W31 series Switch Style Circuit Breakers (SSCB) manufactured by Tyco or Potter Brumfield
- Published
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Owners and operators should follow the original equipment manufacturer’s recommended replacement intervals where available. For aircraft without OEM guidance, replace the SSCBs every 2,000 flight hours for normal use or every 600 flight hours for high-use aircraft such as those used in training. Additionally, implement operational procedures to verify that systems controlled by these circuit breakers are off when the breaker is switched off, and replace any SSCB that fails this check before the next flight.
Summary
The FAA Special Airworthiness Information Bulletin SAIB: CE-13-22 addresses airworthiness concerns related to W31 series switch style circuit breakers (SSCB) manufactured by Tyco or Potter Brumfield. These SSCBs are installed on various Cessna models including 401, 402, 404, 411, 414, 421, 425, and 441, as well as Beechcraft models such as F33 Series, G33, V35B, A36, B36TC, and others. The bulletin highlights failure modes that can cause power loss or overheating, potentially leading to smoke or fire hazards.
What changed
This bulletin provides updated guidance recommending replacement intervals for the affected SSCBs and operational procedures to verify proper switch function. It supplements previous FAA Airworthiness Directives AD 2005-20-25 for Cessna airplanes and AD 2008-13-17 for Beechcraft airplanes but does not mandate new regulatory actions. The FAA also notes that the current production SSCBs incorporate design improvements that mitigate the identified risks.
Why it matters
This information is critical for aviation professionals to maintain electrical system safety and prevent potential in-flight power failures or fire hazards caused by SSCB failures. Operators and maintenance personnel must be aware of the failure modes and implement recommended replacement schedules to ensure continued airworthiness and compliance with existing ADs. Proper operational checks can help detect malfunctioning SSCBs before flight, enhancing safety.
More for Cessna 401
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