System Description:
A heated glass panel is installed on the exterior of the pilot’s windscreen to ensure forward visibility in icing conditions.
Controlled by the WSHLD HEAT switch on the ice protection control panel, the system draws approximately 10 amps when selected on.
System Operation:
The panel quickly becomes very hot and may damage the windscreen if sufficient cold airflow is not present to regulate its temperature. Therefore:
- On the ground, do not switch on the WSHLD HEAT on for more than 30 seconds.
- In the air, the WSHLD HEAT may be selected ON, and remain ON, when the OAT is +5°C or less and visible moisture is present.
- Switch OFF the WSHLD HEAT when OAT increases above +5°C or immediately after landing.
In use, as well as clearing ice from its surface, the heater melts ice in a large area surrounding it as well.
System Test:
The WSHLD HEAT must be tested and functioning before flight in possible icing conditions.
Due to the 30 second limitation above, the system should not be tested during the “A” Check, but should be selected on during the ice protection system checks after engine start.
- Select the WSHLD HEAT on.
- Within 30 seconds, confirm that the additional extra current drawn on the ALTR AMPS is approximately 10 amps.
- Select the WSHLD HEAT off.
