Height loss in turning back

[Bruce Tuncks]

If you have a power loss just after takeoff, how much height do you need?

 

Well I tried it several times, with 2000 ft safety height, and found that a 180 degree turn (power off) took 200ft, while a "teardrop turn" to realign with the runway took 300 ft.

 

The method was to slow immediately to 65 kts and do a 45 degree banked turn holding this speed. Faster speed and less bank lost more height, for example a teardrop at 85kts and 20 degrees of bank lost 600 ft and took a lot longer.

 

Well the Jabiru is light and clean, so this is not surprising, (a glider can do a CLIMBING 180 while slowing from 80 kts to 65), but it is lots less than some books would have you believe.

 

Has anybody else tried this, it would be interesting to compare figures.I reckon the longer wing Jabiru should do better than my little SK, and winglets should help too.

 

Bruce

 

 

[bushpilot]

We need to be careful not to give too much encouragement to the 'turn back' response. And it is not just about height loss to teardrop (180o+), we have to also consider distance from / to the threshold. So at say 800' and assuming your 300' loss, will 500' get you home? The answer will vary with loading and conditions (rate of climb) on the day.

 

 

[Ross]

Some years ago, I had some intermittent engine trouble early in the take off once in the small Jab and was stupidly late deciding to abort so was at +500 ft when I finally decided to abort.

 

Since I then had full engine power however unreliable, I decided better late than never to do a 180 into a very slight cross wind and land back down the same strip but this time with a weak tail wind..

 

There was a short cross strip underneath the a/C most which was down wind of the position of the aircraft. I had immediately decided it was not an option as I would be lucky to be on the ground before the far end of that strip and would have to turn 270 degrees to land back from the far end.

 

During the 180 reverse of course, I probably did about a 45 degree climbing banked turn to slow it down and convert the excess speed into height. Ex Glider pilot.

 

I then went into into full flap landing to slow it down and to get a high sink rate. I really had to watch the air speed as you get a false idea of it from looking at the runway ground speed. You are much tempted to slow down by increasing the angle of attack as you see the runway rapidly being flown over.

 

It took full flaps all the way and full brakes when on the ground to try to stop it before the end of the runway as I had already flown over half of it before the wheels were on the ground.

 

I think it was still travelling well above my normal taxi speed when I exited the runway close to the end of the strip. There was still a couple of hundred yards of clear ground beyond the end of the designated runway.

 

I was so surprised at the long ground run that I took particular note of the now tail wind strength according to the windsock and I estimated it was probably well less than 5 knots with an equally weak cross wind component in the wrong direction for the situation.

 

I had stupidly passed up a lengthy opportunity in time to abort before it became critical once I was airborne at low altitude.

 

I survived a number of lessons that day that will stick in my memory for a long time.

 

 

[poteroo]

'The Proficient Pilot' by Capt Barry Schiff

 

Recommended reading. A practical pilots' book. Good section on 'turning back'

 

Mods: Might be worth re-locating this thread into General Discussion?

 

happy days,

 

 

[slartibartfast]

'The Proficient Pilot' by Capt Barry SchiffRecommended reading. A practical pilots' book. Good section on 'turning back'

 

Mods: Might be worth re-locating this thread into General Discussion?

 

happy days,

Agreed and actioned.

 

 

[Yenn]

I have done a few tests in the Corby Starlet and reckon I need 800' to be able to get back to the strip, then I have to contend with the tail wind and this results in an approach path that will seem to be far too low and very flat. If there is any chance of getting safely on the ground straight ahead go for it, unless you have done the tests yourself at a safe height.

 

 

[facthunter]

reality.

 

There is nothing wrong in knowing how you plane will perform if you want to do a course reversal without power. How you apply it is another matter. As Ian (Yenn), says you still have to contend with the downwind landing, which will appear very flat on the approach and you will think that you are coming in like a "bat out of hell". and the tendency is to raise the nose and end up with inadequate airspeed.

 

The reality of this is that MOST pilots when they do this manoeuver for real, muck it up and end up stalling in the turn, and end up dead. A gliding steep turn requires a high degree of flying skill and you will have a very high sink rate.That is why you are generally advised to land more or less straight ahead, just turning to miss objects that you don't want to tangle with.. IF there is a considerable headwind this is a more attractive proposition as your actual speed (groundspeed)will be quite low if you land straight ahead, and you can actually pull up in a very short distance. Also in these circumstances the groundspeed for your turn back landing will be very high, and the approach aspect will be quite unfamiliar to you and you are unlikely to do it well and if you don't quite make it to the field you have put yourself in the worst possible position. Nev

 

 

[Captain]

I agree with most of facty's post.

 

If you barely have enough height to turn back you are more likely to muck it up from the pressure of the moment ... and spinning in from a low turn has wiped out lots of reasonable pilots.

 

There is a good reason why the "don't turn more than 30 degrees off heading" rule of thumb has evolved.

 

My rule (for me) is don't turn back unless I have enough height to be sure of making the cross strip.

 

I have practiced 180 degree power-off turns at height and you lose less height than you think.

 

When learning to fly gliders they do a simulated rope break on an aero-tow at lowish level and it is surprising what you can do with a turn-back.

 

But in the real world, if the engine goes quiet, and you tighten up, it will be much different.

 

Hope this helps.

 

 

[Guest brentc]

The turn-back caught fellow forumer Pip Boorman. I'd hate for it to catch anyone else.

 

 

[Guest Graham Lea]

And a good mate, Ron Bertram. But he had no where else to go, other than into a roof.

 

 

[Guest pelorus32]

G'day Bruce,

 

this subject has been covered before in the forum:

 

http://www.recreationalflying.com/forum/general-discussion/4731-engine-failure-turn-back-altitude.html

 

The bottom line is that whilst in an ideal situation where you know what is happening you might pull it off, too many people have died turning back.

 

There are good rules about when we should and should not attempt to turn back and we should stick with them.

 

This isssue really got going in the gliding world, where despite a capacity to glide for the distance stall/spin is often the outcome.

 

Good advice from Captain, Facthunter and others.

 

Regards

 

Mike