The International Cessna^® 170 Association

Theoretically.... if an airplane climbs at Vy and glides at Vy and if it climbs/glides at the same ratios.... then it is impossible to accomplish the task unless a significant headwind exists on takeoff and/or a liftoff occurs well before the end of the runway departure end. For example, if the airplane climbs at 400 fpm and glides at 400 fpm.... in zero wind it will not be possible to climb to any altitude at that climb angle.... and make a return and reach the airport at the same glide angle.... because a portion of the altitude lost will be in navigating the 180-degree turn. I.E., you will land short. (In fact a 180-degree turn will not even align you with the runway... you'll be offset to a parallel track.... a 225 degree turn would be required with a 45 degree correction when the extended centerline is reached. The lateral path covered during that turn would be additional distance travelled at the aforementioned glide angle, which is additional altitude loss, which will result in an impact short of the lift-off point.

To add further complexity to the task, the recognition time, the momentary loss of best speed, and the resultant, unavoidable loss of valuable altitude regaining best glide will also penalize the effort. This can be understood with a simple piece of graph-paper and a pencil. Sketch out the climb angle to any selected distance.... then use the exact same descent angle from the point of proposed engine failure. 'Sketch out the descent pathway and use some valuable alititude reversing course and navigating to the runway centerline... then lose a bit more aligning with the runway.... then use the same descent angle as you used during climb.... and you'll see you'll end up at field elevation much before the lift-off point (the presumed departure end of the runway.)

Hence the well-worn-advice.... do not attempt a return to the runway.

The only way such a condition would be workable would be with a much longer than necessary runway and/or a significant headwind which will assist the the returning groundspeed...and therefore the resultant angle of descent.

In my Cessna 140A a turn back can be made in less than 400 feet. When the power fails the nose drops by itself and the airspeed in the steep bank is near stall. But it can be done and I was taught this by an old Navy instructor. I practice ever now and then at altitude. You absolutely must keep the ball centered or else a spin. Never tried it in a 170.

This response could not even come close to what George has wisely written but I thought I would share an experience I had a few years ago in Colorado. I was managing a small glider (sailplane) operation north of Colo Spgs. We had a few United pilots that would come soar with us. One young pilot who was transitioning to gliders (many houred 737 pilot) was about to solo and I went through rope break procedures which will typically happen either on roll out or shortly after take off (actually a rope break can happen at any stage of the tow) but for safety reason and depending upon current winds the rope break would never (unless on roll out) happen under 200'AGL, which is the bare minmum one could safely accomplish this. So at about 300'AGL, I pulled the release - we were on a northerly heading and had a l/v wind at about 30 degrees. Instinctively the pilot in front seat made a "left" (about 330 dgrees) turn back to the runway. At this point I took over. Safely on the ground we had a "chalk talk" actually a stick in the dirt talk. After the very brief chat he looked at me and smiled.

It is common practice when learning to fly sailplanes to call out either to your instructor or to yourself "200 feet!" I routinely practice this at altitude with about 10 degrees of flap and or no flap just to see what altitude I do lose under certain wind conditions. Certainly in a metal powered craft the glide angle will be significantly reduced.

I would not even attempt to return to field with an engine out under 400'. There could be some mnor exceptions to this like a very strong head wind that becomes a tail wind and a clear unobstructed departure end.

FWIW

Joel
N3437D

Altitude to turn back to the airport: twice as high as when the engine stops. :

Another consideration is the effect of wind velocity on your landing in either situation. Two years ago we had a serious accident at our local airport resulting from the decision to return to the airport after an engine failure. The pilot took off in a lightly-loaded 172 into a 20+ knot headwind. The engine failed high enough that they were able to make it back the the airport property, but they were not able to properly line up with any of the 3 runways. The consequent landing in the infield (a plowed wheat field) ended when the nose wheel failed, both wings and the engine tore away, and the fuselage was ripped in two just aft of the rear cockpit bulkhead (it was a later 272 model with rear window). It was a miracle that both occupants walked away. They could have easily been killed.

Had they continued straight ahead, their landing options were less than perfect, but there were some open areas available and they could have touched down with ground speeds in the 20-30 knot range. The plane would have had to have been trucked out but the damage could have been minimal or non existent. Instead they attempted a downwind landing with ground speeds likely between 60-70 knots. Yes, they did have the large open area to attempt to land in but the effects of the increased kinetic energy were obvious.

There are many factors that will make every situation different. I fly off an 1800' strip at home so my options of turning back are limited. The Air Force Base in town (joint-use civil field) has four runways, the longest being 13,000 x 300 feet. There are a lot more options here.

A consideration for short fields may be to plan a downwind departure - turn crosswind around 400 feet and turn downwind to remain or quickly return to within gliding distance of the field. This will not help it she gives up the ghost early on, but would give you more options than continuing a straight out departure with the limited climb performance we typically deal with under moderate to heavy loads or warmer conditions. Another consideration is to plan your initial departure ground track to position yourself properly in relation to the best available landing spots around your airport, to include the runway you just departed from.

In my opinion the priorities are:

1. Safety of your passengers
2. Safety of yourself
3. Safety of those on the ground
4. Safety of the airplane.

If it is windy, a downwind landing may not be your best choice. Lots to consider on every departure.

Bruce

Here is what the FAA is teaching student pilots like me. The 2004 edition of Airplane Flying Handbook (FAA-H-8083-3A) at pages 16-5 and 16-6 states:

"The altitude available is, in many ways, the controlling factor in the successful accomplishment of an emergency landing. If an actual engine failure should occur immediately after takeoff and before a safe maneuvering altitude is attained, it is usually inadvisable to attempt to turn back to the field from where the takeoff was made. Instead, it is safer to immediately establish the proper glide attitude, and select a field directly ahead or slightly to either side of the takeoff path.
The decision to continue straight ahead is often difficult to make unless the problems involved in attempting to turn back are seriously considered. In the first place, the takeoff was in all probability made into the wind. To get back to the takeoff field, a downwind turn must be made. This increases the ground speed and rushes the pilot even more in the performance of procedures and in planning the landing approach. Secondly, the airplane will be losing considerable altitude during the turn and it might still be in a bank when the ground is contacted, resulting in the airplane cartwheeling (which would be a catastrophe for the occupants, as well as the airplane). After turning downwind, the apparent increase in ground speed could mislead the pilot into attempting to prematurely slow down the airplane and cause it to stall. On the other hand, continuing straight ahead or making a slight turn allows the pilot more time to establish a safe landing attitude, and the landing can be made as slowly as possible, but more importantly, the airplane can be landed while under control.
Concerning the subject of turning back to the runway following an engine failure on takeoff, the pilot should determine the minimum altitude an attempt of such a maneuver should be made in a particular airplane. Experimentation at a safe altitude should give the pilot an approximation of height lost in a descending 180° turn at idle power. By adding a safety factor of about 25 percent, the pilot should arrive at a practical decision height. The ability to make a 180° turn does not necessarily mean that the departure runway can be reached in a power-off glide; this depends on the wind, the distance traveled during the climb, the height reached, and the glide distance of the airplane without power. The pilot should also remember that a turn back to the departure runway may in fact require more than a 180° change in direction.
Consider the following example of an airplane which has taken off in climb to an altitude of 300 feet AGL when the engine fails. After a typical 4 second reaction time, the pilot elects to turn back to the runway. Using a standard rate (3° change in direction per second) turn, it will take 1 minute to turn 180°. At a glide speed of 65 knots, the radius of the turn is 2100 feet, so at the completion of the turn, the airplane will be 4200 feet to one side of the runway. The pilot must turn another 45° to head the airplane toward the runway. By this time the total change in direction is 225° equating to 75 seconds plus the 4 second reaction time. If the airplane in a power off glide descends at approximately 1000 f.p.m., it will have descended 1316 feet, placing it 1016 feet below the runway."

Any distance below the runway is too much for me.

Joel

This is a good discussion. One other thing to consider on takeoff is the direction of a crosswind. If you do have the altitude to turn back to the runway, one thing to consider is turning downwind (with the wind, not the pattern leg) first then turning toward the runway. This should put you closer to lineup with the runway and will have you at least approaching into the wind if you are unable to make it. This is basically a cropduster turn, it is the method used in order to tun the quickest with line up, without resorting to aerobatics.
David

trial lawyer wrote:Here is what the FAA is teaching student pilots like me. The 2004 edition of Airplane Flying Handbook (FAA-H-8083-3A) at pages 16-5 and 16-6 states:

... Using a standard rate (3° change in direction per second) turn, it will take 1 minute to turn 180°....

I wonder why they assume a standard rate turn in this situation, other than to make sure it won't work ? Why not the 30 degrees we teach is normal for turns in the pattern? Under the circumstances, if I decided to turn back, and depending on winds and how far away the runway is, I'd consider pointing the nose right down to make sure I had plenty of speed for a high-performance turn. Having practiced the maneuver at altitude, of course.

You guys are killing me!

AR Dave……..I don’t savvy your post……..???

I agree with jwrenick……….get the nose down and pull on the pole as my IP in Huns told me……..If your airport is user friendly like mine is, what I do is just after takeoff I
start a shallow turn toward the downwind side of the runway. I continue that turn until
I am displaced down wind at least a couple runway widths………now if she quits all I need is a 180 to get to the runway. Hopefully the downwind side is to the right so
turning into the wind will be to the left. Crosswind makes a terrific difference…..I sprayed for 25+ years and when “cotter keying” a field you pulled off down wind (sink,sink, sink depending how heavy you were) to a 90 and then back into the wind for
a 270. I believe it is much better to have the nose down too low than not low enough even if you don’t make it back to the runway. If you don’t make it back and have to pick the nose up just prior to touching down that is MUCH better than a stall or mush in the turn.

So much depends upon the situation of the airport and the winds at the time that I don’t think a person can lay down a set of rules.

I know that when I’m on floats with very little wind it takes me 600 ft. to get around the turn if I chop the power abeam my target landing area. The “pucker factor” comes in when you get close to the ground/water and still have some turn to complete. The temptation is VERY strong to tweak up the nose a little but this is NOT the thing to do unless you are well above vy………stick with it keep the speed and if you are close you will probably make it…………if not roll wings level and grit your teeth.

My .01 ½

Buck, Galena

The standard rate turn is not that different from what might be available due to loss of power/speed anyway. (22 degrees versus 30 isn't that much)

Some other considerations in this discussion are:
1- some other aircraft might have followed your departure by taxying upon the runway you intend to return to.

2- landing off-site will likely make it difficult for arriving emergency equipment, while a return to the field... even if not entirely successfully placed upon a runway.... will probably result in emergency vehicles and EMS personnel being on the scene much faster. (I'd rather flip the airplane ON the airport grounds than a 1-1/2 miles across fence-lines, woodlots, and rough terrain.) I.E. - give it some thought before brake release, and make a decision before takeoff roll ... at what altitude a return to field is likely to be successful. (I think 1,000 might be a nice round figure in no-wind conditions.)

gahorn wrote:The standard rate turn is not that different from what might be available due to loss of power/speed anyway. (22 degrees versus 30 isn't that much)

Do the math... the slower the true airspeed, the shallower the bank required for a given turn rate. At 60 knots, the bank angle for a 3-deg/sec turn would be less than 10 degrees. The speed to make a 22 degree bank angle a standard rate turn is almost 150 knots.

Miles

cessna170bdriver wrote:

gahorn wrote:The standard rate turn is not that different from what might be available due to loss of power/speed anyway. (22 degrees versus 30 isn't that much)

Do the math... the slower the true airspeed, the shallower the bank required for a given turn rate. At 60 knots, the bank angle for a 3-deg/sec turn would be less than 10 degrees. The speed to make a 22 degree bank angle a standard rate turn is almost 150 knots.

Miles

I have a red B-model.

gahorn wrote: Miles - -I have a red B-model.

YEW DOAN'T HAVE A "RED 170 B MODEL" YEWS ES PLANE DUM ! YEW HAS A SILVER ONE WITH RED STRIPES. IFN IT WUZ ALL RED IT WOUDNT BE SO SLO

Barry Schiff - Proficient Flying - http://www.ipilot.com/shop/product.aspx?pid=16960

I have this DVD set and he covers the 180 return to the field maneuver. It is an advanced maneuver and depends on many factors. I have done the practice maneuvers he recommends in a 172, 182 and Citabria and came to the conclusion that 700 to 800 ft. was my personal limit under ideal conditions to attempt the maneuver. And I would choose almost any possible alternative to this if available. BTW, there didn't seem to be much differene between the 172 and 182 other than the 182 needed alot more trimming. The Citabria had a faster sink rate but turned much tighter and the transitions were faster so the altitude lost was basically the same.

He recommends 45 degrees as the best bank angle for the manuever. I tried 30, 45 and 60 degrees and found his recommendations to be correct, at least for my abilities and the airplanes I was flying.

I'm sure I'll try this when I get the new 170 home.