Airworthiness Directives; McDonnell Douglas Model MD-90-30 Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all McDonnell Douglas Model MD-90-30 airplanes. This proposed AD would require replacing existing dual anti-skid control manifolds (DACM) with new, improved or reworked and reidentified DACMs; inspecting the inlet filters and other components of the DACMs for damage; replacing any damaged DACM components with new or serviceable components; and flushing/cleaning the braking system prior to replacing the inlet filters. This proposed AD is prompted by reports of multiple incidents of blown tires on landing while using maximum autobrake. We are proposing this AD to prevent metallic fibers from the first stage filter of the servo valves inside the DACM from becoming lodged in the first stage nozzle of the servo valve, which could lead to tire failure during high speed/high energy braking and possible subsequent runway departure.

DATES:

We must receive comments on this proposed AD by January 31, 2005.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590.
• By fax: (202) 493-2251.
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024).

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2004-19867; the directorate identifier for this docket is 2004-NM-58-AD.

FOR FURTHER INFORMATION CONTACT:

Technical information: Cheyenne Del Carmen, Aerospace Engineer, Cabin Safety, Mechanical & Environmental Branch, ANM-150L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5338; fax (562) 627-5210.

Plain language information: Marcia Walters, marcia.walters@faa.gov.

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

The FAA has implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, new AD actions are posted on DMS and assigned a docket number. We track each action and assign a corresponding directorate identifier. The DMS AD docket number is in the form “Docket No. FAA-2004-99999.” The Transport Airplane Directorate identifier is in the form “Directorate Identifier 2004-NM-999-AD.” Each DMS AD docket also lists the directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes.

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2004-19867; Directorate Identifier 2004-NM-58-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments submitted by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the Docket

You can examine the AD docket in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

Discussion

We have received reports of multiple incidents of blown tires on landing while using maximum autobrake on McDonnell Douglas Model MD-90-30 airplanes. The reports indicate that, due to filter contamination, structural damage, or excessive wear, metallic fibers from the first stage filter of the servo valves inside the dual anti-skid control manifold (DACM) are becoming lodged in the first stage nozzle of the servo valve. This condition, if not corrected, could result in tire failure during high speed/high energy braking and possible subsequent runway departure.

Relevant Service Information

We have reviewed McDonnell Douglas Service Bulletin MD90-32-056, dated October 7, 2003. The service bulletin describes procedures for replacing existing DACMs with new, improved or reworked and reidentified DACMs.

Service Bulletin MD90-32-056 specifies prior or concurrent accomplishment of McDonnell Douglas Service Bulletin MD90-32-043, Revision 01, dated November 9, 2000.

We have reviewed Service Bulletin MD90-32-043, which describes procedures for replacing the metered pressure inlet filters of the DACM with new filters. Service Bulletin MD90-32-043 also describes procedures for inspecting the inlet filters and other components of the DACM for damage, and flushing/cleaning the braking system prior to replacing the inlet filters.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

Service Bulletin MD90-32-056 refers to Aircraft Braking Systems Corporation (ABSC) Service Bulletin MD-90 6006079-32-02, dated August 7, 2003, as an additional source of service information for reworking and reidentifying DACMs.

Service Bulletin MD90-32-043 refers to ABSC Service Bulletin MD90-32-12, dated January 12, 2000, as an additional source of service information for inspecting components of the DACM for cleanliness, structural damage, or excessive wear, and replacing any damaged components with new or serviceable components.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. Therefore, we are proposing this AD, which would require replacing DACMs with new, improved or reworked and reidentified DACMs; inspecting the inlet filters and other components of the DACMs for damage; replacing any damaged DACM components with new or serviceable components; and flushing/cleaning the braking system prior to replacing the inlet filters; in accordance with Service Bulletin MD90-32-056, dated October 7, 2003, and Service Bulletin MD90-32-043, Revision 01, dated November 9, 2000; except as discussed under “Differences Between Service Information and the Proposed AD.”

Differences Between Service Information and the Proposed AD

Although Service Bulletin MD90-32-056 recommends that “operators do this service bulletin at a scheduled maintenance period when manpower, materials, and facilities are available,” we have determined that this imprecise compliance time would not address the identified unsafe condition in a timely manner. In developing an appropriate compliance time for this proposed AD, we considered not only the manufacturer's recommendation, but also the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the modifications. In light of all of these factors, we find a compliance time of 18 months for completing the required actions to be warranted, in that it represents an appropriate interval of time for affected airplanes to continue to operate without compromising safety.

Although Service Bulletin MD90-32-043, Revision 01, specifies inspecting the DACM assembly inlet filters for damage, this proposed AD would require a detailed inspection of the filters to eliminate any possible confusion about the proper type of inspection. Note 3 of this proposed AD includes a definition of this type of inspection.

Costs of Compliance

This proposed AD would affect about 115 airplanes worldwide and 24 airplanes of U.S. registry. The proposed actions would take about 8 work hours per airplane, at an average labor rate of $65 per work hour. Required parts would cost between $8,000 and $240,780 per airplane. Based on these figures, the estimated cost of the proposed AD for U.S. operators is between $204,480 and $5,791,200, or between $8,520 and $241,300 per airplane.

Regulatory Authority and Findings

This rulemaking is promulgated under the authority described in subtitle VII, part A, subpart III, section 44701, General requirements. Under that section, the FAA is charged with prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety and air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this AD.

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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.