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Old 9th November 2007 | 07:22
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CharterJake
 
Joined: Dec 2006
Posts: 18
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From: Established on the LOC
Sunbird !

In the all engine scenarios both the wet and the dry rwy cases have the same safety factor (15% for JARs) TODR,TORR. In the engine out cases: there is no safety factor and there's always some kind of reduction: TODR: screen from 35 to 15 feet (DRY to WET), TORR: distance equidistant from lift-off point to screen(DRY) to just lift-off point on the WET rwy. These all take into account the slower acceleration etc. on the wet rwy. ASDA: only gross distances, but again there is allowance for the WET rwy scenario.
Balanced field: TODA=ASDA, or any Clearway= Stopway, TODC computers ignore some of the clearway available, just to make the calculations easier(and of course your clearway cannot exceed 50% of the rwy length that it is associated with). The TODC might unbalance the field for a wet rwy, but if you play around with it a little bit you will see, that 90% of the time it just plain reduces your V1 by 10 knots (737 JARs,allows for the degraded braking performance during an RTO on a WET rwy), and leaves all other aspects the same (reduced thrust, VR, V2...). If you have contamination (wet snow , slush...)that is a different story...
Hope this helps
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