Uplink ALPA - The Voice of Aviation

The New Zealand Air Line Pilots' Association Newsletter. As of April 2020 Uplink ALPA is a 6-monthly publication.

ICAO’s runway surface condition reporting scheme – the Global Runway Format

NZALPA’s Senior Technical Officer David Reynolds looks at the new runway surface condition reporting scheme expected to be introduced in New Zealand later this year. NZALPA is working as part of a Civil Aviation Authority (CAA) established group preparing for implementation of a runway surface condition reporting scheme in this country. Airports and Airways are also involved in the group. 

The Global Runway Format, or GRF, is a runway surface condition reporting scheme which aims to standardise the way runway surface conditions are reported to and used by pilots. 

Runway safety-related accidents are one (if not the number one) category of accident, with runway surface conditions contributing significantly to many of these accidents. 

Surface contamination by snow, ice, slush or water can lead to a significant loss of braking action and controllability, resulting in runway and/or taxiway excursions. 

Shortfalls in the accuracy and validity of surface condition reporting are a significant and common causal factor in many accidents according to the International Civil Aviation Organisation (ICAO). 

In an attempt to reduce the number of these accidents, ICAO has developed a coherent and coordinated scheme in the form of the GRF. CAA planning for the roll out of the GRF in New Zealand is well underway with a planned implementation target of November 2020. NZALPA is part of that preparatory work. 

As the name suggests, the GRF is intended to be a global application, taking into account all the varying runway surface conditions experienced, and allowing aerodrome operators to rapidly assess and report these conditions. 

For each third of the runway (analogous to RVR touchdown, midpoint and stop end measurement protocols) contaminant type, depth and coverage are measured and evaluated by trained aerodrome staff. Their data goes into a matrix known as the Runway Condition Code or RWYCC. The RWYCC is completed when either one third of the runway is contaminated by 25 per cent or more, or the total runway length divided by three has contamination of more than 25 per cent. The RWYCC is passed on to air traffic control and aeronautical information services. The information is then passed on to pilots – most likely through the automatic terminal information service (ATIS). 

Aircraft landing and take-off performance can then be calculated by pilots using both the RWYCC and aircraft-specific information sourced by the aircraft type’s manufacturer.

As well as the RWYCC, pilots can also provide their own personal observations of the conditions experienced, either confirming its validity or advising of changing conditions.

Although it may not be apparent from this article, the format is straightforward in its application and comprehensive in its applicability. GRF is also a key part of ICAO’s strategy to reduce excursion incidents and accidents.

A good overview of the GRF was given at the recent ICAO GRF Forum and may be found here.



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