Airworthiness Directive · Amendment 39-21492 · Tail rotor drive shaft
Airbus Helicopters
This airworthiness directive (AD) applies to Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350C, AS350D, AS350D1, AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters, certificated in any category, with a tail rotor (TR) drive shaft bearing (bearing) part number (P/N) 593404, 6007-2RS1MT47CA, P9107NPP7, 83A851BC3, or 83A851B-1C3, or manufacturer part number (MP/N) 704A33-651-010, 704A33-651-111, 704A33-651-143, or 704A33-651-181, installed.
The FAA is superseding Airworthiness Directive (AD) 82-20-05 for Societe Nationale Industrielle Aerospatiale (now Airbus Helicopters) Model AS-350 and AS-355 series helicopters. AD 82-20-05 required inspecting and establishing a life limit for the tail rotor (TR) drive shaft bearing (bearing). This new AD requires replacing certain part-numbered TR bearings with one part-numbered bearing and repetitively inspecting one part-numbered bearing. This AD was prompted by inconsistencies that have been identified between inspections and maintenance actions required by ADs and inspections and maintenance actions specified in the applicable maintenance manual. The actions of this AD are intended to address an unsafe condition on these products.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
(1) For helicopters with TR bearing P/N 593404 or MP/N 704A33-651-181 installed, within 100 hours time-in-service (TIS) and thereafter at intervals not to exceed 165 hours TIS:
(i) Inspect each bearing holder damper bushing for wear, a crack, tears, and play between each bushing and support plate. If there is any wear, a crack, tears, or play between the bushing and support plate, remove the bearing holder damper bushing from service.
(ii) Inspect each bearing holder for a crack, fretting, and corrosion around the attachment holes. If there is a crack, fretting, or corrosion, remove the bearing holder from service.
(iii) Inspect each rubber sleeve for rotation, crazing, play between the inner races and the rubber sleeve, and lack of integrity of the elastomer. For the purposes of this inspection, lack of integrity may be indicated by brittle or cracked rubber. If there is any rotation, crazing, play between the inner races and the rubber sleeve, or lack of integrity of the elastomer, remove the rubber sleeve from service.
(2) Within 100 hours TIS:
(i) Make a mark with white paint on the rubber sleeves and on the shaft.
(ii) For helicopters with TR shaft bearing P/N 6007-2RS1MT47CA, P9107NPP7, 83A851BC3, or 83A851B-1C3, or MP/N 704A33-651-010, 704A33-651-111, or 704A33-651-143 installed, remove the affected bearings from service and replace with bearing P/N 593404 or MP/N 704A33-651-181.
(3) After the effective date of this AD, do not install bearing P/N 6007-2RS1MT47CA, P9107NPP7, 83A851BC3, or 83A851B-1C3, or MP/N 704A33-651-010, 704A33-651-111, or 704A33-651-143 on any helicopter.
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.
