C90 Ice & Rain Flashcards
Windshield Anti-ice
Operations
POH 7-78
A transparent material (Stannic) is incorporated in the laminations of each windshield in addition to temperature sensing elements, Current from the XXXX Bus is passed through the Stannic material increasing the temperature of the glass and providing anti-ice protection. Automatically controls required temperature (range between 32°C and 43°C)
PILOT & COPILOT NORMAL
the secondary areas of the windshield are heated
HI
The primary areas (smaller areas, heated to a higher temp) are heated
Flight In Known Icing Conditions
Limitations
POH 4-25
POH 3A-10 Abnormal Procedures
Minimum IAS for sustained icing is not below 140kts
Sustained flight in icing conditions with flaps extended is prohibited, except for approach and landing
Conditions of +5°C or lower require engine anti-ice if conditions free of visible moisture cannot be assured
Windshield Anti-ice
Limitations
Erratic operation of the magnetic compass may occur while windshield heat is being used
Windshield Anti-ice must be operational for flight in icing conditions
Cracks must not impair visibility
Flights may be continued up to 25 flight hours with inspected damage
Engine Anti-ice:
The lip around each engine air inlet is heated by hot engine exhaust to counteract ice accumulation on the engine inlet. A scoop in the left exhaust stack on each engine diverts a portion of the hot exhaust downward through a duct into the hollow lip of each engine inlet.
The exhaust is then ducted back to the right exhaust stack of each engine where it is expelled into the atmosphere
This system is in operation any time the engines are running and will require little maintenance
This system is in addition, and not to be confused with the Engine Inertial Separator.
The Inertial Separator, has a main ‘Normal’ Mode and a ‘Standby’ mode as a backup. This allows redundancy in case the main flap actuators fail.
Propeller Deice:
POH 7-79
**The systems is not to be used when propeller blades are stationary as overheating will occur. **
The automatic Propeller Deice uses thermal eclectic mats to provide propeller de-icing. The timer directs current to the single-element propeller boot in the following sequence:
* 90 sec to all boots on Propeller Group 1 (4 propeller blades per engine)
* 90 sec to all boots on Propeller Group 2
The timer completes 1 cycle in 3 minutes. During operation, the propeller ammeter (overhead panel) will indicate a range of 18 to 24 amperes. Constant electrical connection to the Triple feed bus is permitted through the use of a slip ring and contactor arrangement on the propeller hub
The systems is not to be used when propeller blades are stationary as overheating will occur.
Surface Deice:
POH 7-80
Pneumatic de-icing is available for the leading edge of the aerofoil and the leading edge of the vertical and horizontal tailplanes.
The de-icer and vacuum system is operated with pressure obtained by bleeding air from the engine compressors. This air is routed through a regulator valve that is set to maintain the pressure required to inflate the de-icer boots on the leading edge of each wing and the horizontal stabilizers.
To assure operation of the system should one engine fail, a check valve is incorporated into the bleed air line from each engine to prevent the escape of air pressure into the chamber of the inoperative boot.
The bleed air from the engine is also routed through ejectors that employ the venturi effect to reduce vacuum for deflation of the de-icer boot. This vacuum pressure also holds the boots flush with the aerofoils when not in use
Operation below -40°C can cause permanent damage to deice boots
Surface Deice:
Cycle
**SINGLE: **
6 seconds cycle. A timer acts to deflate the wing boots, and then a 4 second inflation begins in the empennage boots. When these boots have inflated and deflated, the cycle is complete
**MANUAL: **
All of the boots will inflate simultaneously and remain inflated until the switch is released.
Ancillary System DeIce
Pitot Mast Heat
When operating there will be a slight increase on the load meter
Stall Warning Anti-ice:
The level of heat is minimal for ground operation Automatically increased for flight operation via air-ground logic
Fuel Heat:
An oil-to-heat exchanger located in the engine accessory case. Operates continuously to heat the fuel sufficiently to prevent ice from collecting in the fuel control unit
Fuel Vent Heat:
The fuel vents for each tank are electrically heated to prevent ice formation, that could possibly result in fuel starvation
Windscreen Wipers:
The system is activated via a switch located in the overhead panel
Selecting off will stop the wipers in their current position. Park must be selected to return them to the home position
The wipers must not be used on a dry surface, as damage will occur.
NO Rain repellent is available on this aircraft.
