How long must the static switch be ON prior to takeoff in icing conditions?

How long must the static switch be ON prior to takeoff in icing conditions?

• A. 15 seconds, with a maximum of 2 minutes
• B. 1 minute
• C. 5 seconds
• D. 30 seconds

Answer: (A)

Icing can cause the static ports to ice over, which would give you incorrect airspeed readings and other unreliable air data. Turning the static port heater on during icing conditions warms the ports so any ice melts off before you take off, giving you accurate data as you depart. The recommended practice is to have the static switch ON for at least 15 seconds before takeoff to allow the ports to begin warming and clear any ice. Do not run it longer than about two minutes; this limits electrical load and avoids unnecessary prolonged heating. This timing keeps the air data honest during the critical takeoff phase.

Icing can cause the static ports to ice over, which would give you incorrect airspeed readings and other unreliable air data. Turning the static port heater on during icing conditions warms the ports so any ice melts off before you take off, giving you accurate data as you depart.

The recommended practice is to have the static switch ON for at least 15 seconds before takeoff to allow the ports to begin warming and clear any ice. Do not run it longer than about two minutes; this limits electrical load and avoids unnecessary prolonged heating. This timing keeps the air data honest during the critical takeoff phase.