Page 11-8
Pilot’s Operating Manual
Revision A1: Nov, 2002
Sub-section 11
ICE PROTECTION
Hawker 800XP Pro Line 21
Section III - SYSTEMS DESCRIPTION
ENGINE BLEED AIR ANTI-ICING
Air is bled from two stages of the engine compressor to provide supplies for:
• Nacelle inlet cowl anti-icing
• Airplane services
An ENG ANTICE ON-OFF switch, located on the roof panel ice protection section, is provided for each
engine. With either or both switches selected to ON, an ICE PROT SELECTED annunciator on the
MWS panel is illuminated.
Each switch controls a servo-operated anti-icing on-off valve. When ON is selected, the following events
occur:
• The anti-icing valve opens and high pressure air is bled from the HP compressor and ducted
forward to anti-ice the nacelle inlet cowl.
• Electrical power is supplied, via the fuel computer switch when set to AUTO, to the Pt
2
and Tt
2
sensor probe heaters located in the inlet.
• In flight, the engine digital computers are reset to a schedule that incorporates a raised idle rpm to
compensate for the effect on thrust.
• The temperature provided by the A panel windscreen heating film is raised from the normal setting
to ensure adequate anti-icing performance.
Warning Annunciators
With the ENG ANTICE switched ON, low pressure flow into the inlet cowl is detected by a pressure
switch set at 6 psi and indicated by the illumination of the MWS annunciators ENG A/ICE and ICE PROT
repeater. Full details of the bleed air anti-icing system are contained in Sub-section 2 ENGINES.
ICE PROT
SELECTED
ENG ANTICE
ON
1
2
OFF
ENG 1
A/ICE
ENG 2
A/ICE
Overhead Roof Panel
MWS Panel
