Advanced air speed stall warning thought

[nels]

In looking at probable cause of most of the fatal plane crashes it seems they are usually in the pattern at departure or final and are usually stall spin killers with virtually no time to recover. I can see how this can easily happen while trying to manage a minimum airspeed on approach to a short runway as an example. I was thinking an electronic warning system that might say “approaching stall” at some speed prior to the “stall” warning seems like it would be nice to have and doable with an electronic system. This could probably be wired to the air speed indicator? I remember my uncle had a 64 Buick Wildcat that had an adjustable warning system on the speedometer that would buzz when he hit what ever speed he set on the needle. Something similar would be nice if you could adjust in a 5 or 6 knot pre warning signal.

Maybe my thinking is flawed? Any thoughts?

[Bob - S50]

I suspect many of the AOA indicating systems available today do or could do this.

[gsxrpilot]

I don't think airspeed is the problem. It's a combination of airspeed, angle of attack, weight, etc. 

This is exactly the problem that all the AOA vendors are trying to solve.

[KSMooniac]

My AOA system perfectly addresses that issue... The first audio annunciation is "Getting Slow", and since it is AOA based that is sensed independent of weight and airspeed, as it should be. Next comes "Too Slow" which usually sounds during the flare for me. It works very well.

Sent from my LG-US996 using Tapatalk

[RobertGary1]

I have such a system. It just wires to the stall horn and says “Check airspeed”. Also monitors gear warning, voltage,  edm, and vacuum pressure. 

Not very expensive although a bit time consuming to install  

http://www.chiefaircraft.com/ei-av-17.html

-Robert 

[nels]

3 minutes ago, RobertGary1 said:

I have such a system. It just wires to the stall horn and says “Check airspeed”. Also monitors gear warning, voltage,  edm, and vacuum pressure. 

Not very expensive although a bit time consuming to install  

http://www.chiefaircraft.com/ei-av-17.html

-Robert 

Robert, I have the AV17 system in my plane and really like it. However, I seem to remember a short delay from the time I trigger the stall horn until the audible warning sounds. I need to verify that but that’s what I seem to remember.

[skydvrboy]

This is a great reminder that we first need to understand the problem before trying to come up with solutions.  As gsxrpilot mentioned, airspeed isn't the problem (alone), so something wired into your airspeed indicator to tell you that you are going too slow won't help.  I can make your plane stall at 100 kts and can fly it well below the stall speed indicated on your ASI without stalling.  In addition to the factors gsxrpilot already mentioned, bank angle and turn coordination are probably the two biggest factors leading to a stall and whether or not that stall will lead into a spin.

The AOA indicator KSMooniac has is a HUGE improvement, but even that has it's limitations.  Remember, the AOA is not the same along the entire surface of the wings if the ailerons are being used.  The down aileron increases the angle of attack and visa versa for the up aileron.  As such, different sections of the wing can stall at different times.  That's why in a skidding turn stall, the plane will just spin into the ground toward the inside of the turn as the inside wing stalls first.  In a slipping turn, the airplane will flip over the top toward the outside of the turn as the outside wing stalls first, which is probably more alarming to the pilot, but actually makes it easier to recover from.

I personally think (private pilot only) that this situation is better addressed through training and understanding the aerodynamics than through technology.  For a "fail safe" technology solution, you would need 3 AOA indicators and even that might not be able to catch every possible scenario.

[steingar]

I've said it before.  Just another expensive box to ignore.  We're already got airspeed and stall horns and we still crash.  Airmanship and ADM is what's needed.  I think I'll give the example from last night.

I'm based at a local Delta (a rather busy one) and have been having radio troubles for some time. Aircraft is scheduled to go back to the avionics shop next week. I thought I'd take her up last night to shake out some cobwebs, haven't flown since Oshkosh.

I've mostly been relying on my number 2 comm, comm 1 has been useless for some while. I used it to talk to ground, scratchy but doable. Used it to talk to tower. Got going. Once airborne I couldn't hear tower at all. This is new, usually I can hear fine but can't transmit.

I was going to fly to a couple local strips and do a couple landings, my first one was so bad I turned it into a touch and go after the second bounce (you guys know what I mean). Decided I was done for the night, time to get back home. Called my home tower 10 miles out, no problem.

I go to report the midfield downwind and I can't hear a thing from tower. Comm2 is fragged, comm1 is now useless. I have my handheld out, start playing with it when a little voice in my head reminds me that low and slow on the downwind is no place to play with radios.

I decide to get predictable and continue my down wind as I suck up the gear and flaps. I fly to a local airport to:

1) land
2) try and sort out the aircraft
3) try and sort myself out

Radio problems are stressful, especially in controlled airspace. They can get the better of you. Time to land, cool down, and figure things out.

So I land, far better than my last one, which isn't saying much. I park the aircraft and walk over to the FBO, where a young man is sitting on a bench. He's a CFI waiting for his student, who's doing his first solo landings, I saw him as I was coming in. I tell him about my plight, and he offers to fly me back to my home base (they're based there as well, in a hangar near mine).

I take him up on it. I hate hate hate leaving my nice aircraft tied down at a strange airport, but with the way my comms are I'll have a tough time getting back to my home drome. Easy enough to get it and fly to where they'll finally be fixed (hopefully, I honestly don't hold out high hopes).

First time I've left an aircraft in a very, very long while.

That's ADM in action, gents.  I saw things going south and got out of dodge before they could get any dicier.  Didn't need an AOA, or a stick shaker, or anything else.  Just some good sense and basic airmanship. 

[kortopates]

3 hours ago, nels said:

“approaching stall” at some speed prior to the “stall”

Statements like the above help support my fundamental belief that the #1 issue is education. In no way is this meant to question @Nels, but nels brings up a very common misunderstanding among the pilot community that airspeed is responsible for stalls even though I am sure all have learned its AOA. Yet unfortunately for too many that is just a poorly understood concept.  So its my belief that too many pilots become fixated to degree on the accelerated 1G stall speed and its relationship to bank angle. That would be great if their understanding allowed for AOA, weight, cg. But without that it leads to unnecessarily (IMO) restricting bank angle to shallower standard rate turns in the pattern and excessively long downwinds rather than flying the standard FAA traffic pattern from 0.5 to no more than 1 mile abeam the runway. We all see it. Its then these long patterns which lead to the the pilot getting low and then slow when they start pulling back on yoke without adding rudder and power to compensate for the increased AOA. In other words, the larger pattern the pilot is consciously choosing to fly to avoid the stall/spin is actually setting the stage for the very event. But in contrast, if the pilot's pattern was the well practiced tighter but normal pattern with a continuous descent that kept the wing unloaded  from abeam the numbers to the point of landing as supposedly taught in primary training their would be no reason to pull back on the yoke and thus very little concern for a stall/spin accident. 

Edited August 24, 2018 by kortopates

[RobertGary1]

The point of a voice annuciator is that it’s harder to ignore than a buzzing.

its why all modern flight decks use va’s for critical notifications  

-Robert

[RobertGary1]

For some odd reason during my last engine failure as I was gliding into the airport it was in the front of my mind that this is where pilots stall on base or forget the landing gear. Odd how in that type of situation you can have such clarity. Landed opposite direction and caused an MD-80 to go around but no other harm done other than my pocket book. FAA determined I didn't miss a gear AD or have an expired medical so they lost interest in the event.

 

-Robert

[Guest tommy123]

1 hour ago, RobertGary1 said:

The point of a voice annuciator is that it’s harder to ignore than a buzzing.

its why all modern flight decks use va’s for critical notifications  

-Robert

Actually voice warnings are used in transport category aircraft because of the number of warnings available. Easier than trying to remember what tone means what.

[Guest tommy123]

Stall warning horn does warn of a impending stall, not that it is happening. If your stall warning blares at the stall it is mis adjusted.

[RobertGary1]

1 minute ago, tommy123 said:

Actually voice warnings are used in transport category aircraft because of the number of warnings available. Easier than trying to remember what tone means what.

Applies to us just as well. How many times have pilots landed gear up and reported they thought they did a good job because they got the stall horn on flare?

-Robert

[Guest tommy123]

18 minutes ago, RobertGary1 said:

Applies to us just as well. How many times have pilots landed gear up and reported they thought they did a good job because they got the stall horn on flare?

-Robert

Yeah, horns are cheaper than voice aural warnings. But if someone hears a horn all the way down on final and thinks it’s a stall warning there’s something wrong with their thought process.

[RobertGary1]

43 minutes ago, tommy123 said:

Yeah, horns are cheaper than voice aural warnings. But if someone hears a horn all the way down on final and thinks it’s a stall warning there’s something wrong with their thought process.

I'm not casting stones until the day I turn in my medical.

-Robert

[steingar]

3 hours ago, skydvrboy said:

This is a great reminder that we first need to understand the problem before trying to come up with solutions.  As gsxrpilot mentioned, airspeed isn't the problem (alone), so something wired into your airspeed indicator to tell you that you are going too slow won't help. 

It isn't the only problem, but I'll bet you a crapload of money that everyone who's ever stalled and spun their aircraft to their demise would not have done so had they been going ten knots faster. 

[M20F-1968]

I have a custom version of this annunciator in my plane.  It is made by Proscan and has a regular stall warning from the stall vane, and also an accelerated stall warning based on its own electronics.  The web site is:

https://sites.google.com/site/proscanaerospace/

John Breda

[N201MKTurbo]

It seems to me that a Garmin G5, Aspen or other PFDs already has all the information necessary to generate these alerts. Except for gross weight. It could give the alerts at max weight and give you a little cushion if you didn’t enter it. It would just be software and government red tape. 

While its at it it could adjust the V speeds for you different airspeed arcs.

A side benefit would be forcing us all to actually do a W/B on every flight.

Edited August 24, 2018 by N201MKTurbo

[ShuRugal]

6 hours ago, kortopates said:

it leads to unnecessarily (IMO) restricting bank angle to shallower standard rate turns in the pattern and excessively long downwinds rather than flying the standard FAA traffic pattern from 0.5 to no more than 1 mile abeam the runway.

Saw this a few weeks ago... I entered the pattern on a 2-mile extended downwind with a Beech Musketeer calling crosswind... that Beech proceeded to fly a 2-mile pattern at such a low airspeed that I had to do a 360 before reaching normal downwind, had to fly my downwind at 100 MIAS, and extended my downwind to a full 1-mile final to void passing the idiot.  If I had known he was going to do that, I could have landed in front of him, done a touch and go, and still had to give way to him while he turned base....  never had a 10 minute downwind-base-final before...  If his engine had quit, there is no way in hell he'd've made the runway, and the pattern was on the urban side of the airport.... he'd've come down right into someone's house.

 

Once on the ground, I beat him to parking (despite landing 45 seconds after him) and watched him unload his pax clown-car style... and none of them were what you'd call "petite".  how he managed to drag that thing around the patch at 80 mph, I have no idea.

[Yetti]

5 hours ago, steingar said:

I'm based at a local Delta (a rather busy one) and have been having radio troubles for some time. I thought I'd take her up last night to shake out some cobwebs, haven't flown since Oshkosh.
 

 

You are not backing the accident chain far enough back.  Saying you did great ADM too far down the chain is not great ADM.   Your skills are rusty and your equipment is in bad shape.  Should have stopped right there.   Once you "could not hear the tower".  Should have flown the pattern and put it down on light guns and called it a night.

[Guest]

1 hour ago, ShuRugal said:

Saw this a few weeks ago... I entered the pattern on a 2-mile extended downwind with a Baron calling crosswind... that baron proceeded to fly a 2-mile pattern at such a low airspeed that I had to do a 360 before reaching normal downwind, had to fly my downwind at 100 MIAS, and extended my downwind to a full 1-mile final to void passing the idiot.  If I had known he was going to do that, I could have landed in front of him, done a touch and go, and still had to give way to him while he turned base....  never had a 10 minute downwind-base-final before...  If his engine had quit, there is no way in hell he'd've made the runway, and the pattern was on the urban side of the airport.... he'd've come down right into someone's house.

 

Once on the ground, I beat him to parking (despite landing 45 seconds after him) and watched him unload his pax clown-car style... and none of them were what you'd call "petite".  how he managed to drag that thing around the patch at 80 mph, I have no idea.

If his engine quit in a Baron he could have started the back up engine on the other wing and made the airport.

Clarence 

[kortopates]

2 minutes ago, M20Doc said:

If his engine quit in a Baron he could have started the back up engine on the other wing and made the airport.

Clarence 

Maybe, but the pilots low and slow pattern shows us its a good candidate for a Vmc roll over too

[ShuRugal]

4 minutes ago, M20Doc said:

If his engine quit in a Baron he could have started the back up engine on the other wing and made the airport.

Clarence 

That's my bad, he was a single.  Musketeer, not the Baron.  I can't keep Beech names straight.

[nels]

9 hours ago, kortopates said:

Statements like the above help support my fundamental belief that the #1 issue is education. In no way is this meant to question @Nels, but nels brings up a very common misunderstanding among the pilot community that airspeed is responsible for stalls even though I am sure all have learned its AOA. Yet unfortunately for too many that is just a poorly understood concept.  So its my belief that too many pilots become fixated to degree on the accelerated 1G stall speed and its relationship to bank angle. That would be great if their understanding allowed for AOA, weight, cg. But without that it leads to unnecessarily (IMO) restricting bank angle to shallower standard rate turns in the pattern and excessively long downwinds rather than flying the standard FAA traffic pattern from 0.5 to no more than 1 mile abeam the runway. We all see it. Its then these long patterns which lead to the the pilot getting low and then slow when they start pulling back on yoke without adding rudder and power to compensate for the increased AOA. In other words, the larger pattern the pilot is consciously choosing to fly to avoid the stall/spin is actually setting the stage for the very event. But in contrast, if the pilot's pattern was the well practiced tighter but normal pattern with a continuous descent that kept the wing unloaded  from abeam the numbers to the point of landing as supposedly taught in primary training their would be no reason to pull back on the yoke and thus very little concern for a stall/spin accident. 

 

9 hours ago, kortopates said:

Statements like the above help support my fundamental belief that the #1 issue is education. In no way is this meant to question @Nels, but nels brings up a very common misunderstanding among the pilot community that airspeed is responsible for stalls even though I am sure all have learned its AOA. Yet unfortunately for too many that is just a poorly understood concept.  So its my belief that too many pilots become fixated to degree on the accelerated 1G stall speed and its relationship to bank angle. That would be great if their understanding allowed for AOA, weight, cg. But without that it leads to unnecessarily (IMO) restricting bank angle to shallower standard rate turns in the pattern and excessively long downwinds rather than flying the standard FAA traffic pattern from 0.5 to no more than 1 mile abeam the runway. We all see it. Its then these long patterns which lead to the the pilot getting low and then slow when they start pulling back on yoke without adding rudder and power to compensate for the increased AOA. In other words, the larger pattern the pilot is consciously choosing to fly to avoid the stall/spin is actually setting the stage for the very event. But in contrast, if the pilot's pattern was the well practiced tighter but normal pattern with a continuous descent that kept the wing unloaded  from abeam the numbers to the point of landing as supposedly taught in primary training their would be no reason to pull back on the yoke and thus very little concern for a stall/spin accident. 

I guess my concern arrived in my head yesterday when I was flying the pattern in preparation for landing. Downwind no problem, base... no problem but final I wanted to maintain 80/85 mph slow to 80 at the fence 75 at the numbers etc. When I slowed to 80 and checked the surroundings then rechecked the airspeed I was at 70. No big deal as I just lowered the nose a little and added a little throttle. An audible signal would have been nice at that point. I’m sure I could have dipped into the horn and I’m sure recovered from that but personally I would have felt better if I would get a tap on the shoulder saying do what you need to do to get the landing descent back in order before a stall horn goes off.