UK CAA Winter Operations Trial

CAA Winter Operations TrialMAN looking down the runway

BALPA has been approached by the CAA to assist in the Runway Contamination Trial (Pilot Questionnaire).

The Flight Safety Sub Committee (formally the Flight Safety Group) are very happy to assist them in this trial and will be contacting all members very shortly as well as creating an article for “The LOG” magazine.

We would urge ALL professional pilots to assist the CAA and complete this short questionnaire, this will also enable BALPA to deliver its aim of:

"Making Every Flight a Safe Flight".


Following on from the severe winter weather that was experienced in 2010, the Civil Aviation Authority (CAA) set up a Winter Information Group (WIG).

The feedback from airline members involved in this group was that the work taking place in America under the guise of the Federal Aviation Administration Take-Off and Landing Performance Assessment – Aviation Rulemaking Committee (FAA TALPA-ARC) could be adapted for use in the United Kingdom.

Following on from this, a Runway Contamination Assessment trial was commissioned for the winter of 2010/11.  Due to the limited information which this trial generated, in winter 2011/12 it was expanded to include 17 airfields throughout the UK.  Due to a mild season, only 52 recordings were made, and so the trial is being repeated for winter 2012/13, commencing 1 November 2012 and running until 31 March 2013.

The trial has three key objectives:-
  • To see how the quality of data, gathered by UK aerodrome operations staff and passed to airline operators' crews via ATC, can be improved by the adoption of an enhanced assessment format, which uses phraseology to describe estimated braking action. This is obtained by assessing the runway state against a reference table using type of contaminant and its depth;
  • To see if aircrew understand the phraseology and whether the reports add value to the runway state report promulgated either by SNOWTAM, METAR, Runway State Group or ATIS;
  • To obtain feedback from participating Air Traffic Service Units (ATSUs) concerning the management of data transmission generated by the trial and the usefulness of the data to ATSUs themselves.

The Trial:-MAN looking towards the terminal

The Winter 2012/13 trial is taking place at 17 UK aerodromes (Belfast International, Birmingham, Cardiff, City of Derry, Exeter, Edinburgh, Glasgow Prestwick, Inverness, Leeds Bradford, Liverpool, London Gatwick, London Luton, London Stansted, Manchester, Newcastle, Norwich and Stornoway) and any operator using these trial aerodromes may take part.

When operating into any UK airfield where the runway is contaminated, crews can expect to be given 9 pieces of information by ATC regarding the runway; each third (Touchdown Zone (TDZ)/Mid-Point (MID)/Stop End (STP)) will have a contaminant type, contaminant depth and a percentage coverage reported.  This allows the crew to make an assessment of the suitability of the runway for use.  This information has been standard and unchanged since 2010.

When operating into any of the 17 trial aerodromes, the crew will also be given an estimated braking action for each of the TDZ, MID and STP thirds.  This report will be a qualitative report based on the observed depth, extent and type of contaminant, along with the air temperature if necessary, and will be passed to crews in verbal form (i.e. Good, Good to Medium, Medium, Medium to Poor or Poor).

After landing, ATC will request a verbal PIREP of the perceived braking action experienced and compare this against the current estimated braking action.  To avoid RT frequency congestion, this PIREP may be requested once an aircraft has been handed over to Ground Movement Control.  If the PIREP is worse than the current estimated runway friction, ATC will downgrade this to the reported state and a reassessment of the runway will be triggered.  If the PIREP is better than the current estimated runway friction, it will not be upgraded immediately; however, a reassessment of the runway will be triggered.

Friction readings generated by Continuous Friction Measuring Equipment (CFME) are no longer given in the UK due to the lack of accuracy of these readings on wet snow and slush.
The long term goal of the trial is to simplify operations onto contaminated runways.  If greater accuracy and clarity can be achieved in the information passed from airfield operations staff, through ATC, to crews, it is hoped that an improved level of safety and a reduction in diversions due to winter contamination of runways will result.

To achieve this, however, the trial needs to be successful, and to assess this there needs to be an increased level of feedback from crews.


In addition to providing verbal reports, the CAA requests written feedback from crews using the Pilot Questionnaire.  Last year, disappointingly, only 5 of these reports were submitted (and of these 2 were submitted by the same pilot!).

To try and increase the level of feedback generated, the form has been re-formatted.  To go to this new form click here.

It can be submitted electronically (and is compatible with most smart phones, iPads etc.), via company flight operations departments, by e-mail to or by fax to 01293 573971.

Further Information/References:-