Runway surface condition may be reported using several types of descriptive terms such as type and depth of contamination, readings from a runway friction measuring device, an aeroplane braking action report, or an airport vehicle braking condition report. The described means used for such purpose are not standardised globally.
Investigations of reported runway safety events have identified shortfalls in the accuracy and timeliness of runway surface conditions reporting as contributing factors to many runway excursions.
Such shortfalls include lack of standardisation in the:
- assessment of the runway surface condition and braking action;
- compilation and reporting of runway surface conditions to the end-users (flight crews and flight planners), particularly the use of different terminology, format and reports’ timeliness;
- use of the reported information by flight crews.
A discrepancy between the reported runway surface condition and the actual one may affect the performance calculations, the use of deceleration devices and the flight crew’s ability to maintain directional control which can result in a runway excursion.
The TALPA Aviation Rulemaking Committee (ARC) set up by the U.S. FAA proposed the following corrective actions:
- New standards for runway condition assessment and reporting
- Correlation of the reported runway condition with aircraft performance data
- New operational rules for landing performance calculation at the time of arrival.
The International Civil Aviation Organisation (ICAO) developed an improved global runway condition assessment and reporting format based on the proposals of the TALPA ARC. The methodology, intended for global application, relies on the following:
- An agreed set of criteria used in a consistent manner for runway surface condition assessment, aircraft (performance) certification and operational performance calculation;
- A unique Runway Condition Code (RWYCC) linking the agreed set of criteria with the aircraft performance data, which can be correlated to the braking action experienced and reported by flight crews; and
- A standardised common terminology for runway surface condition description reported by the airport operator’s runway assessors, air traffic controllers and Aeronautical Information Services (AIS) for use by flight crews.
The ICAO Global Reporting Format (GRF) methodology envisages:
- Assessment by trained runway assessors and reporting - by means of a uniform Runway Condition Report (RCR) - of the runway surface conditions, including contaminants, for each third of the runway length. This includes contaminants categorisation according to their effect on aircraft braking performance and information coding in a Runway Condition Assessment Matrix (RCAM).
- RCAM use by aircraft manufacturers to determine the appropriate performance data for specific runway surface conditions and provision of approved data and guidance material to aircraft operators for the safe operation of the aircraft on dry, wet and contaminated runway surfaces.
- Provision of the RCR information to the end users (by AIS) in an improved SNOWTAM form.
- Provision of the RCR information to the flight crews by ATS by means of voice communication, CPDLC and ATIS. The information shall be presented according to the direction of the aircraft movement, with the first runway third being the one nearest to the aircraft approaching to land.
- Use of the reported runway condition data in conjunction with the performance data provided by the aircraft manufacturer to determine - along with other information such as, but not limited to, weather conditions and the weight of the aircraft - if landing or take-off operations can be conducted safely.
- Flight crews shall report the braking action experienced when different from the expected one.
GRF originally was to be implemented by 5 November 2020, but subsequently was delayed until 4 November 2021 because of the impact of the COVID-19 pandemic on the aviation industry.
Recommendation to aircraft operators and flight crews
- Aircraft operators should consider and be aware of the runway surface condition reporting methodology at the airports to which they operate. Special consideration should be given to those aerodromes that are critical in terms of runway length, challenging weather conditions and aerodrome capability, and reliability for runway surface conditions assessment and reporting. Consideration should be given in particular to the runway surface condition reporting format and terminology in use. Operators should base their assessment at least on:
- Aircraft operators include in their flight crew training programme at least the following elements:
- Description of runway surface condition reporting methods
- Types of runway contamination and its effects
- Aeroplane take-off and landing performance on wet and contaminated runways.
- When substantial differences are identified at a particular aerodrome or in a particular State or region in relation to runway surface condition assessment and reporting, the operator should ensure that flight crews are properly informed on the type and format of runway surface condition reports they will get at these locations.
- In case of uncertainty on runway surface condition reporting, conservative assumptions should be made either in terms of aeroplane performance calculations or, when different conditions are reported for different segments of the runway, in terms of assuming the worst condition for the entire runway.
- Flight crews should report the runway braking action encountered when it is not as good as expected according to the values previously reported to them. Flight crew reports should be consistent with the format in use at the aerodrome being operated as they may be used by the aerodrome operator to downgrade the runway condition. They may be used also by the flight crews of subsequent flights using the same runway.
Recommendations to Aerodrome Operators
The GAPPRE makes the following recommendations relevant to runway surface condition reporting:
- Ensure that the procedures to assess runway surface conditions according to ICAO Global Reporting Format include reactive as well as proactive surface assessment to make sure hazardous changes are all identified and communicated in a timely manner.
- Ensure robust procedures are in place for communicating information regarding changing surface conditions as frequently as practicable to the appropriate services according to the ICAO Global Reporting Format. Roles, responsibilities of stakeholders and coordination procedures should be formalised.
- Runway condition codes assessed should be compared against braking action reports by the pilots to ensure the accuracy of the information provided to the pilots.