Engine out after departure LSZH today

Your plane must have an excellent glide performance Peter. I am sure you have read the same Prof Rodgers articles. A turnback is supposed to be impossible unless one does a very sharp turn, on the verge of stall, into wind, and goes straight back.

@eddsPeter

Congratulations for a safe outcome and a very well handled emergency situation!

Do you already have an idea why this engine failure might have happened? It would be interesting to see the data from your engine monitor!
Looks like a thermal runaway, possibly due to detonation.
Did your engine monitor give some kind of warning?

Peter wrote:

Your plane must have an excellent glide performance Peter. I am sure you have read the same Prof Rodgers articles. A turnback is supposed to be impossible unless one does a very sharp turn, on the verge of stall, into wind, and goes straight back.

Not from 2500agl Peter.

Jason can you please add some (considerable, please, because I am really thick on weekends) detail on how climbing further along the same track makes one glide for longer if gliding back to the same airport, in an aircraft whose climb performance is of the same order as the glide performance (about 1000fpm)?

Climbing into wind and gliding downwind will help…also a big nice long runway to aim for, with a touchdown point a lot closer than the lift off point?

Nice job

Peter wrote:

Jason can you please add some (considerable, please, because I am really thick on weekends) detail on how climbing further along the same track makes one glide for longer if gliding back to the same airport, in an aircraft whose climb performance is of the same order as the glide performance (about 1000fpm)?

Because aircraft have been clearly shown to be able to make it back after a 180 followed by a second aligning turn once above a certain altitude. It it were really true that climb rate/nm equals best glide sink rate/nm then this would be impossible given the height loss during the turns and the longer distance back vs out. Also, in a turn back the pilot has control over their drag (flaps, gear etc) and will often have a tailwind which adds twice the wind speed to your ground speed. Even if I don’t land on a runway, in many environments, if I had altitude, I would prefer to crash in an airport environment than over a suburban area.

The problem, below a certain altitude, is not having enough height to safely complete the turns allowing for Optimal or more likely less than optimal technique. It is quite astonishing how much of a pitch change is required going from a climb pitch at full power to a lower glide speed after an engine quits or is pulled back to idle. Even more so when you start a 45 degree bank and have to lower the nose even more.

Obviously there is a specific height or time where the loss of height on a 180 degres steep turn is compensated by the delta between slow step climb and best glide decent

If the impossible turn needs 600ft and you have a 700fpm climb and 500fpm glide, then you need 3min and 2100ft agl (assuming you climb and decend at Vy = Vg)

Peter wrote:

detail on how climbing further along the same track makes one glide for longer if gliding back to the same airport, in an aircraft whose climb performance is of the same order as the glide performance (about 1000fpm)

Climb performance will often exceed glide performance, and climb angle in all but the most anaemic aircraft will exceed the glide angle especially if the climb is upwind and the glide is downwind. For example, my aircraft climbs initially at 1200fpm, but best glide has a sink rate of around 600fpm. Furthermore, we take off into the wind making the climb angle steeper still relative to the glide angle, which on return the tailwind will make shallower. So even if your aircraft climbs at 1000fpm, and has a best glide sink rate of 1000fpm, you will glide considerably further downwind.

Add to that on a long runway, where you take the full length, the departure end of the runway may be a mile closer to your current position than your liftoff point which further reduces the amount of gliding you need to do by a considerable amount.

You may remember my post a couple of years ago where my wife flew “the impossible turn” for real after an EFATO in New Orleans. We had taken the full length of the very long runway designed for lethargic bizjets, and this pretty much guaranteed that we would be able to put the plane somewhere on airport property in our situation, since our liftoff point was a good mile before the airfield boundary. In the actuality, we touched down just about where we lifted off, in other words, we had room to spare.

You have to compute in terms of climb/glide angle/slope, not in terms of vertical speed only (fpm). If you climb at 120kts, but glide at 90kts, then the same angle is obtained at a cruise vertical speed one third more than the glide. E.g. if you glide 500fpm at 90kts, then this corresponds to 670fpm in the climb. Meaning climbing at 700fpm you’ll have the 600ft extra altitude for the turn only after 18 minutes! (At this time scale, your climb performance is probably not constant throughout the glide. Neither is your glide performance… the glide is done at an IAS, but your TAS is higher, leading to a shallower angle.)

EDIT: just saw you put the assumption that Vy=Vg. Missed that. Sorry.

As written before in this thread, wind usually helps (since you takeoff with headwind, and it moves only about 30° in the initial climb), as well as not using the whole runway to takeoff (aiming point closer to glide starting point than takeoff point).