Airworthiness Directive · Amendment 39-11688 · Agusta Model A109A, A109AII, and A109C Helicopters
Agusta Model A109A, A109AII, and A109C Helicopters
Model A109A, A109AII, and A109C helicopters, Serial Number (S/N) 7630, 7633, 7654, 7667, 7671, 7672, 7676, or 7677 with main transmission, part number (P/N) 109-0400-02-5 or 109-0400-03-105, with Gleason crown, P/N 109-0403-07, installed, certified 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 (c) 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 adopts a new airworthiness directive (AD) applicable to Agusta Model A109A, A109AII, and A109C helicopters. This action requires inspecting the main transmission to determine if certain Gleason crowns are installed and replacing any unairworthy Gleason crown with an airworthy Gleason crown. This amendment is prompted by the discovery of a cracked Gleason crown during an unscheduled transmission inspection prompted by abnormal noises coming from the transmission during main rotor deceleration. The actions specified in this AD are intended to prevent failure of the main transmission, loss of rotor drive, and subsequent loss of control of the helicopter.
To prevent failure of the main transmission, loss of rotor drive, and subsequent loss of control of the helicopter, accomplish the following:
(a) Before further flight, determine if a transmission with a S/N specified in Table 1 is installed.
| Transmission P/N | Transmission S/N | Gleason Crown S/N |
|---|---|---|
| 109-0400-02-5 | 171 | A0488 |
| 109-0400-02-5 | 326 | A0490 |
| 109-0400-03-105 | 026 | A0571 |
| 109-0400-03-105 | 028 | A0572 |
| 109-0400-03-105 | 025 | A0578 |
| 109-0400-03-105 | 029 | A0584 |
| 109-0400-03-105 | 036 | A0614 |
| 109-0400-03-105 | 037 | A0618 |
| 109-0400-03-105 | 041 | A0630 |
| 109-0400-03-105 | A2-1274 | A2-0645 |
| 109-0400-03-105 | A2-1356 | B15919 |
(b) If the installed Gleason crown, P/N 109-0403-07, S/N is listed in Table 1, before further flight, replace it with an airworthy Gleason crown, P/N 109-0403-07-103, S/N B58264 or subsequent, except S/N B58271.
(1) After installing the replacement Gleason crown, mark the nomenclature “S.M. 109254” on the “Modification Incorporated” area of the additional nameplate, P/N MS27253-2. Update the main transmission “Assembly Historical Record” or equivalent record, with the P/N and S/N of the Gleason crown installed.
(2) If not previously bonded to the transmission, bond the additional nameplate, P/N MS27253-2, with adhesive EA934NA below the main transmission nameplate.
Note 2: Agusta Bollettino Technico 109-109, dated June 3, 1999, pertains to the subject of this AD.
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.
Aircraft
