Learn what runway condition codes 6 to 0 mean, how airports assign them, and how pilots use RWYCC reports for take-off and landing performance.
In real-world aviation, a runway condition code (RWYCC) is a number from 0 to 6 describing expected braking and directional-control capability on each runway third. Pilots and dispatchers use the three codes with approved performance data to determine whether take-off or landing is permitted and how much runway is required.
For Aviation & Real-World Flying, the critical distinction is that RWYCC is an operational performance input, not a weather score or measured coefficient of friction. It is a time-stamped assessment of the runway surface, with lower numbers indicating worse expected braking.
What do runway condition codes 6 to 0 mean?
RWYCC 6 represents a dry runway, while RWYCC 0 represents braking capability that is less than poor. The following summary reflects the standard Runway Condition Assessment Matrix used under the ICAO Global Reporting Format and aligned national systems; exact contaminant wording can vary by aviation authority.
| RWYCC | Typical runway condition | Expected braking |
|---|---|---|
| 6 | Dry | Normal dry-runway braking |
| 5 | Wet, frost, or up to 3 mm of slush, dry snow or wet snow | Good |
| 4 | Compacted snow at low outside-air temperature, typically −15°C or colder | Good to medium |
| 3 | Slippery when wet, deeper dry or wet snow, or warmer compacted snow | Medium |
| 2 | More than 3 mm of standing water or slush | Medium to poor |
| 1 | Ice | Poor |
| 0 | Wet ice, water over compacted snow, or snow over ice | Less than poor |
A good braking description does not mean dry-runway performance. A code 5 wet runway can still require a longer landing distance and impose take-off limits. Code 0 normally leaves operators without an acceptable performance basis for routine operations; it does not mean that maximum braking will make the runway usable.
How do you read a three-part RWYCC report?
A three-part code gives the condition of the first, second and final thirds of the runway in the report's stated direction. For example, RWY 09 5/5/2 means the first two thirds are code 5 and the final third is code 2.
Do not average those numbers. For an aircraft landing on Runway 09, the code 2 final third may become critical during the rollout even though the touchdown area is code 5. Take-off calculations must also account for the full runway because stopping after a rejected take-off can extend into the worst third.
Direction is a frequent source of errors. ICAO-format reports normally list the runway using its lower designator and order the thirds from that end, so the sequence must be reversed when considering the reciprocal direction. National report formats can present direction differently; always decode the runway identifier and reporting convention before using the numbers.
How do airports assign a runway condition code?
The airport operator normally originates the RWYCC by inspecting the runway and applying the Runway Condition Assessment Matrix. Air traffic control distributes the information but does not ordinarily decide the code.
- Divide the runway into thirds. Each third receives its own assessment rather than one code for the entire surface.
- Identify the contaminant. Inspectors consider water, frost, snow, slush or ice, together with coverage, depth and temperature where applicable.
- Apply the assessment matrix. The observed condition produces an initial code from 6 to 0.
- Validate the result. Pilot braking reports, vehicle observations and changing weather can trigger reassessment or a downgrade. Upgrades require supporting evidence and are restricted by the applicable authority's rules.
- Issue the report. The codes are transmitted through runway condition reports, SNOWTAM or NOTAM products, ATIS and ATC broadcasts, depending on the country and airport.
The code is not simply a friction-meter reading. Surface treatment can also change it quickly, which is why contaminant removal and runway reporting during snow operations must be treated as a continuous process rather than a single inspection.
How do pilots use RWYCC for take-off and landing?
Pilots use the reported codes as inputs to approved aircraft or operator performance data, alongside weight, wind, runway slope, pressure altitude and other required factors. RWYCC alone does not provide a landing distance.
- Check the report time. Use the latest available runway condition report and compare it with precipitation, temperature and recent braking reports.
- Confirm the runway direction. Put each code against the correct physical third, reversing the sequence for reciprocal use when the reporting format requires it.
- Enter the individual codes. Use the aircraft's approved performance application, electronic flight bag or manual tables. If the tool accepts only one code, follow its documented method rather than selecting an average.
- Calculate both distance and limits. For take-off, this includes acceleration and rejected-take-off stopping requirements. For landing, it includes the applicable operational safety factors and available landing distance.
- Make an operational decision. Reduce weight, wait for treatment, choose another runway, delay the flight or divert if the required performance margin is unavailable.
RWYCC is not an autobrake selector. A code 3 does not mean autobrake setting 3; autobrake selection depends on the required deceleration and stopping margin. Likewise, anti-skid prevents excessive wheel slip but cannot create missing runway grip.
Common RWYCC mistakes
- Averaging the three codes: a report of
5/5/2is not equivalent to code 4. - Reading the thirds backwards: this can place the poorest condition at the wrong end of the runway calculation.
- Treating RWYCC as a friction coefficient: the code describes expected aircraft braking behaviour, not a direct numerical coefficient.
- Using a stale report: snowfall, freezing rain, ploughing and temperature changes can invalidate an earlier assessment.
- Inventing performance corrections: if an aircraft's approved data do not cover the reported condition, the code does not supply the missing calculation.
Use in flight simulation
RWYCC can add useful dispatch discipline to a flight simulator, particularly when an aircraft's electronic flight bag accepts runway-condition inputs. Enter the published codes exactly as the aircraft documentation expects and use the resulting limits when planning fuel, payload and runway choice.
Simulator surface physics and add-on aircraft do not always reproduce the official braking categories faithfully. Rain or visible snow therefore does not prove that the simulated runway behaves like a particular RWYCC, and a simulated ATIS value should not be mistaken for a measured real-world report.