Contamination / BA on TO calculations
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Contamination / BA on TO calculations
I don't suppose anyone would be so kind as to provide feedback on the following...
I'm looking at an aircraft type where the only performance charts provided by the AOM dealing with contamination / slippery runway (0.02) are:
- Contamination effect on takeoff-distance
- The Effect of slippery runway on landing distance.
Roll-resistant deposits will of course lengthen the takeoff run, and affect both the accelerate and stop distance in ASD calculations. Low braking action will have minimal effect on TOR (unless static TO-thrust is required), but a large impact on the ASD calculations.
When faced with such a lack of data from the manufacturer, are there industry-accepted factors applicable to the "dry/wet runway" charts when faced with poor BA / contamination. As things are now, the only option is to stop operations when BA is under .05 or more than 3mm WED exists.
Cheers
I'm looking at an aircraft type where the only performance charts provided by the AOM dealing with contamination / slippery runway (0.02) are:
- Contamination effect on takeoff-distance
- The Effect of slippery runway on landing distance.
Roll-resistant deposits will of course lengthen the takeoff run, and affect both the accelerate and stop distance in ASD calculations. Low braking action will have minimal effect on TOR (unless static TO-thrust is required), but a large impact on the ASD calculations.
When faced with such a lack of data from the manufacturer, are there industry-accepted factors applicable to the "dry/wet runway" charts when faced with poor BA / contamination. As things are now, the only option is to stop operations when BA is under .05 or more than 3mm WED exists.
Cheers
Join Date: Oct 2003
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The figures in the AFM or equivalent are usually done in compliance with the certification requirements, so the figure given for TOD is the greatest of ASDR, TODR with an engine failure at V1, or 115% of the all engines TODR. Therefore the contamination effects are taken into account, although you do have to remember the different parameters; reversers are taken into account for stopping and the screen is reduced to 15ft - i.e. the margins are reduced with a cntaminated runway.
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Since the question was about contaminated runway charts, it seems reasonable to assume they refer to a contaminated runway
Seriously, though, you are correct in that another of the standard problems is that the AFM always seems to have charts for every type of contamination except the one you have! To go back to the original question, yes there is a point where you have to stop operating and that point varies with aircraft type; I have to say that BA 0.05 and/or WED 3mm is a pretty awful runway, I think I'd quite happily go back to the coffe bar until the weather improves
Seriously, though, you are correct in that another of the standard problems is that the AFM always seems to have charts for every type of contamination except the one you have! To go back to the original question, yes there is a point where you have to stop operating and that point varies with aircraft type; I have to say that BA 0.05 and/or WED 3mm is a pretty awful runway, I think I'd quite happily go back to the coffe bar until the weather improves
