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Proposed Rule

Airworthiness Directives; McDonnell Douglas Model MD-11 and -11F Airplanes Equipped With Collins LRA-900 Radio Altimeters

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to McDonnell Douglas Model MD-11 series airplanes equipped with certain Collins LRA-900 radio altimeters. That AD currently requires a revision to the Airplane Flight Manual to prohibit autopilot coupled autoland operations in certain conditions; or, for certain airplanes, replacement of certain Collins LRA-900 radio altimeters with Collins LRA-700 radio altimeters. This action would require a one-time inspection to determine whether a Collins LRA-900 radio altimeter receiver/transmitter with a certain part number is installed. This action would also require modification of such a radio altimeter. This proposal is prompted by reports indicating that a fault in Collins LRA-900 radio altimeters having a certain part number could result in an incorrect and unbounded output of radio altitude to other airplanes. The actions specified by the proposed AD are intended to prevent an undetected anomalous radio altitude signal that is passed along to the flare control law of the flight control computer, which could cause the airplane to flare too high or too low during landing, and consequently result in a hard landing.

DATES:

Comments must be received by July 1, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-406-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 (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2000-NM-406-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 for Windows 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). 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.

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FOR FURTHER INFORMATION CONTACT:

Brett Portwood, Aerospace Engineer, Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5350; fax (562) 627-5210.

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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 2000-NM-406-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, Start Printed Page 34638ANM-114, Attention: Rules Docket No. 2000-NM-406-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On November 25, 1998, the FAA issued AD 98-24-51, amendment 39-10929 (63 FR 66422, December 2, 1998), applicable to McDonnell Douglas Model MD-11 series airplanes equipped with Collins LRA-900 radio altimeters having certain part numbers. The AD requires a revision to the Airplane Flight Manual to prohibit autopilot coupled autoland operations in certain conditions; or, for certain airplanes, replacement of Collins LRA-900 radio altimeters having certain part numbers with Collins LRA-700 radio altimeters. That action was prompted by a report that a fault in those radio altimeters could result in an incorrect and unbounded output of radio altitude to other airplane systems. The requirements of that AD are intended to prevent an undetected anomalous radio altitude signal that is passed along to the flare control law of the flight control computer, which could cause the airplane to flare too high or too low during landing, and consequently result in a hard landing.

Actions Since Issuance of Previous AD

When AD 98-24-51 was issued, it was considered to be interim action until final action was identified, at which time the FAA might consider further rulemaking. Since the issuance of that AD, Rockwell Avionics/ Collins, the manufacturer of the LRA-900 radio altimeter transmitter/receiver, has developed a modification that will enable the radio altimeter to process negative altitude correctly. As discussed below, the manufacturer has issued a service bulletin which describes that modification.

Explanation of Relevant Service Information

The existing AD, AD 98-24-51, is applicable to Model MD-11 series airplanes, equipped with Collins LRA-900 radio altimeters, having part number 822-0334-002, 822-0334-020, or 822-0334-220.” However, Collins LRA-900 radio altimeters having part number 822-0334-002 or 822-0334-020 have not been approved for installation on Model MD-11 or “11F airplanes. Therefore, the proposed AD is applicable only to those MD-11 or “11F airplanes which are equipped with Collins LRA-900 radio altimeters having part number 822-0334-220.

The FAA has reviewed and approved McDonnell Douglas Service Bulletin MD11-34-091, dated August 19, 1999, which describes procedures for determining whether or not Collins LRA-900 radio altimeter receiver/transmitters having part number 822-0334-220 are installed, modifying such receiver/transmitters by installing software which handles negative altitude correctly, and re-identifying the receiver/transmitter as having part number 822-0334-221.

The service bulletin refers to Rockwell Avionics/ Collins Service Bulletin LRA-900-34-D, Revision 1, dated May 26, 1999, as an additional source of service information.

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 supersede AD 98-24-51 to require a one-time inspection to determine whether a Collins LRA-900 radio altimeter receiver/transmitter having part number 822-0334-220 is installed. If it is, the proposed AD would require that the radio altimeter receiver/transmitter be modified by installing software which handles negative altitude correctly, and re-identifying the receiver/transmitter as having part number 822-0334-221. The actions would be required to be accomplished in accordance with the service bulletin described previously.

Explanation of Change to Applicability

The FAA has revised the applicability of the existing AD to identify model designations as published in the most recent type certificate data sheet for the affected models. The existing AD specifies the applicability as McDonnell Douglas Model MD-11 series airplanes equipped with certain Collins LRA-900 radio altimeters. The proposed AD specifies the applicability as McDonnell Douglas Model MD-11 and -11F airplanes equipped with certain Rockwell Collins LRA-900 radio altimeters.”

Cost Impact

There are approximately 195 Model MD-11 and -11F airplanes of the affected design in the worldwide fleet. The FAA estimates that 64 airplanes of U.S. registry would be affected by this proposed AD.

The actions that are currently required by AD 98-24-51 take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $3,840, or $60 per airplane.

The new actions that are proposed in this AD action would also take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $3,840, or $60 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or 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.

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List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

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

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

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[Amended]

2. Section 39.13 is amended by removing amendment 39-10929 (63 FR 66422, December 2, 1998), and by adding a new airworthiness directive (AD), to read as follows:

McDonnell Douglas: Docket 2000-NM-406-AD. Supersedes AD 98-24-51, Amendment 39-10929.

Applicability: Model MD-11 and -11F airplanes equipped with certain Rockwell Collins LRA-900 radio altimeters; 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 (d) 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 prevent an undetected anomalous radio altitude signal that is passed along to the flare control law of the flight control computer, which could cause the airplane to flare too high or too low during landing, and consequently result in a hard landing, accomplish the following:

Restatement of Certain Requirements of AD 98-24-51

(a) Within 24 hours after December 7, 1998 (the effective date of AD 98-24-51, amendment 39-10929): accomplish either paragraph (a)(1) or (a)(2) of this AD:

(1) Revise the Limitations Section of the FAA-approved Airplane Flight Manual to include the following statement:

“Autopilot coupled autoland operations below 100 feet above ground level (AGL) are prohibited.”

(2) For airplanes on which the LRA-700 radio altimeter installation has been approved in accordance with Type Certificate or Supplemental Type Certificate procedures: Replace both Collins LRA-900 radio altimeters having part number (P/N) 822-0334-220, with Collins LRA-700 radio altimeters having P/N 622-4542-221.

New Requirements of This AD

(b) Within 90 days after the effective date of this AD: Perform a visual inspection to determine the P/N of the radio altimeter receiver/transmitters, in accordance with McDonnell Douglas Service Bulletin MD11-34-091, dated August 19, 1999.

(1) If the airplane is equipped with Collins LRA-900 radio altimeter receiver/transmitters having P/N 822-0334-220: Prior to further flight, modify the radio altimeter receiver/transmitter in accordance with McDonnell Douglas Service Bulletin MD11-34-091, dated August 19, 1999.

(2) If the airplane is not equipped with Collins LRA-900 radio altimeter receiver/transmitters having P/N 822-0334-220: No further action required.

Note 2:

Upon completion of the actions required by paragraph (b) of this AD, the revised limitations in the AFM, as required by paragraph (a)(1) of this AD, may be removed.

Note 3:

McDonnell Douglas Service Bulletin MD11-34-091, dated August 19, 1999, refers to Rockwell Avionics/Collins Service Bulletin LRA-900-34-D, Revision 1, dated May 26, 1999, as an additional source of service information.

(c) As of the effective date of this AD, no person shall install on any airplane a Collins LRA-900 radio altimeter having P/N 822-0334-220.

Alternative Methods of Compliance

(d) 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 4:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO.

Note 5:

Alternative methods of compliance, approved previously in accordance with AD 98-24-51, amendment 39-10929, are approved as alternative methods of compliance with this AD.

Special Flight Permits

(e) Special flight permits may be issued in accordance with §§ 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.

Start Signature

Issued in Renton, Washington, on May 8, 2002.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. 02-12069 Filed 5-14-02; 8:45 am]

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