Landing Question!
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I tried the same practice in a C172, flying over a disused airfield at 3000ft at less than half a mile out. With 40deg flaps, no throttle, and 75-80 knots the C172 made it onto the glideslope with room to spare. (note. Max Vflaps is 85knots, and no side-slips are allowed with C172s.)
1/2 mile out =2640'
You are at 3,000
Even 60 MPH only gives you 30 seconds to reach the threshold from 1/2 mile out.
ROD 6,000'/min.
Must have been a good day!
1/2 mile out =2640'
You are at 3,000
Even 60 MPH only gives you 30 seconds to reach the threshold from 1/2 mile out.
ROD 6,000'/min.
Must have been a good day!
Last edited by Steve R; 30th Apr 2013 at 10:33.
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In a way maybe we are not seeing the real picture between glide approaches or powered approaches or in fact the pitch for speed argument that has raged for years.
The basic form of flight is the Glider it uses someone elses energy to tow it into the sky and on a still lift free day taps into its own potential energy trading altitude for that energy and hence enough airflow to keep the wing flying.
We then move to very low powered high drag air frames which because of their low power and high drag rely more on the potential energy in the airframe.
Add high powered aircraft and tapping into the airframes potential energy becomes less important.
I always see energy management between the engine and airframe as two sets of throttles, the one which runs to the engine and the control column which allows you to pitch for the second source of energy.
Hence as in the pitch for speed argument neither is wrong as its more about managing the energy and drag available to you and that is very type specific and situation specific
As stated the Glide Approach is one form of approach not THE APPROACH
Your skills as a pilot play a major part managing those two sources of potential energy as well as the various types of drag used for your benefit or against your benefit.
Here the novice pilot has to be protected from his lack of skills by erring on the safer way from getting into low power high drag situations
Pace
The basic form of flight is the Glider it uses someone elses energy to tow it into the sky and on a still lift free day taps into its own potential energy trading altitude for that energy and hence enough airflow to keep the wing flying.
We then move to very low powered high drag air frames which because of their low power and high drag rely more on the potential energy in the airframe.
Add high powered aircraft and tapping into the airframes potential energy becomes less important.
I always see energy management between the engine and airframe as two sets of throttles, the one which runs to the engine and the control column which allows you to pitch for the second source of energy.
Hence as in the pitch for speed argument neither is wrong as its more about managing the energy and drag available to you and that is very type specific and situation specific
As stated the Glide Approach is one form of approach not THE APPROACH
Your skills as a pilot play a major part managing those two sources of potential energy as well as the various types of drag used for your benefit or against your benefit.
Here the novice pilot has to be protected from his lack of skills by erring on the safer way from getting into low power high drag situations
Pace
Last edited by Pace; 30th Apr 2013 at 11:27.
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I've been taught both techniques - and they are appropriate for different situations.
If you are doing a PFL (Practice Forced Landing) then you will be using the glide approach. As your approach is steeper, you need more energy to move from the descent to the flare, so the approach speed is higher.
If you are doing a short field landing, you want to be at the minimum safe speed during the approach. In my aircraft, that is achieved on the back side of the drag curve, so high power, low speed, shallow approach.
I'd say that shallower (powered) approaches are easier. You have longer on final to stabilise and the change in attitude to flare isn't significant.
That doesn't make them the right technique to use though!
I actually find flapless landings the easiest, as you have much longer in the flare (higher approach speed) . However you don't want to do them regularly unless you have a very long runway and you don't mind the additional tyre ware (due to the higher touch down speed).
I believe it comes down to the glide ratio of the airplane. For standard GA planes, its probably around 1:10 making a glide angle of around 6 degrees. This means that if you are on a 3 degree glide slope you can't make the runway in the event of an engine failure. For 737s and the like, the glide ratio is more like 1:15 or more. They might not reach the touchdown point, but if on a 3.5 degree glide, they can probably still make the aerodrome (remember a BA flight into Heathrow a couple of years ago?).
So you have to balance the two safety aspects (engine failure vs slightly more difficult touch down), obstacle clearance (often small airfields have obstacles that makes a steeper approach advised), circuit size (again - can you land back on the runway if an engine fails; what are others doing; noise abatement
efficiency (smaller circuit = quicker, especially at busy places). Just because something is difficult, doesn't mean that you shouldn't learn how to do it.
I normally do a slightly steeper glide (probably around 4 degrees) to land at the CAT touchdown point, since I fly from a large airport. This means I'm not diving onto the runway but since there is lots of extra runway to play with, if the donkey dies, I can still land on.
However despite all of that - I'd do what your instructor says to do. Discuss it with him when on the ground. However you would be considerably wiser to trust your instructor than what you read in an anonymous internet forum. Many people on here are almost certainly experienced pilots and instructors, but the only person that you can be sure is an instructor, is the person sitting beside you in the plane.
If it helps - there have been at least 2 instances of engine failures at my flying club over the years when in the circuit. Because the trained and practised technique is to stay within landing distance when in the circuit - both pilots and aircraft made it to the ground without scratches.
If you are doing a PFL (Practice Forced Landing) then you will be using the glide approach. As your approach is steeper, you need more energy to move from the descent to the flare, so the approach speed is higher.
If you are doing a short field landing, you want to be at the minimum safe speed during the approach. In my aircraft, that is achieved on the back side of the drag curve, so high power, low speed, shallow approach.
I'd say that shallower (powered) approaches are easier. You have longer on final to stabilise and the change in attitude to flare isn't significant.
That doesn't make them the right technique to use though!
I actually find flapless landings the easiest, as you have much longer in the flare (higher approach speed) . However you don't want to do them regularly unless you have a very long runway and you don't mind the additional tyre ware (due to the higher touch down speed).
I believe it comes down to the glide ratio of the airplane. For standard GA planes, its probably around 1:10 making a glide angle of around 6 degrees. This means that if you are on a 3 degree glide slope you can't make the runway in the event of an engine failure. For 737s and the like, the glide ratio is more like 1:15 or more. They might not reach the touchdown point, but if on a 3.5 degree glide, they can probably still make the aerodrome (remember a BA flight into Heathrow a couple of years ago?).
So you have to balance the two safety aspects (engine failure vs slightly more difficult touch down), obstacle clearance (often small airfields have obstacles that makes a steeper approach advised), circuit size (again - can you land back on the runway if an engine fails; what are others doing; noise abatement
efficiency (smaller circuit = quicker, especially at busy places). Just because something is difficult, doesn't mean that you shouldn't learn how to do it.I normally do a slightly steeper glide (probably around 4 degrees) to land at the CAT touchdown point, since I fly from a large airport. This means I'm not diving onto the runway but since there is lots of extra runway to play with, if the donkey dies, I can still land on.
However despite all of that - I'd do what your instructor says to do. Discuss it with him when on the ground. However you would be considerably wiser to trust your instructor than what you read in an anonymous internet forum. Many people on here are almost certainly experienced pilots and instructors, but the only person that you can be sure is an instructor, is the person sitting beside you in the plane.
If it helps - there have been at least 2 instances of engine failures at my flying club over the years when in the circuit. Because the trained and practised technique is to stay within landing distance when in the circuit - both pilots and aircraft made it to the ground without scratches.
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shaggy sheep
you should be on the vasi/papi for all landings except when you are actively avoiding wake turbulence or practicing ''obstacle'' landings.
if you are worried about losing your engine and crashing into surrounding houses, you must ask yourself:
is this airport a safe airport ? perhaps I should fly somewhere else.
and, what will you do if you are flying an ILS and lose your engine?
being on instruments does not guarantee you won't lose your engine.
if you are always high on the VASI/PAPI, you will have more difficulty judging your flare and you will have a higher rate of descent.
a pilot has many tools at his disposal. different approaches for different conditions...but saying that VASI is for instrument flying, or that it is UNPROFESSIONAL to be on VASI is just wrong.
a three degree glideslope works best for most types of planes. and variations, while possible, should be done for a reason.
and if your reason is losing an engine in a convenient position like downwind abeam the numbers, what are you going to do at some other point?
do you takeoff and circle the field to cruise altitude or do you takeoff and , after clearing obstacles, proceed on course?
the idea that you should be alert and know what to do if you lose an engine is a good one...to only make approaches that can be salvaged if the engine quits may just be nuts.
you should be on the vasi/papi for all landings except when you are actively avoiding wake turbulence or practicing ''obstacle'' landings.
if you are worried about losing your engine and crashing into surrounding houses, you must ask yourself:
is this airport a safe airport ? perhaps I should fly somewhere else.
and, what will you do if you are flying an ILS and lose your engine?
being on instruments does not guarantee you won't lose your engine.
if you are always high on the VASI/PAPI, you will have more difficulty judging your flare and you will have a higher rate of descent.
a pilot has many tools at his disposal. different approaches for different conditions...but saying that VASI is for instrument flying, or that it is UNPROFESSIONAL to be on VASI is just wrong.
a three degree glideslope works best for most types of planes. and variations, while possible, should be done for a reason.
and if your reason is losing an engine in a convenient position like downwind abeam the numbers, what are you going to do at some other point?
do you takeoff and circle the field to cruise altitude or do you takeoff and , after clearing obstacles, proceed on course?
the idea that you should be alert and know what to do if you lose an engine is a good one...to only make approaches that can be salvaged if the engine quits may just be nuts.
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you should be on the vasi/papi for all landings except when you are actively avoiding wake turbulence or practicing ''obstacle'' landings.
Mind you, judging by the number of 'bomber circuit' PA28 / C172 pilots I've followed around a circuit which touches several counties, this tosh seems to be widely believed. I blame the airline-wannabe instructors!
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SSD
Why is it Balerdash to fly a 2.5 3 degree glide in a single low powered aircraft?
Its not balsderdash to fly level at 50 feet (if terrain allows from 3 miles out)
It maybe not be an advisable practice but you can do it as much as flying down the runway 10 feet up with flap!
If your saying aircraft X with full flap will not fly level with the power available I take your point but would then question why full flap before being assured of landing or why full flap at all unless on the shortest of strips when I would definately NOT !!! use a glide approach.
If your saying student Y would get into a mess stall and crash I take your point but any approach from zero glidepath to one with all drag available while managing not to accelerate will work too
Conditioning Conditioning Conditioning
Pace
Why is it Balerdash to fly a 2.5 3 degree glide in a single low powered aircraft?
Its not balsderdash to fly level at 50 feet (if terrain allows from 3 miles out)
It maybe not be an advisable practice but you can do it as much as flying down the runway 10 feet up with flap!
If your saying aircraft X with full flap will not fly level with the power available I take your point but would then question why full flap before being assured of landing or why full flap at all unless on the shortest of strips when I would definately NOT !!! use a glide approach.
If your saying student Y would get into a mess stall and crash I take your point but any approach from zero glidepath to one with all drag available while managing not to accelerate will work too
Conditioning Conditioning Conditioning
Pace
Last edited by Pace; 30th Apr 2013 at 13:54.
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you should be on the vasi/papi for all landings except when you are actively avoiding wake turbulence or practicing ''obstacle'' landings.
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Not the first time this video has come up, but it explains how crap instructors are teaching very large circuits and flying PAPIs all the time, which isn't always appropriate for light singles
I would always expect 3 whites on PAPIs in a light single, if not four. The PAPIs are aimed for a 3 degree approach to touch down on the ILS touchdown zone, I'm actually aiming to fly a 3.5-4 degree approach to touchdown on the numbers, so the PAPIs aren't showing anything relevant at all. This is what the second instructor for the OP is trying to get him to do.
sevenstroke(t)roll you're talking out of your arse
I would always expect 3 whites on PAPIs in a light single, if not four. The PAPIs are aimed for a 3 degree approach to touch down on the ILS touchdown zone, I'm actually aiming to fly a 3.5-4 degree approach to touchdown on the numbers, so the PAPIs aren't showing anything relevant at all. This is what the second instructor for the OP is trying to get him to do.
sevenstroke(t)roll you're talking out of your arse
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Chuck put it more succinctly than I. And Captin Eppaulettes in the video is well worth a watch. He is spot-on.
Were you never taught to fly the visual circuit with the runway on the wingtip, and to turn base when the threshold is 45 degrees over your shoulder? How the heck does that correct technique fit a 3 degree glideslope?
Were you never taught to fly the visual circuit with the runway on the wingtip, and to turn base when the threshold is 45 degrees over your shoulder? How the heck does that correct technique fit a 3 degree glideslope?
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Thank you for all the good advice.
I am starting to see that there are two schools of though. Stay on glidescope or come in a bit steep and glide in. If you stay on glidescope then you'll need power and if you are really new to flying, there is the fear that you may stall. Although, I am not sure how realistic is this fear. Probably few stall accidents are on short final. Also, there is probably a reason why we practice slow flight and on lightly loaded aircraft power off stalls need quite a bit of effort, they don't just happen (at least regarding Cessna 172s).
I must tell you that at this point instructor and I are not fighting over glidescope. Either way is fine with me, but like many of the posters he won't stand red over white. We seem to be fighting over slow flight just before landing. I got along with both instructors and I think I can get back to the first one (still fine with the second one in general), but I just can't stand the speed into flare. Maybe it is lack of skill but I don't think so.
I am starting to see that there are two schools of though. Stay on glidescope or come in a bit steep and glide in. If you stay on glidescope then you'll need power and if you are really new to flying, there is the fear that you may stall. Although, I am not sure how realistic is this fear. Probably few stall accidents are on short final. Also, there is probably a reason why we practice slow flight and on lightly loaded aircraft power off stalls need quite a bit of effort, they don't just happen (at least regarding Cessna 172s).
I must tell you that at this point instructor and I are not fighting over glidescope. Either way is fine with me, but like many of the posters he won't stand red over white. We seem to be fighting over slow flight just before landing. I got along with both instructors and I think I can get back to the first one (still fine with the second one in general), but I just can't stand the speed into flare. Maybe it is lack of skill but I don't think so.
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againstgravity - just watch and absorb the video above. It's amusing, but the message is for real. Dragging it in at 3 degrees is for unimaginative aeroplane drivers who have no wish to become skilful pilots.
Do you want to be one of those? If your instructor wants you be one of those, get a new instructor... seriously!
Do you want to be one of those? If your instructor wants you be one of those, get a new instructor... seriously!
Last edited by Shaggy Sheep Driver; 30th Apr 2013 at 16:51.
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Sounds like the school needs to standardise, as being shared by two instructors teaching such opposing methods will only ever confuse a low hours students who doesn't know any better.
When I practice ILS approaches in light singles, it really feels like you're dragging the poor thing in, when it's far more comfortable with a slightly steeper approach.
On all accounts, the speed has to be right. Stalling is a real threat, and I've certainly seen students come to the stall warner early on in an approach where they just kept adding power to stay on glide and ended up on the back of the drag curve.
Where on the runway do you touchdown, and generally how have your touchdowns been? Firm? Main wheels first and keeping the nose up as long as possible? Stall warner sounding at or before touchdown?
When I practice ILS approaches in light singles, it really feels like you're dragging the poor thing in, when it's far more comfortable with a slightly steeper approach.
On all accounts, the speed has to be right. Stalling is a real threat, and I've certainly seen students come to the stall warner early on in an approach where they just kept adding power to stay on glide and ended up on the back of the drag curve.
Where on the runway do you touchdown, and generally how have your touchdowns been? Firm? Main wheels first and keeping the nose up as long as possible? Stall warner sounding at or before touchdown?
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RTN11
I see nothing wrong with flying a steep approach compared to a low approach and I also do not see why dropping like a vertical stone engine throttled back with a sharp flare makes for a good pilot.
Ok the video was funny I will admit that
The problem being there are so many variables in weather and traffic that you should be capable of numerous approaches and not be fixed to one!
There you are high about to turn base for your steep throttle closed descent tight in and there are two other aircraft on finals.
Do you drop down in front of them or extend downwind to slot in behind them?
Do you use the same technique on a really short runway where you need to hit the numbers?
Strong winds and shear? Do you use the extra control ability of the powered approach or the lesser control ability of the closed throttle.
I have even used curved descending approaches from downwind or S turns for spacing!
It is being comfortable in all scenarios and selecting the right approach that IMO is the right way not selecting one approach style to suit all.
As a jet pilot NO I do not want a light single plodding down the approach from 6 miles out at 65 kts causing a missed approach but neither do I want one appearing in my 12 o clock dropping in front of me
I see nothing wrong with flying a steep approach compared to a low approach and I also do not see why dropping like a vertical stone engine throttled back with a sharp flare makes for a good pilot.
Ok the video was funny I will admit that
The problem being there are so many variables in weather and traffic that you should be capable of numerous approaches and not be fixed to one!
There you are high about to turn base for your steep throttle closed descent tight in and there are two other aircraft on finals.
Do you drop down in front of them or extend downwind to slot in behind them?
Do you use the same technique on a really short runway where you need to hit the numbers?
Strong winds and shear? Do you use the extra control ability of the powered approach or the lesser control ability of the closed throttle.
I have even used curved descending approaches from downwind or S turns for spacing!
It is being comfortable in all scenarios and selecting the right approach that IMO is the right way not selecting one approach style to suit all.
As a jet pilot NO I do not want a light single plodding down the approach from 6 miles out at 65 kts causing a missed approach but neither do I want one appearing in my 12 o clock dropping in front of me
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PAPIs? 3degree glide slope? What is the poor guy going to do when he flies into a small grass field? He should be being taught to fly the airplane at this stage of his training, not worrying about this nonsense.
I'm with Shaggy and Chuck all the way.
I'm with Shaggy and Chuck all the way.
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Very true pace
In the case of the OP, the first instructor is only teaching a powered on shallow approach for a long finals, so the student will only go away with the ability to do that one thing.
The second instructor is trying to teach the OP different techniques to approach, by coming in steeper and using the aircraft's energy to your benefit rather than just relying on power to get you down.
I'm not saying every approach should be steep, and will fly instrument approaches in light singles, but early on in training flying steeper low powered approaches are a far better way to get the student to learn the feel of the aircraft and what it is capable of, and then flying a long shallow approach is child's play by comparison.
In the case of the OP, the first instructor is only teaching a powered on shallow approach for a long finals, so the student will only go away with the ability to do that one thing.
The second instructor is trying to teach the OP different techniques to approach, by coming in steeper and using the aircraft's energy to your benefit rather than just relying on power to get you down.
I'm not saying every approach should be steep, and will fly instrument approaches in light singles, but early on in training flying steeper low powered approaches are a far better way to get the student to learn the feel of the aircraft and what it is capable of, and then flying a long shallow approach is child's play by comparison.
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Hi again, there are many differences in the aircraft we fly, and the C172 has some of the dragiest flaps of any; On 40 degrees they are real stoppers.
We have one aircraft at our field.. Lets call him 'The Green Aircraft' that has a very slow stall speed, so that in a stiff breeze he takes an age doing the last few hundred feet onto the runway. For Take Off he climbs almost vertically at an air-speed of about 35 knots.
It was riverrock that mentioned the 10:1 glide ratio... That is the C172s best ratio at max L/D speed. Either side of that, the glide ratio falls to a lot less, especially into wind.
We have one aircraft at our field.. Lets call him 'The Green Aircraft' that has a very slow stall speed, so that in a stiff breeze he takes an age doing the last few hundred feet onto the runway. For Take Off he climbs almost vertically at an air-speed of about 35 knots.
It was riverrock that mentioned the 10:1 glide ratio... That is the C172s best ratio at max L/D speed. Either side of that, the glide ratio falls to a lot less, especially into wind.
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For the record, I have no problem with coming in a bit high, low, whatever, doing what the tower says (assuming no engine problems). Most approaches are in my opinion quite salvageable. Of course, there is always the go around. So, I don't want to give the wrong impression that I have any issues with those parts of the landing.
Before I met this second instructor landings were soft, short, and happy : ). OK maybe small exaggeration, but mostly. Stall warning would sound after level off in ground effect. No problem there. So, why reinvent the wheel?
I do understand that a lot of posters think that I should try to accommodate his landing approach as helping me build skill.
Before I met this second instructor landings were soft, short, and happy : ). OK maybe small exaggeration, but mostly. Stall warning would sound after level off in ground effect. No problem there. So, why reinvent the wheel?
I do understand that a lot of posters think that I should try to accommodate his landing approach as helping me build skill.
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I have no problem with coming in a bit high, low, whatever, doing what the tower says
I've always found UK ATC to be quite excellent and highly professional with a clear understanding of their and the captain's responsibilities, and they have always been a joy to work with; the same isn't always true of A/G or AFISOs (not the Barton guys - they know their stuff!).
Last edited by Shaggy Sheep Driver; 30th Apr 2013 at 18:08.
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I guess, I am not worried about approach angle. I think that seems to be a debate here, but I am a bit indifferent as different angles may be needed for different situations.
I just want to slow the plane down to 1.3Vso on short final (as soon as conditions permit), level off, and then flare. He insists we keep it fast and not level off. Just the perfect change of attitude from descent to flare.
I just want to slow the plane down to 1.3Vso on short final (as soon as conditions permit), level off, and then flare. He insists we keep it fast and not level off. Just the perfect change of attitude from descent to flare.