• Global reporting format

    Runway safety, particularly runway excursions, remain one of the the top aviation safety concerns of the International Civil Aviation Organisation (ICAO). The Flight Safety Foundation echoes these concerns, and  indicate that the third most common landing excursion risk factor is ineffective braking action, due to runway contamination such as snow, ice, slush or water. This trend is also confirmed by the main aircraft manufactures.

    Shortfalls in the accuracy and timeliness of runway assessment and reporting methods by aerodromes have contributed to the problem, despite many decades of research effort to harmonise various friction measurement devices and their linkage to aircraft performance. Whilst friction measurement equipment is useful for runway maintenance purposes, it is misleading to pilots due to the disconnect between the friction measurement and actual aircraft performance. To help mitigate the risk of excursion ICAO has developed a new harmonized methodology for assessing and reporting runway surface conditions.

    This methodology, known as the Global Reporting Format (GRF), will be globally applicable from November 2021 (delayed a year as a result of Covid-19); the UK is intending to comply with that date.

    • Annex 3 - Meteorological Service for International Air Navigation
    • Annex 6 - Operation of Aircraft, Part I - International Commercial Air Transport - Aeroplanes and Part II - International General Aviation - Aeroplanes
    • Annex 8 - Airworthiness of Aircraft
    • Annex 14 - Aerodromes, Volume I - Aerodrome Design and Operations
    • Annex 15 - Aeronautical Information Services
    • Procedures for Air Navigation Services (PANS) - Aerodromes (PANS-Aerodromes, Doc 9981)
    • Procedures for Air Navigation Services (PANS) - Aeronautical Information Management (PANS-AIM, Doc 10066)
    • Procedures for Air Navigation Services (PANS) - Air Traffic Management (PANS-ATM, Doc 4444)
    • Aeroplane Performance Manual (Doc 10064)
    • Airport Services Manual, Part 2 - Pavement Surface Conditions, Part 8 - Airport Operational Services and Part 9 - Airport Maintenance Practices (Doc 9137)

     

  • The agreed ICAO Aerodrome SARPs appeared in Annex 14 in 2016 with additional guidance found in the PANS Aerodromes Doc 9981 and Circular 355. The GRF is a major step forward in cross functional (Aerodromes, ATM and Flight operations) harmonisation that enables runway surface conditions to be reported in a standardized manner, such that flight crew can accurately determine aircraft take-off and landing performance. The GRF also incorporates the potential to communicate actual runway surface conditions to flight crew in real time and in terms that directly relate to aircraft performance data.

    The GRF can be used in all climates and provides a means for aerodrome operators to correctly assess runway surface conditions including rapidly changing conditions such as those experienced during winter or in tropical climates.

    UK aerodromes will already be familiar with runway condition assessments by each third of the runway. The GRF comprises an assessment by airport operations staff using a Runway Condition Assessment Matrix (RCAM) and the consequent assignment of a Runway Condition Code (RWYCC) rangingfrom 6 to 0, see below. This code is complemented by a description of the surface contaminant based on type, depth and % coverage for each third of the runway. The code is based on the effect of the runway conditions on aircraft braking.

    The outcome of the assessment and associated RWYCC are transmitted using a Runway Condition Report (RCR) forwarded to air traffic services and the aeronautical information services for dissemination to pilots. The pilots will use the RWYCC to determine their aircraft’s performance by correlating the code with performance data provided by their aircraft’s manufacturer. This will help pilots to correctly carry out their landing and take-off performance calculations for wet or contaminated runways. 

    Runway condition assessment matrix (RCAM)

    Source: ICAO Document 9981 PANS -ADR
    Assessment criteria Downgrade assessment criteria
    Runway condition code Runway surface description Aeroplane deceleration or directional control observation Pilot report of runway braking action
     6  
    • Dry
    - -
     5  
    • Frost
    • Wet (The runway surface is covered by any visible dampness or water up to and including 3mm depth)

    Up to and including 3mm depth:

    • Slush
    • Dry snow
    • Wet snow
    Braking deceleration is normal for the wheel braking effort applied AND directional control is normal  Good
     4

    -15°C and lower outside air temperature:

    • Compacted snow
    Braking deceleration OR directional control is between Good and Medium Good to Medium
     3  
    • Wet ('slippery wet' runway)
    • Dry snow or wet snow (any depth) on top of compacted snow

    More than 3mm depth:

    • Dry snow
    • Wet snow

    Higher than -15°C outside air temperature¹: 

    • Compacted snow
    Braking deceleration is noticeably reduced for the wheel braking effort applied OR directional control is noticeably reduced  Medium
     2

    More than 3mm depth of water or slush: 

    • Standing water
    • Slush
    Braking deceleration OR directional control is between Medium and Poor Medium to Poor
     1  
    • Ice²
    Braking deceleration is significantly reduced for the wheel braking effort applied OR directional control is significantly reduced Poor 
     0  
    • Wet ice²
    • Water on top of compacted snow²
    • Dry snow or wet snow on top of ice²
    Braking deceleration is minimal to non-existent for the wheel braking effort applied OR directional control is uncertain Less than Poor
    ¹ Runway surface temperature should preferably be used where available 
    ² The aerodrome operator may assign a higher runway condition code (but no higher than code 3) for each third of the runway, provided the procedure in 1.1.3.15 is followed. 


    The GRF also allows pilots to report their own observations of runway conditions, thereby confirming the RWYCC or providing an alert to any changing conditions. The other key attributes to the GRF are its relative simplicity of use and the fact that it is globally applicable.

    Important changes have also been made to ICAO Annex 15 with the inclusion of a new Snowtam format also to be used from November 2020.

    Whilst November 2020 may seem a long way off it is important that both certificated and licensed aerodromes become familiar with the material in both ICAO Annex 14 and PANS Aerodromes. The latter has 18 pages of excellent guidance material on all the elements of the new GRF under Part II – Aerodrome Operational Management. It is also planned that your aerodrome inspectors will organise briefing sessions in the run up to the applicability date. CAA will also take the opportunity to publicise the GRF through industry meetings and conferences.

    Aerodrome operators however may wish to run parallel trials this coming winter. This would enable airport operations staff to continue with the current reporting methodology but see how they would report the runway surface condition in the new GRF format. CAA would encourage aerodrome operators to do this as it will contribute greatly to the full introduction next year. If you do intend to run a parallel trial, please let your aerodrome inspector know so that any lessons learned can be exchanged.  For those aerodromes that are interested, Airports Council International (ACI) have developed an online computer-based training package which you might find useful in training your operation staff.