EASA AD US-2021-20-01
Engine - High Pressure Turbine Stage 1 Hub / Blade Retaining Plate - Replacement
Summary
The Federal Aviation Administration's Airworthiness Directive 2021-20-01 addresses Pratt & Whitney PW1500G and PW1900G series turbofan engines equipped with certain high-pressure turbine (HPT) 1st-stage hubs and HPT rotor 1st-stage blade retaining plates. This directive mandates the removal and replacement of these parts before reaching specified cycle limits to prevent potential failure. The directive applies to multiple engine models including PW1519G, PW1521G, PW1524G, PW1919G, and others.
What Changed
This new airworthiness directive introduces mandatory replacement requirements for the HPT 1st-stage hub and HPT rotor 1st-stage blade retaining plate on affected Pratt & Whitney engines. It specifies detailed compliance thresholds based on cycles since new (CSN) and engine shop visit schedules. The directive also clarifies the cycle limits at which parts must be removed and replaced to mitigate unsafe conditions.
Why It Matters
This directive is critical for aviation professionals as it addresses a safety risk due to parts not meeting published life-cycle limits, which could lead to engine damage or failure. Operators and maintenance organizations must track engine cycles closely to ensure timely replacement of these components. Compliance ensures continued airworthiness and prevents in-service failures that could compromise flight safety.
What To Do
Operators of affected Pratt & Whitney PW1500G and PW1900G series engines must remove and replace the specified HPT 1st-stage hub and blade retaining plate before exceeding the cycle limits outlined in the directive. Compliance deadlines vary depending on the current cycles since new and must be met by the next engine shop visit or within 300 cycles after the effective date, whichever occurs first. The directive became effective on October 27, 2021.
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