Old 15th Apr 2014, 11:20
  #75 (permalink)  
Join Date: Jun 2007
Location: Wanderlust
Posts: 2,324
I have produced below an extract from Airbus magazine on VMC tests conducted for the A380. It does not give the impression that VMCA is below Vs. I am not saying the two have direct connection but you cannot fly below Vs.
When engines and systems are configured, we start about 20 kt above the predicted value, then, we decelerate slowly keeping heading constant. Necessary rudder increases as the speed decreases, eventually up to the stop. Further deceleration will need some bank to still keep the heading constant.
The “true” VMCA is obtained when the bank angle reaches 5° in the opposite sense to the “failed” engine. This bank angle is very important as it allows a further speed reduction of about 5 to 10 kt, compared to the same test performed with wings levelled. Where is this strange rule coming from? It is a mystery

The tests to obtain VMCL and VMCL-2 are similar. But there is more to do. A demonstration that the roll manoeuvrability at VMC is sufficient must be performed.
How do you perform this demonstration when below stall speed?

vilas is offline