Airworthiness Directive · Amendment 39-17091 · Engine eft/tot indicating system
Bell Helicopter Textron Canada, Limited, Helicopters
This AD applies to Model 206, 206A, 206A-1, 206B, 206B-1, 206L, 206L-1, 206L-3, and 206L-4 helicopters, certificated in any category, modified with Aviation Specialties Unlimited, Inc. (ASU), Night Vision Imaging System (NVIS) lighting installed per Supplemental Type Certificate (STC) SR01383SE.
We are adopting a new airworthiness directive (AD) for Bell Helicopter Textron Canada (Bell) Model 206, 206A, 206A-1, 206B, 206B-1, 206L, 206L-1, 206L-3, and 206L-4 helicopters, with Aviation Specialties Unlimited, Inc. (ASU), Night Vision Imaging System (NVIS) lighting modified by Supplemental Type Certificate SR01383SE (STC). This AD requires determining the date of STC installation, determining if the aircraft has an unfiltered turbine outlet temperature (TOT) internal over-temperature warning light, and based on those findings, installing an NVIS filter. This AD was prompted by the finding that an unfiltered TOT indicator over-temperature warning light, when illuminated, created glare and reflections that could degrade the pilot's view while using night vision goggles thereby creating an unsafe condition. The actions of this AD are intended to modify any unfiltered TOT indicator unit over-temperature warning light by installing a filter to prevent degradation of the pilot's vision while using night vision goggles and to prevent subsequent loss of control of the helicopter.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
Within 30 days or 50 hours time-in-service, whichever occurs first:
(1) Determine the date of the STC installation.
(2) If the date of the STC installation is on or before April 6, 2011, or the date is undocumented, determine whether the cockpit TOT indicator unit has an unfiltered internal over-temperature warning light. If the unit has an unfiltered internal over-temperature warning light, install an NVIS filter, part number ASU-TOTGAG-1.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
