Impossible Turn Testing

[ABQ CTLS]

You may never intend to do a return to the runway turn and so never practice for it. But at really low altitude the loss of an engine is possible and landing straight ahead is the only option. How many, I wonder, while on takeoff, climbing at Vx, have put their throttle to idle at 100'? Have you experienced the push necessary to keep enough speed to land?

[Jim]

You may never intend to do a return to the runway turn and so never practice for it. But at really low altitude the loss of an engine is possible and landing straight ahead is the only option. How many, I wonder, while on takeoff, climbing at Vx, have put their throttle to idle at 100'? Have you experienced the push necessary to keep enough speed to land?

 

My instructor did exactly that, a few days from my checkride.  Put the throttle to idle and said "put it back down".  It caught me completely by surprise, but I still did it just fine.  Keep in mind we had a 6000' runway.  It did take a firm push forward on the stick, but nothing scary.

[FastEddieB]

My instructor did exactly that, a few days from my checkride. Put the throttle to idle and said "put it back down". It caught me completely by surprise, but I still did it just fine. Keep in mind we had a 6000' runway. It did take a firm push forward on the stick, but nothing scary.

To clarify, did you land straight ahead on the runway remaining or was this a return to the runway maneuver?

 

And at what altitude did he pull the power?

 

I had a cropduster engine fail on takeoff at Nassau, probably at a couple hundred feet. Lots of runway ahead, so just landed straight ahead. As far as I can recall, lowering the nose was instinctual and rapid - thanks to my training, I think.

[Jim]

To clarify, did you land straight ahead on the runway remaining or was this a return to the runway maneuver?

 

And at what altitude did he pull the power?

 

I had a cropduster engine fail on takeoff at Nassau, probably at a couple hundred feet. Lots of runway ahead, so just landed straight ahead. As far as I can recall, lowering the nose was instinctual and rapid - thanks to my training, I think.

 

Landed straight ahead.  He pulled power somewhere between 50 and 100 feet.  I was too busy to make a proper estimate

[FastEddieB]

Thanks!

 

Finally got up today in the Sky Arrow*.

 

For a goof. I went up to just below 5,000' over Copperhill and set up a 65k climb with 10º flaps - the takeoff setting.

 

At exactly 5,000' I chopped the power, while lined up with RWY2. Held the pitch for about 3 seconds while the speed bled down to about 50k. Then rolled into about a 45º turn to the left, back to the runway. Lost about 400' in the process.

 

Tried it one more time going the other way and got about 350' loss.

 

I'm not advocating anyone try returning to the runway as a first instinct. Just thought I'd give this exercise a try.

 

Still would not mind playing around with Andy one day in the two planes and taking a GoPro along.

 

 

*I would not have thought it, but my last flight was on Nov 22 - almost 2 months between flights! Waaay too long!!!

[Doug G.]

 

*I would not have thought it, but my last flight was on Nov 22 - almost 2 months between flights! Waaay too long!!!

 

Eddie, I feel your pain. It has been over a month for me. There were two great flying days last week but I ended up with a head cold and my self assessment kept me grounded.

[IrishAl]

Eddie,

 

I was wondering if the results of your trial have in any way influenced your DA of 1000 feet for a turnback?  

 

(It's a serious question - I really respect your experience and I guess it concerns me a bit when I form an opinion that's opposite to conventional wisdom.)

[IrishAl]

Here's a video that made me think of you - it's a Hungarian instructor apparently teaching his student standard turnbacks below 200 feet, and a 'scary' on at 50 feet (see the link near the end) - amazing what longer wings can do.

[FastEddieB]

Eddie,

 

I was wondering if the results of your trial have in any way influenced your DA of 1000 feet for a turnback?

 

(It's a serious question - I really respect your experience and I guess it concerns me a bit when I form an opinion that's opposite to conventional wisdom.)

I'm not sure I ever advocated a hard and fast line at 1,000'. If I did, let me clarify.

 

In general, I turn to crosswind at about 400'-500'. So with pattern work, losing the engine on climbout implies being somewhat less than 500'. In that case, for me there's no thinking about a return to the airport.

 

Losing power on crosswind is a whole 'nother thing. At that point, at about 500'+ with the runway only a 90° turn (plus a little) away, the runway, or at least the runway environment, is almost certainly doable.

 

Too many variables for a hard and fast answer. I still think the consequences of continuing straight ahead, or nearly so, are in general less dire than attempting a low altitude 180°+ turn that has proven so deadly time and time again.

 

But I respect the decision of others to come to different conclusions on the matter.

[FastEddieB]

Here's a video that made me think of you - it's a Hungarian instructor apparently teaching his student standard turnbacks below 200 feet, and a 'scary' on at 50 feet (see the link near the end) - amazing what longer wings can do.

Al,

 

The link did not seem to make it into your post.

[IrishAl]

[FlyingMonkey]

The flat terrain and lack of obstacles really help him out...if you tried this at those altitudes at my home airfield, on any of the four runways, you'd be in the trees.

[Ed Cesnalis]

I think the camera angle makes it look flatter than it is and the motor glider performance changes the perspective too.

[Dan Kent]

Another thought on the "turn" is that if your airport has multiple runways (or non parallel taxiways) is a turn to another runway if it is a shorter turn.

 

At my airport there are 2 runways and a very experience pilot died (engine fire) in his experimental plane because he tried to turn 180 degrees when the other runway was a shorter turn. What's really sad is his daughter who was on the plane suggested the shorter turn and he chose the tougher turn. They were less than a mile from the end of the runway but it took 3 hrs for the rescuers to get through the trees.

[FastEddieB]

Another thought on the "turn" is that if your airport has multiple runways (or non parallel taxiways) is a turn to another runway if it is a shorter turn.

That's kind of why I like to refer to it as "a return to the runway environment" rather than a return to the runway.

 

Other runways, taxiways, ramp areas, or even grass areas are all pretty decent places to put down a small airplane. Especially a Light Sport.

 

May not apply to a single runway airport like Copperhill, but my initial training was at Opa Locka where there were usually myriad choices if an engine failed on departure.

[gbigs]

 Even if you succeed making an impossible turn in a practice there is no assurance you can do it when you DO NOT EXPECT the engine to quit.   Even the POH describes the engine out emergency in more dire terms. 

 

If at or near pattern altitude and calm wind and not at MTOW there may be enough room for error and delay in reaction to make the turn, otherwise it's a chute pull and/or a straight ahead set down.

[FastEddieB]

Just watched the video.

 

1) It's showing a successful return from about 100 feet AGL. I do not think that is anywhere close to possible in our airplanes.

 

2) Look closely and on some of the videos he has as much is 1200 RPM after the engine "failure". That's a far cry from what you would have with a completely failed engine.

[Tom Baker]

Just watched the video.

1) It's showing a successful return from about 100 feet AGL. I do not think that is anywhere close to possible in our airplanes.

2) Look closely and on some of the videos he has as much is 1200 RPM after the engine "failure". That's a far cry from what you would have with a completely failed engine.

I don't think 1200 rpm will make the airplane glide farther than with a complete power loss. In my experience there is less drag and the airplane will glide farther with the propeller stopped than with it turning at 1200 rpm. Also most aircraft engines other than the Rotax the engine will continue to windmill when power is lost, unless you slow the airplane to near stall speed. The windmilling propeller could be turning as much as 1200 rpm depending on aircraft speed.

[FastEddieB]

I don't think 1200 rpm will make the airplane glide farther than with a complete power loss.

Yes it will. Stand behind an idling plane and you can feel how much thrust there is. On the other hand, a windmilling prop is a large drag.

 

In my experience there is less drag and the airplane will glide farther with the propeller stopped than with it turning at 1200 rpm. Also most aircraft engines other than the Rotax the engine will continue to windmill when power is lost, unless you slow the airplane to near stall speed. The windmilling propeller could be turning as much as 1200 rpm depending on aircraft speed.

Well, I'll stipulate that a stopped prop has less drag than a windmilling one.

 

I'll further stipulate that ROTAX engines will likely stop rotating with an engine failure.

 

But my comments were about the plane in the video. Loss of idle thrust and a windmilling prop would have degraded performance on the return to the field.

[Jim]

 Even if you succeed making an impossible turn in a practice there is no assurance you can do it when you DO NOT EXPECT the engine to quit.   Even the POH describes the engine out emergency in more dire terms. 

 

If at or near pattern altitude and calm wind and not at MTOW there may be enough room for error and delay in reaction to make the turn, otherwise it's a chute pull and/or a straight ahead set down.

 

I'm wondering why you think you have something to bring to this discussion.  Did you take the time to practice it?

 

You called me a liar a few posts back...

 

 

You did it with total engine out or at idle no fudging....I don't believe it. 

 

By the way, we are not doing party talk and sharing campfire stories here, we are talking about getting killed...giving newbie pilots the impression the impossible turn is possible is not just irresponsible, it's malicious.

 

 

I don't remember an apology or a correction.  Frankly, and I'm trying real hard not to make a personal attack, I think you should just keep your thoughts to yourself if you don't know what you are talking about.

[Tom Baker]

Yes it will. Stand behind an idling plane and you can feel how much thrust there is. On the other hand, a windmilling prop is a large drag.

The idling prop produces drag, it is just less drag than the windmilling prop. The thrust you feel when walking behind an idling plane is not enough to overcome the drag produced by the slow turning propeller.

[FastEddieB]

OK.

 

My only point was idle thrust provides more performance than a failed but turning prop.

 

We can agree on that, right?

[Tom Baker]

OK.

My only point was idle thrust provides more performance than a failed but turning prop.

We can agree on that, right?

As long as you don't delete your post because I disagreed with you.

[Jim Meade]

There are many discussions on line about this kind of situation. It seems to me it is highly dependent on the equipment being discussed.

 

You might find it interesting (but not necessarily very instructive) to watch the video on YouTube and note the comments. Most somewhat uninformed.

 

BTW, it seems generally agreed that the aircraft is a motor glider, though I am not sure of which one, so it is probably around a 23-24:1 or even higher glide ratio, whereas my CTSW is around 9:1. The altimeter is labeled in meters so it looks like the turn was done at around 100 meters, or around 330 feet give or take a few. I've done a turn back in my glider, which is 33:1, at 250 feet, and glider pilots are required to be able to do one at 200 feet. This video may not be much of a feat. It would be expected of a glider pilot in a glider. That doesn't mean it is possible or wise for one of us in a CT.

 

When training in twins, one sometimes sets one engine at zero thrust. That is an RPM that produces what it says. I don't know how close an idling prop in this video aircraft or in a CT is to zero thrust, but it would be interesting to see how it compared in drag to a stopped prop. In my own subjective CTSW experience, there is some reduction in glide distance with a stopped prop, but not a lot. Talking here about fixed pitch props.

[FastEddieB]

The altimeter is labeled in meters...

Nice catch! If that's correct, of course.

 

I guess I'm just provincial enough to assume that all altimeters were calibrated in feet.

 

A bit of a sidetrack, but in Europe are altitudes assigned in meters? It seems like that would be very confusing for pilots of aircraft with altimeters calibrated in feet.