Engine failure and land on remaining runway (calculations)

[DesertNomad]

A friend recently had an engine failure on takeoff (at 300' AGL). They walked away but the Cherokee 6 was totaled. It got me thinking: "how high can I climb and still land straight ahead on the same runway?" I figured my normal (16R) 11,000' runway, elevation 4415', no wind, 37F, altimeter 30.26", typical winter morning conditions at Reno.

My book t/o roll is 1000' so I changed that to 1500' because I am not a test pilot. At my 85kt initial climb speed, a 5 second reaction time uses up 717' and I need 1000' to land and stop.

So 11,000 - 1500 - 717 - 1000 = 7783' (runway I can fly over going up and coming back down).

Assuming an 800fpm climb and 85 knots (143 feet per second) at all times in the air (I could go a bit slower on decent but may not have time to deploy flaps): 7783' / 143 = 54 seconds allowed in a climb or descent.

54/2 = 27 seconds @ 800fpm = 360 feet, or 4775' MSL at Reno.

Does this sound right? Has anyone here done similar calculations?

 

[Clark1961]

A couple er three things: time to accelerate to best climb, temperature, and actual stopping distance vs book. I found that Dakota brakes will fade in an actual aborted take-off situation.

 

[German guy]

Frankly, I am pretty surprised that even on such a long runway, one still has to be pretty low if he want to make it back to the runway.

Our runway is only 2300 ft. Even while still on the ground, but close to Vr, I doubt I'd be able to come to a standstill before the end of the runway. It is also located inside a densely populated area, engine failures are therefore absolutely no option.

 

[wrbix]

Frankly, I am pretty surprised that even on such a long runway, one still has to be pretty low if he want to make it back to the runway.

Our runway is only 2300 ft. Even while still on the ground, but close to Vr, I doubt I'd be able to come to a standstill before the end of the runway. It is also located inside a densely populated area, engine failures are therefore absolutely no option.

I’ve given this same scenario consideration.....force aircraft to ground, brake/brake/brake, use obstacles to forfeit wings rather than fuselage....all in an attempt to eventually crash at lowest possible/most survivable speed. One home field is water (albeit shallow) at both ends....therefore do whatever to keep canopy unjammed.

 

[DesertNomad]

I also would try to sacrifice the left wing because I need the door on the right wing to work and not be blocked by debris or fire.

 

[steingar]

Landing on the runway, forgetaboutit. Too busy trying to get altitude on takeoff. Land on the airport grounds? Possibly. Better to land on airport grounds because most airports are surrounded by big fences. Anything beyond that is going to hurt, since my airport is surrounded by neighborhoods.

 

[Shepherd]

Forget best glide and everything else.
Hold it nose high, on the edge of a stall and let it settle back to the ground with the tail dragging on the runway.
If you need to, slip it hard and scrape the gear off the plane.
The idea is to get rid of as much kinetic energy as fast as possible. Making things crumple lowers your "G" load and eliminates speed faster than just using your brakes.
Unless you got off the ground in the first 400 feet of a 10,000 ft runway, you probably don't have enough time to understand what just happened and react properly to "save" the plane.

And this is why you practice nose high, slow flight.

 

[flyingron]

I'm not sure I buy Sheps approach past forgetting about best glide.

This is the time to do you best SHORT FIELD landing. Pitch it over (you do want to fly to the ground not stall it in on its tail).
Max drag, flaps+slip.

This is why you practice SHORT FIELD landings.

 

[LongRoadBob]

As a student this is the kind of thing I have in the back of my head to ask my CFI about, yet when taking off is as if we students "understand it". The nitty gritty details are just not there, maybe because it takes experience to be able to judge it.

Which is why I am pretty happy I saw this thread. As a novice, it seems like the OP is calculating it well, and it is something I ought to go over with my CFI. Interesting replies also. It's one thing to read "if sufficient runway" but hard to know what that is. Thanks for starting this thread!

 

[Tarheelpilot]

When the outcome is in doubt you do what ever required to walk away and don't worry about the airplane. As far as trying to calculate a known distance required to get stopped in relation to altitude of the engine failure that gets into some highly variable math. The aircraft weight, winds, delay in action after failure and what you do with the aircraft configuration and flight control inputs will all have significant impact on the distance required.

An easier computation is deciding at what minimum altitude you would attempt to turn back to the field. Any failure below that altitude will result in landing straight ahead or pretty close to straight ahead. Obviously the higher you are at the failure point the more time you have for heading changes to pick a spot. The most important concept here is to fly the aircraft to the ground. Do not stall and impact the ground with a high rate of descent. If it works out that the runway or airport environment provide a place to land resulting in no damage to the aircraft then great but if not pick a soft spot and save your own butt.

 

[MauleSkinner]

When the outcome is in doubt you do what ever required to walk away and don't worry about the airplane. As far as trying to calculate a known distance required to get stopped in relation to altitude of the engine failure that gets into some highly variable math. The aircraft weight, winds, delay in action after failure and what you do with the aircraft configuration and flight control inputs will all have significant impact on the distance required.

...The most important concept here is to fly the aircraft to the ground. Do not stall and impact the ground with a high rate of descent. If it works out that the runway or airport environment provide a place to land resulting in no damage to the aircraft then great but if not pick a soft spot and save your own butt.

I'd add that an apparent fixation on landing on the runway has unnecessarily totaled a couple of airplanes that I know of. In both cases, the terrain off the end was safe, but the pilot either slammed the airplane down or used an improper go around technique that resulted in extensive aircraft damage when transitioning off the pavement.

 

[danhagan]

Does this sound right? Has anyone here done similar calculations?

No, but during flight reviews I've had simulated engine out on take off on every review. I knew it was coming due to the airport (Las Cruces KLRU three runways). Immediate choice was remaining runway or next one over. Power off 180's to the captains stripes +/- 50 feet. We've had two fatal accidents in our area with guys I know during take off, and the CFIs are really emphasizing this area. 650+ hours in the plane in the avatar, so all of the simulated emergencies were not stressful whatsoever, tons of lee way.

Edit: Not to sound like a real Yeager, but my area has a good number of off field choices compared to places like Fullerton with a low choice of options.

 

[jkaduk]

Try it with a sim.

 

[jd21476]

Try it with a sim.

I recognize that plane in your profile from Plusone KSEE.

 

[Kritchlow]

I think the best calculator is your eyeballs. You know what a normal glidepath and runway look like.

 

[DesertNomad]

I think the best calculator is your eyeballs. You know what a normal glidepath and runway look like.

I have a policy of no turning back to the airport below 800'. We have parallel runways so it is less turning than a single runway as I can go from 16R to 34R. I think having a "we can land straight ahead without going into the big irrigation ditch" altitude too and it looks like <300'.

 

[Kritchlow]

I have a policy of no turning back to the airport below 800'. We have parallel runways so it is less turning than a single runway as I can go from 16R to 34R. I think having a "we can land straight ahead without going into the big irrigation ditch" altitude too and it looks like <300'.

I’m certain your post makes great sense, but I’m not completely following....

 

[DesertNomad]

I’m certain your post makes great sense, but I’m not completely following....

If you have just one runway, the turn back to the airport is well over 180 degrees. It is about a 225 degree left turn, followed by a 45 degree right turn. With two parallel runways, you don't have to return to the same runway as you can land on the parallel which could even be a 180 degree turn if the runways are far enough apart.

As to the rest, it would be useful to know the altitude after which you can't land straight ahead and remain on pavement.

 

[Kritchlow]

If you have just one runway, the turn back to the airport is well over 180 degrees. It is about a 225 degree left turn, followed by a 45 degree right turn. With two parallel runways, you don't have to return to the same runway as you can land on the parallel which could even be a 180 degree turn if the runways are far enough apart.

As to the rest, it would be useful to know the altitude after which you can't land straight ahead and remain on pavement.

Well I never suggested a turnback, and my advice on landing straight ahead is to use your eyes. That’s actually the method to be used when pulling up the wheels in a light retrac.

 

[tinerj]

It really does depend on the plane, doesn't it. My Fly Baby wings become like giant braking flaps when the tail wheel comes down and it stops remarkably fast.

Once I landed without brakes, and turning off the engine to stop the propeller produced a significant braking action.

 

[BigBadLou]

Assuming an 800fpm climb and 85 knots (143 feet per second) at all times in the air (I could go a bit slower on decent but may not have time to deploy flaps)

You could expand your calculations to account for a different descent rate (different from climb rate).
As suggested, you can slip it down. When the engine quits, you nose it over, yank all the flaps in (you are in the white arc already and I assume you got a flap yank handle in the Cherokee) and slip the hell out of it. I'd be surprised if you don't see your descent rate double of your climb rate. That will get you down sooner and you'd have more rwy to land on.
You can adjust your calculations accordingly and you should be able to see the new height to be 400+ AGL.

And as others have pointed out, you could always try it in the sim (provided you can find one that is faithful to the real model).

 

[Lachlan]

Red handle. Done. Call the chauffeur to come pick you up and order a new airplane over an early lunch.

 

[Lachlan]

I learned “If the engine fails on take off below 1000’ agl, land straight ahead, or turn up to 45°left or right to avoid obstacles. Never attempt to turn back to the rnwy without at least 1000 feet of altitude.”

I believe this concept is based on the notion that many airports have relatively clear approaches, but it allows for a bit of maneuvering to attempt to minimize human injuries. Lots of airports have trees and buildings at both ends, too. Some have no good options, at which point the PIC is out of luck and needs a miracle of physics to get out of that jam. Some good advice in this thread, some great advice, and some interesting calculations.

 

[James331]

I have a policy of no turning back to the airport below 800'. We have parallel runways so it is less turning than a single runway as I can go from 16R to 34R. I think having a "we can land straight ahead without going into the big irrigation ditch" altitude too and it looks like <300'.

 

[bflynn]

Try it with a sim.

You can probably do something in real life too. Bring someone with you. Do a normal landing. Call out every 100' and have them record a landmark that you're next to, something distinctive if you can. Land and have them mark where you stop. Now you can go back to Google maps, find where you were at 300/400/500, etc + where you stopped and you can measure the distance that it takes you to get from that altitude to stop. Might have to hunt around to find a runway that has adequate landmarks.

I know from doing short fields, when I'm on game I can stop the Warrior in under 700' of runway and that includes landing on the numbers and leaving 100+ ft behind me for a safety margin. But I have no idea how long it takes to get down.

BTW, a piece of trivia - the centerline stripes on standard runway markings are 125' long and 75' apart. That means it's 200' from the beginning of one stripe to the beginning of the next stripe. And the 1000 ft marking (aka barn doors) are 150' long, which is why they make a good target for short field practice.

 

[Zeldman]

Not to sound like a real Yeager, but my area has a good number of off field choices compared to places like Fullerton with a low choice of options.

LRU is an ideal airport to have an engine failure after take off... flat as a pool table.

 

[midwestpa24]

I was always taught if an off airport landing was necessary, land wings level with the slowest possible groundspeed, and try not to hit anything too hard head-on, and you will likely survive. Might wreck the plane, and might be hurt, but you will likely live. The danger comes from trying to maneuver at low speed and altitude, and stalling out or striking a wingtip and cartwheeling.

 

[flyingron]

I learned “If the engine fails on take off below 1000’ agl, land straight ahead, or turn up to 45°left or right to avoid obstacles. Never attempt to turn back to the rnwy without at least 1000 feet of altitude.”

Certainly not what I was taught. 400' you are committed to pretty much what you can see out the front window. Above that you can think about moderate (90 degree) turns up to 800 or so when you can think about turning around.

 

[James331]

PC12 can do the 180 at 500' AGL if you feather and drop 15 flaps ASAP.

 

[Lachlan]

Certainly not what I was taught. 400' you are committed to pretty much what you can see out the front window. Above that you can think about moderate (90 degree) turns up to 800 or so when you can think about turning around.

I’m sorry for offending you. I guess it all depends on the terrain and/or features around the airport where you learned to fly. Good day.

 

[Sundancer]

If you have just one runway, the turn back to the airport is well over 180 degrees. It is about a 225 degree left turn, followed by a 45 degree right turn. With two parallel runways, you don't have to return to the same runway as you can land on the parallel which could even be a 180 degree turn if the runways are far enough apart.

As to the rest, it would be useful to know the altitude after which you can't land straight ahead and remain on pavement.

Or a parallel taxiway, or the dirt/grass parallel to the runway. Then again, I'm in a 172, so a 50 foot patch of flat ground will do. . .

 

[Sundancer]

Certainly not what I was taught. 400' you are committed to pretty much what you can see out the front window. Above that you can think about moderate (90 degree) turns up to 800 or so when you can think about turning around.

Depends a lot on the wind - if it's howling down the pipe, versus dead calm. And the airplane, of course.

 

[maddabbo]

If you have just one runway, the turn back to the airport is well over 180 degrees. It is about a 225 degree left turn, followed by a 45 degree right turn. With two parallel runways, you don't have to return to the same runway as you can land on the parallel which could even be a 180 degree turn if the runways are far enough apart.

As to the rest, it would be useful to know the altitude after which you can't land straight ahead and remain on pavement.

Why don't pilots add offset of 30 to 45 degrees immediately on takeoff just in case there is an engine failure? The offset generated would result in a much easier turn back to the same runway or next to if needed??