EASA AD US-2018-02-13
Main Rotor Drive - Drive Shaft - Inspection / Replacement (Life Limitation)
Summary
The FAA Airworthiness Directive 2018-02-13 titled 'Main Rotor Drive - Drive Shaft - Inspection / Replacement (Life Limitation)' applies to Sikorsky Model 269D and Model 269D Configuration A helicopters equipped with KAflex engine side drive shaft P/N SKCP2738-7 and pulley side drive shaft P/N SKCP2738-5. This directive mandates inspections and life limit reductions for these drive shafts to prevent failure. It supersedes a previous directive and requires repeated inspections to ensure continued airworthiness.
What Changed
This directive supersedes AD 2017-07-02 by retaining its requirements and adding repetitive inspections every 100 or 400 hours time-in-service. It reduces the service life limit for drive shafts on Model 269D Configuration A helicopters from 3,000 to 1,200 hours and mandates replacement if certain inspection criteria are met. Additionally, it specifies stricter replacement criteria for spline engagement interference, joint movement, and fretting corrosion than the previous service information.
Why It Matters
This AD addresses a critical safety issue involving potential drive shaft failure that could lead to loss of rotor drive and helicopter control. For operators and maintenance personnel, adhering to these updated inspection intervals and replacement criteria is essential to prevent in-flight failures. Compliance ensures continued airworthiness and reduces the risk of accidents related to drive shaft malfunctions.
What To Do
Operators must remove from service any affected drive shafts exceeding 6,000 hours TIS for Model 269D or 1,200 hours TIS for Model 269D Configuration A before further flight. They must perform repetitive inspections of the drive shafts as specified, including alignment and damage checks, and replace drive shafts if any interference, joint movement, or corrosion is detected. The AD became effective on March 5, 2018, and compliance with all actions is mandatory within the specified time frames.
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