I don’t have statistics, but they are certainly amongst the more dangerous accidents.
The airplane is usually at its highest weight during take off, there is a reasonable amount up to full fuel on board and the engine(s) are at maximum or close to maximum power. Until safe altitude, anything which happens there is high risk. Reland on most cases unsuitable terrain for Singles or most light twins, trying to negotiate OEI climbs in the others.
Apart from engine failures, performance related take off accidents are the main cause. I wonder how many of those were avoidable if proper abort techniques/decision points/speeds would be more observed or how many are due to the simple fact that no performance calculation was done or done improperly.
Take off briefings are essential, but are they done regularly? Do we really have a “plan” every time we take off and how ready are we really to execute those plans if it happens? We’ve had some good examples how things can work out, the reland of that Bonanza at ZRH was a great example, but unfortunately others regularly don’t fare that well.
I’d say trouble on takeoff has a higher rate to end in disaster. The good side of the runway is just in the wrong direction.
But in total numbers landing “mishaps” will be way more, at least 10 times or 50 times or so.
For takeoff, what you can one do to minimize risks? Not too much…
Maintenance is not really in our direct hands, in most cases
Make sure the checklist is read. In particular, make sure that fuel will get to your engine for the next few minutes
Some people do full power runups, but most don‘t as it is hard on the engine, the breaks, and makes noise
Make some sort of emergency briefing, and brief the airport surroundings
Train low level „aborted“ takeoffs occasionally (not often done, as that in itself also carries risks), plus it makes more noise and scares neighbours
boscomantico wrote:
For takeoff, what you can one do to minimize risks? Not too much…
The simple thing to do to minimize risk during takeoff is to lower the nose once airborne, and allow the airplane to accelerate to at least Vy. From that speed, a glide following a sudden engine failure is much more possible than the silly Vx climbs I see from time to time. I did Vx engine cuts at 50 feet in a modified Grand Caravan, and it was terrifying! Vy is not necessarily the best speed for a climb, but it is probably the best speed to be at for an EFATO!
Obviously at low speed and close to the ground, there’s not many options at your disposal if the engine should quit. Gaining speed while you can must be beneficial. Otherwise it seems to me the devil is in the details regarding a happy ending.
silly Vx climbs I see from time to time
Same here… I see some of our guys prop hanging at the RV typical 65kts Vx iso at least accelerating to the 85kts of Vy (no close obstacle).
When light I usually let her accelerate to 100-110kts in a shallow climb and then resume the climb at that speed.
The building up of energy, with the benefit of a better peripheral view, are the main benefits of aiming for Vy initially.
I’m still getting used to how fast the Super Guépard leaves the ground and climbs Vy and Vx become meaningless.
I have a habit of getting the revs up a bit on the brakes, something I usually did with a twin.
Then release brakes and just me and 40litres of fuel I’m off the ground before I can blink and climbing so nose high with speed rising to 140km/ph that I am pushing hard on the stick to get it to something more sensible like 700fpm and then retrimming nose down like crazy and pulling the throttle back to keep from going too far into the yellow.
Twins climb well on both engines but this is crazy for a tubular steel box frame covered in some sort of plastic type material that you might use to cover something in the garden, to which you have added wings and a rudder. I just love it.
BTW Vy is 110km per hour and it is an almost vertical climb. Not yet had the guts to climb at Vx which IIRC is 90km per hour.
gallois wrote:
BTW Vy is 110km per hour and it is an almost vertical climb. Not yet had the guts to climb at Vx which IIRC is 90km per hour.
The Alphatrainer is a bit special in this regards also, but I bet very different from that Guepard.
Minimum sink speed : 58 kts
Vx : 58 kts
Vy :76 kts
Best L/D : 64 knots
Stall speed (clean): 40 kts
Even at Vx, you are at minimum sink speed and 45% above stall speed (clean). According to the POH, the best climb speed for cross country is 100 kts, which gives 800 fpm climb. This feels like normal climb in a “normal” aircraft. Vx feels seriously unnatural. Even Vy is at a steeper angle than most Vx’es. But, if the engine quit at Vx, you have to react fast. Not much inertia, and the speed drops fast (it is seriously slippery though, very much unlike that Guepard). In total you probably have to rotate the aircraft in pitch about 90 degrees before you will gain positive acceleration.
If the engine quits during take off, the Alphatrainer is perhaps one of the safest planes you can get (if you don’t climb at Vx which feels too ridiculous to do anyway in any normal circumstance). It’s more like a motorgiler. Best L/D of 17.
gallois wrote:
Then release brakes and just me and 40litres of fuel I’m off the ground before I can blink and climbing so nose high with speed rising to 140km/ph
Yes ULM (microlight) is a league of its own. They also glide quite ok and very slow. We (flight school) lost a microlight because the pilot set the trim wrong for touch-and-go landing. Put the gas full forward and shot nose high up in the sky to fall down thereafter. He left the plane more or less unhurt, but the plane was a total write-off.
Just another game compared to SEP at MTOW, where I operate practically anytime I fly.
