EASA AD US-2021-22-19
Engine - Stage 3/4 Low Pressure Turbine Blades and LPT-to-Exhaust Case Bolts - Inspection / Replacement
Summary
Airworthiness Directive 2021-22-19 is a final rule issued by the FAA addressing Pratt & Whitney JT8D-209, JT8D-217, JT8D-217A, JT8D-217C, and JT8D-219 turbofan engines. It mandates revised inspection and replacement requirements for the 3rd-stage and 4th-stage low-pressure turbine (LPT) blades and LPT-to-exhaust case bolts to prevent unsafe conditions. This directive applies to engines installed on aircraft such as the MD-82 and aims to enhance engine safety by preventing LPT blade fracture and uncontained blade release.
What Changed
This AD supersedes AD 2011-07-02, updating the inspection thresholds and replacement intervals for the 3rd-stage and 4th-stage LPT blades. It retains certain previous requirements but introduces more restrictive torque inspection intervals and mandates blade replacement before accumulating 5,000 hours time-in-service. Additionally, it continues requirements for replacing LPT-to-exhaust case bolts and nuts and installing crushable sleeve spacers.
Why It Matters
The directive addresses a critical unsafe condition that has led to engine surges and uncontained LPT blade failures, which pose significant risks to aircraft safety. For operators and maintenance organizations, adhering to these updated inspections and replacement schedules is essential to prevent engine damage and potential in-flight hazards. Compliance ensures continued airworthiness and reduces the risk of costly unplanned maintenance or accidents.
What To Do
Operators of affected Pratt & Whitney JT8D engines must perform initial and repetitive torque inspections of the 3rd-stage and 4th-stage LPT blades according to the revised intervals specified in Pratt & Whitney Alert Service Bulletin No. JT8D A6224, Revision No. 7. They must replace LPT blades before reaching 5,000 hours time-in-service and replace LPT-to-exhaust case bolts and nuts with crushable sleeve spacers as required. All actions must be completed by December 28, 2021, or within the compliance times specified in the service bulletin.
AI-generated summary from official EASA source document. Always verify against the original.