2.3.1 Runway surface condition assessment
All certified aerodromes in Kazakhstan assess runway surface condition according principles laid down by ICAO taking into account the contaminant type, coverage and depth of the contaminants, as well as the pilot’s reports on braking efficiency.
These elements are reported in a globally harmonized format and are more commonly known as the Global Reporting Format (GRF).
The GRF works as follows:
Each time there is a significant change in runway surface condition, the aerodrome operator assesses the surface condition for each third of the runway and produces a Runway condition report (RCR), containing a runway condition code (RWYCC) and a set of information describing the runway surface condition, including type of contamination, thickness, coverage for each third of runway.
The determination of the runway condition code is based on the Runway Condition Assessment Matrix (RCAM) which maps the runway surface condition description to aircraft braking performance.
The Runway Condition Assessment Matrix (RCAM) is shown in Table 2.
The runway length taken into account for the assessment and reporting of the runway surface condition is the physical length of the runway excluding runway end safety areas (RESAs), stopways and clearways.
The pilot uses the information disseminated in conjunction with performance data provided by the aircraft manufacturers to determine whether landing or take-off operations can be conducted safely.When the braking performances observed by the pilot do not correspond to that communicated, the pilots produce a braking action report (AIREP) which ATS communicates to the aerodrome operator with a view to a possible new assessment of the runway surface condition.This AIREP will be transmitted by the crew as soon as possible after landing, if possible before leaving the control frequency, in particular to be taken into account by the following crews.The transmission of the AIREP uses the conventional expressions agreed in the RCAM matrix.
Table 2: Runway Condition Assessment Matrix applicable at Kazakhstan aerodromes| Runway condition assessment matrix (RCAM) |
| Assessment criteria | Downgrade assessment criteria |
| Runway condition code | Runway surface description | Aeroplane deceleration or directional control observation | Pilot report of runway braking action |
| 6 | | - | - |
| 5 | - FROST
- WET (The runway surface is covered by any visible dampness or water up to and including 3 mm depth)
Up to and including 3 mm depth: | Braking deceleration is normal for the wheel braking effort applied AND directional control is normal. | GOOD |
| 4 | −15ºC and Lower outside air temperature: | Braking deceleration OR directional control is between Good and Medium. | GOOD TO MEDIUM |
| 3 | - WET (“slippery wet” runway)
- DRY SNOW or WET SNOW (any depth) ON TOP OF COMPACTED SNOW
Higher than −15ºC outside air temperature: | Braking deceleration is noticeably reduced for the wheel braking effort applied OR directional control is noticeably reduced. | MEDIUM |
| 2 | More than 3 mm depth of water or slush: | Braking deceleration OR directional control is between Medium and Poor. | MEDIUM TO POOR |
| 1 | | Braking deceleration is significantly reduced for the wheel braking effort applied OR directional control is significantly reduced. | POOR |
| 0 | - WET ICE
- WATER ON TOP OF COMPACTED SNOW
- DRY SNOW or WET SNOW ON TOP OF ICE
| Braking deceleration is minimal to non-existent for the wheel braking effort applied OR directional control is uncertain. | LESS THAN POOR |
2.3.2 Measuring the depth of deposits
The average depth of the layer on each third of runway is measured with the precision of up to 04 mm for standing water, up to 03 mm for slush, wet snow and dry snow.
Measurements of the depth of these deposits are made on each third of the runway length at a distance of 5-10 m from its axis on the right and left, by triple measurements at the estimated points and calculating the arithmetic mean values of the measured depths on each third of the runway.
The depth of deposit is measured using a metal millimeter ruler, and the water layer is determined using an optical ruler OL-1.
The values of the deposit depth are measured and reported in millimeters.
In cases where there is no need for measurements, information about the depth of deposit is not reported.
When no information is to be reported, insert “NR” at its relevant position in the message of SNOWTAM to indicate to the user that no information exists
2.3.3 Friction measurements
At the aerodromes of Aktau, Aktobe, Almaty, Astana, Atyrau, Karaganda, Kostanay, Kokshetau, Pavlodar, Semey, Taldykorgan, Taraz, Tengiz, Ust-Kamenogorsk, Shymkent, an aerodrome brake trolley ATT-2 is used for the measurement of friction.
At the aerodromes of Kyzylorda, Uralsk, an aerodrome brake trolley ATT-RWY is used for the measurement of friction.
At the aerodromes of Petropavlovsk, Usharal, an aerodrome brake trolley ATT-2M is used for the measurement of friction.
At the aerodromes of Almaty, Astana, Atyrau, Balkhash, Zhezkazgan, Karaganda, Shymkent, electronic portable decelerometer DEP-5A is used for the measurement of friction.
At the aerodromes of Zaisan, Turkistan, Urdzhar, electronic portable decelerometer DE-01 is used for the measurement of friction.
At the aerodromes of Aktau, Turkistan, Skiddometer BV 11 is used for the measurement of friction.
The friction measurement is made on each third along the runway 5-10m on either side of the runway centerline.
When measuring the friction with a decelerometer, the number of measurements on each section should be at least 8 (4 to the right and left of the runway centerline).
If the conditions on the edges of the cleared runway area differ significantly from the conditions within basic measurement area, additional measurements will be made when necessary.
The values of the friction measurements coefficients are published in the situational awareness section of the Runway Condition Report (RCR), provided that the friciton measurements are used as part of the overall assessment of the runway surface covered with compacted snow or ice.
Friction measurements on loose dirt, in particular such as snow and slush, are unreliable and the values of the friction measurements coefficient are provided only at the request of the pilots.
Only the measured friction coefficient values are provided.
Table 3: Conversion of the measured friction coefficient values to the normative value of the friction coefficients for ATT-2.| Measured coefficient | 0,1 | 0,15 | 0,18 | 0,2 | 0,25 | 0,26 | 0,29 | 0,3 | 0,35 | 0,39 | 0,4 | 0,45 | 0,5 |
| Normative friction coefficient | 0,26 | 0,29 | 0,3 | 0,32 | 0,34 | 0,35 | 0,36 | 0,37 | 0,39 | 0,41 | 0,42 | 0,45 | 0,49 |
The measured values of the decelerometer correspond to the normative values of the friction coefficient given in Table 3.