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Introduction
Introduction
Landing performance is a function of the exact landing runway conditions at the time of landing. Indeed, knowing what exact contamination is or remains on the runway at a given point in time is often challenging.
CONTAMINATED RUNWAY: WHAT DOES IT MEAN ?
If weather can to some extent be anticipated, the runway surface conditions with natural contamination may be more difficult to forecast. Indeed, runway surface conditions depend on a variety of factors including state changes due to surface temperature effects, chemical treatment, or run-off and removal.
A variety of contaminants
The most common and natural contaminants are limited in number:
compacted snow (solid contaminant, its depth is irrelevant),
dry or wet snow, depth at or more than 3 mm - 1/8 inch (*)
water, slush, depth at or more than 3 mm - 1/8 inch (*)
ice (solid contaminant, its depth is irrelevant).
(*) DRY and WET normal runway conditions, without abnormal contamination by rubber or other pollution, are by aeronautical language convention classed as “non-contaminated”. Dry or wet snow, water and slush of a depth less than 3 mm - 1/8 inch or frost are considered equivalent to a wet runway (non-contaminated). A wet runway excessively contaminated by rubber, reported by NOTAM as “Slippery when Wet” as defined by ICAO, is a contaminated runway. It is considered to have the same performance as snow (MEDIUM).
FAA recommendations
FAA recommendations
"Amend 14 CFR 139.31 and … 139.33 to require that airports certified under14 CFR Part 139 and located in areas subject to snow or freezing precipitation have an adequate snow removal plan, which includes criteria for closing,inspecting, and clearing contaminated runways following receipt of “poor”or “nil” braking action reports and to define the maximum snow or slush depth permissible for continued flight operations"
"For all 14 CFR Part 121 and 135 operators, require the use of automatic brakes, if available and operative, for landings during wet, slippery, or high crosswind conditions, and verify that these operators include this procedure in their flight manuals, checklists, and training programs"
"Require all 14 Code of Federal Regulations Part 121 and 135 operators to ensure that all on board electronic computing devices they use automatically and clearly display critical performance calculation assumptions"
"Require all 14 Code of Federal Regulations Part 121 and 135 operators to provide clear guidance and training to pilots and dispatchers regarding company policy on surface condition and braking action reports and the assumptions affecting landing distance/stopping margin calculations,to include use of airplane ground deceleration devices, wind conditions and limits, air distance, and safety margins"
"Require all 14 Code of Federal Regulations Part 121, 135, and 91 subpart K operators to accomplish arrival landing distance assessments before every landing based on a standardized methodology involving approved performance data, actual arrival conditions, a means of correlating the airplane’s braking ability with runway surface conditions using the most conservative interpretation available, and including a minimum safety margin of 15 percent"
How braking action feels ?
How braking action feels ?
When is the RCAM Applicable?
When is the RCAM Applicable?
• Only on Paved Runways ( Not on Turf, Dirt, Gravel, or Water Runways)
• Runway Condition Codes are NOT generated on Taxiways, Ramps, Heliports, etc…
• Codes are generated only when the total runway surface (or cleared width) is contaminated by more than 25%.
MANAGEMENT OF FINAL APPROACH, TOUCH-DOWN AND DECELERATION
The following tips are worth keeping in mind:
Consider diversion to an uncontaminated runway when a failure affecting landing performance is present.
Use your full flap settings without speed additives except if required by the conditions and accounted for by appropriate in-flight landing performance assessment, with the auto-brake mode recommended per SOPs
Monitor late wind changes and Go Around if unexpected tailwind (planning to land on contaminated runway with tailwind should be avoided)
Perform early and firm touchdown
Decelerate as much as you can as soon as you can: aerodynamic drag and reverse thrust are most effective at high speed, then moderate braking only at low taxi speed after a safe stop on the runway is assured
Do not delay lowering the nose wheel onto the runway (it increases weight on braked wheels and may activate aircraft systems, such as auto-brake)
Throttles should be changed smoothly from Reverse max to Reverse idle at the usual procedure speed: be ready to maintain Reverse max longer than normal in case of perceived overrun risk.
Do not try to expedite runway vacating at a speed that might lead to lateral control difficulty (Airport taxiway condition assessment might be less accurate than for the runway).
It happens, for more info have a look at the following reports:
It happens, for more info have a look at the following reports:
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