Engine failure after flap zero Take Off
 

Hi

If I lose an engine on a Performance A aircraft, just after V1, with flaps zero, am I supposed to climb at V2 initially anyway? Or can I just go straight to Venr?

V2-V2+10

Indeed V2 is the min manoeuvre speed for your flap configuration. However, V2 - V2+10 will depend on type and what kind of manoeuvring you wish to do, i.e. back angle.

In simple terms yes (as per RAT 5) because that is what your performance charts are based on. However, if you can see that acceleration at a lower height than specified would not interfere with obstacle clearance then there is no practical reason why not. But that still doesn't mean you can. Company, national and local regulations may prevent you from doing so.

Thanks for the replies, guys! I'll have to dig a little deeper into the Company OM to find out if it's OK

Out of interest, which PERF A aircraft are you taking off with no flaps in?

I was always under the impression that 400'AAL was the lowest acceleration altitude that was permitted.

Is V2 the same as VENR for your flap zero take-off?

If yes, then it's a moot point.

If no, then you adhere to the SOP speed for the take-off phase. For the second segment, fly at V2+x (x being whatever correction your company dictates), for the third segment accelerate to VENR, and fly at VENR for the fourth segment.

Remember, that with an engine failure we are concerned more with our angle of climb to get over obstacles. If we fly too much faster than V2 during the second segment, the angle of climb will be degraded and we may exceed the lateral boundaries that a runway analysis is designed around. I've never seen the sense in accelerating to go further down the line when the immediate intent is to get up high in the least distance.

It is. It can be any altitude higher than that based on local topography or company requirements. For example, Aerodata uses 400' AAE where possible, while Aircraft Performance Group (APG) typically uses 1,000' AAE for minimum flap retraction altitude (e.g. end of the second segment). Other companies will use different altitudes based on what they hope to accomplish (normally, increasing the allowable take-off weight).

V2 flaps zero is going to be a MUCH lower speed than Venr. Decreasing pitch attitude to accelerate to Venr from V2 should be done at the computed acceleration altitude. Doing so sooner will invalidate the climb gradient/obstacle clearance calculated during the performance planning process, so why do it sooner? The calculated departure path meets climb/obstacle requirements only if the profile is flown as planned. The obstacle clearance plane doesn't change just because one can see the terrain visually.