[Federal Register Volume 65, Number 153 (Tuesday, August 8, 2000)]
[Proposed Rules]
[Pages 48399-48401]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-20003]


 ========================================================================
 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. 65, No. 153 / Tuesday, August 8, 2000 / 
Proposed Rules  

[[Page 48399]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-52-AD]
RIN 2120-AA64


Airworthiness Directives; Learjet Model 60 Series 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 60 series 
airplanes. This proposal would require inspecting the routing of oxygen 
tubing to ensure that there is adequate clamping of the tubing and 
adequate clearance between the tubing and electrical wiring or 
electrical contacts, and taking corrective action, if necessary. The 
actions specified by the proposed AD are intended to prevent electrical 
arcing between the oxygen tubing and an electrical source which could 
result in an oxygen fire.

DATES: Comments must be received by September 22, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-52-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: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-52-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, 
Small Airplane Directorate, 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, 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:

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 notice 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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-52-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-52-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report of a fire resulting from the puncture 
of an oxygen tube by an electrical arc from the generator control unit. 
The arcing is the result of improper clamping and inadequate spacing 
between the oxygen tubing and electrical sources, such as wires and 
contacts. The incident occurred during a routine functional test of the 
oxygen system on the production line. Improper clamping and inadequate 
spacing, if not corrected, could cause electrical arcing between the 
oxygen tubing and an electrical source, which could result in an oxygen 
fire.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Bombardier Alert Service Bulletin 
(Learjet 60) SB A60-35-2, dated November 4, 1999, which addresses 
certain Learjet Model 60 airplanes. That service bulletin describes 
procedures for inspecting the oxygen tubing system for adequate 
clamping and adequate clearance between the tubing and electrical 
wiring or electrical contacts and for adjusting the clamping of the 
tubing or the clearance between the tubing and electrical wiring or 
electrical contacts, as necessary. Accomplishment of the actions 
specified in the service bulletin 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

[[Page 48400]]

require accomplishment of the actions specified in the service bulletin 
described previously, except as discussed below.

Differences Between Alert Service Bulletin and Proposed AD

    Operators should note that, although the service bulletin 
recommends accomplishing the required inspection within 15 days after 
receipt of the service bulletin, the proposed AD specifies a compliance 
time of 60 days or 80 flight hours after the effective date of the AD, 
whichever comes first.
    In developing this compliance time, the FAA considered not only the 
manufacturer's recommendation, but also the degree of urgency 
associated with addressing the unsafe condition, the schedule of 
regular maintenance, and the average utilization of the affected fleet. 
In light of these factors, the FAA finds that the proposed compliance 
time represents an appropriate interval allowable for affected 
airplanes to continue to operate without compromising safety.

Cost Impact

    There are approximately 58 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 40 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take 1 work hour 
per airplane to accomplish the proposed inspection, and that the 
average labor rate is $60 per work hour. There would be no parts 
required. Based on these figures, the cost impact of the proposed 
inspection on U.S. operators is estimated to be $2,400, or $60 per 
airplane.
    Should an operator be required to adjust the clamping or the 
clearance of the oxygen tubing, the FAA estimates that it would take 
approximately 3 work hours per airplane and that the average labor rate 
is $60 per work hour. The cost of required parts, such as clamps, nuts, 
bolts, and washers, would be negligible. Based on these figures, the 
cost impact of adjusting the clamping or the clearance of the tubing is 
estimated to be $7,200, or $180 per airplane.
    The cost impact figures discussed above are 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-52-AD.

    Applicability: Model 60 airplanes, serial numbers 104 through 
168 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 
otherwise 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 (c) 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 electrical arcing between the oxygen tubing and an 
electrical source which could result in an oxygen fire, accomplish 
the following:

Inspection

    (a) Within 60 days or 80 flight hours after issuance of this AD, 
whichever occurs first, perform a detailed visual inspection of the 
oxygen tubing for adequate clamping and adequate clearance from 
electrical wiring and electrical contacts, in accordance with the 
Accomplishment Instructions of Bombardier Alert Service Bulletin 
(Learjet 60) SB A60-35-2, dated November 4, 1999. If adequate 
clamping and adequate clearance, as specified in the service 
bulletin, is found, no further action is required by this AD.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

Adjustment

    (b) If clamping or clearance of the oxygen tubing from 
electrical wiring or contacts is not adequate as specified in 
Bombardier Alert Service Bulletin (Learjet 60) SB A60-35-2, dated 
November 4, 1999, the clamping or the clearance must be adjusted, in 
accordance with the Accomplishment Instructions of the service 
bulletin.

Alternative Methods of Compliance

    (c) 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 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Wichita ACO.

    Note 3: 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

    (d) 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.


[[Page 48401]]


    Issued in Renton, Washington, on August 2, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-20003 Filed 8-7-00; 8:45 am]
BILLING CODE 4910-13-U