An acceptable landing...

[Genghis the Engineer]

Originally Posted by what next

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]

Originally Posted by 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.

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

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.

[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