Chapter 5 - Ground Crew Supplement

Areas to be Covered

105.  The application strategy should adopt standard techniques while considering unique procedures necessary for specific aircraft design differences. Where possible, mechanical removal of snow, ice or slush accumulations should be considered as well as the proper execution of such procedures.

106.  All windows and doors of the aircraft must be closed during spraying, engine may be shut down or idling and air-conditioning and/or APU air must be off, unless otherwise recommended by the airframe and engine manufacturer.

107.  A spray to provide an even and uniformly distributed film should be used in a continuous process of application.

108.  The surfaces to be treated are typically:

  • Wing leading and trailing edges;
  • Wing and controls upper surfaces;
  • Horizontal stabilizer and elevator upper surfaces;
  • Vertical stabilizer and rudder; and
  • Fuselage upper surfaces on aircraft with rear fuselage mounted engines, depending on amount and type of precipitation.

109.  Care must be taken to ensure that ice, snow and slush has not accumulated or has not been overlooked in critical places such as the flight control hinge areas, auxiliary power unit (APU) intake or between stationary and moveable surfaces. The front and rear sides of fan blades must be checked prior to start-up when engines are not running. Clear ice can form below a layer of snow or slush and can be hard to detect therefore the surface of the aircraft must be carefully examined after deicing. Care must be taken to avoid inadvertently spraying fluid directly onto the cabin and cockpit windows, doors and emergency exits, or into the intake of a running APU.

110.  In general, deicing treatment must be done in a leading edge to trailing edge direction. Failure to follow this methodology may result in contamination being forced into the wing or stabilizer openings where it could re-freeze and jam control systems and thereby result in an unsafe condition.

Note:  T-tail aircraft. These types of aircraft have the potential to tip due to the imbalance caused when the wings are clean and the tail surfaces have a heavy accumulation.