Altitude to turn back to the airport

[AGB]

Hello,
We all know that in case of engine failure after takeoff one should land straight ahead, but at some point there is enough altitude to turn around back to the airport. I was experimenting with my 170A and found that it takes around 250 feet to turn around (180°). I did this about 2000 feet above the terrain, nose down to maintain speed and about 60-70° bank curve. If I really was at 250 feet I think I would not have the courage to turn that aggressively.

So have any of you done something similar? What is the altitude you consider safe to return to the airport in case of an engine failure after takeoff?

Thanks,
Donovan

[Robert Eilers]

There are a multitude of factors that affect the determination of a so-called minimum safe altitude to return to the airport, and these contributing factors change with every flight. Some of the factors are:
1. Winds on takeoff and climb out.
2. Aircraft weight & balance
3. Outside air temperature and humidity
4. Climb indicated air speed
5. Pilot proficiency
In my opinion, all of these factors affect Angle of Climb, or altitude gained versus distance from lift off point. The angle of climb determines how much distance is covered, after lift off, before a certain altitude is attained. Altitude and Distance from the lift off point, or airport, are the factors that determine whether or not you can safely make a 180 degree return to the airport. The minimum safe altitude arrived out through trial and error and one particular day is not going to be the minimum safe altitude on any given subsequent day.

[jlwild]

While learning to fly gliders, I was taught to not attempt a turn back to the field unless I was 500 feet above field elevation. However, this was for a heavy glider trainer and may have no relationship to a Cessna 170.

[jrenwick]

There are too many fatal accidents resulting from attempts to turn back after an engine failure on takeoff. One of the better flight schools here teaches all students to repeat, out loud, before each takeoff:

Engine failure on the runway, brake straight ahead.
Below 500', land within 30 degrees of runway heading.
Between 500' and 1000', within 90 degrees of runway heading.
Above 1000', turn back to the airport.

Or approximately those words. Their trainers are Warriors, which tend to drop like a rock, and 172s, which can glide a little farther. My student learned this in a Warrior, and maybe the school teaches different numbers for their 172s -- but I doubt they do. There's a safety factor built into this, because it's much more important to keep the airplane flying right-side-up through the landing than it is to get it down on a runway.

You don't want to find yourself turning right down to the ground. Any turns have to be done in such a way that you've got some time flying straight on "final" to get your heading, wind correction, airspeed and sink rate under control to make the spot you've picked out, if you're lucky enough to have found one.

There's a guy in Minneapolis who lost power four years ago in a Super Cub at about 200', and put it into the trees in somebody's back yard, right off the end of the runway. The obstructions tore the wings off and he wound up on the ground inverted, but he walked away with just a minor cut on his face. Showed us all how to do it! He wrote this up on the Supercub.org site, and said "One of the least appreciated qualities of these fine airplanes may be their inverted dead-stick tree landing characteristics." See http://www.supercub.org/phpbb2/viewtopic.php?t=3895. The moral is: fly the damn airplane -- don't worry about whether it's safe to turn back.

[bsdunek]

Note that it is not a 180 deg. turn to get back on the runway, but more like 270 deg. You have to turn about 135 deg to head back and 45 deg to line up. That's a lot of turning at low altitude. I think the 1000 ft decision is a good idea, although I have never tried this. I always figure on landing somewhere ahead. Just IMHO

[N3243A]

Another factor to consider is runway length. For example, if you are departing a 4000 foot long runway your altitude at the opposite threshold will be far more than if you are departing some little 1500 foot grass strip, and of course you will have far more usable runway surface to target for your return.

Bruce

[jrenwick]

It's partly because of factors like this that the flight school here teaches not to even think about it below 1000' AGL, IMHO. After your engine quits at a low altitude isn't the time to be weighing the pros and cons of a return to the field under the particular conditions at the moment. Just before takeoff isn't the time, either. They want their students acting based on a drill that never changes, and which gives them the best chance of survival wherever they have to put it down.

Another instructor I respect teaches that at the moment the engine quits, you no longer own the airplane -- it belongs to the insurance company (you do have hull insurance, don't you? ). So stop worrying about keeping the airplane pretty by getting it back to a squeaky-clean runway without power. Just focus on making the crash survivable!

I also fly a J3, and a few years ago I did a project of reading all the NTSB reports on J3 accidents over the preceding five years, and keeping a tally of the accident injury/fatality rate for each of the probable causes listed. It was an eye-opener, and I recommend that exercise to anyone who spends most of their flying time in one aircraft type -- know what the common ways are to get killed in it. The J3 study bore out what some people say: the J3 is so safe (or slow) that it can just barely kill you. I found reports of pilots who had spun a J3 into the ground and survived. I found several reports of engine failures right after takeoff, and the only fatality was the one pilot who tried to turn back. He spun in, apparently. (By the way, the most common cause of engine failure that I found was failure of the little steel clamp that anchors the throttle cable to the engine mount behind the carburetor. I've seen plenty of fabric Pipers that had unauthorized substutions for this $30.00 part -- typically a pair of Adel clamps, and even one that had tie-wraps holding it down. If this lets go, you no longer have throttle control. I've been there.)

I've beat this point to death now, but I really don't think it can be overstated. They always say the most dangerous part of a flight (after surviving the drive to the airport) is the first few seconds after takeoff.

Safe flying!

John

[Roesbery]

The day I soloed in a c-150 the instructor said if you are under 400 feet land straight ahead as best as possible. ( Brush and rocks and a very winding road) And at 400 feet turn back and he pulled the power and said do it. We did a touch and go and on clime out at about 100 feet said if it quits here land in that field there, about 70 degrees to the right and lower than the runway. A few years later my c-170 quit on takeoff and I put it in that field just like he said. The only open field around the airport. Learned that on a steep slow climeout you need to shove the yolk forward instantly to get the nose down and get a glide going, and you will lose at least 50 feet doing that. A light c-170 will be pretty close to doing what a c-150 will do. I would not hesitate to turn back at 500 feet if that was the best option. Other makes of planes are a different ball game.

[voorheesh]

In a recent thread on short field takeoffs, many related how low the indicated airspeed was after takeoff. Think also about the attitude of the airplane on takeoff climb (same attitude as stall entry). If the engine suddenly quits, there will be a second or two reaction time (sometimes referred to as denial). Meanwhile, the drag vector exceeds thrust. Then you will have to PUSH. Immediately, just to keep the wing from stalling. Lets say you push to level flight attitude, you will then have to push further until the weight force on the airplane develops a horizontal component in order for continued controlled flight. Once the inertia builds, you might consider a bank and a turn. Someone compared this to flying gliders. There is a huge diference between a glider and a powered airplane. Assuming an aero tow, a glider tows about 10 knots above its best L/D and the pilot gets a rope break on every flight (hopefully at altitude). This is important because it means that glider pilots are used to and expect rope breaks. When the rope breaks, you do not have to push. If you apply up elevator and slow to best L/D you will find the ship will either gain altitude or at least not lose altitude even in slightly sinking air. Glider pilots practice and are tested on 200' rope breaks but we always consider all parameters before making the 180 back to the runway ie. density altitude, wind, location at the time you reach 200', etc.etc. There are situations where you could probably make a safe 180 deg turn from 150'agl. You might even fly into a thermal and find yourself at pattern altitude. But you could also find that, like in an airplane, the best course is to land straight ahead, and walk away. Finally, a year or so ago a retired Blue Angel and his student died in Oroville, CA practicing low level 180 deg returns in a decathalon. It was a special training course for folks who want to fly in the bush. They were observed to stall/spin out of a low level steep banked turn. The way I figure, if a Blue Angel can't do it, Im sure I can't either.

[blueldr]

If you think you need a thousand feet to turn back, what you really need is practice in the maneuver.
Depending on the terrain in the area, there is probably open area on the airport other than the runway.

[jrenwick]

If you think you need a thousand feet to turn back, what you really need is practice in the maneuver.
Depending on the terrain in the area, there is probably open area on the airport other than the runway.

Yes. But in my flatland environment, that isn't much taught in primary training, maybe not even commercial training. Relative to what I'm talking about, this is an advanced skill, after the student has mastered the power-off 180 for the commercial license.

John

[russfarris]

While learning to fly gliders, I was taught to not attempt a turn back to the field unless I was 500 feet above field elevation. However, this was for a heavy glider trainer and may have no relationship to a Cessna 170.

When I got my glider rating at Calistoga, CA back in 1982, I was amazed by the drill for the simulated towline break - at 200 agl, the instructor pulled the release, and you did a 180 back to the runway very easily - this was in a Schweizer 2-33, the standard trainer for many years and hardly considered a high performance sailplane. As you completed the turn, you had to deploy the spoilers to get it on the runway! On my rating ride, I did this with Jim Indrebo, a World Champion open class sailplane pilot.

For me, 500 agl is my turn-back limit in the 170, depending on wind, density altitude and availibilty of off-airport sites. I've practised this at altitude, and I'm not advocating anyone else do the same.

One thing I learned in the glider - GET THE NOSE DOWN NOW, before you even think of beginning a 180. I think the stall/spin happens mainly because the turn
is intiated immediately while in a deteriorating airspeed situation. I wouldn't even think about a 180 with less than about 100 mph. Again, just my personal opinion on this...Russ Farris

[AR Dave]

Just as I cleared the massive Cottonwood’s, at the end of a frozen lake, the engine went silent. It was meant to be a low altitude, short flight, down the mountain to my house. However with nothing but Cottonwoods and rugged mountain terrain, I found myself with no choice but to get back. I knew my friends where watching from the cabin, behind me, and could pick up the scraps. I immediately lowered the nose and went into a left turn, feeling for that incipient stall. I wasn’t going to make it over the biggest Cottonwoods, and the turn was burning altitude, so at about 150 degs I took aim for a notch in the tree tops and somehow wobbled over. I remember how dead the controls felt and thinking how fortunate the engine didn’t die one second later. The part of the lake I hit was snow packed, so I slid to a happy ending, except for pride and pocket book.

My friends thought I was about twice the height of the 100 foot Cottonwoods. It was a cold crisp Alaskan day, the plane was light, and I did have speed. Since I was going to descend 2000 feet, off the mountain, I had developed speed with the intention of just lifting over the trees.

[jatkins]

I was taught the same, NEVER turn back, I recall it being demostrated , in a C 172 , and at 800ft we just managed to make it back to the runway.

However recently I have been told by a PC-12 Pilot that they train it in there "sim" training. I believe that i was told that from 400 ft they can make it back at max weight !!! Perhaps George can shed some light on this from the Simulator training side ? This Pilot told me that it seemed to take a couple of attempts, but once you get it , he says it goes pretty well.

John

[AR Dave]

Make it back from where? Distance from runway is an important factor!