Best approach airspeed on short final

[nmflyguy]

My question about technique is very basic to backcountry flying, and it's been touched on in other threads, but let me be specific.

Regarding approaches to short/soft fields, which is the case at many if not most backcountry airstrips, I've seen quite a few pilot-posted cockpit videos where on short final, the stall horn is beeping on and off. Some of the posts I've read on this board describe short final approach speeds that are very close to the aircraft stall speed. One fellow who posts here occasionally, whom I've met and flown with, wrote an article published recently in one of the major aviation mags describing his backcountry flying in a Cherokee where he states his airspeed on short final on backcountry airsrips is 60 mph IAS (he's told me the same thing in conversation) ... which is only 3 mph above the Cherokee full flap stall speed (albeit, at full gross weight).

(some of you may be thinking, "So? what's your point?")

This seems, well, unsafe to me. Having done a few (but not many) short/soft field approaches and landings, I understand the need to touch down at the lowest controllable airspeed to avoid running off the end of the runway or damaging landing gear. But touchdown speed is what you're doing just the last foot or two above terra firma, in ground effect, as you round out the flare ... that's not the short final airspeed.

To minimize the risk of landing long, I practice spot landings all the time, whether the runway is paved or not, or short or long. I also practice precise control of engine power thru touchdown (the hershey-bar wing Cherokees prefer at least some power all the way down to the runway to avoid hard landings).

Some of the best published backcountry flyers, such as the late great Sparky Imeson, emphasize that it's far better to land with too much airspeed and run off the end of the runway (unless it's the edge of a cliff, or a gigantic boulder) than it is to do a stall/spin close to the ground. In the former instance, your kinetic energy at the end of a too-long ground roll is vastly lower than your kinetic energy when you're making like an aluminum lawn dart. You'll probably survive the former, but not the latter, in other words.

Standard recommended practice for light GA aircraft at paved, non-short fields is to be at 1.3 Vso on short final ... in my Cherokee with full flaps, that's 74 mph (which also happens to be Vx). Now I can see reducing that to maybe 1.15 Vso on a short field (but not if it's gusty or there's a strong x-wind), but at the point the stall warning light starts flashing (around 62-64 mph IAS, full flaps, with approach power in a PA28), you're down to only 1.1 Vso, and 60 mph is only 1.05 Vso. The slightest error in airspeed control, or even a very modest gust or wind sheer, and your plane becomes the aluminum lawn dart. Even if you're only 50-100 feet off the ground, that's probably a fatality.

What's the consensus on this point amongst the experienced backcountry flyers? (is there a consensus?)

[GumpAir]

You're not factoring in ground effect when you're short, short, short final. (In edit I see you are... Sorry)

Above ground effect, 1.1 Vso gives you plenty of cushion for speed most days, as most light, piston airplanes will have a rapid response to a burst of throttle (high and hot, f**k it, it's full throttle and get out and push). In close, ground effect lowers the Vso a whole bunch, and the published numbers don't mean anything.

And that's the other thing. ASI's are shitty, uncalibrated, and unreliable. The numbers are only a rough guide to aim for. What does the wing feel like? Are you mushing and falling out of the sky uncommanded? Or are you feeling solid through the seat? I see a lot of guys fixating on numbers and not what the airplane is actually doing.

Gump

[nmflyguy]

You're not factoring in ground effect when you're short, short, short final.

Gump

Gump - thanks ... I should have defined "short final" in my question to mean from maybe a half mile out to just above ground effect. Obviously ground effect changes the aerodynamics a lot ... even more so for low wingers.

[GumpAir]

A "stall" out of 1.1 or so Vso doesn't result in a pitch down "we're gonna die" full blown stall. What you're gonna see is a progressive, increasing mushing, and your VSI start to unwind downward... A blip of power, maybe a touch nose down pressure, and you're flying again. Then it's a matter of maybe a bit more nose down trim and increase airspeed a knot or two.

Gump

[nmflyguy]

You're not factoring in ground effect when you're short, short, short final.

Gump

Gump - thanks ... I should have defined "short final" in my question to mean from maybe a half mile out to just above ground effect. Obviously ground effect changes the aerodynamics a lot ... even more so for low wingers.

Gump - thanks for your other point too. I'm not experienced at short finals at around 1.1 Vso ... just slow flight practice at 3,000 ft AGL - which is obviously not the same. I can see how practicing slower final approaches (but starting out up high, then taking it down to the runway environment) would eventually give me the seat-of-the-pants feel that I don't have now.

Duane

[GumpAir]

Another thing to consider is that all this is mostly a moot point. Your Cherokee is like the gutless wonder I have now. It will get in most anywhere, but getting out is a whole different story.

Gump

[Jaerl]

Duane, go out and hold altitude while in landing configuration while bringing the throttle back. You'll know just before it breaks and keep it there. It's like balancing a ball on a log. Your plane will try to roll off one side or the other. Just fly like that for a while.

I always try to land with the stall horn blaring and I have never felt close to what that feels like. Maybe it's the ground effects but your plane stays controllable way below where the horn comes on. I try to look out the window while landing and not at the gauge. You should be able to "feel" if your getting too slow.

[z3skybolt]

GUMP SAID IT ALL....

... and has it right. So I won't repeat his words. Short final.... for short field approaches are flown in my Maule with the stall light blinking(doesn't have a warning horn.) Its the old....."Throttle controls altitude....Elevator controls airspeed"

There is 600 ft. of grass running parallel between my hanger, which is on private property, and the airport runway. I operate off that grass all the time. Usually have to add power to taxi the last 100 ft. after landing. Gives a chance to practice for the real challenges.

Have fun.

Bob

[hotrod150]

..... his airspeed on short final on backcountry airsrips is 60 mph IAS (he's told me the same thing in conversation) ... which is only 3 mph above the Cherokee full flap stall speed (albeit, at full gross weight)......

Sounds ike 57 is the stall speed in the how-to-fly-a-cherokee book. What's more important is what's the IAS in your airplane when it stalls? I've had people talk about short field work & like you, mention the POH stall speed. When I ask them where their airplane stalls at, they shrug their shoulders. Take your airplane up to a reasonable altitude (3000 should be plenty) loaded to it's normal operating weight and see what the power-off, full flap stall speed is. It may or may not be close to what the book sez-- remember, that book stall speed is probably CAS (calibrated airspeed), not IAS (indicated airspeed).
Then start working down from that 1.3x indicated stall speed starting point. And remember, you don't have to fly that slooow approach speed all the way down final-- it only helps you land short when you're slow at touchdown. Sometimes you need to carry more airspeed on final to compensate for gusty conditions.

[shortfielder]

I reajusted my stall horn after I changed my wing so that it goes off when wanted it to.
Gary

[SE6601KF]

One fellow who posts here occasionally, whom I've met and flown with, wrote an article published recently in one of the major aviation mags describing his backcountry flying in a Cherokee where he states his airspeed on short final on backcountry airsrips is 60 mph IAS (he's told me the same thing in conversation) ... which is only 3 mph above the Cherokee full flap stall speed (albeit, at full gross weight).

The stall speed is also figured (Power Off).

Go out and do some stalls with different amounts of throttle.
Your stall speed will be lower.

60 IAS is probably closer to 1.3 vso with some throttle.

Now if the engine should quit while on short final then you have a new ball game.

Speed is the most important thing in a short landing.

Get really comfortable with slow flight at weights from empty up to gross.

[EZFlap]

I'll catch hell for this...

You guys are all talking about airspeed which has almost nothing to do with what the airplane feels. Speed is an easy reference but speed is not what stalls the airplane. And the indicators/pitot-static systems (as mentioned) are not really accurate. What would really make more of a difference in that situation is an angle of attack indicator. I understand the US Navy switched to using AOA indicators for carrier approaches and cut their accident rate significantly. There are a few AOA systems (LRI, etc.) available for light aircraft, which reportedly work very well.

The stock stall warning indicator is actually an angle of attack sensor, not an airspeed sensor. If airspeed was really the key to low speed safety, they would have wired the buzzer straight to the pitot tube and saved twenty bucks and half a man-hour at the factory.

Other pilots here may have a lot more hours than I, but consider this: When flying slowly in a light airplane, pay attention to how much the indicated airspeed rises and falls (by itself) on an average climb after takeoff (due to gusts, thermal currents, wind shear, etc.). That is the same amount that your indicated airspeed can rise and fall on a landing approach. So if you're flying 3 or 4 miles an hour over stall, you damn well better be in pretty calm air...

As mentioned, the rules, speeds and angles all change dramatically when you get into ground effect.

[GumpAir]

I don't know of any AOA system for light aircraft that in real world use is worth a shit.

Also, wind shear is pretty much a non event in our light aircraft. Throttle makes up for changes in airspeed more than adequately.

Gump

[mtv]

I don't know of any AOA system for light aircraft that in real world use is worth a shit.

Also, wind shear is pretty much a non event in our light aircraft. Throttle makes up for changes in airspeed more than adequately.

Gump

Agreed. The guys who promote these "AOA Indicators" for general aviation propeller driven aircraft are snake oil salesmen, pure and simple.

To be accurate, an AOA system really needs more than just one simple sensor. Look at the AOA systems these guys promote: They look remarkably like a.....pitot mast. And, they have the same foibles

The Navy does indeed fly by AOA, but the AOA systems in their aircraft are FAR more sophisticated than anything thats available in the general aviation market.

Consider what happens if you have one AOA sensor on the left wing (the typical mounting location on these things) but you enter a slip.....

The Navy takes care of that by providing multi point sensors.

MTV

[aktahoe1]

It baffles me how often these type of conversations come up.

Get rid of your stall horn, AOI, ASI and everything else that tells you your speed, stall, etc.

Can you still fly your plane?? If your answer is no, then just maybe you should not taxi out of the hanger. GO FLY THE PLANE...

I have always been taught its about the feel and I know most of you have as well. If you dont feel your wing, keep doing laps in the pattern until you do. Hang gliders, parachutes, you name it, dont have the bells and whistles that tell you your about to drop out of the sky. Again, its feeling your wing and getting to know that feeling. If you choose to follow all the bells and whistles great, but you will also keep landing on the 3000' runways.

There are soooo many variables to the type of flying this site (BCP) is about. Winds, weight, type, experience, you name it. Though I dont know him, I bet both testicles that when Coyote Ugly and others on here that are really flying into unique spots, there not looking much at there airspeed or wish they had an AOI, etc. There flying the plane on feel. We can go all day on VY, VX, SEX, etc. You still need to fly your plane on the feeling.

So back to the question here...Best approach speed on short final? In what, a 747 or a cub...its an open ended answer.

Heres one, long and thin or short and thick?

Sorry for the rant Zane...I guess I have nothing better to do here like the rest of us on here every hour of the day.

On a different note, Have had the opportunity to meet and fly with some great folks on here as of late. I am blow away but what some of these guys do for there day job....VICK = U2 Pilot, DLHANST = 777 captain (also a really good digger with his penatration skis ) ...really cool to know and fly with them...

AKT

[shorton]

I dont have a stall warning device, I don't look at the airspeed on landings, I feel the airplane and control the airplane, don't wait for it to do something and respond, control it.

[z3skybolt]

I'll catch hell for this...

You guys are all talking about airspeed which has almost nothing to do with what the airplane feels. Speed is an easy reference but speed is not what stalls the airplane. And the indicators/pitot-static systems (as mentioned) are not really accurate. What would really make more of a difference in that situation is an angle of attack indicator. I understand the US Navy switched to using AOA indicators for carrier approaches and cut their accident rate significantly. There are a few AOA systems (LRI, etc.) available for light aircraft, which reportedly work very well.

The stock stall warning indicator is actually an angle of attack sensor, not an airspeed sensor. If airspeed was really the key to low speed safety, they would have wired the buzzer straight to the pitot tube and saved twenty bucks and half a man-hour at the factory.

Other pilots here may have a lot more hours than I, but consider this: When flying slowly in a light airplane, pay attention to how much the indicated airspeed rises and falls (by itself) on an average climb after takeoff (due to gusts, thermal currents, wind shear, etc.). That is the same amount that your indicated airspeed can rise and fall on a landing approach. So if you're flying 3 or 4 miles an hour over stall, you damn well better be in pretty calm air...

As mentioned, the rules, speeds and angles all change dramatically when you get into ground effect.

Sorry EZFlap,

My experience has been that flying..... slooooooow ......in rough air is no big deal with light, straight wing, recip powered, prop driven airplanes. Like others have said here. Know/Feel your airplane. I happen to know a fella who has flown more than one light airplane VFR.... over great distances and into various situations without a functioning airspeed indicator. He told me that it was no big deal. But....darned if I can remember his name.

Bob

[182 STOL driver]

nmflyguy :
Get yourself a Lift Reserve Indicator and fly it . http://www.liftreserve.com/ It works under all conditions -light or heavy -check it out.

[EZFlap]

Also, wind shear is pretty much a non event in our light aircraft. Throttle makes up for changes in airspeed more than adequately.

Gump

Pardon my mis-statement... I was not referring to wind gradients or gradual changes in IAS. Change "wind shear" to "hard gusts". We've all seen gusts that give or take away 8 or 10 miles an hour back and forth in a couple of seconds.

[EZFlap]

Like others have said here. Know/Feel your airplane. I happen to know a fella who has flown more than one light airplane VFR.... over great distances and into various situations without a functioning airspeed indicator. He told me that it was no big deal.

Bob

I was not inferring that any instrument (ASI, AOA, etc) is a substitute for feel, training, etc. I was addressing the fact that several people were getting all wrapped up about airspeed numbers while flying close to stall, and not dealing with the fact that AOA is more important than airspeed at those times.