AST 473 Cessna Citation II CE550 Systems Dr

AST 473 Cessna Citation II- CE-550 Systems Dr. Barnhart Ice & Rain System

Anti-Ice, De-Ice, and Rain Protection Systems • Anti-Ice Systems: – Wing – Engine Components – Windshield (bleed air and isopropyl alcohol) – Pitot-Static/AOA systems *All components should be activated prior to entering icing conditions

De-Icing Systems • Pneumatic boots on outboard wing sections, horizontal and vertical tail segments. *Activated upon ice accumulation

Rain Protection • Compressor bleed air directed through louvers provides a layer of air directing rain off of the windscreen.

Anti-Ice General Detail • Engine Anti-Ice Protection: – T(1) Temp. probe (bleed air) – Nose Cone (bleed air) – Nacelle Inlet (bleed air) – 1 st set of engine stator vanes (bleed air) – Inboard Wing sections (electric) – Nose cone and T(1) probe are continually protected while the others require the engine anti-ice switch to be positioned on

Pitot/Static Anti-Ice • Pilot switch controls DC power to two pitot masts, four static ports, and the AOA probe (breakers located on pilot’s panel) • P/S HTR OFF annunciator illuminates anytime power is disrupted to this circuit (switch off or failure- AOA heater not on this warning circuit) *Ground operation to P/S Heat limited to two minutes to prevent AOA probe damage.

Windshield Anti-Ice and Rain Removal • Anti-Ice protection controlled via a three- way switch (hi, low, and off) on pilot’s panel, which, along with the two bleed air valve control knobs direct bleed air to the windshield – Main power switch de-energizes the windshield bleed-air valve open and activates a temp. controller

Windshield Anti-ice • HI position- 138 +/- 5 deg. - use when OAT is At or below -18 deg. C , Low 127 +/-5 deg. - use when OAT is above -18 deg. C • Temp. is maintained by the temp. controller which receives 3 inputs: – W/S Bleed switch position – 2 ea. Temp. sensor inputs *Sensor modifies amt. of ram air passing through the heat exchanger

Windshield Anti-ice • Modified Bleed air then passes through a series of nozzles onto the windscreen • Additional temp. sensor located in the bleed air duct- automatically energizes closed the electric bleed air solenoid valve if bleed air temp. > 146 deg. C. – At this point the W/S Air O’HEAT annunciator illuminates (happens at high power/low airspeed config. - valve resets and light extinguishes automatically upon correction

Windshield Anti-ice • If the W/S AIR O’HEAT light illuminates with the switch OFF: – Bleed-air valve opened pressurizing the ductsensed by a duct pressure switch – Pilot action: ensure W/S Bleed Valves OFF – NOT an over pressure but a valve position warning

Windshield Anti-ice • In DC failure: Bleed air Solenoid valve opens- W/S bleed air avail. But no O’Heat warning and temp cnt’l are inop. • Operation of system is verified by the noise when valves are open thus damage should be prevented in a DC pwr. failure

Windshield Alcohol • Back up to W/S Bleed system • Components: – – Reservoir- 2 qts. Capacity isopropyl alcohol Switch- W/S ALCOHOL- 2 pos. Pump Nozzles *Up to 10 min. protection- pilot’s side only- fluid qty. verified on pre-flight via a sight gauge in rt. Hand nose cmpt.

Rain Removal System • Uses Bleed air from Windshield De-ice system via • doors Activated by pulling open the PULL RAIN handle under W/S Bleed Air knobs – Rotate W/S Bleed air knobs to MAX – Position W/S Bleed switch to LOW – During low power settings (landing) rotate co-pilot’s W/S Bleed Air knob to OFF – RAIN handle hard to pull of bleed air already on

Engine Anti-Ice • Meant as an ice preventative measure- activation after ice accumulation cause engine damage • Activate when OAT is between +10 and 30 deg. C • For sustained Ground operation in visible moisture at the above temps. Activate engine anti-ice for 1 min. out of 4 AOA 65%N(2).

Engine Anti-Ice • Components: – Electric Heating elements in inboard scn. Of each wing leading edge – Bleed air heated engine nacelle inlets – First row of stationary stators behind the first state fan and prior to the booster stage – Nose Cone and T(1) probe continually on – Activated by ENGINE ANTI-ICE switch on pilot’s panel

Engine Anti-Ice Operation • Select ENGINE ANTI-ICE ON: – If engines above 60% for > 5 sec. (throttle micro-switch) 2 bleed-air solenoid valves deenergize open allowing bleed air to flow to nacelle inlet and stator vanes • Look for a Rise in ITT and a slight drop in RPM • 5 sec. time delay built in to aid in faster engine spool up during periods of high demand (ie. Goaround)

Engine Anti-Ice Operation • ENG ANTI-ICE LH/RH annunciators illuminate when switches placed on and extinguish when nacelle inlet temps. >224 deg. F AND Stator vane bleed-air solenoid valve open, AND wing leading edge heaters are operating w/ temp AOA 60 deg. F

Engine Anti-Ice • Annunciator will re-illuminate for any of the following: – Stator valve fails to open (5 s delay normal) – Nacelle leading edge temp < 104 deg. C – Inboard wing scn. Temp < 16 deg. C – Failure of 1 or > wing heat elements (Light will illuminate each cycle if one failed) – Failure of the temp. controller (light cycles off when the leading edges are heated and on when temp. limit is reached).

Engine Anti-Ice Caution • During descents in icing conditions avoid throttle settings below 60% as engine bleed-air solenoid valves will close (annunciator will illuminate)

Wing Anti-Ice System • 5 elec. Heating elements in each wing each with • • • it’s own CB and current sensor powered by main DC buses respectively Operated when power is on regardless of throttle position. Maintains skin temp. bet. 54 and 78 C Over-temp sensor on upper surface (cooler) activates at 75 C and opens circuit maintaining temp. @ 69 C. - Activates ENG ANTI-ICE LH/RH

Wing Anti-Ice System • Operation monitored by illumination of green lights above each ignition switch, illumination of the ENG ANTI-ICE LH/RH annunciator and a 150 amp rise on each ammeter. • If throttles are above 60% N(2) • During Electrical Failure both nacelle inlet valve and stator vane valve will fail open and engine will be anti-iced continuously

De-Ice System • Boots on outer wing leading edges, and horizontal and vert. stabilizer • Controlled by SURFACE DE-ICE Switch on pilot’s instrument panel • Bleed air is available to system when engines operating- timer switch controls automatic sequencing of boot operation • Power is via SURFACE DE-ICE CB

De-Ice System Overview • Activate when ¼ to ½ inch of ice present • Use ½ inch thick stall strip on wing leading edge as a guide- early activation may cause bridging- (use L. wing inspn. Light) • Ice thicker than ½ inch may not be able to be removed by boots • If DC fails- avoid icing conditions • Avoid activation below -40 Deg. C- boot damage may occur

De-Ice System Operation • SURFACE DE-ICE switch- de-energized to OFF- all 3 control valves de-energized • In OFF the 3 valves are dumping bleed air overboard via venturis that create vacuum to hold boots deflated • To cycle boots momentarily place switch in SURFACE DE-ICE Position- energized system timer for 2 ea. 6 sec. cycles- 1 st cycle is empennage (wings held tight)

De-Ice System Operation • 2 nd cycle- wings (empennage held tight) • After 12 seconds (2 ea. 6 sec. cycles) all 3 valves • • are de-energized closed and vacuum is applied to all boots to hold closed During operation (as each set is inflated) the white SURF DEICE annunciator is illuminated by a pressure switch In the event of a malfunction and boots remain inflated- cycle switch to RESET- overrides the system timer and de-energizes all control valvesholds boots deflated.

The End