EASA SIB SW-11-24
Garmin 400/500 series GPS on Rotorcraft with Aeroplane (fixed-wing) TAWS Function Activated
Summary
The FAA Special Airworthiness Information Bulletin SAIB: SW-11-24 addresses the use of Garmin 400/500 series GPS Navigation Systems with the airplane Terrain Awareness and Warning System (TAWS) function activated on rotorcraft. It highlights that these TAWS functions are designed for fixed-wing airplanes and are not approved for rotorcraft, such as helicopters, due to differences in operational altitudes and system algorithms. The bulletin specifically mentions rotorcraft equipped with these Garmin systems and the Bell 206B helicopter model with an approved HTAWS STC.
What Changed
This bulletin informs operators that activating the airplane TAWS function on rotorcraft equipped with Garmin 400/500 series GPS units is an airworthiness concern but does not currently warrant an airworthiness directive. It introduces the recommendation to deactivate the airplane TAWS function until an approved Helicopter Terrain Awareness and Warning System (HTAWS) installation is incorporated. Garmin has obtained an STC for HTAWS functionality on the Bell 206B helicopter.
Why It Matters
This information is important for aviation professionals because operating a TAWS system designed for fixed-wing aircraft on rotorcraft can cause nuisance alerts and distractions, increasing pilot workload and potentially reducing safety during low-altitude flight. Operators and maintenance personnel need to be aware of the limitations and regulatory status to ensure compliance and maintain safe operations. It also guides compliance teams on the appropriate TAWS systems to install on rotorcraft.
What To Do
Operators of rotorcraft with Garmin 400/500 series GPS units should deactivate the airplane TAWS function using the procedure in the Garmin installation manuals until an approved HTAWS system is installed. They are encouraged to seek installation of an approved HTAWS system to gain terrain awareness benefits safely. No specific compliance deadline is provided in the bulletin.
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