2001-03-02: Compressor Rotor 2nd, 3rd and 4th Stage Drum Assembly

2001- 03-02 Pratt & Whitney Canada: Amendment 39-12103 Docket No. 2000-NE-51-AD. Applicability: Pratt & Whitney Canada (PWC) models PW306A and PW306B turbofan engines with compressor rotor 2nd, 3rd, and 4th stage drum assembly part numbers (P/N's) 30B4149-01, 30B4539-01, and 30B4725-01, and impellers P/N's 30B4183-01, 30B4494-01, and 30B4564-01 installed. These engines are installed on but not limited to Dornier Luftfahrt GmbH 328-300 Jet, and Israel Aircraft Industries, LTD. Galaxy airplanes. Note 1: This airworthiness directive (AD) applies to each engine 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 engines 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. Compliance Compliance with this AD is required as indicated, unless already done. To prevent premature cracking of compressor rotor 2nd, 3rd, and 4th stage drum assemblies and impellers which could result in an uncontained engine failure and damage to the airplane, accomplish the following: Compressor Rotor 2nd, 3rd, and 4th Stage Drum Assembly, and Impeller New Life Limit (a) Remove compressor rotor 2nd, 3rd, and 4th stage drum assembly P/N's 30B4149-01, 30B4539-01, or 30B4725-01, and impeller P/N's 30B4183-01, 30B4494-01, or 30B4564-01 before exceeding their new life limits in Table 1, and replace with serviceable parts. Table 1. New Life Limits. Engine Model Part Name Part NumbersFlight Count Factor Life Limit in Cycles PW306A Compressor Rotor 2nd, 3rd, and 4th Stage Drum Assembly Impeller 30B4149-01 30B4539-01 30B4725-01 30B4183-01 30B4494-01 30B4564-01 0.9 0.9 0.9 0.9 0.9 0.9 3,000 3,000 3,000 3,000 3,000 3,000 PW306B Compressor Rotor 2nd, 3rd, and 4th Stage Drum Assembly Impeller 30B4149-01 30B4539-01 30B4725-01 30B4183-01 30B4494-01 30B4564-01 1.0 1.0 1.0 1.0 1.0 1.0 3,000 3,000 3,000 3,000 3,000 3,000 Use of Flight Count Factor (b) For PW306A engines only, multiply number of flights (takeoffs and landings) by 0.9 to determine cycles. Examples: 3,333 (flights) x 0.9 (flight count factor) = 3,000 cycles. 2,850 (flights) x 0.9 (flight count factor) = 2,565 cycles. (c) Except as provided for in paragraph (d) of this AD, do not install any part identified by P/N in paragraph (a) of this AD, that exceed the new life limit. Alternative Method of Compliance (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, Engine Certification Office (ECO). Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO. Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO. Special Flight Permits (e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. Effective Date of this AD (f) This amendment becomes effective on February 21, 2001.