When a runway is wet, slushy or snow-covered, the question a pilot needs answered is simple: how much braking and directional control can I count on? The Global Reporting Format is the worldwide answer to that question, written in one language every controller, dispatcher and pilot can read the same way.
This is general educational information, not operational, legal, or regulatory advice. Rules differ by authority and change over time. Always verify against current official sources and follow your operator's approved procedures.
One format, worldwide
The Global Reporting Format (GRF) is the harmonised method for assessing and reporting the surface condition of a runway, applicable worldwide since 4 November 2021. It is set out in ICAO Doc 9981 (PANS-Aerodromes) and Annex 14, and the same scheme is used in the United States as the FAA's RCAM and in the United Kingdom under CAA guidance.
Before the GRF, runway-state reporting was a patchwork of friction readings and local braking descriptions that did not always transfer cleanly between countries or correlate well with how an aircraft actually stopped. The GRF replaced that with a single chain: assess the contaminant, read a code from a matrix, and report it in a fixed form that everyone decodes the same way.
The runway condition code: 6 to 0
At the heart of the format is the runway condition code (RWYCC), a single digit from 6 down to 0. Each value carries a plain braking-action word, as SKYbrary and the source documents set out:
- 6: dry.
- 5: good.
- 4: good to medium.
- 3: medium.
- 2: medium to poor.
- 1: poor.
- 0: less than poor.
A higher number is a better surface. A 6 is reported for a dry runway; the lower the number, the less braking and directional control the surface offers.
The assessment matrix (RCAM)
The code does not come from a friction reading. It comes from the Runway Condition Assessment Matrix (RCAM), a table that maps the type of contaminant (for example frost, wet, slush, dry snow, compacted snow or ice) and its depth to a starting condition code and the matching braking-action word. The assessor then checks that against other cues, including the outside air temperature and, importantly, pilot reports of braking action: a special air-report of braking worse than the matrix implies can downgrade the code.
This is the key idea of the GRF. The aerodrome describes what is physically on the runway, the matrix turns that into a code, and the code is the same currency the flight crew use to look up their aircraft's performance.
How the report is built
A GRF report describes the runway in three equal-length thirds, and gives, for each third, its condition code, the contaminant type, the depth in millimetres, and the percentage of that third the contaminant covers. The thirds are always listed in the direction of the lower runway designator number, so a report for runway 09/27 is read in the 09 direction whichever end you are landing on.
The full report has two parts:
- The aeroplane performance section: the per-third codes, contaminant, depth and coverage, plus any reduced declared distance. This is the part that feeds landing and take-off performance.
- The situational awareness section: plain-language detail such as drifting snow, snow banks, a reduced runway width, or the state of taxiways and aprons.
The report is distributed in the SNOWTAM format and can also be passed by ATIS or by voice, so the same coded assessment reaches you whether you are reading a briefing pack or listening on the radio.
A worked example
Suppose a report gives runway 09 the codes 5/5/3, with the first two thirds wet and the final third covered by 5 mm of wet snow over half its area.
Reading it through:
- The thirds are listed in the 09 direction, so 5 is the first third you cross on landing on 09.
- 5/5/3 means the first two thirds are good and the final third is medium.
- The final third is the one to plan around: 5 mm of wet snow over 50 per cent of it has pulled that third down to a 3.
- Land on runway 27 instead and you meet the thirds in reverse, so the medium third is now first, near the touchdown zone.
The figures are awareness. The stopping numbers come from your aircraft's approved performance data for that contaminant and code.
Common pitfalls
- The codes are read in a fixed direction. They follow the lower runway designator, not your landing direction, so on the reciprocal runway the order is reversed.
- A good first third is not a good runway. The worst third is usually what matters most, and where it sits relative to your touchdown and stop changes with the runway in use.
- The code is a starting point, not a stopping distance. Pair it with your aircraft's contaminated-runway performance data, and treat a worse pilot braking-action report as the more current picture.
In Pilot EFB
Pilot EFB brings the NOTAMs for your aerodrome, including runway-state notices, into the briefing, shown as the raw text alongside a decoded view so a runway-condition report is in front of you rather than buried. A briefing you have already pulled stays readable offline; fetching the latest runway state needs a connection. Pilot EFB is offline-first and is not a certified Electronic Flight Bag, so confirm the current report and apply your aircraft's approved performance data before you commit to a runway.