2002-15-02: Compressor Wheels

2002-15-02 Hamilton Sundstrand Power Systems (formerly Sundstrand Power Systems, Turbomach, and Solar): Amendment 39-12830. Docket No. 2002-NE-01-AD. Applicability This airworthiness directive (AD) is applicable to Hamilton Sundstrand Power Systems (formerly Sundstrand Power Systems, Turbomach, and Solar) models T-62T-2C, T-62T-25, T-62T-29, and T-62T-39 auxiliary power units (APU's) that have compressor wheel part number (P/N) 100636-1 installed. These APU's are installed on, but not limited to, Fairchild FH-227, Dassault Falcon 20, Lockheed 1329 series (Jetstar), British Aerospace Jetstream 3101, Raytheon Aircraft HS125-600, -700, -800, and Sabreliner Corporation 60 and 80 airplanes, and Boeing Defense & Space Group 234 Series helicopters. Note 1: This AD applies to each APU identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For APU's that have beenmodified, 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 (e) 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. Compliance Compliance with this AD is required as indicated, unless already done. To replace affected compressor wheels P/N 100636-1, which if not replaced, could result in uncontained compressor wheel failure and damage to the airplane, do the following: Cast Steel Compressor Wheel Replacement (a) For compressor wheels, P/N 100636-1, made of cast steel, identifiable by a four-digit casting lot vendor identification number used as a prefix to the serial number, replace compressor wheels with compressor wheel P/N 4503164, 4504174, or M4504174 as follows: (1) Replace cast steel compressor wheels with 2,350 or greater cycles-since-new (CSN) on the effective date of this AD within 250 cycles-in-service (CIS) after the effective date of this AD. (2) Replace cast steel compressor wheels with less than 2,350 CSN on the effective date of this AD before accumulating 2,600 CSN. Wrought Steel Compressor Wheel Replacement (b) For compressor wheels, P/N 100636-1 made of wrought steel, identifiable by a serial number beginning with the letter W, replace compressor wheels with compressor wheel P/N 4503164, 4504174, or M4504174 as follows: (1) Replace wrought steel compressor wheels with 3,600 or greater CSN on the effective date of this AD within 500 CIS after the effective date of this AD. (2) Replace wrought steel compressor wheels with less than 3,600 CSN on the effective date of this AD before accumulating 4,100 CSN. (c) Information onprocedures for replacing compressor wheel P/N 100636-1 may be found in Hamilton Sundstrand Power Systems service bulletin No. SB-T-62T-49-148, Revision 1, dated December 20, 2001. Reduced Life Limits (d) This AD establishes new cyclic life limits for compressor wheels P/N 100636-1, of 2,600 CSN for cast steel compressor wheels and 4,100 CSN for wrought steel compressor wheels. Except as provided in paragraph (e) of this AD, no alternate life limits for these parts may be approved. Alternative Methods of Compliance (e) 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, Los Angeles Aircraft Certification Office (ACO). Operators must submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO. Note 2: Information concerning the existence of approved alternative methods ofcompliance with this airworthiness directive, if any, may be obtained from the Los Angeles ACO. Special Flight Permits (f) Special flight permits may be issued in accordance with Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the requirements of this AD can be done. Effective Date (g) This amendment becomes effective on August 28, 2002.