AD 2004-18-04

Effective September 20, 2004.

We must receive comments on this AD by November 2, 2004.

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

• DOT Docket Web site: Go to http://dms.dot.gov and follow 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.

• 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 trough Friday, except Federal holidays.

You can examine this information at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

• You can examine the contents of this AD docket on the Internet at http://dms.dot.gov, or 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.

Technical information: Jim Webre, Flight Test Pilot, Flight Test Branch, ANM-160L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5364; fax (562) 627-5210.

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

We have received a report of two violations of the selected flight control panel (FCP) altitude during flight management system (FMS) profile (PROF) descents on McDonnell Douglas Model MD-11 airplanes. Investigation by the airplane and avionics manufacturers revealed that under certain conditions during an FMS PROF descent, the FMS will allow an airplane to descend below the selected FCP altitude or FMS-constrained altitude or both. In addition, the FMS will not command the autopilot or flight director to level off at the next altitude constraint, if a specific series of events occur and the airspeed of the airplane is within the overspeed detection window during an FMS descent. Under certain conditions during the FMS PROF descent, the uncommanded descent of the airplane below the selected level-off altitude, if not corrected, could result in an unacceptable reduction in the separation between the airplane and nearby air traffic or terrain.

The FMS software on Model MD-10-10F, MD-10-30F, MD-11F, and 717-200 airplanes is identical to that on the affected Model MD-11 airplanes. Therefore, all of these models may be subject to the same unsafe condition.

The unsafe condition described previously is likely to exist or develop on other airplanes of the same type design, which use the same FMS software. Therefore, we are issuing this AD to prevent, under certain conditions during the FMS PROF descent, the uncommanded descent of an airplane below the selected level-off altitude, which could result in reducing the separation between the airplane and nearby air traffic or terrain. This AD requires a revision to the Limitations section of the Airplane Flight Manual (AFM) to prohibit use of the FMS PROF mode for descent and/or approach operations unless certain conditions are met.

This is considered to be interim action. The manufacturer has advised that it currently is developing a software modification that will address the unsafe condition addressed by this AD. Once this modification is developed, approved, and available, the FAA may consider additional rulemaking.

An unsafe condition exists that requires the immediate adoption of this AD; therefore, providing notice and opportunity for public comment before the AD is issued is impracticable, and good cause exists to make this AD effective in less than 30 days.

This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2004-19017; Directorate Identifier 2004-NM-144-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the 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 AD. Using the search function of our docket 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 can review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can 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 with you. You can get more information about plain language at http://www/faa.gov/language and http://www.plainlanguage.gov.

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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 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 AD. See the ADDRESSES section for a location to examine the regulatory evaluation.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

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

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):