In the previous post, we introduced ICAO flowchart that has been published as a guidance material for the runway inspectors to report runway conditions according to GRF regulations and by using RCAM table. The previous blog focused on ICAO flowchart during winter season (Flowchart A). In this blog, we continue this topic by introducing Flowchart B which should be followed by the runway inspectors during summertime.
Step 1: RCAM applicability
If there was no water, snow, slush, ice or frost associated with winter conditions on any runway third, the inspector should monitor any runway third to assess is there water present on any runway third? If the answer is YES, the inspector should follow flowchart B (summer conditions). If the answer is NO, then there is basically no need for a runway report.
Flowchart B (adapted from ICAO, 2019, Circular 355, Assessment, Measurement and Reporting of Runway Surface Conditions)
Step 2: Apply coverage criteria
In the summer season, the flowchart begins by assessing the water coverage for each runway third. The runway inspector should assess is more than 25% of any runway third wet?
- If the answer is NO, there is basically no need for a runway report because if wet area is less than or equal to 25%, it is considered as a dry runway regarding the aircraft performance. However, even in this case, it is never wrong to issue a runway report.
Step 3: Apply assessment criteria
- If the answer to coverage criteria is YES, the inspector should assess the water depth for each runway third to check is the water depth more than 3mm?
- If the answer is NO, then the inspector should assess is the specific runway third slippery wet? Slippery wet condition is normally a result of rubber accumulation on the runway which decreases drainage capability and friction of the runway surface and the runway becomes more slippery than normally in the wet condition. The slippery wet limits can be determined by using runway friction tester with self-wetting system.
- If the answer for slippery wet condition is NO, a runway report wet and RWYCC #5 should be issued for the ATC, but SNOWTAM publishing is not necessary. Wet and dry conditions are in principal in the responsibility of air traffic control.
- If the answer to slippery wet question is YES, a runway report with slippery wet condition and RWYCC #3 should be issued for that specific runway third.
- If the answer to water depth over 3mm is YES, then the runway condition is not anymore wet, but it would be standing water. If it has been observed that there is water over 3mm depth with coverage over 25% on a specific runway third, then the inspector should assess is there a need to downgrade the runway condition code?
- If the answer to the downgrade question is NO, the runway inspector should report standing water and RWYCC #2 for that specific runway third.
Step 4: Apply downgrade/upgrade criteria
- If the answer to downgrade question is YES, the inspector should determine the downgrade need by using all available information. It means all indications should support the downgrade decision and the RCAM table should be used in the downgrade assessment. In this case, the inspector should report standing water and the downgraded RWYCC for that specific runway third.
In the last two blogs, we went through a step-by-step guide on how to use ICAO flowchart as a guidance to assess runway conditions during winter and summer. The ICAO flowchart should always be used together with the RCAM table. However, it is important to know that ICAO flowchart does not include all practicalities regarding runway assessment. Here are some important issues that need to be considered by the runway inspectors:
- The flowchart does not consider and does not give any guidance regarding the aircraft thin and thick contaminants, i.e. are the contaminants creating drag or are they only slippery? Thus, it is the inspector responsibility to evaluate and select the correct contaminant in respect to the aircraft performance effect. This is especially important when multiple contaminants have been observed on a specific runway third.
- The flowchart and the RCAM table underlines landing performance which means to find out the contaminant representing minimum runway condition code.
- The flowchart does not consider wet downgrade possibility.
- The flowchart is not addressing SNOWTAM syntax and how the SNOWTAM message should be created. SNOWTAM syntax is the message that is published in the AFTN network.
Global Runway Reporter (GRR) software, Mobile module:
Assessment of runway conditions can efficiently be handled by using Global Runway Reporter Mobile application. GRRM software is the actual runway inspector’s tool to make runway conditions report. The software calculates automatically RCAM contaminants and helps the inspector to select the correct RCAM code. The runway inspector reports contaminants directly from the inspection vehicle and generates consistent SNOWTAM syntax.