Airworthiness Directive · Amendment 39-13771 · Eurocopter France Model AS-365N2, AS 365 N3, EC 155B, EC155B1, SA-365N and N1, and SA-366G1 Helicopters
Eurocopter France Model AS-365N2, AS 365 N3, EC 155B, EC155B1, SA-365N and N1, and SA-366G1 Helicopters
Superseded. A later AD replaced this one: AD 2004-16-15 R1. Comply with the one in force.
Eurocopter France Model AS-365N2, AS 365 N3, EC 155B, EC155B1, SA-365N and N1, and SA-366G1 helicopters with a main gearbox (MGB) base plate, part number (P/N) 366A32-1062-03 or P/N 366A32-1062-06, installed, certificated in any category.
This amendment adopts a new airworthiness directive (AD) for the specified Eurocopter France (Eurocopter) helicopters. This action requires inspecting the main gearbox (MGB) baseplate for a crack and replacing the MGB if a crack is found in the MGB base plate. This amendment is prompted by the discovery of a crack in a MGB base plate. The actions specified in this AD are intended to detect a crack in a MGB base plate and prevent failure of one of the MGB attachment points to the frame, which could result in severe vibration and subsequent loss of control of the helicopter.
| For... | Then... | Or... | Or... |
|---|---|---|---|
| Model SA-365N and N1, and Model SA-366G1 helicopters | If a MGB is installed that has less than 9,900 cycles and has never been overhauled or repaired. On or before accumulating 9,900 cycles, unless accomplished previously, and thereafter, at intervals not to exceed 15 hours time-in-service (TIS) | If a MGB is installed that has 9,900 or more cycles and has never been overhauled or repaired, before further flight, unless accomplished previously, and thereafter, at intervals not to exceed 15 hours TIS | If a MGB is installed that is overhauled or repaired, before further flight, unless accomplished previously, and thereafter, at intervals not to exceed 15 hours TIS. |
| Model AS-365N2 and AS 365 N3 helicopters | If a MGB is installed that has less than 7,300 cycles and has never been overhauled or repaired, on or before accumulating 7,300 cycles, unless accomplished previously, and thereafter, at intervals not to exceed 15 hours TIS | If a MGB is installed that has 7,300 or more cycles and has never been overhauled or repaired, before further flight, and thereafter, at intervals not to exceed 15 hours TIS | If a MGB is installed that has been overhauled or repaired, before further flight, and thereafter, at intervals not to exceed 15 hours TIS. |
| Model EC 155B and EC155B1 helicopters | If a MGB base plate is installed that has less than 2,600 cycles, no later than 2,600 cycles, unless accomplished previously, and thereafter, before the first flight of each day and on or before reaching each 9 hours TIS interval during the day | If a MGB base plate is installed that has 2,600 or more cycles, unless accomplished previously, before further flight, and thereafter, before the first flight of each day and on or before reaching each 9 hours TIS interval during the day |
To detect a crack in the MGB base plate and prevent failure of a MGB attachment point to the frame, which could result in severe vibration and subsequent loss of control of the helicopter:
(a) Before the initial inspection at the time indicated in the compliance table, strip the paint from area “D” on both sides (“B” and “C”) of the MGB base plate as depicted in Figure 1.
(b) At the times indicated in the compliance table, inspect area “D” of the MGB base plate for a crack using a 10x or higher magnifying glass.
Note 1: Eurocopter France Alert Telex No. 05.00.45, applicable to Model AS-365N2, AS 365 N3, SA-365N and SA-365N1 helicopters; Alert Telex No. 05.29, applicable to Model SA-366G1 helicopters, and Alert Telex No. 05A005, applicable to Model EC 155B and EC155B1 helicopters, pertain to the subject of this AD. All three alert telexes are dated February 5, 2004.
(c) If a crack is found in a MGB base plate, remove and replace the MGB with an airworthy MGB before further flight.
(d) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Safety Management Group, Rotorcraft Directorate, FAA, for information about previously approved alternative methods of compliance.
