Airworthiness Directive · Amendment 39-14154 · Agusta S.p.A. Model AB412 Series Helicopters
Agusta S.p.A. Model AB412 Series Helicopters
Model AB412 Series helicopters, with a tail rotor blade (blade), part number (P/N) 212-010-750-All, having a serial number (S/N) with a prefix of “A” or “A-FS” and number 11530 through 13618, except numbers 13595 through 13602, installed, certificated in any category.
This amendment adopts a new airworthiness directive (AD) for the Agusta S.p.A. (Agusta) Model AB412 Series helicopters. This action requires inspecting each affected tail rotor blade (blade) forward tip weight retention block (tip block) and the aft tip closure (tip closure) for adhesive bond voids, and removing any blade with an excessive void from service. This AD also requires modifying certain blades by installing shear pins and tip closure rivets on all affected blades. This amendment is prompted by reports of in-flight loss of tip blocks and tip closures resulting in minor to substantial damage. The actions specified in this AD are intended to prevent loss of the tip block or tip closure, loss of a blade, and subsequent loss of control of the helicopter.
To prevent loss of the forward tip weight retention block (tip block) or aft tip closure (tip closure), loss of a blade, and subsequent loss of control of the helicopter, accomplish the following:
(a) Inspect the tip block and tip closure for voids. Before further flight, remove any blade with a void in excess of that allowed by the Component Repair and Overhaul Manual limitations.
(b) Inspect the tip block attachment countersink screws in four locations to determine if the head of each countersunk screw is flush with the surface of the abrasion strip and the skin. The location of these four screws is depicted on Figure 2 of Agusta Bollettino Tecnico No. 412-88, Revision A, dated August 17, 2004 (BT 412-88, Revision A). If any of these screws are set below the surface of the abrasion strip or are covered with filler material, before further flight, install shear pins by following the Accomplishment Instructions, Part A, Tip Block: Shear Pin Installation, paragraphs 1 through 3, of BT 412-88, Revision A.
(c) Install the tip closure rivets on all affected blades by following the Accomplishment Instructions, Part B, Aft Tip Closure: Rivet Installation, paragraphs 1 through 6, of BT 412-88, Revision A.
(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, FAA, for information about previously approved alternative methods of compliance.
(e) The inspections and modification must be done by following the specified portions of Agusta Bollettino Tecnico No. 412-88, Revision A, dated August 17, 2004. The Director of the Federal Register approved this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Agusta, 21017 Cascina Costa di Samarate (VA) Italy, Via Giovanni Agusta 520, telephone 39 (0331) 229111, fax 39 (0331) 229605-222595. Copies may be inspected at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
