QUESTION - EMERGENCY LANDING

N

navigator44

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Navigator44
I am relatively new to flying so this may not appear to be an intelligent question, but I have always wondered:

If I were flying at 5000, and suddenly my engine died, I setup for best glide, all re-start attempts failed which would be the best scenario?

90 degrees to my right, I have an airport 5 miles away, and to the left 90 degrees, I have another airport 5 miles away. If I turn to the right I have a 10 knot tailwind, and to the left I have a 10 knot headwind, which way should I go?

Turning into the 10 knot headwind head would create some additional lift, but then there's the drag coefficient. Turning to the left with the 10 knot tailwind would increase airspeed, but the there would be some loss of lift due to tailwind.

What would you do, and am I right in my assumptions about the differences in lift, airspeed and drag?

I've always wondered about this and wonder if my thinking is skewed. I really don't know if it would make any difference at all as far as being able to reach either airport with sufficient altitude to land.

Thanks

Jim
 
Go with the tailwind. You'll cover more ground gliding. The airplane doesn't know it has a tailwind... there's no more or less lift, it's the same with the same airspeed. Remember that the ONLY time you really have to worry about a tailwind is when you're trying to go from rolling toflying, or flying to rolling. You can always either fly a pattern to land upwind, or land long & fast if you have to ad have enough runway.
 
Remember that the airplane will fly at a given AIR SPEED. The air molecules will flow over the plane at the same speed no matter what. Even flying into a 200kt headwind you won't have extra lift or drag ( ok, at least not after the first few seconds while the plane reestablishes best glide speed). The only difference will be your GROUND SPEED. So pick the tailwind, all other factors being equal. You'll get there faster and the wings won't know the difference.
 
interesting. So if the plane is at optimum glide, regardless of if you are in a headwind or tailwind, it's going to hit the ground at the same time. The only difference is how far it traveled over the ground before it hit?

I take it that's what you are saying?
 
Mafoo said:
interesting. So if the plane is at optimum glide, regardless of if you are in a headwind or tailwind, it's going to hit the ground at the same time. The only difference is how far it traveled over the ground before it hit?

I take it that's what you are saying?
Click to expand...

yep - its that simple - there is no 'additional' lift from the headwind . . . 88kias is 88kias is 88kias.
 
Mafoo said:
interesting. So if the plane is at optimum glide, regardless of if you are in a headwind or tailwind, it's going to hit the ground at the same time. The only difference is how far it traveled over the ground before it hit?

I take it that's what you are saying?
Click to expand...

Yep, the aircraft is traveling within that parcel of air like a boat in a current. Your indicated airspeed (unless it's wind shear) will be the same you're going to hit the ground at the same time but the distance will be different. Of course it won't be exactly the same because most likely you have differences in terrain.
 
Mafoo said:
interesting. So if the plane is at optimum glide, regardless of if you are in a headwind or tailwind, it's going to hit the ground at the same time. The only difference is how far it traveled over the ground before it hit?

I take it that's what you are saying?
Click to expand...

The airplane is at optimum glide in an air mass that is moving over the ground. The best glide speed will give a certain rate of descent or xx minutes to the ground. So turning into the wind reduces the resultant ground speed turning with the wind increases ground speed. You have a better chance of reaching the airport downwind with altitude to spare, than reaching the upwind airport.

Flying gliders with no motor, your theory says if I need more lift to turn into the wind and I can reduce my rate of descent, increasing my L/d? I never knew that.
 
You might also consider 1 mile per 1000 feet of altitude the absolute maximum possible. That 90 * turn will cost you as well as the headwind. Maneuvering and mental issues such as denial and indecision steal from you, too.

Congrats on thinking it out ahead.
 
Turning into the 10 knot headwind head would create some additional lift, but then there's the drag coefficient. Turning to the left with the 10 knot tailwind would increase airspeed, but the there would be some loss of lift due to tailwind.
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Nav,

There's no additional lift or loss of lift with the wind; it's as others here have noted. You're moving with the air mass. You won't gain 10 knots of airspeed by pointing into the wind. You'll lose 10 knots of groundspeed, assuming you hold a constant airspeed. If you turn downwind, you won't lose 10 knots of airspeed; you'll gain ten knots of groundspeed.

Your descent rate will remain the same, but you'll go farther headed downwind.

A more important question you'll need to address is whether you should fixate on the airport.

When flying, especially in a single engine airplane, you should always be looking for a place to put the airplane on the ground in the event of an emergency. Don't start looking when the emergency begins; you should already have something in mind at that point.

When your engine does fail, or you have another emergency that requires returning to earth, you're "in the moment." What was an ideal place to land 30 seconds ago is behind you, and what would have been ideal in a few miles hasn't arrived yet. It's what's immediately available to you that counts.

Don't get too wrapped up in the mindset that you need to reach an airport. You need to make a safe landing: that's the important thing. Whether it's on a road, in a field, on a runway, or some other place is inconsequential. It just needs to be somewhere you can get down and get stopped safely, and if you're conducting the flight properly, there should be such a place under you or very nearby all the time. Don't get caught up in the need to make it to a runway; most of the time with a power loss, that's not going to happen. If you're relatively close to an airport, the temptation is there, but it can sucker you into making a bad choice, too. Be realistic, don't try to stretch the glide somewhere. It's not going to go as far as you think or wish it might. Instead, focus on a realistic possibility for the landing and concentrate on making it as routine and safe as possible.
 
As others have noted, your number of seconds in the air is going to be same either way, but the amount of ground you can cover during those seconds is greater if you turn downwind, which expands the amount of ground you can cover in search of a suitable landing spot. You can think of the same scenario in a boat with limited fuel - will you go farther upstream against the current, or downstream with the current? Either way you are moving through same distance of water but the water is moving relative to the shore - same situation.

I'm waiting to see how long this takes to degenerate into the dreaded "downwind turn" argument....

:stirpot:
 
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AuntPeggy said:
You might also consider 1 mile per 1000 feet of altitude the absolute maximum possible. That 90 * turn will cost you as well as the headwind. Maneuvering and mental issues such as denial and indecision steal from you, too.
Click to expand...

C172 is talked about as an 11:1 glide ratio. If you were perfect, you'd get 11,0000 ft (2 miles) laterally per 1000' of descent.

Granted, nobody is perfect, but surely we're better than 50%?
 
It's an easy thing to check with a GPS these days. Start at four thousand feet AGL, and drift down 3000'. Note the mileage, see what the actual ratio is. Try it a few times, see how it averages out at your best glide speed. Try other speeds for comparison. See what you get.
 
Nav, thank you for this thread (and thanks for the input from all you other thread contributors)
As a student pilot nearing my PPL checkride :hairraise:, the emergency scenario discussed has certainly added something positive to my limited knowledge.:thumbsup:
 
DouglasBader said:
Nav,

Don't get caught up in the need to make it to a runway; most of the time with a power loss, that's not going to happen. If you're relatively close to an airport, the temptation is there, but it can sucker you into making a bad choice, too. Be realistic, don't try to stretch the glide somewhere. It's not going to go as far as you think or wish it might. Instead, focus on a realistic possibility for the landing and concentrate on making it as routine and safe as possible.
Click to expand...

:yeahthat:
When my engine failed due to swallowing an exhaust valve, I was 99% certain I could make the airport off my wing. BUT all the way there, which seemed an eternity, I was checking the ground below me in case I had to get down NOW because of fire or another complication. It is something to keep in your scan.

In my case I deliberately had to loose altitude on final but if it wasn't in the cards, I had alternatives all the way onto the runway.

Cheers
 
AuntPeggy said:
You might also consider 1 mile per 1000 feet of altitude the absolute maximum possible. That 90 * turn will cost you as well as the headwind. Maneuvering and mental issues such as denial and indecision steal from you, too.

Congrats on thinking it out ahead.
Click to expand...

I suggest that anytime you see a rule of thumb like this you test it on paper and maybe even in the air to see if it fits your situation. Don't blindly accept a protocol without thinking it through to be sure it is appropriate.

And for info no gliding in an airmass, try the free Glider Flying Handbook.

http://www.faa.gov/library/manuals/aircraft/glider_handbook/
 
bflynn said:
C172 is talked about as an 11:1 glide ratio. If you were perfect, you'd get 11,0000 ft (2 miles) laterally per 1000' of descent.

Granted, nobody is perfect, but surely we're better than 50%?
Click to expand...

You would need to be perfectly in coordination with the propeller spinning, no airframe modifications (extra lights, antennas, STOL kit, etc.), windows closed, with no turns and no excursions from best glide. And the air would have to be smooth and the stars aligned. If any of that differs, you won't make anywhere near 2 miles per thousand feet.

It's much easier to lose extra altitude than to gain a deficiency while gliding, so a healthy margin is called for. If you think you might really need more than a 5 mile glide (e.g., over mountains), cruise higher.
 
navigator44 said:
Turning into the 10 knot headwind head would create some additional lift,
Click to expand...


:no:
This myth that headwinds create lift must come from power pilots observing that on takeoff with a good breeze on the nose, the plane gets higher while covering less runway than without wind. Vice-versa for landings. Either that or someone told them it's so, and they took it as fact, even though they've never actually seen a higher vertical speed at a given airspeed, power setting, and weight.

Whatever the explanation, it's definitely a myth, and one I've heard too many times. While climbing or gliding, or in cruise, a headwind only reduces your groundspeed. Period. Lift is dependent on wing area, camber, chord, angle of attack, weight and airspeed. Not wind.

I've also heard of tailwinds forcing airplanes into the ground on takeoff... also balderdash. Take off with a tailwind, and you might not clear those trees or whatever, but it's not because the airplane can't climb... it just uses more runway while doing so. A tailwind merely increases your groundspeed... it doesn't lock you into ground effect or any such nonsense.

I know it's glaringly obvious to just about any pilot reading these forums, but it's scary how often I hear experienced pilots as well as students describing these magical wind effects. :dunno:

Anyone who disagrees should try flying a glider... I understood it all before I started soaring, but flying without thrust makes it much clearer.

Glider experience also makes the choice in the OP's scenario obvious: head downwind!! You will have more altitude "in the bank" on arrival if you do that, and thus more options. I don't care if the heading for the upwind airport will lead me straight down the runway centerline and the other will require at least part of a pattern; I'm going downwind.

It's wise to assume that if anything changes between the emergence of your emergency and your landing, it will be a change for the worse. You don't want to bet your life on a chance that things might get better for you- that's a sucker bet. Sure, that tailwind might slack off, or even turn into a headwind, but start gliding upwind and things get worse, and you will still be in a worse position. So in this scenario, you should go downwind, be thankful for the advantage as long as it lasts, and definitely look for any spot along the way that might be useful, just in case your luck changes. I'll take a hay field downwind over a runway upwind any day when I am gliding without power.
 
It is a good idea to keep the wind direction over the ground in mind. There is much less energy to dissipate in a crash if you can manage to crash into the wind.

If you can make an airport, don't try to land on the end of the runway. Aim closer to the middle. There will usually be enough length left to land. And, it is much better to go through the trees at the end of a landing roll than the trees short of the runway.

Look for water. People are seldom hurt in a proper ditching, I can't remember even one. Land close to shore with the doors open. Much better than trees, buildings, rocks.
 
you can prove it to yourself -

use a flight simulator - set up a place thats equidistant between 2 airports and set up a 10kt wind from one toward the other - turn off the engine using mixture and glide into the wind and away and see how high up you are when you reach the airports -
 
Yeah, headwinds vs. tailwinds do not affect lift. Only ground speed.

HOWEVER, rising or sinking air is another story entirely. Avoid sinking air when you're gliding.

If there is significant terrain and wind, there will be areas of sinking air, particularly downwind of ridges. Upwind, there may be rising air.

Unless you have a lot of practice at that sort of gliding, I suspect it's not practical to take advantage of it in an emergency situation.
 
Seems glider experience causes one to constantly (if subconciously) think about WCA all the time.
 
bflynn said:
C172 is talked about as an 11:1 glide ratio. If you were perfect, you'd get 11,0000 ft (2 miles) laterally per 1000' of descent.

Granted, nobody is perfect, but surely we're better than 50%?
Click to expand...

Might want to double check that number for your plane. The 172P and 172SP manuals I have show 9:1, a mile and a half per thousand feet. With that, a mile per 1000 feet isn't so unreasonable.

I've heard that rule of thumb several times, but i wouldn't repeat it without noting that it is aircraft specific. There are some aircraft that will easily exceed that glide, and others that would struggle to make it that far on a good day.

Best bet is to know what your plane is capable of (usually stated in the POH with no wind) and be aware of the current wind and how it changes your options. The glider handbook Jim linked to above has some good info. I didn't know any of that stuff until I started flying gliders. From talking with other pilots, I think my ignorance on the topic is fairly common.
 
Thank all of you for your answers. The lot of you has made it very clear. I understand it now. Thanks. If I ever lose an engine I will constantly be looking at what's at hand below me and not counting on an airport arrival.

Thanks, again.
 
It was touched on in a previous post, but bears repeating. If the engine quits, the insurance company now owns the airplane. Your job is to put it on the ground in a fashion that allows everyone on board to walk away. If that means sacrificing the airframe, so be it. It cheated on you by quitting, so you don't owe it anything. Remember - "Skin, tin, ticket". The order of priorities when dealing with an emergency. You are more important than the airplane.
 
Ghery said:
It was touched on in a previous post, but bears repeating. If the engine quits, the insurance company now owns the airplane. Your job is to put it on the ground in a fashion that allows everyone on board to walk away. If that means sacrificing the airframe, so be it. It cheated on you by quitting, so you don't owe it anything. Remember - "Skin, tin, ticket". The order of priorities when dealing with an emergency. You are more important than the airplane.
Click to expand...
Absolutely. Burn that into your thinking--If the engine quits, the insurance company owns the airplane.

Here is a thread describing what happened to the man who told me that concept over and over again BEFORE the event in this thread.

http://www.pilotsofamerica.com/forum/showthread.php?t=50387
 
bflynn said:
C172 is talked about as an 11:1 glide ratio. If you were perfect, you'd get 11,0000 ft (2 miles) laterally per 1000' of descent.

Granted, nobody is perfect, but surely we're better than 50%?
Click to expand...
Hmmmh. My experience is closer to 8:1. However, that is in very good conditions when I had planned to glide the plane and measure the descent. However, my thinking in coming up with a 1 mile to 1000 feet ratio is this:
1) The math is incredibly easy. When my mind is being overloaded, I need easy math.
2) Mistakes in estimation are easier to survive if the initial estimation is actually doable. I need easy when overloaded.
3) I've made it even easier for myself in my plane. I plant my fist on the glareshield. Pitch for best glide. Anything higher on the windscreen than my fist is unreachable. No math, no estimation, no overload, easy.
 
AuntPeggy said:
Hmmmh. My experience is closer to 8:1. However, that is in very good conditions when I had planned to glide the plane and measure the descent. However, my thinking in coming up with a 1 mile to 1000 feet ratio is this:
1) The math is incredibly easy. When my mind is being overloaded, I need easy math.
2) Mistakes in estimation are easier to survive if the initial estimation is actually doable. I need easy when overloaded.
3) I've made it even easier for myself in my plane. I plant my fist on the glareshield. Pitch for best glide. Anything higher on the windscreen than my fist is unreachable. No math, no estimation, no overload, easy.
Click to expand...

A factor that's often overlooked is the altitude you need to maneuver for landing. If you arrive at the airport/landing area on a midfield downwind, you'll need to be something like 1200-1500 AGL at that point yet you're only a fraction of a mile from the runway/field.
 
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