Cabin Ventilation Air Scoop Draining

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FAA Aviation Safety SPECIAL AIRWORTHINESS INFORMATION BULLETIN SUBJ: Cabin Ventilation Air Scoop Draining SAIB: SW-15-04 Date: November 25, 2014 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin alerts owners and operators of all versions of Airbus Helicopters AS350 and AS355 helicopters of the possibility of a total loss of electrical power due to water entering into the cabin.

At this time, the airworthiness concern is not an unsafe condition that would warrant airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part 39.

Background

During flight, the pilot of an AS355 helicopter was splashed with water, while the source of the water could not be identified. Immediately after, the display on the Vehicle and Engine Multifunction Display (VEMD) was affected. A few days after this incident, a total loss of the electrical power system in-flight was reported and after landing it was not possible to stop the engines with the dedicated selectors. The engines were stopped using the fuel shut-off controls.

Further analysis determined that the loss of the electrical power supply was probably due to water ingress, affecting the electrical connectors of the instrument panel equipment items. This was likely caused by a partially obstructed or blocked drain of the cabin ventilation air scoop. Depending on the flight parameters (speed, attitude, rain, etc.), the water inside this scoop may ingress inside the cabin and can affect various avionics and vehicle systems.

Recommendations

Inspect the ventilation air scoop drain for blockage. Clear any blockage found.

For Further Information Contact

Matt Wilbanks, Aerospace Engineer, FAA, Rotorcraft Directorate, Regulations and Policy Group, Fort Worth, Texas 76137; phone: (817) 222-5110; fax: (817) 222-5961; e-mail: [email protected].