03-21414. Airworthiness Directives; McDonnell Douglas Model MD-90-30 Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes to revise an existing airworthiness directive (AD), applicable to all McDonnell Douglas Model MD-90-30 airplanes, that currently requires replacing the lanyards on the pressure relief door for the thrust reverser with new, improved lanyards, and doing associated modifications. The actions specified by that AD are intended 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 proposed AD is prompted by the fact that a certain paragraph of the existing AD prohibits installation of certain part numbers of lanyards; the numbers listed in that paragraph correspond to new, improved lanyards that are acceptable for installation. This action would correct these part numbers to prohibit installation of suspect lanyards while allowing installation of the new, improved lanyards. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by October 6, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-169-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. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-169-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Aircraft Group, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024); and Rohr, Inc., 850 Lagoon Drive, Chula Vista, California 91910-2098. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT:

Stephen Kolb, Aerospace Engineer, Propulsion Branch, ANM-140L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone [phone]; fax [phone].

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 action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• 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 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 action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2003-NM-169-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. 2003-NM-169-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On May 27, 2003, the FAA issued AD 2003-11-15, amendment 39-13174 (68 FR 33355, June 4, 2003), applicable to all McDonnell Douglas Model MD-90-30 airplanes. That AD requires replacing the lanyards on the pressure relief door for the thrust reverser with new, improved lanyards, and doing associated modifications. That action was prompted by a report indicating that the lanyards on the pressure relief door for the thrust reversers on the subject airplanes do not meet the certification requirements for strength. The requirements of that AD are intended 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. This condition could result in reduced controllability of the airplane.

Actions Since Issuance of Previous Rule

Paragraph (b) of AD 2003-11-15 prohibits installation of pressure relief door lanyards having certain part numbers. Since the issuance of that AD, the FAA has determined that the part numbers listed in that paragraph are incorrect. The numbers in that paragraph are Illustrated Parts Catalog numbers that correspond to new, improved lanyard assemblies that are acceptable for installation per the requirements of the existing AD. Paragraph (b) should have referred to the part numbers of the pressure relief door lanyards that paragraph (a) of AD 2003-11-15 requires to be replaced.

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 revise AD 2003-11-15 to continue to require replacing the lanyards on the pressure relief door for the thrust reverser with new, improved lanyards, and doing associated modifications. The proposed AD would also prohibit installation of certain pressure relief door lanyards.

Explanation of Additional Change to Existing Requirements

We have revised the heading that precedes paragraph (b) of this AD from “Spares” to “Parts Installation.” We find the heading “Parts Installation” more accurately describes the contents of that paragraph.

Changes to 14 CFR Part 39/Effect on the AD

On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance (AMOCs). Because we have now included this material in part 39, only the office authorized to approve AMOCs is identified in each individual AD. However, for clarity and consistency in this proposed AD, we have retained the language of the existing AD regarding that material.

Change to Labor Rate Estimate

We have reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate.

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. The proposed changes in this action add no additional economic burden. The current costs for this proposed AD are repeated for the convenience of affected operators, as follows:

It takes approximately 8 work hours per airplane to accomplish the actions currently required by AD 2003-11-15, at an average labor rate of $65 per work hour. Required parts are provided at no cost to the operator. Based on these figures, the cost impact of the actions currently required by AD 2003-11-15 is estimated to be $10,920, or $520 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 action, and that no operator would accomplish those actions in the future if this 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 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. Section 39.13 is amended by removing amendment 39-13174 (68 FR 33355, June 4, 2003), and by adding a new airworthiness directive (AD), to read as follows:

McDonnell Douglas: Docket 2003-NM-169-AD. Revises AD 2003-11-15, Amendment 39-13174.

Applicability: All Model MD-90-30 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 MD90-78-048, 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 re-identifying the door with a new part number), modifying the lower track beam (including removing terminals, replacing the aft quick-release pin with a new pin, and re-identifying 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 MD90-78-048, dated February 15, 2001, refers to International Aero Engines Service Bulletin V2500-NAC-78-0184, dated February 16, 2001, for instructions on replacing the lanyards on the pressure relief door for the thrust reverser.

Parts Installation

(b) After the effective date of this AD, no person may install a lanyard having part number (S700M1392A170) or (S700M1392A161) 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 August 15, 2003.

Kyle L. Olsen,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.