maintenance visit when manpower, materials, and facilities are available. The FAA has determined that such a nonspecific compliance time would not ensure that the identified unsafe condition is addressed in a timely manner. In developing an appropriate compliance time for this AD, the FAA considered not only the manufacturer's recommendation, but also the degree of urgency associated with addressing the subject unsafe condition, and the time necessary to perform the proposed actions. In light of all of these factors, the FAA finds that a compliance time of 18 months after the effective date of the AD for completing the proposed actions is warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Cost Impact

There are approximately 110 airplanes of the affected design in the worldwide fleet. The FAA estimates that 21 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 8 work hours per airplane to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Required parts would be provided at no cost to the operator. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $10,080, or $480 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD
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action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein would not have a substantial direct effect 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, it is determined that this proposal would not have federalism implications under Executive Order 13132.

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 39AIRWORTHINESS 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 2001NM125AD.

Applicability: All Model MD9030 airplanes; certificated in any category.

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 (c) 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 lanyards on the pressure relief door for the thrust reverser have adequate strength so that the door will not detach from the thrust reverser in the event that an engine bleed air duct bursts, which could result in the door striking and damaging the horizontal stabilizer, accomplish the following: Replacement of Lanyards on the Thrust Reverser Pressure Relief Door (a) Within 18 months after the effective date of the AD, replace the lanyards on the pressure relief door for the thrust reverser with new, improved lanyards, and accomplish associated
modifications, per the Accomplishment Instructions of Boeing Service Bulletin MD9078048, excluding Evaluation Form, dated February 15, 2001. The associated modifications include removing the pressure relief door, modifying the pressure relief door (including replacing existing brackets with new brackets and reidentifying the door with a new part number), modifying the lower track beam (including removing terminals, replacing the aft quickrelease pin with a new pin, and reidentifying the beam with a new part number), modifying the heat shield on the lanyard assembly attach lugs, and re installing the pressure relief door.

Note 2: Boeing Service Bulletin MD9078048, excluding Evaluation Form, dated February 15, 2001, refers to International Aero Engines Service Bulletin V2500NAC780184, dated February 16, 2001, for instructions on replacing the lanyards on the pressure relief door for the thrust reverser.
Spares
(b) After the effective date of this AD, no person may install a lanyard having part number (01250) or (01255) on the pressure relief door for the thrust reverser on any airplane.
Alternative Methods of Compliance
(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), FAA. 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO.
Special Flight Permits
(d) 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 February 20, 2003. Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 034587 Filed 22603; 8:45 am]
BILLING CODE 491013P

FOR FURTHER INFORMATION CONTACT William S. Bond, Aerospace Engineer, Propulsion Branch, ANM140L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 907124137; telephone (562) 6275253; fax (562) 6275210.