EASA SIB 2008-28
CASA Australia AWB 80-002 - Sikorsky S-76 Helicopters - Corrosion of #1 and #2 DC Starter/Generator Earth Points
Summary
CASA Australia AWB 80-002 is an Airworthiness Bulletin addressing corrosion issues on the #1 and #2 DC Starter/Generator earth points of Sikorsky S-76 series helicopters. The bulletin highlights the risk of generator failure due to corrosion and insufficient torque at these earth points. It applies to all models and serial numbers of Sikorsky S-76 rotorcraft.
What Changed
This bulletin introduces a new safety advisory to operators and maintainers of Sikorsky S-76 helicopters regarding the inspection and maintenance of DC Starter/Generator earth points. It identifies corrosion and loose connections as causes of generator failure and recommends inspection, replacement, and re-torquing of affected components. The bulletin is informational and endorsed by EASA despite CASA not being the State of Design authority.
Why It Matters
The corrosion and loose earth points can cause generator failures, which may lead to electrical system malfunctions and impact flight safety. Operators and maintenance organizations need to be aware of this issue to prevent unexpected generator outages. Compliance with the bulletin helps ensure continued airworthiness and reliability of Sikorsky S-76 helicopters.
What To Do
Operators of Sikorsky S-76 helicopters should inspect all DC Starter/Generator earth points for corrosion and correct torque settings. Any corroded or damaged earth points must be replaced, and loose connections should be re-torqued to the recommended specifications. Findings of corrosion or damage should be reported to CASA via the standard SDR reporting system. No explicit compliance deadline is stated.
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