Airworthiness Directive · Amendment 39-11991 · Learjet Model 60 Airplanes
Learjet Model 60 Airplanes
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.
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.
To prevent electrical arcing between the oxygen tubing and an electrical source which could result in an oxygen fire, accomplish the following:
(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.”
(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.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
