COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Eurocopter AS 355 (Twin Ecureuil) Series Helicopters
AD/AS 355/31 Tail Rotor Gearbox Casing 1/88
Applicability: All model AS 355 Series helicopters.
Requirement: 1. Inspect the tail rotor gearbox casing in accordance with Para 1C(2) of SB No 05.18.
2. Inspect and modify the tail rotor gearbox in accordance with Para 1C(3) of SB No 05.18.
Compliance: For Para 1: Within 50 hours time in service after 18 November 1987 and thereafter at intervals not exceeding 50 hours time in service, until modification AMS 350A07- 8535 (polishing blend radii) is incorporated. After modification, inspect at intervals not exceeding 400 hours time in service.
For Para 2: Prior to exceeding 1100 hours total time in service or within 100 hours time in service after 18 November 1987, whichever is the later.
Background: The manufacturer has received reports of cracking in the blade horn support yoke radius just inboard of where the tail rotor control bellcrank pivot bolt is located.