Short Approach? I cannot see any practical alternative other than temporarily closing the runway as above. With more accurate measurements and improved landing performance calculations we might only show / proove that the runway is not long enough; thus closing it until the contamination is cleared is both practical and safe.
Meanwhile perhaps all AFM data should be marked:
”Operation on runways contaminated with water, slush, snow, ice or other contaminants implies uncertainties with regard to runway friction and contaminant drag and therefore to the achievable performance … since the actual conditions may not completely match the assumptions on which the performance information is based. Where possible, every effort should be made to ensure that the runway surface is cleared of any significant contamination.
… it is not possible to produce performance data that will precisely correlate with each specific operation on a contaminated surface".
Also all runway condition / friction reports should be prefixed with the following warning:
… there is not, at present, a common friction index for all ground friction measuring devices. Therefore it is not practicable at the present time to determine aeroplane performance on the basis of an internationally accepted friction index measured by ground friction devices.
The text above is taken from
EASA / JAA NPA 14 2004 (thanks
Tribo). The NPA also comments, “Notwithstanding this lack of a common index, the applicant may optionally choose to present takeoff and landing performance data as a function of a wheel braking coefficient constant with ground speed. The responsibility for relating this data to a friction index measured by a ground friction device will fall on the operator and the Operating Authority.”
Operators again have to take responsibility for safety, yet where are all of the assumptions and guidelines to be published, and what practical help will be provided for the pilots preparing for the approach and landing.