Stall landing/Slow landing
 

Hi guys,

The POH for several Cessna's I fly say to gently fly the plane onto the runway but instructors say to stall it on to the runway. It seems to me that a smoother landing could be achieved by flying in at the correct speeds, flaring and gently lowering it on to the runway without having to float above it for ages until it stalls.

Also a Cirrus I went in the other day must be flown gently on to the runway in this way otherwise there will be a tail strike.

How do you do it?

I'd try to do everything the way my instructor suggests. You are, after all, paying him or her large sums of money to teach you how to fly: why doubt what they are telling and showing you?

(In the instance you ask about, your instructor is right by the way. The aim is to touch down with the main wheels first at the lowest practical airspeed. This protects the nosewheel, which is easily damaged, and gives a shorter ground roll. These things may not seem important if you are flying from a huge tarmac runway in ideal weather, but that won't always be the case. You need to learn to do it well right from the start.
The aim is not to land as gently as possible! Its to land as safely as possible. They are not always the same thing.)

Most airplanes land smoother with a little power kept in to be reduced by roundout. My old twin can simply not be landed fully stalled smoothly - you have to keep a little power in for greasers. That said, a fully stalled landing has benefits as it's easier on the brakes, uses less rwy etc. Do whatever he says, but if you want to impress your first female/male date, keep a trickle of power in.;)

I try to stall it 1mm above the runway or less. Then it is smooth. I am in a different camp than Adam though, I prefer power off, unless I have screwed up, or wild sink requires a burst of power to sort things out. Those landings are generally not smooth though, just survivable!
If you are floating down the runway, power will make that worse.
Bryan

Usually caused by having the approach speed too high, and best avoided by not having the approach speed too high.

A so-called full stall landing is one whereby the aircraft is held off within a foot of the ground for as long as elevator authority will allow, before settling onto the runway at a low forward speed with the stall warner blaring. Ground effect delays an actual stall in this condition.

Use of this technique is probably the practical ideal for simple single-engine training aircraft. The landing performance charts for these aircraft usually stipulate 'power off' and the normal operations section usually advocates touching down at the slowest possible speed. Both of these conditions allude to the aircraft having been designed to perform 'full stall' landings.

Aircraft with high wing loadings typically need to be flown onto the runway as they tend to drop like a stone when power is removed.

Obviously each pilot has a favourite technique, hopefully aligned to the 'plane he has, but as ever in life, no one Rule fits all !

I fly a fixed wing 'Cub look alike' Microlight, in my case a Rans S4 - delightful little creature with delicate ways and excellent characteristics. BUT if you dare come in without power she'll fall out of the air far too high. (Unless you master the high speed powerless dive onto the deck).

With similar microlight a/c you do have to fly in with power, till like the man above says, a few mm above the ground. Even alternatively waiting a moment longer & doing a wheeler gives a very short and controlled landing.

[BTW. The Rans S6 approach/landing technique is quite different].

mike hallam.

Some wise words above. Just watch out that "fly it on gently" does not become an excuse for slack technique, with approach speeds too high. I see that with many pilots and I wouldn't mind betting it's something your instructor is trying to avoid. There's also quite a lot of incorrect folklore out there. For example, when I started flying a Comanche single, lots of people advised intermediate flap settings, faster than required approach speeds, and so on. But done correctly, it's beautiful aircraft to land in the classical slow, full flap mode - and does wonderfully on many of the short strips we have here in Oz. You do need what my instructor used to call a "chuckle" of power in the flare sometimes, but it rewards you with a great touchdown. Given the traps many people fall into, I'd be with your instructor in saying to learn to land your C172 etc in full stall mode, barring any really extreme conditions. (And, even there, watch out for the folklore. 10kt of crosswind is not excuse enough to start arbitrary increases in approach speeds, less than recommended flap settings, and so on). Excess approach speed is a really bad habit; too many people are complacent about it in both GA and recreational aviation (your "microlight" and similar community). Good luck!

During my CPL I was told that I need to keep some power on for touchdown and avoid the stall warner.

I keep the aircraft off the ground until it's at the correct landing attitude.

In a nosewheel aircraft that means that the aircraft will touch down on the mainwheels only. It won't actually be stalled at touchdown, although many of us think of it as a stalled landing. If you hold off until you reach the landing attitude, & then maintain that attitude, then as drag slows the aircraft down, the wings create less lift & the aircraft will descend. If the wheels were less than 1m off the ground, it will be a reasonable touchdown.

If you had the right airspeed as you crossed the threshold, the hold off will last about 2 seconds. That's just enough airspeed on approach to give you a margin above the stall but not so much that you float for ages down the runway.

Trying to fly the aircraft onto the ground conjures up images of nosewheel first touchdowns & wheelbarrowing down the runway. If you really, really try to stall before touchdown then you could indeed have a tailstrike, particularly in a low wing aircraft.

Good landings are the result of the right airspeed on approach & the right attitude before touching down.

Full stall landing is a in my opinion the best and easiest way to teach how to land an SEP. And it certainly has the benefits of bringing the aircraft down as slow as possible.

Now with some more experience and in some more fancy aircraft I prefer flying the thing onto the runway. You can still do that with power idle actually all you need to do is adjust is the flare.

1mm above the runway? How the heck do you judge that without a radio altimeter ;-)

But seriously, my instructor said he wanted to hear the stall warner sounding on landing - it was nothing to do with the speed but more to do with the attitude of the plane, on nose wheel planes hearing the stall warning means the nose is high enough to ensure the main gear touches down first and I've stuck to that - if I don't hear the stall warner, something wasn't quite right with the landing....

However, that doesn't mean I want to hear the stall warner whilst still descending, just whilst flaring..... :=

In the 172s I fly I follow the POH approach speeds, fully retard the power as I cross the numbers and then just fly the aircraft onto the runway. I couldn't tell you exactly what speed I touch down at as I'm 'eyes out' judging the flare, but I occasionally hear the stall warner go off just before touchdown. As mentioned above ground effect delays the stall and published stall speeds are 'clean air' (i.e. out of ground effect).

During my PPL the instructors seemed to teach very high approach speeds. Fine on the 1500m runway at the field I learned at, but would be dangerous at some of the short strips I have visited as a PPL.

Agreed up to a point. I imagine the higher speeds taught during the PPL are to add a safety margin for students, I don't really see why its necessary to add 5-10 knots over and above the POH speeds once you're qualified and proficient at landing. Surely the most important thing is getting the aircraft down and stopped safely in the distance available. 172s balloon like nobody's business if you come in too fast which could be lethal at a 600m grass strip.

Its more to do with instructors not being taught properly themselves and pretending to be flying an airliner.

there is no reason to add anything onto the POH speeds.

As a rank amateur I think good landings are for the most part a result of a disciplined approach speed, I do my utmost to stay to the approach speeds in the POH, my particular plane does not list the approach speeds so I use the following calculations to determine what speed I should fly

Weight Stall Speed
Stall @ Gross with power in landing config from POH 2400LBS = 47 MPH
Usual landing Weight with 2 person and half tanks = 2000LBS = 42 MPH*
Stall Speed adjusted for Weight X 1.3 for final = 55 MPH
Stall Speed Adjusted for Weight X 1.25 for over the fence=53 MPH

*Weight difference = 400LBS divided by 1 MPH per 80LBS = 5MPH

Now this may be all academic due to the airspeed indicator not being worth a **** on final but its the only speed reference i have other than feel and sound. The second thing i do is keep a scan from the cowling out to the end of the strip and use peripheral vision for the edges of the runway for depth perception.

When I make an arse of it, it is usually due to a feeling of familiarity especially at my home field were I tend to get a little loose on the speeds and not do the runway end scan which normally results in either dumping it in or gliding for what I deem as to far before the plane is done flying. Also as i fly a taildragger i tend to keep a little power on for longer thru the flare to maintain a little rudder authority, which I probably would not do in a trike

Steve,
No radio altimeter, I just trust the Force!

Gertrude the Wombat has it right. Too fast is no good. I have just recently been re-introduced to the 152 & 172 and the stall horn does honk on my landings.

On my commercial I was taught to land power off. Also on my private.

Bryan

But there may be a reason to lower speeds listed in the POH due to those numbers being based on gross weight, The aircraft manufacturer has no way of knowing if the plane is loaded with 10 gallons and a svelte chap like myself or it has full tanks and a couple of Aberdeenshire farmers daughters in the back

I guess the other thing to point out here (it'll be obvious to some, but not all) is the stall warner going off does not necessarily mean you've actually stalled, as by design it starts before the point at which a stall will occur - as such your instructor wanting the stall warner to go off does not necessarily mean they actually want you to stall it onto the runway, just that they want you to be very close to that point...

Nail the approach speed, and, while looking well ahead, do a gradual change of attitude into the roundout, at about 6 inches above the ground..... the roundout or flare is often too hastily done.

A few years back I was flying a Piper TriPacer into Annapolis, Maryland USA, home of the United States Naval Academy. The Piper Tripacer is not a speedy aircraft, along the motorway, the cars were overtaking us without difficulty. What upset me most was that an impatient Naval Academy aircraft cut in front of our stately final approach. (there was no ATC, traffic was self-regulating at the small local airfield.)

We had the last laugh, however. The Navy pilot did a carrier style landing in front of us, and his undercarriage gave way.

I'm firmly in the "land as slowly as possible" camp, but I learnt by experience, that is a good idea to brief your passengers about the stall warner to avoid scaring them.

I once had to do a full-throttle, flaps-up ILS in a 172, to assist ATC in traffic sequencing (in VMC). It took a VERY long time to slow down and I had a tendency to try to flare too soon and consequently balloon. Luckily, it was a 12,500' runway. ;)