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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-NM-85-AD; Amendment 39-11699; AD 2000-08-13] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Final rule; request for comments.

# SUMMARY:

                        This amendment adopts a new airworthiness directive (AD) that is                               ( print page 24871)                            applicable to certain Learjet Model 45 airplanes. This action requires revising the Airplane Flight Manual to provide the flight crew with certain instructions associated with an exterior preflight inspection and ground operations. This amendment is prompted by a report indicating the occurrence of an uncommanded brake application condition that was not annunciated in the cockpit. The actions specified in this AD are intended to provide the flight crew with procedures to detect an uncommanded brake application condition during taxi and takeoff. Such a condition could result in a possible wheel/brake fire and/or a high-speed rejected takeoff.                     

# DATES:

Effective May 15, 2000. 

The incorporation by reference of certain publications in this rule is approved by the Director of the Federal Register as of May 15, 2000. 

Comments for inclusion in the Rules Docket must be received on or before June 27, 2000. 

# ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-85-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. 

The information concerning this amendment may be obtained from or examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Small Airplane Directorate, Wichita Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

# FOR FURTHER INFORMATION CONTACT:

Shane Bertish, Aerospace Engineer, Systems and Equipment Branch, ACE-116W, FAA, Small Airplane Directorate, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4156; fax (316) 946-4407. 

# SUPPLEMENTARY INFORMATION:

The FAA has received a report indicating the occurrence of an uncommanded brake application condition that was not annunciated in the cockpit, in which the airplane experienced a dragging brake (uncommanded brake application condition) when the pilot released the parking brake. Not realizing the severity or cause of the problem, the pilot increased the thrust control to taxi the airplane. During takeoff, the airplane failed to accelerate properly, and the pilot performed a rejected takeoff. After the airplane returned to the ramp, investigation revealed that one or more brake pistons had failed, causing a small brake oil fire. 

## Explanation of Relevant Service Information 

The manufacturer has issued Learjet Temporary Flight Manual (TFM) Changes TFM 2000-01, 2000-02, 2000-03, 2000-04, 2000-05, 2000-06, 2000-07, and 2000-08, each dated April 6, 2000. These TFM changes provide information for the flight crew with certain instructions to detect possible brake problems during exterior preflight inspections and ground operations. 

## Explanation of the Requirements of the Rule 

Since an unsafe condition has been identified that is likely to exist or develop on other Learjet Model 45 airplanes of the same type design, this AD is being issued to provide the flight crew with procedures to detect an uncommanded brake application condition during taxi and takeoff. Such a condition could result in a possible wheel/brake fire and/or a high-speed rejected takeoff. This AD requires revising the Limitations and Normal Procedures Sections of the FAA-approved AFM to provide the flight crew with certain instructions to detect possible brake problems during exterior preflight inspections and ground operations. 

## Interim Action 

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

## Determination of Rule's Effective Date 

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. 

## Comments Invited 

                    Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption                     **ADDRESSES**                    . All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.                 

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. 

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-85-AD.” The postcard will be date stamped and returned to the commenter. 

## Regulatory Impact 

The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. 

                    The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a “significant regulatory action” under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption                     **ADDRESSES**                    .                

      ( print page 24872)    

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Incorporation by reference
      - Safety

## Adoption of the Amendment 

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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 

2. Section 39.13 is amended by adding the following new airworthiness directive: 

**2000-08-13 Learjet:**                             Amendment 39-11699. Docket 2000-NM-85-AD.                        

*Applicability:*                             Model 45 airplanes on which Crane Hydro-Aire brake control unit part number (P/N) 42-933-2 is installed; certificated in any category.                         

*Compliance:*                             Required as indicated, unless accomplished previously.                         

To provide the flight crew with procedures to detect an uncommanded brake application condition during taxi and takeoff, which could result in a possible wheel/brake fire and/or a high-speed rejected takeoff, accomplish the following: 

## Airplane Flight Manual (AFM) Revision 

(a) Within 10 days after the effective date of this AD, revise the Limitations and Normal Procedures Sections of the FAA-approved AFM to include Learjet Temporary Flight Manual (TFM) Changes 2000-01, 2000-02, 2000-03, 2000-04, 2000-05, 2000-06, 2000-07, and 2000-08, each dated April 6, 2000. 

# Note 1:

The AFM revision required by paragraph (a) of this AD may be accomplished by inserting a copy of the applicable TFM Change into the applicable section of the AFM. When these TFM Changes have been incorporated into the general revisions of the AFM, the general revisions may be inserted into the AFM, provided that the information contained in the general revisions is identical to that specified in the TFM Changes.

## Alternative Methods of Compliance 

(b) 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, Wichita Aircraft Certification Office (ACO), FAA, Small Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Operations Inspector, who may add comments and then send it to the Manager, Wichita ACO. 

# Note 2:

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

## Special Flight Permits 

(c) 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. 

## Incorporation by Reference 

(d) The Airplane Flight Manual revisions shall be done in accordance with Learjet Temporary Flight Manual Change 2000-01, dated April 6, 2000; Learjet Temporary Flight Manual Change 2000-02, dated April 6, 2000; Learjet Temporary Flight Manual Change 2000-03, dated April 6, 2000; Learjet Temporary Flight Manual Change 2000-04, dated April 6, 2000; Learjet Temporary Flight Manual Change 2000-05, dated April 6, 2000; Learjet Temporary Flight Manual Change 2000-06, dated April 6, 2000; Learjet Temporary Flight Manual Change 2000-07, dated April 6, 2000; and Learjet Temporary Flight Manual Changes 2000-08, dated April 6, 2000. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Bombardier Aerospace, Learjet, One Learjet Way, Wichita, Kansas 67277-7707. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at Small Airplane Directorate, Wichita Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

(e) This amendment becomes effective on May 15, 2000. 

Issued in Renton, Washington, on April 17, 2000. 

Donald L. Riggin, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 00-10050 Filed 4-27-00; 8:45 am] 

BILLING CODE 4910-13-P