[Federal Register Volume 66, Number 53 (Monday, March 19, 2001)]
[Proposed Rules]
[Pages 15362-15363]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-6646]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 66, No. 53 / Monday, March 19, 2001 / 
Proposed Rules  

[[Page 15362]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-128-AD]
RIN 2120-AA64


Airworthiness Directives; Learjet Model 55 Series Airplanes and 
Model 60 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Learjet Model 55 Series 
Airplanes and Model 60 Airplanes. This proposal would require 
replacement of the brake valve adjustment screw with a new improved 
screw, and for certain airplanes, it would also require installation of 
a new brake valve lever stop. This action is necessary to prevent 
bottoming of the valve components before contact of the brake valve 
lever with the stop, which could result in loss of all hydraulic fluid 
and consequent loss of normal braking. This action is intended to 
address the identified unsafe condition.

DATES: Comments must be received by May 3, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-128-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 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: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-128-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 Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-
2942. This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, 
Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, 
Mid-Continent Airport, Wichita, Kansas.

FOR FURTHER INFORMATION CONTACT: Shane Bertish, Aerospace Engineer, 
Systems and Propulsion Branch, ACE-116W, FAA, 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:

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-128-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. 2000-NM-128-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received numerous reports of sheared brake valve 
adjustment bolts on certain Learjet Model 60 airplanes. Additionally, 
we have received a report indicating that loss of all hydraulic fluid 
during taxi occurred on one airplane, which was attributed to broken 
brake valve adjustment bolts. Loss of all hydraulic fluid, if not 
prevented, could result in loss of normal braking capability.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Bomardier Service Bulletins 60-
32-10, Revision 1, dated June 22, 2000 (for Learjet Model 60 
airplanes), and 55-32-14, dated November 9, 1999 (for Learjet Model 55 
series airplanes). Both service bulletins describe procedures for 
installing a new brake valve lever stop and replacing the brake valve 
adjustment screws with new improved screws. Accomplishment of the 
actions specified in the service bulletins is intended to adequately 
address the identified unsafe condition.

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 require accomplishment of the actions specified in 
the service bulletins described previously.

[[Page 15363]]

Cost Impact

    There are approximately 331 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 285 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
16 work hours per airplane to accomplish the proposed actions, and that 
the average labor rate is $60 per work hour. Required parts would cost 
approximately $2,368 per airplane. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be 
$948,480, or $3,328, 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 proposed 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.


Sec. 39.13  [Amended]

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

Learjet: Docket 2000-NM-128-AD.

    Applicability: Model 55 series airplanes, serial numbers 55-003 
through 55-147 inclusive, and Model 60 airplanes, serial numbers 60-
002 through 60-189 inclusive; 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 (b) 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 bottoming of the valve components before contact of 
the brake valve lever with the stop, which could result in loss of 
all hydraulic fluid and consequent loss of normal braking; 
accomplish the following:

Replacement of Brake Valve Lever Stop Switch

    (a) Within 300 flight hours or one year after the effective date 
of this AD, whichever occurs first, accomplish the actions specified 
in paragraph (a)(1), (a)(2), or (a)(3), as applicable.
    (1) For Learjet Model 60 airplanes having serial numbers 60-002 
through 60-093 inclusive, and 60-095 through 60-188 inclusive: 
Replace the existing brake valve lever stop switch with a new brake 
valve lever stop switch, and replace the brake valve adjustment 
screws with new improved screws, per Bombardier Service Bulletin 60-
32-10, Revision 1, dated June 22, 2000.
    (2) For Learjet Model 60 airplanes having serial number 60-094 
or 60-189: Replace the brake valve adjustment screws with new 
improved screws, per Bombardier Service Bulletin 60-32-10, Revision 
1, dated June 22, 2000.
    (3) For Learjet Model 55 series airplanes having serial numbers 
55-003 through 55-147 inclusive: Replace the existing brake valve 
lever stop with a new brake valve lever stop, and replace the brake 
valve adjustment screws with new improved screws, per Bombardier 
Service Bulletin 55-32-14, dated November 9, 1999.

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, FAA. Operators shall submit their requests through an 
appropriate FAA Principal Maintenance 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.

    Issued in Renton, Washington, on March 12, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-6646 Filed 3-16-01; 8:45 am]
BILLING CODE 4910-13-U