AD 2012-23-11 Airworthiness Directives; Erickson Air-Crane Incorporated Helicopters

This AD becomes effective January 14, 2013.

Special flight permits may be issued in accordance with 14 CFR 21.197 and 21.199 to operate the helicopter to a location where the inspection requirements of this AD can be accomplished. No special flight permits will be issued to accomplish replacements or repairs, or if a crack is suspected.

(1) The Manager, Rotorcraft Certification Office, FAA, may approve AMOCs for this AD. Send your proposal to: Michael Kohner, Aviation Safety Engineer, Rotorcraft Certification Office, Rotorcraft Directorate, FAA, 2601 Meacham Blvd., Fort Worth, Texas 76137; telephone (817) 222-5170; email 7-avs-asw-170@faa.gov. (2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 CFR part 91, subpart K, we suggest that you notify your principal inspector, or lacking a principal inspector, the manager of the local flight standards district office or certificate holding district office before operating any aircraft complying with this AD through an AMOC.

(1) Within 20 hours time-in-service (TIS), and thereafter at intervals not to exceed 20 hours (TIS): (i) Visually inspect each transition fitting, P/N 6420-66341-101, -102, -103, or -104, for a crack or working rivets on the inboard face of the rotary rudder boom and pylon, paying particular attention to the fastener attachment holes, as depicted in Figure 1, Detail A, of the Accomplishment Instructions in Erickson Air-Crane Incorporated Service Bulletin No. 64B20-6, Revision A, dated December 12, 2007 (SB). (ii) Visually inspect the outboard face of each rotary rudder boom and pylon skin panel (skin panel) that attaches to the transition fittings for a crack or working rivets in the transition fitting attachment areas, paying particular attention to the fastener attachment holes, as shown in Figure 1, Detail B, of the Accomplishment Instructions in the SB. (iii) Visually inspect the forward and aft sides of each bulkhead assembly, P/N 6420-66340-043 or -044, for a crack. Pay particular attention to the circled areas shown in Figure 2 of the Accomplishment Instructions in the SB. (iv) Visually inspect the upper 12 inches of each strap, P/N 6420-66301-119 or -127, for a crack or for working rivets as shown in Figure 3 of the Accomplishment Instructions in the SB. (v) Visually inspect the pylon for a crack or working rivets on each side of the upper 12 inches of the strap, and also 6 inches above the end of the strap as shown in Figure 3 of the Accomplishment Instructions in the SB. (2) For any pylon with a strap installed, within 155 hours TIS, and thereafter at intervals not to exceed 155 hours TIS, remove the inspection access covers, P/N 6420-66304-109 and P/N 6420-66303-125, on the forward and aft sides of the pylon and visually inspect the left-hand cap angle (longeron), P/N 6420-66304-136, and the interior area of the pylon adjacent to the upper 12 inches of the strap, as well as 6 inches above the end of the strap, for a crack or working rivets, as shown in Figure 3 of the Accomplishment Instructions in the SB. (3) At each transition fitting replacement, which is required at intervals not to exceed 8,300 hours TIS: (i) With each transition fitting removed, visually inspect both sides of each skin panel for a crack in the areas to which the transition fitting attaches, paying particular attention to the fastener attachment holes, as depicted in Details A and B, Figure 1, of the Accomplishment Instructions in the SB. (ii) Perform a fluorescent penetrant inspection of each skin panel for a crack in the areas around the fastener holes where the transition fittings attach to the rotary rudder boom and pylon. (4) If there is a crack, before further flight, replace any cracked part with an airworthy part, or repair the cracked part if the damage is within the maximum repair damage limits. Note to paragraph (e)(4) of this AD: The maximum repair damage limitations are stated in the applicable Component and Repair Overhaul Manual. (5) If any loose or working rivets are found, before further flight, remove the rivets and visually inspect the fastener holes and surrounding area for a crack or any other damage. Replace any part that is cracked with an airworthy part; replace any damaged part with damage exceeding the maximum repair damage limits with an airworthy part; or repair any damaged part that is within the maximum repair damage limits. Also, replace any loose or working rivets.

This AD defines the unsafe condition as cracking in the rotary rudder boom or pylon due to fatigue, failure from static overload, and subsequent loss of control of the helicopter.