AD 2003-04-15 Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76A, B, and C Helicopters

Models named: S-76A, B, C. Read the applicability below — it usually turns on serial or part numbers too.

Model S-76A, B, and C helicopters, certificated 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 (d) 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.

Required as indicated, unless accomplished previously. To prevent failure of the rotor brake disc (RBD), damage to the rotor blades and nearby hydraulic and fuel lines, and subsequent loss of control of the helicopter, accomplish the following: (a) Before further flight, determine the manufacturer of each RBD by examining the part number (P/N) markings, and perform the required actions as follows: (1) If the P/N is 76363-09101-102, the manufacturer is Goodyear. No further action is required by this AD. (2) If the P/N 76363-09103-102 is pressure stamped on the RBD, the manufacturer is BF Goodrich. No further action is required by this AD. (3) If the P/N 76363-09103-102 is electrolytically etched on the RBD, the manufacturer is Parker Hannifin Corporation (PHC). For each PHC RBD with a P/N 76363-09103-102 and serial number (S/N) other than 38 through 379, remark the P/N as P/N 76363-09103-105 using the vibropeen method. No further action is required by this AD. (4) If the RBD serial number or the manufacturer cannot be determined and for PHC RBDs with P/N 76363-09103-102 and S/N's 38 through 379, reidentify or mark the P/N as 76363-09103-104 or replace the RBD in accordance with paragraph (c) of this AD. Note 2: Sikorsky Aircraft Corporation Alert Service Bulletin (ASB) Nos. 76-66-36, dated November 12, 2002, and ASB 76-66-37, dated January 31, 2003, pertain to the subject of this AD. (b) Before the first flight of the next day following any day in which the RBD was used, visually inspect each RBD, P/N 76363-09103-104, for a crack, and perform the following actions. See Figure 1. BILLING CODE 4910-13-P ER27FE03.219 (1) If you find a crack through the entire RBD thickness as shown in Figure 1, View A, replace the RBD with an airworthy RBD, other than P/N 76363-09103-104, before further flight. (2) If you find two or more surface cracks between adjacent boltholes as shown in Figure 1, View B, replace the RBD with an airworthy RBD, other than P/N 76363-09103-104, before further flight. (3) If you find a surface crack or surface cracks separated by the boltholes as shown in Figure 1, View C, replace the RBD with an airworthy RBD, other than P/N 76363-09103-104, or deactivate the RBD before further flight. Note 3: Short “glazing” cracks are not a cause for rejection. Note 4: PHC Component Maintenance Manual with Illustrated Parts List PH030-21300MM, Rotor Brake Assembly, P/N 030-21300, Revision C, dated November 1, 2002, pertains to the subject of this AD. (c) Replace PHC RBD, P/N 76363-09103-104, with an airworthy RBD on or before May 31, 2003, or within 60 days after the effective date of this AD, whichever occurs later. Any replacement RBD, P/N 76363-09103-104, is not airworthy. (d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Boston Aircraft Certification Office, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Boston Aircraft Certification Office. Note 5: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Boston Aircraft Certification Office. (e) Special flight permits will not be issued. (f) This amendment becomes effective on February 27, 2003. Issued in Fort Worth, Texas, on February 14, 2003. David A. Downey, Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 03-4474 Filed 2-26-03; 8:45 am] BILLING CODE 4910-13-C