Airworthiness Directive · Amendment 39-11627 · Eurocopter France Model EC 120B Helicopters
Eurocopter France Model EC 120B Helicopters
Superseded. A later AD replaced this one: AD 2016-12-13. Comply with the one in force.
Model EC 120B helicopters with engine coupling tube (coupling tube), part number (P/N) C631A1002101, installed, certificated in any category.
Note 1: This AD applies to each helicopter 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 helicopters 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 (e) 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 supersedes an existing airworthiness directive (AD), applicable to Eurocopter France Model EC 120B helicopters, that currently requires, at specified time intervals, inspecting the engine coupling tube for cracks and replacing any cracked engine coupling tube with an airworthy engine coupling tube. This amendment requires, at specified time intervals, visually inspecting and dye-penetrant inspecting the coupling tube for any crack and replacing any cracked coupling tube with a reinforced, airworthy coupling tube. Replacing all coupling tubes and certain engine support fitting components is required on or before March 31, 2000. This amendment is prompted by the discovery of cracks in several coupling tubes. The actions specified by this AD are intended to prevent coupling failure, loss of engine drive, and a subsequent forced landing.
To prevent coupling failure, loss of engine drive, and a subsequent forced landing, accomplish the following:
(a) Within 10 hours time-in-service (TIS), and thereafter at intervals not to exceed 10 hours TIS except when required to perform the inspection required by paragraph (b) of this AD while each coupling tube, P/N C631A1002101, is installed, inspect for any crack in accordance with the Accomplishment Instructions, paragraph 2.B.1., of Eurocopter Service Bulletin No. 05-001, dated September 23, 1999 (SB 05-001).
(b) Within 10 hours TIS, and thereafter at intervals not to exceed 30 hours TIS, after each coupling tube, P/N C631A1002101, has been removed, inspect for any crack in accordance with paragraph 2.B.2. of SB 05-001.
Note 2: Operators are not required to inform the manufacturer when a crack is found.
(c) When a crack is found as a result of the inspections conducted in accordance with either paragraph (a) or (b) of this AD, or by March 31, 2000, whichever occurs first, replace the coupling tube with a reinforced, airworthy coupling tube, P/N C631A1101101, and replace the engine mount fittings in accordance with Eurocopter Service Bulletin No. SB 63-001, dated November 10, 1999, using new, airworthy, engine mount fitting components to replace the following:
• Teflon spacer, P/N C714A1010208;
• Black-colored spring washers, 10.2 x 28 Type-C;
• Blue-colored hinge yoke, P/N C714A1010212; and
• Special washer, P/N C714A1010213.
Note 3: Eurocopter Service Bulletin No. 01-002 pertains to unairworthiness of the four engine mount fitting components listed in paragraph (c) of this AD.
(d) Installing the reinforced, airworthy coupling tubes, P/N C631A1101101, and replacing the engine mount fitting components using new, airworthy, engine mount fitting components, as specified in paragraph (c) of this AD, constitutes terminating action for the requirements of this AD.
