EASA AD US-2020-15-17
Indicating / Recording System - Remote Data Acquisition and Display Units - Software Update
Summary
The Federal Aviation Administration's Airworthiness Directive 2020-15-17 addresses certain Sikorsky Aircraft Corporation Model S-76C helicopters equipped with specific remote data acquisition units (RDAU) part numbers 76450-01098-106, 76450-01098-107, or 76450-01098-109. This directive mandates software updates to the RDAU and, for some helicopters, the display unit (DU) software to correct inaccurate main gear box (MGB) indications during flight. The directive aims to enhance flight safety by ensuring accurate MGB data is displayed to flight crews.
What Changed
This new airworthiness directive introduces mandatory software updates for the RDAU and, where applicable, the DU on affected Sikorsky S-76C helicopters. It requires re-identification of these units after software updates to address erroneous MGB indications that could lead to unsafe flight conditions. The directive sets a compliance time of 500 flight hours for completing these updates.
Why It Matters
Accurate main gear box indications are critical for safe helicopter operation, and erroneous readings could cause unnecessary emergency landings or accidents. For operators and maintenance organizations, complying with this directive prevents potential safety hazards and ensures regulatory compliance. The updates reduce the risk of injury, fatality, and aircraft loss associated with faulty MGB data.
What To Do
Operators of affected Sikorsky S-76C helicopters must update the RDAU software and re-identify the unit within 500 hours time-in-service from the directive's effective date. For helicopters equipped with certain display units, the DU software must also be updated and re-identified within the same timeframe. Additionally, operators must report inspection results to Sikorsky Aircraft Corporation as specified in the service bulletins.
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