AD 2021-14-06 Airworthiness Directives; Pratt & Whitney Turbofan Engines

This AD applies to Pratt & Whitney (PW) PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-3, PW1525G, PW1525G-3, PW1919G, PW1921G, PW1922G, PW1923G, and PW1923G-A model turbofan engines.

Comply with this AD within the compliance times specified, unless already done.

(1) Except for those model turbofan engines identified in paragraph (g)(2) of this AD, perform a borescope inspection (BSI) of the LPC R1 for damage and cracks as follows: (i) For engines that have accumulated fewer than 300 flight cycles since new (CSN), perform a BSI within 50 flight cycles (FCs) from September 26, 2019 (the effective date of AD 2019-19-11), or before further flight, whichever occurs later. (ii) For engines that have accumulated fewer than 300 FCs since installation of V2.11.7 or V2.11.8 electronic engine control (EEC) full authority digital electronic control (FADEC) software, perform a BSI within 50 FCs from October 29, 2019 (the effective date of AD 2019-21-11), or before further flight, whichever occurs later. (iii) Thereafter, at intervals not to exceed 50 FCs until the engine accumulates 300 flight CSN or accumulates 300 FCs since the installation of V2.11.7 or V2.11.8 EEC FADEC software, whichever occurs later, repeat the BSI for damage and cracks. (iv) Perform the BSI required by paragraphs (g)(1)(i) through (iii) of this AD at the following LPC R1 locations: (A) The blade tip; (B) The leading edge; (C) The leading edge fillet to rotor platform radius; and (D) The airfoil convex side root fillet to rotor platform radius. (2) For any affected PW model turbofan engine installed as a “zero time spare,” except for PW1519G, PW1521GA, PW1919G, and PW1922G model turbofan engines, within 15 FCs from the effective date of this AD, and thereafter at intervals not to exceed 15 FCs until the engine accumulates 300 flight CSN, perform a BSI of the LPC R1 for damage and cracks at the locations in paragraph (g)(1)(iv) of this AD. (3) Based on the results of the BSIs required by paragraphs (g)(1) and (2) of this AD, before further flight, remove and replace the LPC R1 if: (i) There is damage on an LPC R1 that exceeds serviceable limits; or (ii) Any crack in the LPC R1 exists. Note 1 to paragraph (g)(3): Guidance on determining the serviceable limits in paragraph (g)(3) of this AD can be found in PW Service Bulletin (SB) PW1000G-A-72-00-0125-00A-930A-D, Issue No. 002, dated October 24, 2019, and PW SB PW1000G-A-72-00-0075-00B-930A-D, Issue No. 003, dated October 24, 2019. (4) For PW PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-3, PW1525G, and PW1525G-3 model turbofan engines, within 120 days from the effective date of this AD, remove the EEC FADEC software if the version is earlier than EEC FADEC software version V2.11.10.4 and install EEC FADEC software that is eligible for installation. (5) For PW PW1919G, PW1921G, PW1922G, PW1923G, and PW1923G-A model turbofan engines, within 120 days of the effective date of this AD, remove the EEC FADEC software if the version is earlier than EEC FADEC software version V9.5.6.7 and install EEC FADEC software that is eligible for installation. (6) For PW PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-3, PW1525G, and PW1525G-3 model turbofan engines with EEC FADEC software version V2.11.10.4 or later installed, within 15 FCs after receipt of Onboard Maintenance Message fault code 7100F0029 or 7100F0030, perform a BSI of the LPC R1 for damage and cracks at the locations in paragraph (g)(1)(iv) of this AD if the fault code is displayed on the “Active Failure Messages” and meets the following criteria: (i) N1 Exceedance is above 95.2%; (ii) N1 Exceedance occurred above 29,100 feet; and (iii) N1 Exceedance occurs for a duration of 40 seconds (15 seconds of cockpit display) or more during any flight. Note 2 to paragraph (g)(6): Guidance on determining the N1 Exceedance duration can be found in PW Section PW1000G-A-72-00-00-02A-0B5A-A of PW Engine Maintenance Manual (EMM), Issue No. 016, dated January 15, 2021. Note 3 to paragraph (g)(6): Guidance on performing the BSI can be found in PW Section PW1000G-A-72-31-00-00A-312A-D of PW EMM, Issue No. 016, dated January 11, 2021. (7) As the result of the BSI of the LPC R1 required by paragraph (g)(6) of this AD, before further flight, remove and replace the LPC R1 if: (i) There is damage on an LPC R1 that exceeds serviceable limits; or (ii) Any crack in the LPC R1 exists.

This AD was prompted by reports of in-flight shutdowns due to failure of the low-pressure compressor (LPC) rotor 1 (R1) and by subsequent findings of cracked LPC R1s during inspection. The FAA is issuing this AD to prevent failure of the LPC R1. The unsafe condition, if not addressed, could result in uncontained release of the LPC R1, damage to the engine, damage to the airplane, and loss of control of the airplane.

This AD replaces AD 2019-21-11, Amendment 39-19777 (84 FR 57813, October 29, 2019); and AD 2020-07-02, Amendment 39-21106 (85 FR 17742, March 31, 2020).