View Full Version : V1 speed and slush

29th Mar 2023, 16:07
Hello everyone! First of all, sorry to bother you with such a boring question about PERF. While I was taking an ATPL refresher test, I came across a quite easy question, but the explanation is not very well worded and I would like to clear up doubts. The question says that with increasing slush thickness, the V1 reduction will be smaller. I assume that this is due to VMCG limiting V1, right? Here you have the exact explanation on my perf book: "It is useful to note that, as the contamination depth increases, the majority of the correction is allowed for in the greater reduction in take-off mass. The lighter TOM results in all V speeds becoming slower, with the extra V1 reduction causing a further decrease. As the contamination thickness increases the extra V1 reduction decreases in magnitude due to the potential V1 limitation of Vmcg". So V1 reduction is smaller to prevent V1 being below VMCG, right? Thx in advance!