Engine Controls — Microswitches — Inspection / Modification
- Published
- Effective
- Replaces
- 2023-0133
- Replaces
- 2023-0187
- Replaces
- 2017-0059
- Replaces
- 2017-0052
- Replaces
- 2013-0191-E
- Replaces
- 2013-0061
- Replaces
- 2009-0256
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators must modify affected helicopters by installing or updating modifications MOD 074263, MOD 074699, and MOD 074782 within specified compliance times, including within 6 months or 10 flight hours depending on the helicopter configuration. Repetitive inspections and functional tests of the 'IDLE' and 'FLIGHT' controls on pilot and co-pilot twist grips must be conducted at intervals defined in the directive. Helicopters already modified per previous instructions require additional corrective work as specified in the updated service bulletins.
Summary
EASA Airworthiness Directive 2023-0187R1 is an updated regulatory document addressing inspection and modification requirements for engine control microswitches on Airbus Helicopters AS 350 and EC 130 models. It focuses on affected microswitches with Part Number T3933-3 and pilot twist grips with specific part numbers, aiming to ensure safe operation of the engine power control system. The directive applies to all serial numbers of AS 350 B3, EC 130 B4, and EC 130 T2 helicopters.
What changed
This revision refines the definition of salt-laden atmospheric conditions to align with Airbus Helicopters' maintenance manual and amends modification procedures to correct previous errors. It updates compliance requirements for installation and inspection of modifications MOD 074263, MOD 074699, and MOD 074782, including additional work for helicopters already modified. The directive retains prior inspection and modification mandates while adjusting compliance timelines and applicability.
Why it matters
The directive addresses a critical safety issue where failure of engine control microswitches could prevent pilots from switching from 'IDLE' to 'FLIGHT' mode, potentially leading to inability to abort autorotation landings. For operators and maintenance organizations, compliance ensures continued airworthiness and mitigates risks of engine power loss due to corrosion or faulty microswitch operation. It also clarifies maintenance procedures and compliance deadlines, aiding regulatory adherence and operational safety.
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