Airworthiness Directive · Amendment 39-11931 · Eurocopter France Model AS-350B, BA, B1, B2, B3, C, D, and D1, and AS-355E, F, F1, F2 and N Helicopters
Eurocopter France Model AS-350B, BA, B1, B2, B3, C, D, and D1, and AS-355E, F, F1, F2 and N Helicopters
Model AS-350B, BA, B1, B2, B3, C, D, and D1, and AS-355E, F, F1, F2 and N helicopters, 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 (f) 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) for Eurocopter France Model AS-350B, BA, B1, B2, C, D, and D1, and AS-355E, F, F1, and F2 helicopters. That AD currently requires inspections of the main rotor head components, the main gearbox (MGB) suspension bars, and the ground resonance prevention system components. This amendment requires those same inspections, but would also apply to Model AS-350B3 and AS-355N helicopters. This amendment is prompted by the inadvertent omission of those model helicopters from the previous AD. The actions specified by this AD are intended to prevent ground resonance due to reduced structural stiffness, which could lead to failure of a main rotor head or MGB suspension component and subsequent loss of control of the helicopter.
To prevent ground resonance due to reduced structural stiffness, which could lead to failure of a main rotor head or main gearbox (MGB) suspension component and subsequent loss of control of the helicopter, accomplish the following:
(a) Within 10 hours time-in-service (TIS):
(1) For Model AS-350B, BA, B1, B2, B3, C, D, and D1 helicopters, inspect the main rotor head components, the MGB suspension bars (struts), and the landing gear ground resonance prevention components (aft spring blades and hydraulic shock absorbers) in accordance with paragraph CC.3 of Aerospatiale Service Bulletin (SB) No. 01.17a (not dated).
(2) For Model AS-355E, F, F1, F2, and N helicopters, inspect the main rotor head components, the MGB suspension bars (struts), and the landing gear ground resonance prevention components (aft spring blades and hydraulic shock absorbers) in accordance with paragraph CC.3 of SB No. 01.14a (not dated).
(b) Rework or replace damaged components in accordance with SB No. 01.17a or SB No. 01.14a, as applicable.
(c) Repeat the inspections and rework required by paragraphs (a) and (b) of this AD at intervals not to exceed 500 hours TIS.
(d) If the helicopter is subjected to a hard landing or to high surface winds when parked without effective tiedown straps installed, repeat the inspections required by paragraph (a) of this AD for the main rotor head star arms and the MGB suspension bars (struts) before further flight.
(e) After a landing with abnormal self-sustained dynamic vibrations (ground resonance type vibrations), repeat all the inspections required by paragraph (a) of this AD.
