Runway Surface Conditions: Ensuring Better Assessments and Reporting

A statistical analysis of high-risk accidents from 2008 to 2016 has shown that runway safety-related accidents, notably runway excursions, remain aviation’s number one safety risk category. The top contributing factors included poor braking action due to contaminated runways or taxiways combined with shortfalls in the accuracy and timeliness of runway surface conditions. In 2017, ICAO’s Global Runway Safety Action Plan called for the widespread deployment of the ICAO format for assessing and reporting runway surface conditions as an effective mitigation.

This new methodology, commonly known as the Global Reporting Format (GRF), has its origins in the FAA’s Take-off and Landing Performance Assessment (TALPA), will become applicable in 5 November 2020. The GRF targets the standardized reporting of runway surface conditions on wet and contaminated runways, the impact of which is then directly correlated with an aircraft’s performance, enabling a better flight crew prediction of their take-off and landing performance as well as an improved situation awareness.

Although the ability to link the output of a measuring device (such as the Mu-meter) to actual aircraft performance has long been an aspiration, there is currently no universally accepted relationship. Therefore, to avoid any misunderstanding, the GRF is based upon human observation and standardized reporting.

The methodology, intended to cover conditions found in all climates, provides a means for aerodrome operators to rapidly and correctly assess runway surface conditions, whether they are exposed to wet runway conditions, snow, slush, ice or frost. It comprises the evaluation of a runway and the assignment of a Runway Condition Code (RWYCC) ranging from 0 for a very slippery surface to 6 for a dry surface. This code is complemented by a description of the surface contaminant, based upon its type, depth and coverage, for each third of the runway. This information is then used to complete a standard report called the Runway Condition Report (RCR) for dissemination to flight crew.

Figure 1: Reporting of runway condition code from ATS to flight crew for runway thirds (Source PANS-Aerodromes, Part II, Chapter 1)

This information is then used to complete a standard report called the Runway Condition Report (RCR) which is forwarded to air traffic services for dissemination to the flight crew. If needed, the RCR will also be disseminated to users through a SNOWTAM.

The RCR is used by flight crew to make a correlation between the reported surface conditions and their aircraft’s performance, based upon data provided by manufacturers. This correlation is made using another important element of the GRF methodology, the Runway Condition Assessment Matrix (RCAM).

The RCR encompasses important information that may be required by flight crew throughout their flight, in particular when there are rapidly changing weather conditions (i.e. winter or tropical) when timely decisions may be required. As a consequence, the aerodrome is expected to closely monitor runway conditions and be ready to issue a new RCR whenever a significant change occurs.

Another important element of the GRF is a process that enables a pilot to provide ATC, aerodrome personnel and other pilots with their own observation confirming the assessment or providing an alert of deteriorating (or improving) conditions based upon their experience of actual braking action or lateral control. A corresponding mechanism for the airport operator to downgrade (or upgrade) the RWYCC on the basis of such reports has been incorporated in the GRF.

To ensure a global and harmonized implementation of this new methodology, the importance of training cannot be overstated. In this regard, a joint ICAO/ACI symposium will be hosted in Montreal from 26 to 28 March 2019. The principal objectives will be to ensure international awareness and knowledge of the GRF in preparation for deployment, and to develop an understanding of the training required and resources available. All stakeholders are strongly encouraged to actively participate in this symposium.

Moreover, considering the importance to reach out international airports globally, this symposium will be followed-up through more focussed regional seminars between March 2019 and November 2020. These will address local stakeholders and their needs in more detail, reflecting regional particularities such as weather conditions, airport characteristics and stakeholder expectations that will take place.