An acceptable landing...

[ct8282]

My landing on 25 at Shoreham today...

http://i1176.photobucket.com/albums/x325/sammylou7/th_56d3230d.jpg (http://s1176.photobucket.com/albums/x325/sammylou7/?action=view&current=56d3230d.mp4)

Think my round out was a little too early so had a couple of extra feet to lose with the flare, hence a bit too much stall warning.

[goldeneaglepilot]

Wow, that was one of the most exciting videos I have watched in years, you obviously impressed the female passenger with her proclomation of "nice Landing". Nicely ironed and pressed high vis jacket your wearing as well....

Personally I think the one below shows a little more skill

http://www.youtube.com/watch?v=m-QAVHtOqRM&feature=related

[gyrotyro]

It may be the perspective but to me the view of the runway looked as if the a/c was a bit behind the drag curve and a flat approach.

[Whopity]

The whole approach was far too low, if you had experienced an engine failure you would have had nowhere to go! Wearing nylon high vis jackets in an aeroplane is a flight safety hazard, they are highly flammable, and in a fire weld themselves to your skin!

[The500man]

An acceptable landing... is one you walk away from without having broken anything. ;) Nicely done!


Wearing nylon high vis jackets in an aeroplane is a flight safety hazard


I was told in no uncertain terms by a CFI a while back that flight crew were not supposed to wear high vis jackets in the cockpit because they are bright and distracting. The fire aspect makes more sense to me though.

[vanHorck]

Shame the Seneca kept the left engine running, looks like a shock load on that engine just after touch down.

I had an emergency landing due to unsafe gear at Brussels Int'l once and shut both engines prior to landing, she floated like a dream without any risk of shock loading the engines


BvH

[Deeday]

Rolling shutter recorders should be banned on board propeller aircraft. The result is too painful to watch. :bored:

[Echo Romeo]

To much throttle play, but at least it wasn't a yellow hi vis tabard:(

[what next]

Shame the Seneca kept the left engine running,...

Shame? Common sense I would call it. When you are alone on board of your own aeroplane you can do what you want. But this guy had passengers on board and probably never flown a deadstick landing before (who has, apart from you and some glider pilots?), so keeping the left engine running gave him the chance for a second attempt if necessary. To hell with the engine and shockloading. Why risk peoples health or life to save the insurer some money?

And regarding the original post: How can you see anything from your cockpit with all those propeller blades? :O

[Obi_Wan]

Was that the stall warning I could hear? Pretty much at touch down. :eek:

[Gertrude the Wombat]

Given that a "good" landing is one you can walk away from, as any fule kno, and following on from that an "excellent" landing is one where you can use the aeroplane again afterwards, what are we to make of "acceptable"? It's clearly worse than "good", so I guess it means that you couldn't walk away but the resulting injuries were non-permanent.

[Genghis the Engineer]

Was that the stall warning I could hear? Pretty much at touch down. :eek:

Something he did right then - if an aeroplane with an artificial stall warning isn't touching down with the warner operating, it's probably too fast.

Too many pilots add speed "for the wife and kids" and hit the far hedge as a result one day when they go into a short runway with that sort of inappropriate technique.

Worse still some instructors encourage this sort of behaviour, rather than flying to POH speeds with good speed control through the approach and landing. My personal record is an FAA FI who had us come over the hedge at 75knots in a lightweight aeroplane whose book approach speed at Max Weight was 63.

G

[what next]

...if an aeroplane with an artificial stall warning isn't touching down with the warner operating, it's too fast and at risk of overrunning.

So you say every airliner should touch down with the stick shaker (also an artificial stall warning) activated before touchdown?

I was instructed - and instruct - differently. Fly the final approach at the correct speed and touch down before the stall warning activates. If you are too fast over the threshold, it makes zero difference regarding the landing distance if you bleed the speed off in ground effect and touch down when the stall warner operates or touch down a little faster immediately. Or rather on the contrary: Wheel brakes together with drag will slow you down in less distance than drag alone.

[robin]

Hmm

The touchdown was acceptable but the approach left a lot to be desired.

Definitely too low from a long way out and too much throttle play. If you tried that sort of approach at any site with curl-over problems you'd have landed 1/2 mile short or ploughed through a hedge

Try a higher approach next time so you don't limit your options

[Almost]

Worth mentioning I guess that on that particular approach, one should anticipate a bit of sink, as you cross the river.

[robin]

Quite

So I think CT8282 needs to look a bit more deeply into his interpretation of this landing.

Forget the stall warner, look at the 'picture' that, in this case, was wrong.

[overun]

my feeling is that it`s best not to interfere, put the aircraft into a position where it wants to land and then let it get on with it.
seems to work.

[plucka]

What Next,
I hope you don't do any instructing on tail draggers, if you do I think you will soon change your opinion.
All singles should touch down as slow as possible.

[overun]

like a favorite labrador, let it settle itself.

[overun]

l don`t mean to be rude but speed doesn`t bleed off in ground effect.

You are probably thinking about form drag, the space shuttle etc. raising its nose to slow.

Ground effect is a wonderful thing, the induced drag wingtip contrails being cut off by contact with the ground.

What you won`t get to know is how close to the ground you have to be.

l`ll share some hard won experience and research. Not available elsewhere without a price.

One quarter of the span above the surface.

l did fly in ground effect through an Australian supermarket carpark, below the sagging telephone wires, more years ago than l dare admit to achieve a goal.

Best avoided.


Sorry guys, just looking for friends l didn`t mean to cause silence. Pardon.

[Genghis the Engineer]

So you say every airliner should touch down with the stick shaker (also an artificial stall warning) activated before touchdown?

I was instructed - and instruct - differently. Fly the final approach at the correct speed and touch down before the stall warning activates. If you are too fast over the threshold, it makes zero difference regarding the landing distance if you bleed the speed off in ground effect and touch down when the stall warner operates or touch down a little faster immediately. Or rather on the contrary: Wheel brakes together with drag will slow you down in less distance than drag alone.

Well, apart from the fact that stick shakers should in most cases have a configuration interlock to stop them going off in this way with gear and flaps down, that kinetic energy is proportional to the square of airspeed and you are substantially increasing landing distance (and potentially loads on the brakes) . Oh yes, and that the stall warner is an AoA not a speed device so should go off again as soon as the nosewheel is on the ground (plus on an Airbus for example there's a further automatic disconnect with IAS goes below 60 to avoid spurious warnings on the ground).

Plus as has already been pointed out, floating in ground effect is a very inefficient way of getting rid of speed.

So yes, apart from your lack of understanding of airliner systems, and lack of understanding of basic flight mechanics, you are of-course absolutely right.

Best you don't make a habit of teaching landings on any airfield actually close to your performance minima, or anything on taildraggers.

Would I be right in guessing that you normally teach on standard Pipers and Cessnas from an 800m+ runway?

G

[ct8282]

Aha ha ha ha ha. Lol at goldeneaglepilot.

I spent an extra few minutes ironing the high vis, just for the video shoot. Nice huh.

[jxc]

Now you have ironed and worn the hi viz bin it or put in the boot of the car for when you breakdown

[aussiefan]

Question please?

Someone mentioned being behind the drag curve. I am very much an inexperienced ppl, moving onto cpl. What is meant by being behind the curve?

FWIW
I have just changed schools. First school looked for a steepish descent and slow cross of threshold, stall warning going off just before/at touch down is a good thing.
New school, I got the instructor to demo and it was a very flat approach, holding a fair bit of speed.
First c172 second tb10.

[ct8282]

Question please?

Someone mentioned being behind the drag curve. I am very much an inexperienced ppl, moving onto cpl. What is meant by being behind the curve?

FWIW
I have just changed schools. First school looked for a steepish descent and slow cross of threshold, stall warning going off just before/at touch down is a good thing.
New school, I got the instructor to demo and it was a very flat approach, holding a fair bit of speed.
First c172 second tb10.

If you remember from your theory study the bit about parasite (form) drag, and induced drag.....

Parasite drag increases with airspeed but induced drag reduces with airspeed and vice versa. When you overly the drag characteristics of induced drag and parasite drag on one graph you will have almost a 'u' shaped line. May I draw your attention to the following:

UNIFIED PROPULSION LECTURE #1 (http://web.mit.edu/16.unified/www/SPRING/propulsion/UnifiedPropulsion4/UnifiedPropulsion4.htm)

Now, when you fly at the very bottom of the curve you can fly as slow as possible with the minimum power setting, but if you start to fly slower you will actually need to apply more power to maintain the slower flight, without losing lift. It's hard for non aviators to understand as most people assume that more power means you go faster, just like in a car. Ultimately when you are behind the drag curve you would need a very high nose attitude and more power to maintain straight and level flight. You may remember part of your PPL training was slow flight? That was a practical demonstration of flying behind the drag curve.

Hopefully that makes sense.

[what next]

Good morning!

Plus as has already been pointed out, floating in ground effect is a very inefficient way of getting rid of speed.

Exactly what I wrote. Holding off a short distance above the runway and waiting for the stall warner before settling down will increase the total landing distance considerably.

Well, apart from the fact that stick shakers should in most cases have a configuration interlock to stop them going off in this way with gear and flaps down...

If you really believe that I invite you to come along my next checkride. I don't exactly fly airliners, but transport category aircraft which system-wise are very similar as you know. Believe me, in landing configuration stalls and windshear go-arounds we get plenty of stick shaker...

So yes, apart from your lack of understanding of airliner systems, and lack of understanding of basic flight mechanics...

Sorry Sir, I will not contradict you again. Obvoiusly, german univerities and aviation authoritities are much worse than british ones because I got away with my serious lack of understanding for all those years...

...or anything on taildraggers.

I must confess, the only taildraggers I have flown were gliders. Back then, I was taught not to stall them during landing, because misjudging the height during the flare may drop the nose onto the runway from a considerable distance. Which is not good for your back because there is not much dampening in the wheel of most gliders. But maybe, motorised taildraggers behave differently?

Would I be right in guessing that you normally teach on standard Pipers and Cessnas from an 800m+ runway?

Mostly yes. And mostly, I teach students who are on integrated ATPL courses, heading straight for the airlines, with most of them probably never setting foot on a taildragger. And most of them may never hear or feel a stall warner during landing. Ever. But again, I promised not to contradict you any more, so please delete my last sentence.

Happy landings,
Max

[mad_jock]

In alot of big aircraft if you pitch until the stick shaker goes off (if it does in landing config) in the flare you will be scraping the tail down the runway. Yes on my types it does go off very occassionally. This is mostly due to the fact that its the old sprung lever on the leading edge and a gust gets underneither it. The more modern aircraft with AoA sensors don't seem to be as prone to it.

You have 2 speeds Vat and Vref which is the speed you put the wheels on the deck. Once you do that and the weight on wheels comes on there is either spoilers or lift dump which stops it flying.

There is no problem at all with the stall warner going off as it did in the flare in the vid. Unfortunately the OP is proberly thinking why are they all moaning about that approach, its the way I have been taught to do it. And they proberly have been taught that way. There is a whole raft of instructors out there that think flying a 3 deg approach is normal in a light aircraft with various additions to the book approach speed.

If you have a look at your theory books on drag you see that as you increase speed the drag intially drops then comes down to a low and then increases again. Behind the drag curve or on the dirty side is when a decrease in speed causes an increase in drag which if you don't apply more power will cause a decrease in speed and yet more drag etc etc. Where as on the clean side of the drag curve a decrease in speed causes a reduction in drag.

[ct8282]

So I might as well chuck a few comments back at you all in regards to the approach.

Firstly the video was shot on an iPhone and I don't believe the angle of view in that video is necessarily representative of the actual approach. Those of you who know Shoreham will know that the Papis on Runway 20 (the tarmac runway) is configured for a 4.5 deg approach angle. This is pretty much the picture I try to have when I use runway 25 as I did yesterday. Personally, I was quite happy with my approach angle yesterday and when I said 'acceptable landing' I was commenting more on what I considered to be an early round out and flare resulting in too much height to bleed before touching down.

The wind yesterday at time of landing was 240 12G20 or there abouts and whilst the cross wind factor was small there was still work to do and as a result my airspeed on approach was about 72 - 75 knots with 2 stages of flaps, and the throttle was being exercised a little bit more than normal. This may account for what does look like a slightly flat approach on the not so good iPhone video but I was trying to keep the airspeed up a little due to the gust factor. I could be wrong but I figured this was a sensible approach as a sudden drop of 7 to 10 knots in the wind could put you a lot closer to the stall then you want to be on short final over the houses at Shoreham for runway 25.

I was taught, and again correct me if this is wrong, that on approach you control airspeed with nose attitude and height with throttle (power), not the other way around. Therefore, if my desired airspeed was 72 - 75 knots on approach, and my nose attitude was maintaining this airspeed nicely I would suggest that my approach angle was pretty good.

I am a perfectionist and to be fair, was pretty pleased with the approach and overall landing yesterday, albeit the touch down wasn't that great hence my use of the term acceptable. I have heard people say that any landing that doesn't damage the plane and or occupants is a good one, but I set my standards very high and wont consider my landing as a good one unless it is spot on.

[goldeneaglepilot]

Its strange to read the vast range of opinions about landing / approach technique. There are many variations, some safer than others. That techniques will vary with type. Some aircraft demand landing in a stalled three point mode, others need flying (at the correct speed) onto the runway. Try landing a Citation Jet like a Piper Cub and its going to be a mess. Try approaching the runway in a Pitts Special with the same technique as a Cub and that too will end up in a mess.

The technique in the I-phone video was perhaps a little shallow, the clue is second stage flap - why not full flap? You still get to the field, your relative approach is steeper, your forward view is better. The wind was almost on the nose, yes 12g20 is a little bumpy, but certainly not warrenting an almost flapless style shallow approach. Yes - its fine to intercept the PAPI's late on finals in most club aircraft, you only want to be established on them several miles out when your flying something heavy and fast. The problem with the approach style in the video is when the engine stops, you have nothing left, either altitude or speed to get you safely onto the runway. I dont think its a question of it being an iphone video, it still shows the trend for the picture in the aeroplane window - low and shallow. With lots of use of throttle to drag it to the runway. One day that technique will end in problems after a stopped or rough engine.

Its good to be a perfectionist, but its important to consider the "what if" factor and try to make all elements of the flight as safe as possible.

It might be worth getting someone to show CT8282 some advanced sideslipping techniques to loose height. Its a great confidence builder for short runways with steep approaches.

[mad_jock]

Just do the POH book speeds if it says to add for gust then do so but I would be suprised if it did.

There are two ways of doing the approach your method and point and power and both methods have there merits and both are correct.

You are flying a VFR approach not a Instrument approach so the PAPIS arn't really in the equation again its instructors making students fly SEP as an airliner.

If at any point during your approach your engine failed and you couldn't have made the runway its not a good approach. If it had failed short finals you would have been in the houses.

[ct8282]

Ok ok. My landings suck and I'm a ****e pilot :{

As I stated, acceptable landing. Not my best, and probably not my worst either. I'm certain that even seasoned pro's like yourself goldeneagle don't get every aspect of your flights perfect, every time.

While we're on the subject, I made a cock up of my nav prior to this approach as well, and all in all the whole flight was a flipping disaster. But, I enjoyed it and I got the aircraft back safely, learned lots from the whole experience and will hopefully make some slight improvements and adjustments on the next flight.

:ok:

[mad_jock]

your not a ****e pilot.

But get some grumpy auld fart who has been flying for years in multiple types to run some ideas and demonstrate some stuff to you.

As I said you have proberly been taught by some airline wannabie who doesn't know any better

[The500man]

The landing was fine.

I'll stick my kneck out though and say that generally alot of pilots seem to get into the habit of only thinking a landing was good if it was a greaser, and it's this mindset that quite likely leads to some extended hold-offs and floats down the runway.

I was taught that sometimes it's good to land firmly in the right place rather than floating down the runway with the wheels brushing the blades of grass while you float off into the trees and bushes!

[Pace]

8282

You were taught wrong you do not control speed with pitch and altitude with throttle! You may do but you also may do the opposite.
If you like you have two throttles one the conventional throttle that connects to your supply of power / energy from the engine and your elevator which allows you to tap into the potential energy available in the airframe.
So you have two sources of potential energy! Some times you use one! Sometimes the other and other times both together.

That idea is taught to low time students as the pitch also controls AOA which can equal drag. Pitching for speed means keeing away from the stall and high drag but the theory is flawed not from a safety angle with students but with with it's theory
When my citation is in app mode locked onto the
ILS all I have to control speed is thrust !

Pace

Pace

[englishal]

My theory is...do whatever it takes to get safely down on the runway ;) I tend to like dragging it in under power, especially as our runway doesn't leave much room for a balls up if you do float too far, so that way you stick it on the end and still have a third left to play with when you have stopped.

[24Carrot]

Surely if you come 'over the fence' at a sensible height and the correct speed, then the amount of runway you will use is practically set in stone, (for given flap setting and conditions on the day), it's just an energy thing.

How much power you had on during approach is just history.

[Pace]

Until you get a massive downdraft as you approach the flair ; )You havent landed until you have landed. I may even add until you have stopped!

Pace

[Echo Romeo]

Until you get a massive downdraft as you approach the flair ; )You havent landed until you have landed. I may even add until you have stopped!

Pace That last sentence is so very applicable to the Terrier, occasionally I have made a perfectly good landing, then whilst in the ground roll, run over a bump or undulation, a gust of cross wind or some other deviation and all hell breaks momentarily loose, as you say 'it aint over until you've stopped!

[Torque Tonight]

I can understand posting videos of particularly noteworthy landings but it could get pretty tedious if every pruner posts videos of every bog-standard landing they do. Yes, I know, I didn't have to look at it, but I am wondering what the point is.

Flying a Cub like a 737 or a 737 like a Cub is daft - use the appropriate technique for each aircraft type and comparing landing techniques for vastly different aircraft classes is meaningless. Light aircraft are rarely limited by landing distance, brake cooling schedule and ground body attitude so making reference to airliner landing techniques is irrelevant. Pitch for speed and power for RoD works very well for SEP. Crossing the threshold at the correct speed, flaring at the right height and gently transferring the weight to the wheels at the point of the stall, is for most SEPs a perfect landing. Dragging the aircraft under power down a flat approach, 15 kts too fast, flaring at 10ft and floating half a mile, or forcing it onto the ground and bouncing - not so much.

Finally, another vote to take the damn high-viz off inside the aircraft. The reflections inside the canopy impair lookout, it'll melt to your skin in a fire and worst of all, you look like a proper Health & Safety inspector, but hey, maybe the girlfriend likes the hi-viz.;)

[Final 3 Greens]

I want that prop.

It must have had at least 12 blades :E

[Genghis the Engineer]

What next: nothing personal (although I think that the theory I was spouting was pretty much from the JAR CPL/ATPL syllabi which I think are the same in the UK and Germany). You perhaps got me at a grumpy moment, but equally contradict me any time - nothing like a good aviation technical argument.

8282: whatever else you did, you got a great discussion going. My complements for that. I do agree with others about the flat approach, but a great many instructors do teach light aeroplane flying as if it was airliner flying so this is almost certainly their fault not yours. But get rid of the hi-viz!

Pace: I'm pretty certain that any experienced pilot, such as yourself, will use power and pitch (and possibly other services) holistically to control speed and flightpath. However, it used to be standard teaching to do RoD/ flightpath with power and speed with pitch; in recent years that has reversed, and if you're going to be regimented about it, certainly that works best on an instrument approach in a jet: it is much more debateable on a visual approach with (a) piston engine(s). I'd venture that anybody without a lot of hours both overall and on type, probably should stick to one or the other.


Everybody: I was taught some years ago that a landing is never over until ALL of the bits have stopped moving. It's an adage that's served me well so far.

Also, the use of flat powered approaches operating power against services should be regarded as more of a jet thing - in most turbine aeroplanes it is quicker to get rid of gear and flap than it is to spool an engine up from near-idle. In most piston engined aeroplanes, particularly anything with electric flaps, the converse is true.

G

[Pace]

Genghis

As you are aware the pitch for speed or power for speed arguement has raged for a long time.
I do not think either is correct! All that is correct is that both allow you to tap into potential energy.
Being conditioned to one or the other could in certain situations lead to problems but being open to tapping into both, playing both has to be the most effective way of extracting the maximum from the airframe and engine when needed.
Low powered aeroplanes with low experience pilots are better taught the pitch for speed as that will protect them from getting into high drag situations and away from the stall.
But with more experience I feel pilots should regard both as energy sources they can use and as such regard them as one.

Pace

[flybymike]

I want that prop.

It must have had at least 12 blades

Judging by the sound of the engine I think it was a cylinder mower.

[Whopity]

What is meant by being behind the curve?You should have seen this demonstrated as part of slow flight/stalling but in case you didn't.

At a safe height, slow the aircraft down to about 80 Kts and maintain level, check the power setting.

Now slow it down to about 70Kts and maintain level, again check the power setting.

Repeat this until you find the point where you need more power to maintain level at the lower speed, than at the higher speed; you are now behind the drag curve.

Now apply full power, maintain level and see what happens - basically very little, until the aircraft accelerates slowly over and away from the drag curve. The reason why we use full power for a stall recovery.

[The500man]

The reason why we use full power for a stall recovery.

...is to minimise height loss and is otherwise not required. :)

[Flyingmac]

Some interesting comments. Here's one of my landings. Fairly typical, apart from the snow. Approach flown at around 7°. Full flap and no Hi-vis.
(Speed is pitch controlled). Stall warner inop. Comments welcomed.

YouTube - ‪Bagby‬‏

[The500man]

Flyingmac nice vid! :D

Was that runway half grass half tarmac? The best bit for me was the engine noise!

[Flyingmac]

There's a 40mtr strip of concrete where vehicles cross. Rest grass.
The nice engine noise comes from having six cylinders.

[mary meagher]

Well, flying mac, I'm glad you were able to stop before you taxied into the hangar!

Seems to me with all this discussion of the perfect approach, whether to touch down fully stalled or with flying speed, does not give sufficient emphasis to the weather conditions of the day. Maybe airlines can land happily with a 15 mph tailwind, but it don't half make a difference to a light aircraft, or a glider. And a 20 knot crosswind can be a zero headwind.

Still remember a nice single anxious to get down where his wife was waiting with the car, airfield unattended in lousy viz, everyone else had packed up flying for the day. We all watched him approach with an interesting tailwind, he didn't touch down untill at least half way along the runway, and then ended up in the hedge. Bent his airplane and his ego and he blamed it because nobody had told him over the radio what the wind strength and direction were.

[Flyingmac]

Well, flying mac, I'm glad you were able to stop before you taxied into the hangar!


Can't hose off the mud/slush inside the hangar. Otherwise......

[mikehallam]

Could be the perspective, but looks like FlyingMac made a massive 'bomber' circuit and a rather low flat approach which didn't (apparently) improve/ shorten the landing roll ?

Hearing the stall warner (in a strip operated Jodel) was a neat aural guide to flare speed without having to look down at the panel.
The stall warner is just that, not the actual stall but some useful mph above the wing drop, so our tyro did rather well I thought, if it was while u/training !

[Fuji Abound]

It is interesting for me both approaches look very flat. Watching aircraft come and go generally I think there is a tendency for more pilots to land flat, so perhaps teaching methods have changed? Personally I aim to be above the PAPIs on the approach until very late final and definitely look to stall the aircraft on (unless there is some good reason not to do so).

Each to there own.

[Whopity]

The500man...is to minimise height loss and is otherwise not required.
I think you've missed the point! Power is used to minimise height loss, but what I was referring to is Why we use full power as opposed to any other power setting. In a typical light aircraft we demonstrate the use of Full Power to overcome the high initial drag associated with being on the wrong side of the drag curve, or we will not minimise the height loss.

[kevmusic]

It is interesting for me both approaches look very flat. Watching aircraft come and go generally I think there is a tendency for more pilots to land flat, so perhaps teaching methods have changed?

If so, give me the old steep(-ish) approach everytime - I like to see where I'm going! Plus, I still like the fairground-ride flare. :E There's something about "dragging it in" that I inherently dislike.

[Fuji Abound]

Yes, I agree and something satisfying about the round out and gentle kiss with the ground ;).

In fact I often find myself driving twins the same way.

However to be fair steep approaches require a degree more confidence and cant be considered as stable as a constant aspect approach positioned firmly on the localiser.

Equally I have seen a fair few flying approaches that are really flat. Where does this tendency come from - do we for some reason feel inherently more comfortable flying flat approaches or does it come back to the way we were taught. If you send a newish PPL off to an unkonwn strip with out the benefit of PAPIs where is he most likely to position himself on the approach?

[Pace]

I would love someone here to explain the theory and physics of pitching for speed ?

I can understand the benefits in protecting low time students by using pitch to keep well away from high drag/stall situations.

I can understand in V low powered high drag aircraft that pitching for speed becomes more important as they are power limited.

I would also like someone from the power for speed club to explain their theory and physics?

Ok I fly corporate business jets as a Captain but I also fly twin engined pistons and on occasions single engine pistons.

Lets get away from the jets and look at a piston twin also on autopilot locked on the ILS.

The graph of such an approach would show a fairly consistant descent profile ie the aircraft will be pitching to maintain that profile NOT for speed.
In that scenario speed will be controlled by adding drag ie the flaps and gear and power.

Obviously in that scenario pitching for speed has gone out the window! As on a set glidepath with a given amount of drag the only speed adjuster will be power. Has anyone designed an autopilot based on pitching for speed?

On the flip side of the coin and aircraft with a lot of drag and a high angle of attack may not have enough power in its own right to increase speed and in that situation pitching will recover speed.

The sooner we regard the elevator and the throttle as means of tapping into energy the more accurate we will become on realising that both camps are incorrect?

Someone prove me wrong?

As for the arguement against powered approaches re glide approaches?
In the glide approach with the engine throttled back you wont know you have a power problem until you need it.

Your stall speed will be higher than in a powered approach.
Your chances of missing your touchdown point will be greater.

Finally in the event of an engine failure never fixate on reaching a point as that is the surest way of hitting the houses on the approach.

Pace

[flybymike]

Runway 06 at Bagby (shown in the vid) has a very marked upslope which will have increased the tendency for the approach to look flat.

[what next]

Hello!

Obviously in that scenario pitching for speed has gone out the window!
No, it hasen't! Because once you are fully configured (depending on what you have - gear, flaps, prop) it's back to pitch and power again. If only for the remaining two or three miles.

Has anyone designed an autopilot based on pitching for speed?Mr. Cessna has, at least sort of. Try flying an approach in "FLC" mode on your Citation (FLC (=flight level change for the non-Citation-flyers) essentially is pitch for speed!) and you will realise why no manufacturer uses this mode for approaches. Zero passenger comfort and corporate pilots who have to clean the cabin after every landing...

In our FTO, we teach both methods nowadays. Pitch for speed to students who want to become private pilots (to reduce the likelihood of stalling during finals) and power for speed to the ones who want to become commercial pilots (over 90 percent). Starting from lesson one.

[The500man]

I think you've missed the point!

Yeah I frequently do! :hmm:

Going back to the low approaches; be honest are you going to make the runway from 1000 ft while on a 2 mile final if the engine quits? How close to the runway do you need to be downwind to glide with idle power onto it? I doubt anyone flies a steep enough final from sufficient height to make the runway without an engine. If you did the "ideal" approach would be the power-off glide final.

I think we're all taught to land as close to the numbers as possible, and for good reason if you fly into short strips. Much more runway gets used up rounding out from a steep final then dragging the thing in on a flatter approach. If you get too high on final you're either going to be too fast at the threshold (pitching down) or you'll have a higher AoA (reducing power). You likely don't want either.

On the pitch/ power thing, if you are flying at the right speed, regardless of whether you are high or low you will need to change power setting to get back on profile. I don't see the point in pitching for speed. If you are too fast and too high, pitching for speed is surely going to lead to a go-around unless you pull the power and accept the higher AoA.

I maybe missing the point again though! :)

[englishal]

The pitch for speed thing comes presumably because if you get slow in a spamcan, then speed will react to pitch far faster than power. On an ILS I'd use the opposite because you are flying much faster at typically 100 kts in a single or piston twin. On an ILS you pitch for glide path and power for speed. Also heavier aeroplanes are easier to fly a stabilised approach as they are less reactive to gusts and thermals to some extent.

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.

That's my theory anyway!

[Pace]

What next

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

[ct8282]

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 :ok:

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 ;)

[what next]

Once established on the ILS glideslope it is not back to pitch and power as you imply.

I should have written: "point and power" = Power for speed and pitch for glideslope.

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.

[Mark1234]

Englishal - I'm struggling to understand the relationship between glideslope and speed that you're suggesting:

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.


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..

[what next]

Is one better than the other?

Who can tell...

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.

[Pace]

What Next

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.

[mikehallam]

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 !

[Pace]

Mike

We are covering a lot in this thread :E 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

[The500man]

500man - I think you're maybe missing something important about AOAMark1234 I was perhaps being a little black and white. I wasn't speaking of maintaining an airspeed but of the effect of pitch and power. If all you do is pitch the nose down you will fly faster and if all you do is reduce power you will descend faster with a higher AoA (at a lower airspeed).

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. :ok:

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!

[robin]

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

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.

[ct8282]

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.

Think you may have missed the irony in what I was saying.

Nevermind.

P.S which airfields are you referring to?

[overun]

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.

[mad_jock]

An aircraft that has to be wrestled to the ground is an oxymoron.

Either that or it was built by British Aerospace

[Big Pistons Forever]

YouTube - ‪Plane Crash Lands at Shoreham Airport 1993‬‏ (http://www.youtube.com/watch?v=m-QAVHtOqRM&feature=related)

At the risk of playing the Monday morning referee, there are IMO several poor techniques illustrated in this video

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:uhoh:

[Pace]

Big Pistons

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

[Big Pistons Forever]

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.

[vanHorck]

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