Take-Offs during Winter Operations

Guidance for Aircraft Operators

Runway Condition and Contamination Assessment

EU-OPS specifically requires account to be taken of the conditions of the surface of the runway from which the take-off will be made. Consequently, in the absence of approved contaminated runway performance data, operations from contaminated runways are not permitted. The CAA should be consulted about the data that is required to be obtained.

Take-offs should not be attempted in depths of dry snow greater than 60 mm or depths of water, slush or wet snow greater than 15 mm. If the snow is very dry, the depth limit may be increased to 80 mm. In all cases the Aircraft Flight Manual (AFM) limits, if more severe, should be observed.

Weather changes since the last runway surface condition report (particularly precipitation and temperature), the possible effect on stopping or acceleration performance and whether subsequent contaminant depths exceed Flight Manual limits should be reviewed.

Flight Planning Considerations

Fuel planning should include a review of all aspects of the operation; including whether the carriage of excess fuel is justified.

Flight crews should be aware that using Electronic Flight Bag products for performance calculations on a contaminated runway often produces a flap setting for take-off which uses the available runway length to accelerate the aeroplane to a higher speed in order to improve the climb performance. This is unlikely to be appropriate in conditions where a shorter ground roll is preferred.

Manoeuvring
  

Aircraft should taxi slowly and adopt other taxiing techniques which will avoid snow/slush adherence to the airframe or accumulation around the flap/slat or landing gear areas. Particularly avoid the use of reverse thrust, other than necessary serviceability checks which should be carried out away from contaminated runway areas. Avoid taxiing too closely behind other aircraft and be cautious of making sharp turns on a slippery surface.

Configuration

Consider all aspects when selecting the flap/slat configuration from the range permitted in the Flight Manual. Generally greater increments of flaps/slats will reduce the un-stick speed but could, for example, increase the effect of impingement drag for a low wing aircraft.

Handling
  

Maximum take-off power should be used.

Take-off should not be attempted with a tail wind or, if there is any doubt about runway conditions, with a crosswind in excess of the slippery runway crosswind limit. In the absence of a specified limit take-off should not be attempted in crosswinds exceeding 10 kt.

Runway Dimensions
  

The dimensions and nature of any overrun area that is available, and the consequences of an overrun off that particular runway, should be considered.

An accurate assessment of the runway distance available for take-off and the amount of runway to be used to line up should be made and any reduction should be subtracted from the declared distances for the purpose of calculating the Regulated Take-Off Weight (RTOW).

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FOP.Admin@caa.co.uk