AD 2000-23-18

This amendment adopts a new airworthiness directive (AD), applicable to certain Learjet Model 60 airplanes, that requires 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 this AD are intended to prevent electrical arcing between the oxygen tubing and an electrical source, which could result in an oxygen fire.

Final rule

2000-23-18 LEARJET: Amendment 39-11991. 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 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, are 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. 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 approvedalternative 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.

Incorporation by Reference
(e) The actions shall be done in accordance with Bombardier Alert Service Bulletin (Learjet 60) SB A60-35-2, dated November 4, 1999. 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 Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 101, Mid-Continent Airport, Wichita, Kansas;or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date
(f) This amendment becomes effective on December 26, 2000.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Learjet Model 60 airplanes was published in the Federal Register on August 8, 2000 (65 FR 48399). That action proposed to 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. That action also proposed to require corrective action, if necessary.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

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 will be affected by this AD, that it will take 1 work hour per airplane to accomplish the required inspection, and that the average labor rate is $60 per work hour. There will be no parts required. Based on these figures, the cost impact of the required 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 will 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, will 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 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 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.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a"significant rule" under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

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