Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Airbus Helicopters Model AS 365 N2, AS 365 N3, EC 155 B, EC 155 B1, SA 365 N, and SA 365 N1 helicopters. This proposed AD was prompted by gaps between the seals and engine cowling, which were found during an investigation related to an engine compartment fire. Gaps between the seals and engine cowling could cause inadequate sealing of the engine compartment firewalls leading to fire propagation between engine compartments and reduced effectiveness of the extinguishing agent. This proposed AD would require modifying the engine compartment firewalls by installing angle-brackets along the firewalls. The FAA is proposing this AD to address the unsafe condition on these products.