An acceptable landing...
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Once established on the ILS glideslope it is not back to pitch and power as you imply.
Flying down the glide configured you hit sinking air! The aircraft will pitch for the glideslope.
Power at idle and speed will decay until the aircraft gains the glide.
Then again it will pitch down with the result that at that point the aircraft will be gaining speed again.
Bigger downdraught, power at idle and there could be a stall situation as the aircraft tries to capture the glide unless you advance the throttles and add power.
But this is the point I am not arguing for one against the other but saying that both elevator and throttles are means of tapping into potential energy and both should be used.
Both methods pitch for speed or power for speed are flawed.
Both are good in certain situations but flawed in other ways.
Only together do they make sense.
I cannot remember the last time I did a bad landing in all weather scenarios so must be doing something right ( prob do a bad one now I have said that ) : )
Pace
Once established on the ILS glideslope it is not back to pitch and power as you imply.
Flying down the glide configured you hit sinking air! The aircraft will pitch for the glideslope.
Power at idle and speed will decay until the aircraft gains the glide.
Then again it will pitch down with the result that at that point the aircraft will be gaining speed again.
Bigger downdraught, power at idle and there could be a stall situation as the aircraft tries to capture the glide unless you advance the throttles and add power.
But this is the point I am not arguing for one against the other but saying that both elevator and throttles are means of tapping into potential energy and both should be used.
Both methods pitch for speed or power for speed are flawed.
Both are good in certain situations but flawed in other ways.
Only together do they make sense.
I cannot remember the last time I did a bad landing in all weather scenarios so must be doing something right ( prob do a bad one now I have said that ) : )
Pace
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Well, some fascinating opinions on this thread. Wasn't quite expecting this kind of reaction but it's certainly been interesting reading through the different ideas on the ideal landing approach.
Is one better than the other? I think the many different styles discussed all have their own merit.
Is it worth mentioning at this stage that the PA28 flown in the video is a Diesel FADEC with variable pitch propeller. Much greater power inputs are required to achieve the same result in this aircraft when flying at low speed on approaches than if I were flying a standard PA28, and this would explain the 'lawnmower' type noise instead of the slightly meatier horizontally opposed 4 cylinder avgas engine. The FADEC computers adjust the pitch and engine RPM as a result of changes to the throttle position which explains why it sounds like I was making significant throttle adjustments moments before crossing the threshold.
I still maintain that I wasn't as flat as it appears in the video and was relatively pleased with my acceptable airliner approach/landing
I touched down not much after the numbers and was able to slow the aircraft and vacate around midway along 25 which isn't a long runway, so all in all I was pleased, my passenger was pleased, the aircraft was in the same condition as when I took her, ATC were pleased, the flyingclub were pleased. Job well done I reckon
Is one better than the other? I think the many different styles discussed all have their own merit.
Is it worth mentioning at this stage that the PA28 flown in the video is a Diesel FADEC with variable pitch propeller. Much greater power inputs are required to achieve the same result in this aircraft when flying at low speed on approaches than if I were flying a standard PA28, and this would explain the 'lawnmower' type noise instead of the slightly meatier horizontally opposed 4 cylinder avgas engine. The FADEC computers adjust the pitch and engine RPM as a result of changes to the throttle position which explains why it sounds like I was making significant throttle adjustments moments before crossing the threshold.
I still maintain that I wasn't as flat as it appears in the video and was relatively pleased with my acceptable airliner approach/landing
I touched down not much after the numbers and was able to slow the aircraft and vacate around midway along 25 which isn't a long runway, so all in all I was pleased, my passenger was pleased, the aircraft was in the same condition as when I took her, ATC were pleased, the flyingclub were pleased. Job well done I reckon
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Once established on the ILS glideslope it is not back to pitch and power as you imply.
Personally, like yourself, when flying I don't think about this at all. It's really only when instructing a student who has trouble staying on the glideslope and maintaining his speed constant at the same time that one has to come up with a simple solution.
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Englishal - I'm struggling to understand the relationship between glideslope and speed that you're suggesting:
Within a 'normal' range of glideslopes, you pick whatever speed you want for approach surely - You just have less power for the same speed on a steeper approach; the 'steep' limit being a glide approach, the flat limit being whatever you need to clear the trees (hopefully plus a bit more). Or are you suggesting a 'back of drag curve shortfield' type of approach? I'd take that as a rather different proposition, a perfectly valid one, but a little specialist.
500man - I think you're maybe missing something important about AOA: for a given a/c at a given weight, the AOA at a given speed is the same* - a steeper approach at the same speed gives you the same AOA.
*Just for completeness - there is a slight difference due to difference in flight path angle and resolving gravity parallel and perpendicular to that, but it is insignificant for our purposes
Another thing that I think is missing as a concept is the difference between approach speed, and touchdown speed. I only hold approach to the hedge/fence/whatever. I'm then slowing down and pitching for landing attitude/stall long before there's tarmac under me, not floating down the tarmac slowing - I aim to be putting it near the numbers near stall. I can be slowing in the air before there's ground that I can put it on and get slowing with the brakes. It's also easier on the undercart, especially if landing on grass to do it slowly.
As for pitch and power, my experience is that once you've got a few hours under your belt you don't mechanicaly follow either by rote. You just juggle power and stick to put it where you want, on speed - well, I do. I'll also freely admit I'm a proponent of glide approaches, and sideslipping, and so on.
The difference in stall speed for a powered approach is frankly minimal in most sane cases, and only due to the fan blowing air over the wing. Frankly I think a lot of it might just be that flat approaches are easier to make good landings off..
Originally Posted by englishal
Flying a relatively flat approach with some power also means you are approaching slower so that when you touch down you stop flying ASAP. Our stall speed (dirty) is 54 kts, s/f approch is 72 kts and normal landing is 82 kts. If you land at 82 kts then obviously the gound roll is going to be longer so it is better to come in slower (on a short runway) and to give you a more stabilised slow approach, come in with a relatively high AoA and some power.
500man - I think you're maybe missing something important about AOA: for a given a/c at a given weight, the AOA at a given speed is the same* - a steeper approach at the same speed gives you the same AOA.
*Just for completeness - there is a slight difference due to difference in flight path angle and resolving gravity parallel and perpendicular to that, but it is insignificant for our purposes
Another thing that I think is missing as a concept is the difference between approach speed, and touchdown speed. I only hold approach to the hedge/fence/whatever. I'm then slowing down and pitching for landing attitude/stall long before there's tarmac under me, not floating down the tarmac slowing - I aim to be putting it near the numbers near stall. I can be slowing in the air before there's ground that I can put it on and get slowing with the brakes. It's also easier on the undercart, especially if landing on grass to do it slowly.
As for pitch and power, my experience is that once you've got a few hours under your belt you don't mechanicaly follow either by rote. You just juggle power and stick to put it where you want, on speed - well, I do. I'll also freely admit I'm a proponent of glide approaches, and sideslipping, and so on.
The difference in stall speed for a powered approach is frankly minimal in most sane cases, and only due to the fan blowing air over the wing. Frankly I think a lot of it might just be that flat approaches are easier to make good landings off..
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Is one better than the other?
But there are no "good" or "bad" landings anyway. Only safe and unsafe ones. A safe landing is one where the pilot puts down his aircraft close to his intended landing spot at the correct speed and sinkrate (both depending on the type of aircraft and the prevailing conditions) whilst maintaing full control all the time. A greaser "somewhere" down the runway to me is one of the worst landings because there is no aiming point and usually not much control either.
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There are in the Citation
The owner doesnt half get grumpy if you flat spot them at their huge cost.
But this is the whole point no one way is right for every occasion.
If you have miles of runway its quite in order to hold off for the Chairmans Landing!
If the runway is short you just put it down.
If its windy and gusty you dont want to be holding in the flair 10 feet up with the stall warning coming on, Control column in the chest otherwise that perfect landing your aiming for might turn into something very embarrassing!
The perfect landing USUALLY comes from getting a perfect approach. A managed approach bringing in various degress of drag with gear and flap and a fairly constant power setting.
Dont fear keeping speed high down the approach especially in windy gusty days.
There is nothing worse than being at VREF 2-3 miles out and hitting a massive sink.
If you play all your controls its easy to pull speed off close in.
Whats next the above is not directed at you but at the thread as I am sure most of us speak the same language in a different way
As another poster added it all becomes second nature and you no longer think pitch for speed or power for speed but a natural use of all the inputs available to you.
There are in the Citation
The owner doesnt half get grumpy if you flat spot them at their huge cost.But this is the whole point no one way is right for every occasion.
If you have miles of runway its quite in order to hold off for the Chairmans Landing!
If the runway is short you just put it down.
If its windy and gusty you dont want to be holding in the flair 10 feet up with the stall warning coming on, Control column in the chest otherwise that perfect landing your aiming for might turn into something very embarrassing!
The perfect landing USUALLY comes from getting a perfect approach. A managed approach bringing in various degress of drag with gear and flap and a fairly constant power setting.
Dont fear keeping speed high down the approach especially in windy gusty days.
There is nothing worse than being at VREF 2-3 miles out and hitting a massive sink.
If you play all your controls its easy to pull speed off close in.
Whats next the above is not directed at you but at the thread as I am sure most of us speak the same language in a different way
As another poster added it all becomes second nature and you no longer think pitch for speed or power for speed but a natural use of all the inputs available to you.
Apropos glide landing some posts back now where the writer suggests if you're in need of engine & it ain't there you're no better off than simply dragging it in.
Light singles at strips can glide in but do it more steeply with flap and side slip as appropriate. Easing them off is like 'adding power' by reducing drag and descent angle.
Thus there's no need to add power every time !
Light singles at strips can glide in but do it more steeply with flap and side slip as appropriate. Easing them off is like 'adding power' by reducing drag and descent angle.
Thus there's no need to add power every time !
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Mike
We are covering a lot in this thread
One of the biggest killers engine out is fixating on one point and trying to get there.
If you are high enough and close enough to make it chances are that you will be on a closed or almost closed throttle.
The only time your likely to realise that you have lost the engine is when you get sink so it will take you by surprise.
But forget all that!
How likely are you to loose that engine on the least stressed portion of the flight?
I know quite a few single engine ferry pilots who trust those units to carry them over thousands of miles of sea and inhospitable terrain (they have far more guts than me! ( at least 2 engines and preferably turbines)
The chances of Joe Bloggs loosing the engine on finals while flying a summer evening flight must be minute to such an extent as to be almost non existant.
If it happens I would rather be aware of possible fields either side of me and at 45 degrees to me rather than a distant piece of airfield which I will try to make at all costs.
Ok I take your point that some aircraft are almost like gliders and you can control the glide by adding or removing drag and thats a valid point but most tourers are not.
I personally would not design my circuits or approach around the extreme unlikely event of an engine failure and making it tio the field but thats me
I think statistically you are far more likely on a high glide approach to get it wrong, come in too high too fast and vanish through the far hedge
Pace
We are covering a lot in this thread
One of the biggest killers engine out is fixating on one point and trying to get there.If you are high enough and close enough to make it chances are that you will be on a closed or almost closed throttle.
The only time your likely to realise that you have lost the engine is when you get sink so it will take you by surprise.
But forget all that!
How likely are you to loose that engine on the least stressed portion of the flight?
I know quite a few single engine ferry pilots who trust those units to carry them over thousands of miles of sea and inhospitable terrain (they have far more guts than me! ( at least 2 engines and preferably turbines)
The chances of Joe Bloggs loosing the engine on finals while flying a summer evening flight must be minute to such an extent as to be almost non existant.
If it happens I would rather be aware of possible fields either side of me and at 45 degrees to me rather than a distant piece of airfield which I will try to make at all costs.
Ok I take your point that some aircraft are almost like gliders and you can control the glide by adding or removing drag and thats a valid point but most tourers are not.
I personally would not design my circuits or approach around the extreme unlikely event of an engine failure and making it tio the field but thats me
I think statistically you are far more likely on a high glide approach to get it wrong, come in too high too fast and vanish through the far hedge
Pace
Last edited by Pace; 11th Jul 2011 at 18:24.
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500man - I think you're maybe missing something important about AOA
Pitching for speed, if you are too fast and too high as in my example, you will be increasing your AoA and reducing speed to begin with but you are already too high so you will need to pull power to come down faster. Then you would re-pitch for speed and repeat the process.
Surely it's better to pick an aiming point and maintain pitch, adjusting power as required? That's my view anyway.
As a side note since prop-wash was mentioned; this will have some effect however big or small on the Vs1g stall speed. So obviously you would have a smaller effective AoA with power-on compared to power-off at the same aerofoil AoA. The significance will no doubt depend on the configuration of the aircraft and the thrust available. Correct me if I'm wrong.
Edit: This has turned out to be a great thread with the various topics discussed and with a few interesting vids too!
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I still maintain that I wasn't as flat as it appears in the video and was relatively pleased with my acceptable airliner approach/landing
I touched down not much after the numbers and was able to slow the aircraft and vacate around midway along 25 which isn't a long runway, so all in all I was pleased, my passenger was pleased, the aircraft was in the same condition as when I took her, ATC were pleased, the flyingclub were pleased. Job well done I reckon
I touched down not much after the numbers and was able to slow the aircraft and vacate around midway along 25 which isn't a long runway, so all in all I was pleased, my passenger was pleased, the aircraft was in the same condition as when I took her, ATC were pleased, the flyingclub were pleased. Job well done I reckon
I have a list of airfields you might want to try an approach like that and I can guarantee you'll land 2 fields short.
Personally I don't much care what my passengers think of my landings. Generally they don't know what I know - I got away with a half-decent landing but I know I could have done better.
You asked for our views and it is always good to get your flying critiqued. But you have to accept that when others give you comments you don't like, they may have a point.
It's important that we don't get smug and accept second best, so I would recommend you try a slightly higher approach and not use the airliner version - unless you are flying an airliner.
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Keep on saying this and one day you might believe it.......
I have a list of airfields you might want to try an approach like that and I can guarantee you'll land 2 fields short.
Personally I don't much care what my passengers think of my landings. Generally they don't know what I know - I got away with a half-decent landing but I know I could have done better.
You asked for our views and it is always good to get your flying critiqued. But you have to accept that when others give you comments you don't like, they may have a point.
It's important that we don't get smug and accept second best, so I would recommend you try a slightly higher approach and not use the airliner version - unless you are flying an airliner.
I have a list of airfields you might want to try an approach like that and I can guarantee you'll land 2 fields short.
Personally I don't much care what my passengers think of my landings. Generally they don't know what I know - I got away with a half-decent landing but I know I could have done better.
You asked for our views and it is always good to get your flying critiqued. But you have to accept that when others give you comments you don't like, they may have a point.
It's important that we don't get smug and accept second best, so I would recommend you try a slightly higher approach and not use the airliner version - unless you are flying an airliner.
Nevermind.
P.S which airfields are you referring to?
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l really can`t add anymore for those who will not listen.
Put the aircraft into a position where it wants to land and let it get on with it.
Don`t touch.
lf your greaser was half way down the strip you were too fast.
An aircraft that has to be wrestled to the ground is an oxymoron.
Look chaps, even the Starfighter pilots benefited from further training, too late admittedly.
Put the aircraft into a position where it wants to land and let it get on with it.
Don`t touch.
lf your greaser was half way down the strip you were too fast.
An aircraft that has to be wrestled to the ground is an oxymoron.
Look chaps, even the Starfighter pilots benefited from further training, too late admittedly.
1) The right engine was shut down on final. I think this is a very poor idea because it probably eliminated the ability to over shoot as the mangle U/C probably would not have retracted. As for the idea of saving the engine.....well that is why you have insurance. The insurance companies would rather pay for two props and engines on a sure thing landing then replace the whole aircraft on a hero move gone bad, or even worse have to settle personal injury claims.
2) There was some pretty extreme manoevering at touch down. The pilot made it work but IMO the best thing to do in these kind of emergencies is to plan a fly a totally normal approach and touch down and then do your best to keep it straight.
3) The guys all bailed out when the aircraft stopped, which is good, but the strobes (and probably the boost pumps) were still on so the pilot had not taken the 5 extra seconds to turn off the master before exiting the aircraft and thus reduce the potential for fire. I had a right gear collapse on a Seneca I was instructing on during rollout on a paved runway. When the wing hit the runway the outboard fuel quick drain was sheared off and within seconds there was a big pool of fuel under and around the wing
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Very odd to shut one engine down and not the other!
It can only be a mistake where the pilot had thought he had shut both down!
Really they should have been shut down only when assured of landing ie in the last 50 odd feet.
I witnessed a cessna push pull twin belly land at Gloucester a number of years back who shut both down just prior to landing.
The pilot of that aircraft did a good job!
He landed with no gear on tarmac.
Whether it would be safer onto grass rather than spark inducing Tarmac ?
The other point other than saving damage to the engines is the threat of the props under power coming into the cockpit and killing an occupant as occurred with a humberside golden Eagle crash
Difficult call ?
Pace
Very odd to shut one engine down and not the other!
It can only be a mistake where the pilot had thought he had shut both down!
Really they should have been shut down only when assured of landing ie in the last 50 odd feet.
I witnessed a cessna push pull twin belly land at Gloucester a number of years back who shut both down just prior to landing.
The pilot of that aircraft did a good job!
He landed with no gear on tarmac.
Whether it would be safer onto grass rather than spark inducing Tarmac ?
The other point other than saving damage to the engines is the threat of the props under power coming into the cockpit and killing an occupant as occurred with a humberside golden Eagle crash
Difficult call ?
Pace
I believe there has never been prop which has disintegrated and penetrated the cabin of a GA piston twin, if the prop stike was at idle power. The only instances of props coming apart involved prop strikes at high power settings.
Deliberately shutting down one engine on approach, like the Seneca pilot did, very much increases the risk of the other engine being at high power. Flying an unstabilized approach and flare also increases the risk. In the video he comes very close to a prop strike on the left (running) engine just after the wheels touch.
I feel quite strongly that in the case of a malfunctioning landing gear the best method is a normal all engine approach with a normal wings level, nose high touchdown. At touch down both mixtures can be placed in idle cutoff and when the aircraft comes to a stop the electrics turned off and the aircraft vacated.
Deliberately shutting down one engine on approach, like the Seneca pilot did, very much increases the risk of the other engine being at high power. Flying an unstabilized approach and flare also increases the risk. In the video he comes very close to a prop strike on the left (running) engine just after the wheels touch.
I feel quite strongly that in the case of a malfunctioning landing gear the best method is a normal all engine approach with a normal wings level, nose high touchdown. At touch down both mixtures can be placed in idle cutoff and when the aircraft comes to a stop the electrics turned off and the aircraft vacated.
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Seneca IV Brussels potential unsafe gear landing
I completely agree that switching a single engine off would be ridiculous and dangerous. And I'd bet he did have a prop strike, this does not have to mean disintegration, but just a bent prop and a shock loaded engine.
The full procedure we followed at Brussels was:
low fly past with engineer checking gear from the ground
vectored around
just prior to the threshold check clear runway
when over the threshold fuel idle cut, closed fuel tanks and throttle and electrics off
hold off the nose as long as possible (it was the nose gear which seemed unsafe)
We were 3 up in the Seneca, 2 pilots and a passenger, doors unlatched.
I would make the same choice again.
BvH
The full procedure we followed at Brussels was:
low fly past with engineer checking gear from the ground
vectored around
just prior to the threshold check clear runway
when over the threshold fuel idle cut, closed fuel tanks and throttle and electrics off
hold off the nose as long as possible (it was the nose gear which seemed unsafe)
We were 3 up in the Seneca, 2 pilots and a passenger, doors unlatched.
I would make the same choice again.
BvH
