AD 2007-25-14

Before further flight, and thereafter at intervals not to exceed 25 hours time-in-service (TIS), access the rear areas of each tailpipe assembly by removing the rear cowlings.

(1) Visually inspect each tailpipe assembly inside the cowling for a crack. If you find a crack, before further flight, replace the cracked tailpipe assembly with an airworthy tailpipe assembly.

(2) Visually inspect the structure surrounding each tailpipe assembly for overheating. If you find areas of overheating in the structure surrounding each tailpipe assembly, inspect for overheating in the underlying structure including on the upper deck thermal protection. Repair any damaged areas before further flight.

(3) Visually inspect at the internal part of the tailpipe assembly exhaust outside the cowling as depicted by Area A, Figure 1, of Agusta Bollettino Tecnico No. 139-069, Revision A, dated November 8, 2006 (ABT).

(i) Clean the end of each tailpipe assembly with a cloth. While applying slight pressure on it, inspect for a crack using a flashlight.

(ii) Inspect each tailpipe assembly toward the centerline of the helicopter for a crack using a flashlight.

(iii) Inspect each tailpipe assembly toward the outboard side of the helicopter for a crack using a mirror and a flashlight.

If you find a crack in the exhaust area outside the cowling, do the following:

(1) If any crack turns off abruptly (at an angle of greater than 45°) from the original direction, before further flight, replace that tailpipe assembly with an airworthy tailpipe assembly.

(2) If you find only one crack in a tailpipe assembly and the crack does not make an abrupt turn and is 50mm or less in length—

(i) Stop-drill the crack with a No. 30 drill bit, or

(ii) Repair that tailpipe assembly in accordance with the Compliance Instructions, paragraph 7) d), of the ABT.

(iii) If you choose to stop-drill the crack as indicated in paragraph (f)(2)(i) of this AD, thereafter, before the first flight of each day, inspect the stop-drill hole to determine whether another crack has started at the stop-drill hole. If you find during any inspection that another crack has started, before further flight, replace that tailpipe assembly with an airworthy tailpipe assembly.

(3) If you find more than one crack and no crack makes an abrupt turn as stated in paragraph (f)(1) of this AD and the cracks are within the allowable limits stated in the Compliance Instructions, paragraph 7) d), of the ABT, repair the tailpipe assembly in accordance with the Compliance Instructions, paragraph 7) d) of the ABT.

(g) Repairing or replacing the affected tailpipe assembly does not constitute terminating action for the repetitive inspection as required by paragraph (e) of this AD.

None.

The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, Safety and Management Group, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Ed Cuevas, Aerospace Engineer, Safety Management Group, FAA, Rotorcraft Directorate, Fort Worth, Texas 76193-0111, telephone (817) 222-5355, fax (817) 222-5961.

(2) Airworthy Product: Use only FAA-approved corrective actions. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent) if the State of Design has an appropriate bilateral agreement with the United States. You are required to assure the product is airworthy before it is returned to service.

(3) Reporting Requirements: For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act, the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120-0056.