De-icing Procedures

 

October 6, 2009

 

As we approach the changing season and as the temperatures drop, please read the following regarding de-icing procedures.

 

Isopropyl alcohol will be used for deicing procedures.

 

Cautions:

1.         Isopropyl alcohol is extremely flammable.

2.         Persons apply pressurized de-icing fluid must wear proper eye protection.

 

Any flight with contaminated critical surfaces is prohibited.  All wing surfaces must be clear of any snow or ice.

 

The following procedures shall be used for the de-icing of the aircraft:

 

Place aircraft into sun if applicable.

 

Remove any accumulation of ice or snow from the surface with a soft bristle brush.

 

Prior to the application of de-icing solution, ensure the aircraft is ready to immediately proceed to the hold-short line, and receive a takeoff clearance-that is, the aircraft has been completely pre-flighted for the flight, and the checklist run-up procedures have been completed (the pre-takeoff checks should be completed in route to the hold-short line).

 

The de-icing solution should be applied using the pressurized spray bottle which contains a 50/50 mixture of Isopropyl alcohol and hot tap water; if the temperature is colder than -4°C, the solution should contain 100% Isopropyl alcohol.  Note the hot water in the solution will melt the ice and the Isopropyl alcohol will prevent refreezing.  Isopropyl alcohol alone will not melt the ice and snow.  It will only prevent refreezing.

 

Below the freezing temperature, hot water alone shall NOT be used as this will refreeze and could jam the control surfaces.  Additionally this water will refreeze on the ground causing a potential slipping hazard.

 

After the application, ensure that all critical surfaces are free of any ice and snow, and ensure that all moveable flight surfaces have free travel in all applicable directions.

 

The upper wing surface must be visually scanned immediately after the application of take-off power to ensure ice-crystals have not formed; if ice-crystals are apparent, the take-off shall be rejected and the aircraft shall be returned to the ramp for another de-icing application.

 

Students are permitted to de-ice their aircraft provided they have been advised of the above procedures and they are wearing eye protection and under the direct supervision of a flight instructor.

 

Peter Waddington,

Senior Flight Instructor