WINDOW HEAT & PITOT STATIC HEAT

Question 1

OVERHEAT Lights

What could potentially cause the overheat lights to illuminate? (1sp)

Answer 1

[1sp - it means that the respective window has overheated. Remember below 10,000’ limited to 250 kts]

Illuminated (Amber):

• overheat condition is detected
• also illuminate if electrical power is interrupted (i.e. loss of electrical power)
• when this comes on, power is removed from window and [ON] light goes OUT
• MC + ANTI-ICE caution lights
• reset by turning window heat switches OFF then back on after 2-5 minutes of cooling

Question 2

ON Lights

Scenario Question - you show up to a/c and put all 4 window heat switches on.. and you only see 2 of the lights illuminated - is the system broken? (1sp)

Answer 2

[1sp - its not broken. when green light is not on it means that the respective window has reached the appropriate temperature. You will see the green lights go on and off to get them to correct temperature - its a thermostate that will cycle on and off]

Illuminated (green):

• on when window heat is being applied to selected windows

Extinguished:

• Switch is OFF
• Overheat detected
• System failure occured
• System already at correct temperature

if ON light does NOT come on - use PWR TEST to check the lights that are NOT illuminated

Question 3

WINDOW HEAT Switches

When we put the switches ‘ON’ are all sensors heated? (1sp)

Answer 3

​[1sp No - all work on the ground EXCEPT the TAT which is heated only in flight (works off the air/ground sensor)]

• there is a L and R side - both have an OFF and ON switch

ON: window heat is applied to selected windows

OFF: window heat not in use

SIDE: controls #2 (and 4 & 5 if installed)

FWD: controls heat to #1 window

Question 4

WINDOW HEAT Test Switch

• 2 positions -

OVHT

PWR TEST

Answer 4

OVHT:

• simulates an OVERHEAT condition after switch held for 1 sec and released (ON lights go out after 1 min)
• verify OVERHEAT lights go out within 5 SECONDS after resetting switch

PWR TEST: provides a confidence test

• verifies operation of the window heat system
• DO NOT TEST if ALL 4 lights are ON
• release switch as soon as test is verified (prevent overheating windows)

switch is spring loaded to Neutral

Question 5

PROBE HEAT Lights

• 4 on each side -

CAPT / FO

L / R ELEV PITOT

L / R ALPHA VANE

TEMP PROBE (L)

AUX PITOT (R)

What does this light(s) mean if on? (1sp)

Answer 5

[1sp - it means the respective probe is not receiving heat]

Illuminated (Amber):

• related probe is NOT HEATED
• if on STANDBY power - probe heat lights do NOT indicate system status
• MC + ANTI-ICE caution lights

Question 6

PROBE HEAT Switches

Answer 6

ON: power is supplied to heat the system

OFF: power is OFF

AUTO: power is automatically supplied to BOTH A and B probe heat systems when either engine is running

* Static ports are NOT heated