Engine Failure on Take-Off Flashcards
For a given runway distance the max speed to reject the take-off (Vstop) will vary with …
The stop calculation is performed both for … and … situations
aircraft mass
all engine and engine out
Minimum speed to continue, Vgo, is lower when … because …
When the aircraft is heavy though, the engine failure can only be accepted near to … as the aircraft is very difficult to accelerate (possibly not making V2 at screen height in the TODA)
the aircraft mass is low
a light aircraft accelerates relatively easily, even with an engine out
Vr
For the mass plotted on the graph there is a range of speeds between the max speed to stop, Vstop, and the min speed to go, Vgo, where if an engine fails we can neither …
stop nor go, we are going to die
Below Vgo, why can’t we continue the take-off after an engine failure?
we will not have enough take-off distance remaining to make the screen height at V2 with the thrust available on the remaining engine(s)
Above Vstop, why can’t we stop in the event of engine failure?
we will not have enough of the ASDA left to safely come to a stop
the engine failure consideration of field length restricts our … to the intersection of the two lines on the Vstop and Vgo graph
this is called the …
MTOM
one engine inoperative field length limited take-off mass
The speed at the intersection of Vstop and Vgo is called …
the decision speed, V1
V1 defined as
the max speed during the take-off at which the pilot must take the first action to stop the aeroplane within the ASDA. It is also the minimum speed during take-off following failure of the critical engine at Vef, at which the pilot can continue the take-off and achieve the screen height within the TODA
CS 25 allows a minimum recognition time of … between the engine failure speed, Vef and the decision
one second
(one second between Vef and V1)
There is a … gap between V1 and starting to stop
two second
A range of decision speeds exists below …
the one engine out FLL TOM
The engine out take-off calculation uses … performance because ….
gross
of the improbability of an engine failing at exactly Vef on a field length limiting runway
(The failure at this precise time is assessed as having a probability of less than 1:1000000 so no further safety factors are used)
the screen height for wet runway is …
why is it used?
15 ft
A V1 greater than Vr cannot be used
Performance manuals compare V1wet to Vr in the calculation of TOM so you will never find a V1wet greater than Vr
As V1dry is 10 or 11 KT higher than V1 wet (doesn’t have to account for the increased stopping distance) you could find V1 dry greater than Vr
The normal procedure in this case is to restrict V1dry to Vr. This implies that, if you go from the restricted V1, you will not make a 35ft screen height (because your speed will be slightly below the Vgo line) but you will at least make 15 ft
is V1 wet higher or lower than V1dry?
Why?
lower than V1dry because you have to account for the increased stopping distance on a wet runway
(you will be too fast to stop at a lower speed)
If V1 is less than Vmcg then the aircraft …
If a range of speeds exists for V1 that encompasses Vmcg a higher speed can be chosen that satisfies the requirement. If not …
will not be able to be kept straight on the runway if a ‘go’ decision is made
the TOM will have to be reduced
(As the TOM is reduced the available range of decision speeds widens out to eventually include Vmcg and at that point the take-off becomes legal by using the max V1 which is also Vmcg. Basically, a high Vmcg may limit TOM)
