Airworthiness Directive · Amendment 39-14521 · Aerospatiale Model ATR72 Airplanes
Aerospatiale Model ATR72 Airplanes
This AD applies to Aerospatiale Model ATR72-101, -102, -201, -202, -211, -212, and -212A airplanes, certificated in any category; except airplanes that have received ATR Modification 5522 in production.
The FAA is adopting a new airworthiness directive (AD) for certain Aerospatiale Model ATR72 airplanes. This AD requires a one-time general visual inspection for contamination of the surface of the upper arms of the main landing gear (MLG) secondary side brace assemblies; and repetitive eddy current inspections for cracking of the upper arms, and related specified and corrective actions if necessary. This AD also mandates eventual replacement of aluminum upper arms with steel upper arms, which would end the repetitive inspections. This AD results from two reports of rupture of the upper arm of the MLG secondary side brace due to fatigue cracking. We are issuing this AD to prevent cracking of the upper arms of the secondary side brace assemblies of the MLG, which could result in collapse of the MLG during takeoff or landing, damage to the airplane, and possible injury to the flightcrew and passengers.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
At the latest of the times specified in paragraphs (f)(1), (f)(2), and (f)(3) of this AD: Accomplish a general visual inspection for contamination of the surface of the upper arms of the MLG secondary side brace assemblies, and an eddy current inspection for cracking of the upper arms by doing all the actions specified in Parts A and B of the Accomplishment Instructions of Messier-Dowty Special Inspection Service Bulletin 631-32-178, Revision 1, dated September 30, 2004. Repeat the eddy current inspection at intervals not to exceed 800 flight cycles until accomplishment of paragraph (h) of this AD.
(1) Before the accumulation of 4,000 total flight cycles on the secondary side brace.
(2) Before the accumulation of 800 flight cycles on the secondary side brace since overhauled.
(3) Within 200 flight cycles after the effective date of this AD.
Note 1: For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”
If any cracking is found during any inspection required by paragraph (f) of this AD: Before further flight, replace the affected upper arm of the MLG secondary side brace assembly as specified in paragraph (g)(1) or (g)(2) of this AD.
(1) Replace the aluminum upper arm of the MLG secondary side brace assembly with a steel upper arm by doing the applicable actions specified in the Accomplishment Instructions of Messier-Dowty Service Bulletin 631-32-183, dated October 6, 2004. This replacement ends the repetitive inspections required by paragraph (f) of this AD for that side brace only.
(2) Replace the aluminum upper arm of the MLG secondary side brace assembly with a new or serviceable aluminum upper arm in accordance with a method approved by either the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the Direction Générale de l'Aviation Civile (or its delegated agent). ATR Component Maintenance Manual, Chapter 32-18-41, Revision 3, dated September 30, 2002, is one approved method. Accomplish a general visual inspection for contamination of the surface of the upper arm before the accumulation of 4,000 total flight cycles on the replacement aluminum upper arm, and if cracks are found, before further flight, replace the aluminum upper arm with a steel upper arm as required by paragraph (g)(1) of this AD. If no cracks are found, repeat the eddy current inspection thereafter at intervals not to exceed 800 flight cycles until accomplishment of paragraph (h) of this AD.
Replace all aluminum upper arms of the MLG secondary side brace assembly with steel upper arms by doing all the applicable actions in accordance with the Accomplishment Instructions of Messier-Dowty Service Bulletin 631-32-183, dated October 6, 2004; at the applicable time specified in paragraph (h)(1), (h)(2), (h)(3), or (h)(4) of this AD. Accomplishing this replacement ends the repetitive inspections required by paragraph (f) of this AD.
(1) For airplanes on which any upper arm has been overhauled before the effective date of this AD and on which Messier-Bugatti Service Bulletin 631-32-085, dated August 21, 1992, has not been accomplished, as of the effective date of this AD: Within 15,000 flight cycles or 96 months, whichever is first, since overhaul on the affected upper arm.
(2) For airplanes on which any upper arm has been overhauled before the effective date of this AD and on which Messier-Bugatti Service Bulletin 631-32-085, dated August 21, 1992, has been accomplished, as of the effective date of this AD: Within 18,000 flight cycles or 96 months, whichever is first, since overhaul on the affected upper arm.
(3) For airplanes on which any upper arm has not been overhauled and on which Messier-Bugatti Service Bulletin 631-32-085, dated August 21, 1992, has not been accomplished, as of the effective date of this AD: Before the accumulation of 15,000 total flight cycles on an upper arm since new, or within 96 months on an upper arm since new, whichever is first.
(4) For airplanes on which any upper arm has not been overhauled and on which Messier-Bugatti Service Bulletin 631-32-085, dated August 21, 1992, has been accomplished, as of the effective date of this AD: Before the accumulation of 18,000 total flight cycles on an upper arm since new, or within 96 months on an upper arm since new, whichever is first.
(i) Messier-Dowty Special Inspection Service Bulletin 631-32-178, Revision 1, dated September 30, 2004, recommends sending an inspection report to Messier-Dowty, but this AD does not contain that requirement.
As of the effective date of this AD, no person may install, on any airplane, an aluminum upper arm of the MLG secondary side brace assembly, unless the applicable requirements specified in paragraphs (f) and (g) of this AD have been accomplished.
