Knowledge of your IAS and awareness of approach to the stall is fundamental. As both the pitot probe and stall warning vanes have to be forward facing, they are very prone to icing. Therefore both are fitted with heaters that should be selected ON before takeoff and OFF after landing.
Both heaters are controlled by one switch on the Ice Protection System control panel marked PITOT STALL WARN HEAT. When selected on the heaters gain temperature very quickly and will burn if touched.
Due to the high temperature achieved when stationary, use of the PITOT STALL WARN HEAT is limited to 3 minutes when the aircraft is on the ground.
The system must be checked during the ‘A’ Check, but care must be taken to avoid burns and exceeding the 3 minute limitation.
The system must be checked again during the After Start checks:
- Select PITOT STALL WARN HEAT to ON.
- Check that the PITOT HEAT OFF message on the CAS extinguishes.
- Ensure that approximately 10 amps of additional current is drawn from the alternators
- Check that no PITOT HEAT FAIL message appears on the CAS.
- Select PITOT STALL WARN HEAT to OFF.