EASA SIB 2026-08
Diode Cooler Assembly Insulation - Inspection
Summary
EASA Safety Information Bulletin 2026-08 is an airworthiness bulletin addressing inspection of diode cooler assembly insulation on small aeroplanes certified under CS-23, including the Piper PA-28RT-201T Arrow IV. The bulletin highlights an in-flight fire incident caused by electrical failure due to insulation faults in the diode cooler assembly and references related investigations and FAA guidance. It provides safety information and recommendations to prevent similar electrical failures.
What Changed
EASA SIB 2026-08 introduces recommendations for detailed inspections of diode cooler assemblies and their insulation to detect wear, damage, or contamination that could lead to electrical short circuits and fires. It draws attention to Piper Aircraft Service Bulletin No. 1428 and FAA notices emphasizing recurring inspections and maintenance practices. The bulletin does not mandate regulatory action but encourages inclusion of these inspections in maintenance programs.
Why It Matters
This bulletin matters because electrical failures in diode cooler assemblies can cause in-flight fires, posing significant safety risks. Operators and maintenance personnel need to be aware of potential insulation degradation and contamination that may not be covered by existing inspection requirements. Proactive inspections and adherence to recommended practices help mitigate fire risks and enhance aircraft safety.
What To Do
Aircraft owners and operators should incorporate detailed inspections of diode cooler assemblies and their insulation into their maintenance programs, performing them at the next scheduled inspection and subsequently at each maintenance interval. Maintenance personnel must inspect for heat damage, wiring issues, insulation wear, and contamination following applicable instructions for continued airworthiness and accepted maintenance standards. Manufacturers are advised to review designs and update maintenance instructions as needed.
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