Contaminated Performance Bamboozler
Anyone out there who can clarify this for me?...
Have been looking over Contam Perf the last couple of days in preparation for the winter.
My query is this:
When calculating a contaminated V1, my Company Ops Manual states that if the calculated V1 is less than V1mcg, then you should set V1=V1mcg.
But surely then you are above the speed at which you are guaranteed to stop within the remaining distance if you decide to reject. For example, on the 737-700 at about 60 tons, using QRH poor braking action slippery perf, the V1 reduction is about 31knots, resulting in a typical V1(contam) of about 97 knots. V1mcg is typically 103 knots, so at 97 knots you are too slow to guarantee control if you decide to continue the take-off. This why we are asked to raise V1(contam) to 103 knots.
However, this extra 6 knots must surely put you at severe risk of an overrun.
Would it not be more prudent to reduce your aircraft weight until V1(contam) raises a few knots to equal V1(mcg), therefore guranteeing that at V1 the decision you have made will ensure a safe stop, AND a safe take-off???
Any clarification would be much appreciated from performance boffs...
Cheers,
DTD.
PS, for the critics: No, I would not consider taking off from a poor braking action surface, and yes, I would rather wait for it to clear. Just a query, that's all.