Emergency ldg

Richard said:
How many of you were NOT taught the Hi and Lo key positions to a successful off fld landing?
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I've not heard that particular terminology.
Do you mean not too high to expect an overshoot and not too low to make the landing site ?
 
Richard said:
How many of you were NOT taught the Hi and Lo key positions to a successful off fld landing?
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Never heard of this, can you edumcate us???
 
Never heard of it.


I just make sure that I always know exactly where my touchdown point is and every landing I pick a point. The more you do this the better. It's very rare now for be not to be able to touchdown on the numbers if I desire.

That's not everytihng though. You need to be able to do that engine out also. One thing I like to practice and I usually do this at a controlled field is cut the power to idle on down wind and then glide and touch on the numbers, Just because it's a large target that is easy to tell if you touch down on. This is easy in somehting like a 150 or a 172 or a cub. But I find that you have to be on the ball to do it in the Beech Sierra as it drops like a rock when it looses power and making sure you have enough energy left to flare takes quite a bit of airspeed.

http://korrupt.com/video/rst20short.wmv this is in a 172 on Saturday. The winds were 26 gusting 34 so I ended up touching down at the end of the numbers it looks like, as I was fighting the side drift before I'd let it touch down.
 
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High key and low key are two imaginary windows in the sky positioned vertically and horizontally in a fixed relationship to the touchdown point, their positions depending on what you're flying. The concept is that if you fly through the two key positions on speed, altitude, and heading, your path to the touchdown point is assured. The two key position method is more used in teaching flameout approaches in single-engine jets, while a single key position is usually used for light single-engine planes. See http://www.aztucs.ang.af.mil/maca/sfo_pattern.htm for an example of the F-16 flameout pattern.
 
I had learned only the single key position. My problem was how to connect the dots when given only one point? I was never comfortable turning away from the selected fld while also trying to judge being on the correct heading when I reached the magic altitude. Too much judgement with too little margin for error if you ask me.

So several years ago I started to look at how the mil does it. They use a two point system as described by Ron. Connecting the dots became much easier. With two points it is so much easier to judge being on alt and course and how it will ultimately play out. I mentioned this to an experienced CFII (not my original II) I was flying with at the time and she said that is how she learned in Germany. She then said she knows of several Part 61 schools in the USA which teach that method.
 
Richard said:
So several years ago I started to look at how the mil does it. They use a two point system as described by Ron. Connecting the dots became much easier. With two points it is so much easier to judge being on alt and course and how it will ultimately play out. I mentioned this to an experienced CFII (not my original II) I was flying with at the time and she said that is how she learned in Germany. She then said she knows of several Part 61 schools in the USA which teach that method.
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Keep in mind that the hi/low-key system is quite aircraft-specific as it depends on glide speed and L/D ratio. You can't carry the key altitudes/airspeeds and distances from the touchdown point from one plane to another, and I know of no simple equations for computing those numbers.
 
Ron Levy said:
Keep in mind that the hi/low-key system is quite aircraft-specific as it depends on glide speed and L/D ratio. You can't carry the key altitudes/airspeeds and distances from the touchdown point from one plane to another, and I know of no simple equations for computing those numbers.
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What I learned and found most helpful was a simple concept (probably the snigle key positon) of being abeam the touchdown point on downwind at whatever ideal altitude you needed for your aircraft. So, for example, in a C172, 1000 feet works just fine. From there, you simply maintain best glide with no flaps, fly a tightish or continuous base to final, and add flaps only when the field is made. In a C182 I like 1200 feet because she sinks faster. Once you were at that key position, you flew to be high on final, because you knew you could always shed altitude when you were sure the field was made.

(I had some dramatic demonstrations of what happens when you try to fly at what you think is the ideal altitude all the way down. I remember turning final at Martin State and watching myself sink right down into the water well before the beginning of Rwy 33! My CFI let me fly that pattern, because it taught me better than any words would have done!)

Flying from the key position to touchdown isn't really that hard, but getting to that position may be difficult. So, you have to know your aircraft's glide characteristics. One thing I liked to do when "losing" the engine above 2000 feet was simply to fly to the key position right away, and make adjustments once there.

I welcome the comments and criticisms of CFIs
 
wangmyers said:
What I learned and found most helpful was a simple concept (probably the snigle key positon) of being abeam the touchdown point on downwind at whatever ideal altitude you needed for your aircraft. So, for example, in a C172, 1000 feet works just fine. From there, you simply maintain best glide with no flaps, fly a tightish or continuous base to final, and add flaps only when the field is made. In a C182 I like 1200 feet because she sinks faster. Once you were at that key position, you flew to be high on final, because you knew you could always shed altitude when you were sure the field was made.

(I had some dramatic demonstrations of what happens when you try to fly at what you think is the ideal altitude all the way down. I remember turning final at Martin State and watching myself sink right down into the water well before the beginning of Rwy 33! My CFI let me fly that pattern, because it taught me better than any words would have done!)

Flying from the key position to touchdown isn't really that hard, but getting to that position may be difficult. So, you have to know your aircraft's glide characteristics. One thing I liked to do when "losing" the engine above 2000 feet was simply to fly to the key position right away, and make adjustments once there.

I welcome the comments and criticisms of CFIs
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Right, I sure do also like to get well above a glide path to the landing site threshold ASAP and as high as possible while remembering how to use aggressive S turns, slips and/or 360s as needed to lose altitude to avoid the over-run which, although generally undesirable, is often safer than a botched glide path leading to landing short onto the rough-whatever -unless that particular over-run takes you over a cliff into the ocean or worse.
 
What do you guys say to arriving in the vicinity, fat on energy, with full flaps, gear out.
Then if you are coming up short -- lose some drag. I have tried it in mine and it seems like a reasonable way to provide some control over the approach.

In glider class they taught a variation. Pick up the speed a bit, spoilers half. If short, suck the spoiler in. Too long; full spoilers will bring her down. In fact they discussed thinking of the spoilers as a 'throttle'.
 
Let'sgoflying! said:
What do you guys say to arriving in the vicinity, fat on energy, with full flaps, gear out.
Then if you are coming up short -- lose some drag. I have tried it in mine and it seems like a reasonable way to provide some control over the approach.

In glider class they taught a variation. Pick up the speed a bit, spoilers half. If short, suck the spoiler in. Too long; full spoilers will bring her down. In fact they discussed thinking of the spoilers as a 'throttle'.
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That would be great if you could modulate the drag from the gear and flaps like spoilers on a glider. Personally, I think that if spoilers were required on all light airplanes, landing short/long accidents would practically go away, but that's not going to happen. Messing with the gear as a means of shortening or extending your final sounds like a recipe for landings with the gear partially extended (or fully retracted) so I'd stay away from that one unless I found myself coming up a little short where the difference between a little short and just long enough was a life and death choice (think landing on a plateau with sheer cliffs all around). You'd also have to account for the fact that on many retractables there is a noticeable loss of lift and sometimes an increase in drag during part of the retraction cycle, like when the gear doors are open, so when you raise the gear you may actually shorten the glide unless you were fairly high to begin with.

Using flaps this way would likely be very dependent on the type of flaps and the flap control. Slow moving electric flaps aren't going to be as controllable as something with a Johnson bar and spilt flaps (which are mostly drag with little effect on lift) would be better than fowler flaps which increase the wing area and lift significantly. With flaps that increase lift, you might find that raising already deployed flaps significantly shortened the glide due to the need to decrease AOA and increase airspeed to counter the loss of lift.

So, IMO that leaves one or two reliable means of controlling your glide. One obvious one is a slip. You could plan the final descent with some yaw which can be removed if you're coming up short or increased if you are going long. A slightly simpler alternative is to plan the approach a little on the high side and use a slip when you get fairly close to the intended touchdown point to lose altitude and airspeed. Adjusting a slip is very quick and AFaIK the only issue is that an agressive slip makes the ASI inaccurate. Method two is to use the prop control on an airplane with a C/S prop and an engine that's still windmilling. On many complex airplanes, the L/D can be adjusted over about a 1.5 to 1 range with the prop control. The downsides are that if the engine stops or the prop governor fails (lack of oil would cause this) you lose that capability, and the control works backwards of anything else you might be used to for controlling speed (pull back to go faster).
 
lancefisher said:
That would be great if you could modulate the drag from the gear and flaps like spoilers on a glider. Personally, I think that if spoilers were required on all light airplanes, landing short/long accidents would practically go away, but that's not going to happen. Messing with the gear as a means of shortening or extending your final sounds like a recipe for landings with the gear partially extended (or fully retracted) so I'd stay away from that one unless I found myself coming up a little short where the difference between a little short and just long enough was a life and death choice (think landing on a plateau with sheer cliffs all around). You'd also have to account for the fact that on many retractables there is a noticeable loss of lift and sometimes an increase in drag during part of the retraction cycle, like when the gear doors are open, so when you raise the gear you may actually shorten the glide unless you were fairly high to begin with.

Using flaps this way would likely be very dependent on the type of flaps and the flap control. Slow moving electric flaps aren't going to be as controllable as something with a Johnson bar and spilt flaps (which are mostly drag with little effect on lift) would be better than fowler flaps which increase the wing area and lift significantly. With flaps that increase lift, you might find that raising already deployed flaps significantly shortened the glide due to the need to decrease AOA and increase airspeed to counter the loss of lift.

So, IMO that leaves one or two reliable means of controlling your glide. One obvious one is a slip. You could plan the final descent with some yaw which can be removed if you're coming up short or increased if you are going long.

A slightly simpler alternative is to plan the approach a little on the high side and use a slip when you get fairly close to the intended touchdown point to lose altitude and airspeed. Adjusting a slip is very quick and AFaIK the only issue is that an agressive slip makes the ASI inaccurate.
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Method two is to use the prop control on an airplane with a C/S prop and an engine that's still windmilling. On many complex airplanes, the L/D can be adjusted over about a 1.5 to 1 range with the prop control. The downsides are that if the engine stops or the prop governor fails (lack of oil would cause this) you lose that capability, and the control works backwards of anything else you might be used to for controlling speed (pull back to go faster).
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The more aggressive the slip, the more the aircraft's nose should be forced to pitch downward to assure adequate airspeed and avoid the dangerous uncoordinated stall. Practised skill, slightly beyond reading the increasingly erroneous Airspeed Indicator is required to do this elementary maneuver safely and the speed at which vertical speed can be adjusted through a wide range without even taking the hands off the primary airframe controls, makes it among the most valuable of any pilot skills both for emergency LDGs and normal ones.
 
The other aspect that I was never formally taught and has always concerned me is how do I get to the key position from all kinds of weird relationships. Most of the time this is practiced you are in the pattern at pattern altitude and they pull the throttle abeam the numbers. If you are over open ground and trying to hit a field, the target is a whole lot bigger, usually. It's the scenario where you are trying to reach a runway that I'm talking about.

If you lose an engine at a typical cruise altitude, say 7000-9000 msl, and try to make a nearby airfield, you have to factor in winds aloft with various shears, distance to the field, descent rate, etc. All of that to hit a point abeam the numbers 1000 ft agl.

Even simply spiralling down over a field, if you only have two turns before hitting the key point, how do you work out how tight to turn etc.

I can sit here and think through a scenario and do the calculations, but when everything has hit the fan and the adrenal levels are off the chart, there should be a KISS means to get close.
 
Larry Liebscher said:
The other aspect that I was never formally taught and has always concerned me is how do I get to the key position from all kinds of weird relationships. Most of the time this is practiced you are in the pattern at pattern altitude and they pull the throttle abeam the numbers. If you are over open ground and trying to hit a field, the target is a whole lot bigger, usually. It's the scenario where you are trying to reach a runway that I'm talking about.

If you lose an engine at a typical cruise altitude, say 7000-9000 msl, and try to make a nearby airfield, you have to factor in winds aloft with various shears, distance to the field, descent rate, etc. All of that to hit a point abeam the numbers 1000 ft agl.

Even simply spiralling down over a field, if you only have two turns before hitting the key point, how do you work out how tight to turn etc.

I can sit here and think through a scenario and do the calculations, but when everything has hit the fan and the adrenal levels are off the chart, there should be a KISS means to get close.
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During my flight ride, the old Commercial DE summed up emergency landings in unfamiliar surroundings as I was braking to the MAX to avoid the over-run on a short airstrip after the simulated engine out to LDG:

"Judgin' 'em is hard."
 
Larry Liebscher said:
The other aspect that I was never formally taught and has always concerned me is how do I get to the key position from all kinds of weird relationships. Most of the time this is practiced you are in the pattern at pattern altitude and they pull the throttle abeam the numbers. If you are over open ground and trying to hit a field, the target is a whole lot bigger, usually. It's the scenario where you are trying to reach a runway that I'm talking about.

If you lose an engine at a typical cruise altitude, say 7000-9000 msl, and try to make a nearby airfield, you have to factor in winds aloft with various shears, distance to the field, descent rate, etc. All of that to hit a point abeam the numbers 1000 ft agl.

Even simply spiralling down over a field, if you only have two turns before hitting the key point, how do you work out how tight to turn etc.

I can sit here and think through a scenario and do the calculations, but when everything has hit the fan and the adrenal levels are off the chart, there should be a KISS means to get close.
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Larry, you so eloquently nailed the EXACT reason why I am so uncomfortable with the single key position. A spiral in the lo key position (abeam the landing point) means turning away from the selected field at a rather lo alt. Sure, slips and other adjustments on final, but what if there is a better way? Leaving the single key position early usually results in a too long downwind leg.

A two key position method allows the pilot to more acurately judge the approach because two points will indicate a trend in the flight path, something a single point cannot do. Ron made a very good point about the 2 point method being aircraft specific, even still it is easier to judge the approach.

Disappointed is too strong of a word for what I want to say but for lack of another word I am disappointed that all a CFI can respond to your excellent post is that his DE once told him the judging is the hard part. Heck yeah, it's the hard part, for me the 2 key position is a KISS method because it simplifies the judgement.
 
Going back to the article Bruce cites above from the Handbook, I pulled this quote.

"Utilizing any combination of normal gliding maneuvers,
from wings level to spirals, the pilot should eventually
arrive at the normal key position at a normal traffic pattern
altitude for the selected landing area. From this
point on, the approach will be as nearly as possible a
normal power-off approach. [Figure 8-29]"

In all of the books and articles I've read on this, that is about as much help as I've seen.

It's kinda like saying, "After you have swung the club back from the ball on the backswing, you reach a position at the top of the swing that will allow you to return the club face back to the position perfectly square to the line of flight, with the club head traveling down the intended path at 120 mph, at the precise moment the club meets the ball." Well, yeah I know that. It's just that I haven't been able to do that reliably despite trying untold times over 50 years.

I'm reasonably confident that I could get the plane on the ground safely from the key point. It's getting close to that key point from 10 miles away and 7000 ft up with a 35 kts wind at 3000 ft and an 18 kts wind from a different direction at the surface that worries me.​
 
Larry Liebscher said:
Going back to the article Bruce cites above from the Handbook, I pulled this quote.


"Utilizing any combination of normal gliding maneuvers,
from wings level to spirals, the pilot should eventually
arrive at the normal key position at a normal traffic pattern
altitude for the selected landing area. From this
point on, the approach will be as nearly as possible a
normal power-off approach. [Figure 8-29]"

In all of the books and articles I've read on this, that is about as much help as I've seen.

It's kinda like saying, "After you have swung the club back from the ball on the backswing, you reach a position at the top of the swing that will allow you to return the club face back to the position perfectly square to the line of flight, with the club head traveling down the intended path at 120 mph, at the precise moment the club meets the ball." Well, yeah I know that. It's just that I haven't been able to do that reliably despite trying untold times over 50 years.

I'm reasonably confident that I could get the plane on the ground safely from the key point. It's getting close to that key point from 10 miles away and 7000 ft up with a 35 kts wind at 3000 ft and an 18 kts wind from a different direction at the surface that worries me.
​
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Flying is nothing if not judgement.

Is it really any more complicated than having enough altitude (luck) at engine failure and then using Best Glide to get above your touchdown zone and then using any combination (judgin' it, Richard) of the aforementioned basic maneuvers from ones history of flight training to effect a passable emergency LDG ?

If judgin' it ain't good enough, then punch-up your GPS and get some distance data to werever you're gonna go, have the GPS compute the unknown wind and then also enter a vertical flight profile for your aircraft.
 
Hi and low key is a great skill to have in one's tool box. I was also taught to control my glide and distance, altitude, and time to touch down by spiral to a altitude and a point and then using S-turns on final(allowing you to never turn away from your field), combined with flaps at the right time, a slip, as well as the Key techniques, and any other skill you can use to make your field. I guess my point is that in my experience in aviation its great to be current in all of these skills because there are sooooo many variables out there in your flying that I think its naive to expect to be current and proficient in just one technique or skill that will bail you out.

Obivously folks will be better at one techique than another...in the end most people probalby fly what they know, are current with and get the best consistent desired outcome from. But I still think that everyone should strive to stay current in all of the techniques they can educate themselves about.

I think currency is huge in the realm of EMER LANDINGS. I used to leave my students with the theory that being proficient, and current in them is perhaps the most important objective they could have as a pilot. How often should one practice, and to what extent and it what conditions?

I haven't flown small piston aircraft with any frequency in over 3 years and I now have the opportunity to fly a 172....after going out and doing some bounces the other day....I came to the harsh reality that currrency IS everything...there is no way I can jump out of the Citation X or Excel and fly a good Emer Landing profile without significant practice.

There are a million ways to skin a cat in aviation. And every 150hr Astronaut has their opinion on how to skin every cat in aviation.

Whether you are using the Hi/Low key profile, or another technique, practice and currency in the technique and other techniques is what will keep you alive....along with being able to decide what skills or technique to use for a particular Emer Landing situation.

Currency, Currency, Currency....Train the way you fly and Fly the way you train.
 
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