Airworthiness Directive · Amendment 39-17882 · Engine exhaust
Learjet Inc. Airplanes
This AD applies to Learjet Inc. Model 45 airplanes having serial numbers (S/Ns) 45-005 through 45-436 inclusive, and 45-2001 through 45-2132 inclusive, certificated in any category, that are equipped with composite engine fan bypass ducts.
Note 1 to paragraph (c) of this AD: Learjet Model 45 airplanes having S/Ns 45-2001 and subsequent are commonly referred to as “Model 40” airplanes or Learjet 40 airplanes as marketing designations.
We are adopting a new airworthiness directive (AD) for certain Learjet Inc. Model 45 airplanes. This AD was prompted by a report of two cases of premature corrosion found on the structural support flange for the engine thrust reverser. This AD requires inspecting for any corrosion, and damage to the sealant; installing sealants and gaskets; and related investigative and corrective actions as necessary. We are issuing this AD to prevent failure of the thrust reverser structural support, which could result in departure of the thrust reverser from the engine that could subsequently result in damage to the adjacent support structure and engine controls, airframe structure, and control surfaces. Departing thrust reversers could also result in injury to persons on the ground.
Within 1,200 flight hours or 48 months after the effective date of this AD, whichever occurs first, do the requirements of paragraph (g)(1) of this AD; and for the airplanes identified in paragraph (g)(2) of this AD, do the requirements of paragraph (g)(2) of this AD concurrently.
(1) Do a detailed inspection of the thrust reverser flange for damage to the sealant, as applicable, and install sealants and gaskets before further flight, as applicable, to the thrust reverser flanges and service island flanges, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 40-78-03, Revision 1, dated November 5, 2012 (for Model 45 airplanes having S/Ns 45-2001 through 45-2132 inclusive); or Bombardier Service Bulletin 45-78-9, Revision 1, dated November 5, 2012 (for Model 45 airplanes having S/Ns 45-005 through 45-436 inclusive).
(2) For Model 45 airplanes having S/Ns 45-2001 through 45-2129 inclusive and S/Ns 45-005 through 45-420 inclusive: Do a fluorescent penetrant inspection for corrosion of the metallic components of the thrust reverser's attach flange for any corrosion, and all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Nordam Service Bulletin 5045 78-13, dated January 17, 2012, except as required by paragraph (h) of this AD. Do all applicable related investigative and corrective actions before further flight.
If any material thickness less than the minimum allowable thickness is found during any inspection required by paragraph (g)(2) of this AD, and Nordam Service Bulletin 5045 78-13, dated January 17, 2012, specifies contacting Bombardier Learjet for appropriate action: Before further flight, repair the thrust reverser's attach flange in accordance with a method approved by the Manager, Wichita Aircraft Certification Office (ACO), FAA. For a repair method to be approved by the Manager, Wichita ACO, as required by this paragraph, the Manager's approval letter must specifically refer to this AD.
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
