Originally Posted by
Centaurus
There is a school of thought that it is better to deliberately leave the landing gear down in a twin after take off until the pilot judges he can no longer make an airborne abort on the remaining runway length if an engine fails. It will take longer to accelerate to Blue Line speed with gear hanging out but that is seen as acceptable.
Question: How does one judge whether or not there is sufficient runway ahead on which to make a successful stop. Should instructors be required to demonstrate this procedure and if so, what publication furnishes the official required performance data that covers the overall distance required on wet and dry runways? How about day or night procedure knowing it is more difficult to judge remaining distances at night than in daylight?
The other school of thought is to retract the landing gear as soon as a positive rate of climb is achieved after lift off and accelerate through best single engine rate of climb speed (Blue Line) as early as practical. If an engine fails when airborne and below Blue Line speed, simply land ahead on remaining runway length. Accept there will be a 5-10 second period where an engine failure in that time requires an airborne abort within the remaining runway length. There will however be more runway ahead within which to to stop, than aborting from further down the runway from a higher altitude with gear down.
Comments on either procedure invited.
For normal takeoff: It is flaps up 20 inches on the brakes, engine check then brakes release. At Vr it is rotate, positive rate, blue line, gear up. Blue line line is maintained until 400 AGL then the aircraft is accelerated to normal climb speed and climb power set. If the there is an engine failure before blueline the automatic reaction is both throttles to idle. If there is a failure after blueline the failed engine is identified and feathered and the aircraft is flown away.
I do not like the the leave the gear down until no runway available method for several reasons.
1) Altitude = life. The airplane will climb better with the gear up. The first few hundred feet AGL is the danger zone.
2) Actually judging when you still have sufficient runway is pretty hard. Most students will IMO leave the gear down far longer then is practicable to return to the runway.
3) To make the runway particularly if it is narrow, the yaw after the engine failure must be perfectly controlled otherwise the aircraft will have to be manoevered back to the runway centerline inviting low level turns, an often deadly scenario.
4) There is reams of human factors research that shows pilots have great difficulty in making quick judgement decisions when under sudden great stress. This is the foundation of the concept of V1. Over time the idea that there was still room for Captains discretion after V1 has been debunked by the fact that late rejects usually end badly, and this is with very experienced pilots. Since someone training for the ME rating is by definition inexperienced I believe teaching a series of predicable actions which are followed for every takeoff produces the safest outcome.