Stalls in the Pattern

[rwanttaja]

This is the NTSB preliminary for the crash of a RANS S-6S earlier this month:

http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20130504X50339&key=1

"...as the accident airplane approached the runway, it entered an aerodynamic stall during the turn from the base leg of the traffic pattern to the final leg of the traffic pattern. The airplane then appeared to recover from the stall and aborted the landing.

"As the accident airplane approached the runway for a second time, it again appeared to stall during the base-to-final turn. The airplane again recovered from the stall, aborted the landing, and continued in the traffic pattern. During the third traffic pattern circuit, and while turning from the downwind leg to the base leg, the airplane appeared to stall; however, the airplane did not recover and subsequently entered a spin."

Three approaches, three stalls. Going to be interesting to see the final report on this one.

Ron Wanttaja

[steveinindy]

*facepalm* Good grief....

[martymayes]

failure to obtain/maintain flying speed? (x3)

[Floatsflyer]

3 stalls--2 on turns from base to final and 1 from downwind to base. Apparently no turning problems from upwind to crosswind or crosswind to downwind where you might believe a stall was more likely to occur(banking/climbing). Mystifying. Perhaps the banks to final were too steep with inattention to airspeed?

[Bill Berson]

Might have been a strong tailwind on base. Gives the unwary pilot an allusion of excess speed that he is not accustomed to. ( pilot sees high ground speed and pulls stick to slow down)

[JimRice85]

Damn

[Bill Berson]

I wonder why the NTSB said " aerodynamic stall".

Seems they have used various words over the years:
failure to maintain airspeed...
loss of control while maneuvering...

I sort of felt the government agencies just didn't want to accept that STALLS / SPINS was still killing pilots, so they keep finding other words.

[rwanttaja]

3 stalls--2 on turns from base to final and 1 from downwind to base. Apparently no turning problems from upwind to crosswind or crosswind to downwind where you might believe a stall was more likely to occur(banking/climbing). Mystifying. Perhaps the banks to final were too steep with inattention to airspeed?
When stalls occur in the pattern, it's usually on the base-to-final turn. It's the only place where the pilot is trying to precisely align with a ground feature. Upwind-to-crosswind, crosswind-to-downwind, you're basically following an invisible track. But turning from base to final, you're converting from the virtual path to a fixed ground reference, and that's usually where the stalls occur.

Wind conditions can throw off pilots even more. As Bill mentioned, a tailwind on base tends to make pilot suck that base-to-final turn a bit tighter.

Pilots have by dying from stalls on base-to-final for a hundred years. That's not what bothers me about this one.

Like many of us, I've made some dumb mistakes flying but managed to live through them. When they have happened, I become a bit paranoid and do everything I can to keep it from happening again.

For some reason...this pilot didn't.

Think about it. You accidentally stall on base-to-final. You ram on the throttle, get the wings flying again, pull up and go around.

On your next approach, are you going to do everything *exactly* like the first one?

Hey-el no. After you re-cage your heart, you are going to fly a wide-damn pattern. You're going to extend downwind to make sure you have a long final to help you get on centerline. You are going to watch the airspeed like a hawk through the turns.

But that's not what happened. The pilot apparently flew the same kind of approach, stalled again, went around again, then had what was apparently the same kind of stall on the third try. After the second stall, I would have been well and truly freaked, and flew off somewhere for 15 minutes or so to cool down (and fly a long, long, straight-in approach afterwards). But no, quickly around for a third (and fatal) try.

There may be some other factors at work here, either mechanical, physiological, or psychological.

Ron Wanttaja

[WLIU]

Well, to stir the pot, I will throw out the suggestion that too much of our training is repetition of "politically correct" formulas and emphasis on approved procedures. What I mean by that statement is that I see too many instructors teach, and pilots with many hours insist that there is only one procedure appropriate for a situation when in fact common sense says that is not true.

In this case what I see is that the pilot had the full length of the runway in front of him and he went around because he had a problem with the turn to final. All he had to do after stabilizing the airplane was get lined up and land. Someone taught that pilot that no matter what, if you have a problem in the pattern, do not land! I see that at at my local 6000' runway airport. A student who could land 3 times in the length of the runway gets some turbulence on final and aborts the landing. I suggest that student is being taught poor judgement.

An extreme case of this was the KLM crash where the airplane had a fire on board but the captain would not land at the nearest airports because they were not listed in the airline's ops spec (approved airports). For that deceased captain the procedure was more important than saving the airplane and his and his passengers lives. What's up with that?!

Food for thought.

Wes
N78PS

[danielfindling]

I like this discussion and agree with Ron's opinions.

As a pilot who flys recreationally, I usually fly when the weather is nice. Yesterday, the winds at my local airport were 310 degrees @ 19kts gusting to 26 kts. I fly a small tailwheel airplane (Cessna 140A) At lunch, I went to the airport and flew three circuits to practice crosswind Landings in gusty conditions (runway 27) After a lousy first landing, I flew a wider pattern, lengthened the downwind etc. for more time to adapt on base and final. In each landing I tried something different - three point with flaps, wheeled with flaps, and bounced without flaps. I am hopeful that this practice will make me a safer pilot.

As for the instant accident, absent a mechanical/design problem, this accident appears related to pilot skill. In either case, I am hopeful we can learn from this accident and remind each of us of the importance of safety and practice.

Daniel

[Joe Delene]

5000 & 4700' runways, should be plenty to work with. If it did transpire as written you would think one could try something different, like widen the pattern with more speed. I'd think some answers may be evident once recent experience & training of the accident pilot are looked into.

[Joe LaMantia]

It sounds like this guy was stuck on flying a tight pattern and determined to make it work. Everyday is different regarding wind direction and speed as noted, THINK and ADJUST, the objective is a stabilized approach. Ron is right, there is no shame in extending the pattern and cutting the corner to keep the bank angle low. I'm guessing this aircraft doesn't have a stall warning horn system so compensate by scanning the airspeed indicator every few seconds while flying the pattern. We've all been told to practice slow flight and learn how your aircraft handles at low airspeed. This was so avoidable!!

Joe
:cool:

[cub builder]

This pilot had some basic competency in order to become a pilot. If I believe that, I've also got to believe he was dealing with some kind of situation that was confusing to him. Three stalls in the pattern indicates that all was not normal during this flight. My best guess would be that he was likely flying a plane with a plugged pitot or static port and had always flown the airspeed indicator for approaches.

At some point in most of our flying careers, things like airspeed indicators will fail or worse yet, fail to indicate correctly. If you don't practice landings without it, how are you going to deal with it when it does fail? How many of us are comfortable landing without a functioning airspeed indicator? I don't think I would be so quick to assume the accident pilot was an idiot and that you wouldn't ever do the same.

-CubBuilder

[rwanttaja]

Well, to stir the pot, I will throw out the suggestion that too much of our training is repetition of "politically correct" formulas and emphasis on approved procedures. What I mean by that statement is that I see too many instructors teach, and pilots with many hours insist that there is only one procedure appropriate for a situation when in fact common sense says that is not true.

In this case what I see is that the pilot had the full length of the runway in front of him and he went around because he had a problem with the turn to final. All he had to do after stabilizing the airplane was get lined up and land. Someone taught that pilot that no matter what, if you have a problem in the pattern, do not land!
Wes, I have tremendous respect for you, but I disagree with you, here. It wasn't just a problem, it was loss of control of the aircraft at a relatively low altitude. We do have rote training for stall recovery...break the stall, full power, pitch up and get a positive rate of climb...and I think it would have been the right choice here.

Besides, we don't know the aircraft heading at recovery...it might have been 45 degrees off the runway heading. Better to power up, get out of Dodge, and try it again.

You really have to imagine what's going through the pilot's mind just after recovery. I've got an oft-told story how, when carrying my first passenger after getting my Private, I got into an accidental stall-spin (you can tell how many times I've told it, since I increment the number of spin turns every time I tell the story. I'm up to 473 turns :-). For the first 15 seconds after recovery, I was good for little more than climbing straight and speaking four-letter words. From 15-30 seconds, I graduated to adjectives (****er ****ing S**-of-a-*****). Andrenaline was shooting through my system, sweat was drenching my back. I was in no condition to immediately land the aircraft, and don't fault the accident pilot for not doing so.

Something else occurred to me, as I was reviewing this accident: All the current evidence would match a case of pilot incapacitation with a non-pilot passenger trying to land the plane. Two other aircraft of the same type had landed normally. A temporary tower was in operation, but the NTSB Preliminary doesn't say that the accident airplane was in contact (the other two RANS had been). No PTT switch on the pax side? Three apparently identical approaches were flown, like a non-pilot trying to reproduce what he'd seen in the past. Three stalls occurred, where a pilot would have understood the cause of the first one and worked to avoid a repeat.

On the other hand, the passenger was the pilot/builder's middle-aged son. Likely he would have had some stick time, quite possibly a license.

The autopsy should settle this...there are characteristic injuries to the hand of the person holding the stick at impact.

Ron Wanttaja

[Bill Greenwood]

I think Cub builder and perhaps Ron have something here. It is unlikely that this was just a normal pilot flying in normal conditions and continuing to make the same mistake.
The report as I read in does not say if there were any radio call or what the weather was.
And in most cases, depending on how far off normal you are, if there is a problem in the pattern, especially on final approach, best practice is not to try to force the landing with some type of large, last minute correction and make the landing despite it, better to go around and do it again and do it right.
This is especially true if something is really out of the ordinary.

I read a story about a famous test pilot who trains civilian warbird pilots these days at Duxford, England. Now some trainers like a Tiger Moth or T-6/ Harvard are two seat and dual control.
But when the day comes to fly the fighters, Hurricane or Spitfire or P-38, stc, they are single seat. Your are there by yourself and need to do it right. And some of these planes are historic types and like national treasures ,not to mention worth several million dollars. Duxford is pretty much hallowed ground from WWII and it is considered very bad form to bend one of these planes on the same runway where people like Douglas Bader used to land.

I read about one man on his first solo in the Spitfire Mk V. The tolerance on final approach was 5 mphfast, 0 mph slow on short final. He did a go around the first approach, just as he had been taught siince he was about 10 mph fast and went out and reentered the pattern and made a good landing.

[WLIU]

Ron,

Thanks for the excellent insight. And it will be interesting to look at the data that has not been released yet.

And please know that I believe that all internet opinions, including mine, may be worth exactly what you pay for them. :)

One thing that this accident appears to reinforce is that crashes seem to occur on the third attempt to do something - instrument approach, ribbon cut, whatever. The stress level seems to go up exponentially with each miss. Food for thought.

Fly safe,

Wes
N78PS

[martymayes]

Think about it. You accidentally stall on base-to-final. You ram on the throttle, get the wings flying again, pull up and go around.

On your next approach, are you going to do everything *exactly* like the first one?

Hey-el no. After you re-cage your heart, you are going to fly a wide-damn pattern. You're going to extend downwind to make sure you have a long final to help you get on centerline. You are going to watch the airspeed like a hawk through the turns.

But that's not what happened. The pilot apparently flew the same kind of approach, stalled again, went around again, then had what was apparently the same kind of stall on the third try. After the second stall, I would have been well and truly freaked, and flew off somewhere for 15 minutes or so to cool down (and fly a long, long, straight-in approach afterwards). But no, quickly around for a third (and fatal) try.



Apparently, he was fairly skilled with stall recoveries. He just had a problem with stall recognition.

[Bill Berson]

I sort of agree with Wes, a go around attempt can also result in stall (a far worse stall than power off).
When bewildered, the natural tendency is to pull up. But if you pull first then hit full power, the prop blast will make the elevator very effective and you can get a bad stall/ spin.
I teach RC pilots. Often they will stall on the go around.

Not saying you should avoid go arounds in all cases. But as a glider pilot, I don't go around much.

[Ron Blum]

Without knowing a lot of information, I would suggest that the pilot was trying to fly a too small, ground referenced pattern with a crosswind that was a tailwind on base leg. As the pilot banked to reach the runway centerline, the airspeed was insufficient to maintain "level" flight. Guessing (again), most pilots try to rudder around the base to final portion of the pattern if they are over shooting the runway centerline. A spin is a result of uncoordinated, stalled flight. The fact that he recovered from 2 previous stalls is actually pretty amazing. This, by the way, is the #1 cause of aircraft fatalities.

What could have prevented this accident?

Would an AOA device have prevented this accident?

[JimRice85]

This is why hours in the pattern in various situations are hours well spent. I love shooting landings in whatever I am flying. I guess I have a few thousand in my Cub. Even in my Swift, I try to shoot a few every time I fly it.

This also makes me glad my dad (former USAF IP in T-6s) drilled me on proper rudder use and coordinated flight...and kept me in the pattern learning to know the plane and making it do what I want it to do.

[WLIU]

"most pilots try to rudder around the base to final" - I am not willing to engage in that generality any more. It sounds good to folks looking for an easy point of blame, but my personal observation is that these days "most pilots" do not use the rudder for very much. The airplanes that are used for training hardly need any rudder inputs at all. The common rental aircraft need hardly any rudder inputs. So my conclusion is that it is unlikely that "most pilots" resort to over-ruddering the base to final turn. When I fly with other pilots I often find myself thinking that too many of my peers under use the rudder. I would find a theory that involved over banking or over elevator-ing, with inadequate rudder coordination more likely. That said, that sort of pilot error could simply result in a spin away from the turn rather than a spin into the turn, so without more info any theory could correctly explain the data.

Speculation on inadequate data produces questionable educational value.

Be safe,

Wes
N78PS

[Bill Greenwood]

The accident report does not give much info on the pilot, how many hours he had and how many in type, so it is hard to judge his experience level. but it does say he already made two landings that day. No weather data given, so I don't see where you guys are getting a tailwind on base as a factor.

Would an AOA indicator have helped. Well, if he had a clogged pitot or some airspeed indicator malfunction, and the AOA came from a separate source, it could have helped, but only if he looked at it.
I wonder if he really did 2 stalls and recoveries at low altitude on the previous approaches or if he might have been hitting wake turbulence from other planes as it was a fly in.

It seems strange that we don't know anything about radio talk with the advisory tower while he is doing the 3 approaches.

[rwanttaja]

The accident report does not give much info on the pilot, how many hours he had and how many in type, so it is hard to judge his experience level. but it does say he already made two landings that day. No weather data given, so I don't see where you guys are getting a tailwind on base as a factor.

Looked up the pilot's license information. He got his Private ticket just over three years ago. It's probable he had less than ~300 hours. This data isn't available in the preliminary, but this and any weather data will come out in the factual (~10 or so months from now). As Bill mentioned, he had landed fine twice earlier that day, and two other RANS landed about the same time without mishap.

Going to be out of pocket for a few days, but when things settle down, I may call the NTSB investigator for a bit more information.

I did check, it appears his passenger did not have a license.


Would an AOA indicator have helped. Well, if he had a clogged pitot or some airspeed indicator malfunction, and the AOA came from a separate source, it could have helped, but only if he looked at it.

I've never flown with an AOA, but the more I think about it, the better idea it seems.

In my experience, a clogged pitot makes the airspeed read too low, not too high. I had a clogged pitot line in my student days, and the biggest danger was me shoving forward thinking the plane was about to stall. The gauge indicated pretty much OK at pattern altitude, but when I descended on final the airspeed dropped (increasing static pressure with the decrease in altitude gave the same indication as decreasing pitot). I kept shoving the stick forward to try to "correct" it. Scared the bejesus out of me, especially when airspeed descended past zero. Take my word for it, the actual airspeed getting TOO slow never was a danger. :-)

However, if the static line stopped up, I think there'd be a danger of the airspeed reading too high. As the plane descended, the pressure on the pitot side would rise due to the higher atmospheric pressure, which would make the indicator read higher than actual.

I think I've got an old airspeed indicator sitting in the parts box. I might rig up a temporary mount and pitot/static connection and play around with various failures.


I wonder if he really did 2 stalls and recoveries at low altitude on the previous approaches or if he might have been hitting wake turbulence from other planes as it was a fly in.

It seems strange that we don't know anything about radio talk with the advisory tower while he is doing the 3 approaches.
The preliminary report is basically taken from the immediate interviews, so it may not reflect everything that was going on. Since it was an advisory, apparently unofficial, tower, there wouldn't be any recordings to listen to.

Ron Wanttaja

[Janet Davidson]

Wes,

Just a quick correction, the accident to which you refer in you first post was Swissair, not KLM. http://en.wikipedia.org/wiki/Swissair_Flight_111

[Frank Giger]

Hmmm, a lot to take in.

First, I'll agree that spin training and flying without looking at the dash is good sense. I'm just a humble Sport Pilot and had both. One doesn't need to go under the hood to get some basic panel failure training. I'm beginning to think my CFI is way under-rated.

Of course I won't talk about the time the geewhiz glass panel of a CTLS decided to go completely dark on takeoff as part of the syallabus, because it wasn't. I will never own a glass panel because of it. No danger of wrecking if they decide to crap out, but having absolutely nothing but a compass because all the other instruments (tac, oil pressure, RPM, plus all flight instrumentation) are in one point of failure is unacceptable to me.

The Champ with a standard six seems more reliable to me.

Second, I've stalled on final. Not in the turn, but on line up. Classic case of aimpoint fixation - I wanted to land on my imaginary mark and pitched up to slow down and increase descent.....a little power and easing the stick did it (since I wasn't jerking the stick around walked up to the stall) and I landed a little long. 5,000 feet of pavement and I'm being dumb, focusing on erping the numbers in an aircraft that only needs 500 feet of it.

I'll also say that when I made the mistake I desperately wanted to go-around. It's drilled into one - crashes are expensive, go-arounds are free, so if something isn't right do the latter. I didn't though...I just landed longer than I had planned, shook my head at how stupid I can be, and did another touch-and-go, which set me up for nearly the same scenario (my personal goal for the day was short field landings), but I didn't fall for it and resigned myself to "regular" landings.

Passengers matter, particularly if one is introducing them to GA. The most stressful landing I ever made was when I conned* my wife into getting into the Champ. A rough landing would have convinced her that my hobby was dangerous and I was crappy at it. It was also the second best landing I've ever made....but I was sweating bullets the whole time.

* I lied and told her I needed a "passenger endorsement" to fill out my ticket.

[steveinindy]

The autopsy should settle this...there are characteristic injuries to the hand of the person holding the stick at impact.

Ron Wanttaja
Ron, the so called control surface injuries to the hands and feet are poor indicators of who was actively in control at the moment of the crash. A lot of known pilots do not have them (poor sensitivity) and a lot of non-pilots have them from contact with cockpit structures during crashes (poor specificity). Les Folio addressed this in one of his articles out of the AFIP. I can send you a copy of you like. Basically unless you have a black box or the hand is clenched in cadaveric spasm around the controls, there does not appear to be a reliable indicator as to who was in control.

[rwanttaja]

Ron, the so called control surface injuries to the hands and feet are poor indicators of who was actively in control at the moment of the crash. A lot of known pilots do not have them (poor sensitivity) and a lot of non-pilots have them from contact with cockpit structures during crashes (poor specificity). Les Folio addressed this in one of his articles out of the AFIP. I can send you a copy of you like. Basically unless you have a black box or the hand is clenched in cadaveric spasm around the controls, there does not appear to be a reliable indicator as to who was in control.
Gotcha, understand. Lots of tubing and whatnot for the passenger to be clutching....

I heard the hand-injury thing at an NTSB presentation ~25 years ago, undoubtedly the state of the art is improved.

Ron Wanttaja

[steveinindy]

Gotcha, understand. Lots of tubing and whatnot for the passenger to be clutching....

I heard the hand-injury thing at an NTSB presentation ~25 years ago, undoubtedly the state of the art is improved.

Ron Wanttaja

Well, among the folks who actually bother to read the forensic literature, yes it has. You still hear folks- including NTSB investigators and even their safety and survivability folks- treat it like gospel because it is so ingrained in the literature (there are references to it that I have found dating back to the 1920s) and lore of aviation pathology and crash investigation that you can't convince them otherwise. That is a major problem with these folks in that they treat the practice of investigation more like a religion rather than a scientifically grounded exercise.

You can also get similar injuries from someone's arms and legs flailing during the crash deceleration. This is an area that really needs to have more research before it is finally dismissed or is able to be applied in a more rigorous manner. Myself and a couple of colleagues (a forensic pathologist and a forensic radiologist respectively) are working on a retrospective review to see if we can do something about that.

[Mayhemxpc]

Just a couple of anecdotes about rudders, ASIs and low-time pilots...

Some years ago, when providing flight instruction at a Civil Air Patrol National Flight Academy, I overheard this joke told between the student pilots (All 16 and 17 year old cadets): "Why does an airplane have rudder pedals? To give the flight instructor something to say." At another iteration of the NFA, all 12 airplanes taxied out for departure together, shortly after a squall line came through (after pre-flight, before starting engines.) One of the first planes off quickly called back for a priority landing having experienced complete pitot/static failure. (There is more to that, but for another time.) We were number two for take-off and due for the line-up check. I asked the student, "Everything OK? Are we ready for take-off?" "Sure" came the reply. I then asked, "Do you really think we are doing 40 knots just sitting here?" While he was flummoxed, I advised all the other planes to drain their pitot static systems as part of the run-up check that morning.

Ruddering through the turn is possible but, as pointed out above, not too likely (the turns may have still been uncoordinated.) Blocks in the pitot-static system CAN cause a false high reading. That said, a pilot should be able to fly a light aircraft base to final SAFELY -- and land without looking at any instruments.

I will be very interested in reading the final report.

[Bob Dingley]

Ron, the so called control surface injuries to the hands and feet are poor indicators of who was actively in control at the moment of the crash. A lot of known pilots do not have them (poor sensitivity) and a lot of non-pilots have them from contact with cockpit structures during crashes (poor specificity). Les Folio addressed this in one of his articles out of the AFIP. I can send you a copy of you like. Basically unless you have a black box or the hand is clenched in cadaveric spasm around the controls, there does not appear to be a reliable indicator as to who was in control.
Just asking. I was told in the class room that whoever's cadaver had the highest CO2 level was likely the one on the controls at the time of impact. The FAA guys in the room agreed. Could this be another urban legend? The bone injuries were also covered as indicators.

Bob

[PA11]

I'll save the speculation for later, but I wanted to comment on all the ASI failure / AOA crutch commotion. Can we not fly airplanes without airspeed indicators?

If we have a reference for pitch in the pattern and on final, and a general power setting that holds a desired airspeed in the varied configurations and stages of the pattern, can't we negate having to look inside and just fly the airplane?

Even at merely 10 hours, students have demonstrated mastery of aircraft control without having to look at an ASI, let alone an AOA. Perhaps the next few tries around the patch, bring a safety pilot or CFI with you and try a few circuits without the ASI.

[steveinindy]

Just asking. I was told in the class room that whoever's cadaver had the highest CO2 level was likely the one on the controls at the time of impact. The FAA guys in the room agreed. Could this be another urban legend? The bone injuries were also covered as indicators.

Bob

Again it is one of those things that the field came to treat as true without any evidence to back it up. CO2 levels will increase postmortem and a short burst of exertion immediately prior to impact is unlikely to create a significant elevation. As for the fractures, that was part of what I mentioned in the earlier post.

[Ron Blum]

Sorry, I had to go on vacation :o) The accident was a stall-spin; how the pilot arrived there is irrelevant. I agree with everyone that you should be able to fly the airplane without an airspeed indicator (in a safe, reduced envelope). Although I am an engineer with 25+ years of Flight Test experience, I am not good enough to calculate stall speed real-time as I'm yanking and banking. I also agree that an AOA indicator on the panel is useless in VFR flight. That is why bigger, certificated airplanes have stick shakers and/or pushers. Yes, airplanes like Cubs give plenty of stall warning, but as we try to get more and more out of our designs, stall warning typically is reduced. For those that think that they haven't ever flown AOA, they have never flown a Piper, Beech or Cessna because that little horn you hear (or light in some Pipers ... which is not currently legal per the regulations) is AOA based. What I am suggesting is some kind of tactile stall warning in all airplanes ... including experimentals. It is coming; ask ASTM, GAMA, AOPA, FAA, etc.

I am not sure what the S-6 has in it for stall warning; it is probably up to the builder/owner. Randy makes good airplanes.

[Ron Blum]

I am not sure what the S-6 has in it for stall warning; it is probably up to the builder/owner. Update: The S-6 owner that I know says that there was not a stall warning device on his airplane, and he didn't think that a stall warning device was an option. He also noted that the airplane has good control up through the stall and releasing back pressure recovered the airplane.

[Bill Berson]

Update: The S-6 owner that I know says that there was not a stall warning device on his airplane, and he didn't think that a stall warning device was an option. He also noted that the airplane has good control up through the stall and releasing back pressure recovered the airplane.
It helps to specify stalls behavior at different power levels. Most planes have gentle power off stalls. But try a full power go around stall. Most pilots have little exposure to this. ( do it above 4000 agl, and be prepared for a spin recovery)

[Ron Blum]

Agree with you, Bill. Some airplanes will also stall well at a 1knot/sec deceleration rate (or higher) and flip on their back at <0.5 knot/sec rate. So many factors.

[David Pavlich]

About the best analysis of a stall/spin I've read is in the latest issue of Flight Training titled "The Not-So-Obvious cause of stall/spin accidents" by Budd Davisson. I've read a lot and viewed a few DVDs and all that I've read (training stuff mostly) discuss the classic stall as is taught in flight school. This article goes beyond that and does give this non-pilot a much better perspective when reading the NTSB accident reports.

David

[martymayes]

What I am suggesting is some kind of tactile stall warning in all airplanes ... including experimentals. It is coming; ask ASTM, GAMA, AOPA, FAA, etc.

Ron, what's your source for forecasting tactile stall warnings are forthcoming for GA lightplanes? Is it being discussed in a steering comitttee or something?

Personally, I don't see it happening anytime soon, x3 for experimentals. I think the 9L-3704 crash in Buffalo has made it clear even sophisticated stall warning systems are not 100% idiot proof. The real solution is training but I know that's a dirty word in many aviation circles.

[Ron Blum]

I am on the ASTM F44 Committee that is in the process of putting current part 23 into ASTM standards (similar to LSA). There are several stages of how the work is going to progress, but eventually the compliance will all be within ASTM standards. The FAA, foreign Agencies, OEMs and users are very involved in this process (unlike LSA) to get common guidance throughout the world. Anyhow, on the first day of the first face-to-face meetings the entire group was briefed on why this process was being done (1/2 cost to certify and 1/2 accident rates). The #1 item on the safety list was stall/spin or what the group has titled "Loss of Control". For the aerobatic person on this thread, I didn't choose those words as I think that Shawn Tucker and the likes would be offended if people referred to him being out of control for 1/2 of his routine (loss of control means something else in the flight test world, too). AOA was discussed as the silver bullet solution to the stall-spin problem. You're correct in that you can't make anything idiot proof ... we'll just make better idiots. The AF447 stall is a great example of the highest technology not saving the airplane and all the people on-board. Personally, I think that if we continue to make systems smarter and smarter, we, as a people, will get dumber and dumber.

[steveinindy]

I think the 9L-3704 crash in Buffalo has made it clear even sophisticated stall warning systems are not 100% idiot proof.

I think that crew catches a lot more **** than they should honestly. They were in the mindset of icing (references to transcripts about "the worst icing they had ever seen" etc) and in an aircraft where it is drilled into your head (thanks to the Comair crash on approach to Detroit Metro) that tailplane icing stall is a major concern. The onset of that is an abrupt and unexpected pitchdown possibly proceeded by control vibrations and a change in configuration. The upset came after they extended the flaps. The response they gave (flaps up and stick back) is exactly what you would expect if someone were responding to the tailplane stall. The unfortunate thing is that they were too low to have time to figure the problem out. I am not excusing their culpability in causing the crash. I am simply pointing out that instead of painting them as a pair of clueless stupid idiots who didn't deserve their licenses, let's look at the bigger problems here and find real solutions to them. The problem of "tunnel vision", confirmation bias and attention blindness needs to be looked at here unless we wish to see this same issue come up again. Maybe not in this same exact scenario for the implications are much broader than a lot of us are comfortable admitting.

Were they not paying attention to airspeed? Yeah but then again you try working that schedule and see how attentive you are. Did they misidentify things? Yeah but welcome to how the human brain works. All too often you see what you want to see. It's easier to look at this as "stupid pilots" than to look into the system that produced the accident. It's the same thing that happens when you have a midair on a clear day. You get "the pilots failed to maintain adequate lookout" or "how stupid is that!?" versus question whether or not "see and avoid" has some glaring shortcomings that the average VFR pilot is either not aware or chooses to ignore because of hubris or whatever else you want to chalk it up to. Either we are rank amateurs or we are professionals and are willing to ask and be asked the hard questions. As Gene Krantz put it in the aftermath of Apollo 1, being "tough and competent" is the price of admission to places where the lives of others are in your hands.

I'll put away my soapbox now.....

[steveinindy]

You're correct in that you can't make anything idiot proof ... we'll just make better idiots. The AF447 stall is a great example of the highest technology not saving the airplane and all the people on-board. Personally, I think that if we continue to make systems smarter and smarter, we, as a people, will get dumber and dumber.

Panic and fear are more powerful than almost any other force on the human mind. As someone else pointed out, training is a partial answer but even then you are still going to get folks who will freeze no matter despite the best training and screening in the world. The answer is probably a combination of technology AND training. I think all too often folks tend to get in the mindset that technology means you can neglect training and others have this mindset that technology is a crutch that "real pilots" don't need. After helping pick up pieces of shattered pilots who crashed for want of a GPWS or instrument training, I can say that (at least in my book) real pilots use whatever they have at their disposal to try to avoid getting hurt or killed.

[Ron Blum]

Along those lines, GPS has shown to reduce the number of fatal accidents of VFR pilots into IMC. In other words, they now know where the mountain is. GPS doesn't address the special disorientation in IMC, though.

[Bill Greenwood]

I am not sure what a GPWS is, but I am pretty sure I don't have one. I have been lucky enough to fly for 34 years. I have some specific training, some probably better than average skills in some areas like stall recognition and recovery. But I don't get to train as much as I'd like, I don't have regular access to a T-6 like I used to.

As much or more than being a skilled pilot, my approach to danger is to plan and fly so as to avoid trouble. The simple old motto of "Using your superior judgement to avoid having to use superior skill."

I am fortunate to live in an area where I don't do much bad weather flying in actual IMC. Here in the mountains we often have very nice days where the visibility is 50 miles or more, and if it if really bad it is much too bad to fly.

[martymayes]

I think that crew catches a lot more shit than they should honestly. They were in the mindset of icing (references to transcripts about "the worst icing they had ever seen" etc) and in an aircraft where it is drilled into your head (thanks to the Comair crash on approach to Detroit Metro) that tailplane icing stall is a major concern.

That's interesting, because "tailplane icing stall" is not mentioned in the Comair 3272 probable cause published by the NTSB. "Tailplane icing stall" was never part of Colgan's stall training curriculum. In fact, no US certificated aircraft has been identified as being succeptible to "tailplane icing stall." Perhaps you can enlighten us as to who exactly is drilling this into the heads of pilots? Also, I believe the "worst icing" comment from the FO was it was the worst she had seen in a long time.

What happen is the crew, while going though the motions, was totally disengaged from the tasks at hand. The speed decayed below profile and stayed there for most of the arrival up to the loss of control point. Not once is a speed callout recorded on voice recorder. The light was on but nobody was home.


The onset of that is an abrupt and unexpected pitchdown possibly proceeded by control vibrations and a change in configuration. The upset came after they extended the flaps. The response they gave (flaps up and stick back) is exactly what you would expect if someone were responding to the tailplane stall.

Yes, when the stick pusher activates, there is a very abrupt pitchdown. That's what it's designed to do.

If pilots of a 121 operator are inventing their own stall recovery methods, contrary to published company manuals, and contrary to how they are trained, then the training problem would be even more serious. But pilots are not doing that. The SPS activated on this aircraft, exactly as designed, startled the pilot back into real time where panic replaced a trained response that could have saved the aircraft. There was adequate room to recover, as evidenced by subsequent simulation events.


The unfortunate thing is that they were too low to have time to figure the problem out. I am not excusing their culpability in causing the crash. I am simply pointing out that instead of painting them as a pair of clueless stupid idiots who didn't deserve their licenses, let's look at the bigger problems here and find real solutions to them.

The bigger problem there was a marginal pilot was trained to minimum standards and placed on the line where skills atrophied to a dangerous level. Trying to "figure the problem out" after the aircraft departs controlled flight is usually not a good strategy. Didn't help being paired with a non-assertive crewmember who was still mostly disengaged (quite possibly from illness/fatigue/lack of rest).

[Flyfalcons]

Let's not discount that in training, stalls only go to the first indication of stall and at the time, recovery procedures focused on minimum altitude loss while accelerating out. I don't know how the Dash handles large power changes but in a couple jets I've flown, there is a large pitch-down moment when advancing thrust to full. Because of those two factors, stall recovery muscle memory for me was increase thrust to full power and pull back on the stick hard to avoid the nose-down pitch moment to avoid altitude loss (the Excel is particularly bad with this). In my opinion, stall training in the simulator should go to fully stalled or stick pusher before recovering.

[PA11]

It's more about being trained that the aircraft can power out of the stall, not about pitch changes with the addition of power. After Colgan, all that changed. Now we lower the nose just like we did in Cessnas.

[martymayes]

recovery procedures focused on minimum altitude loss while accelerating out.
Not anymore. There is no reference to altitude. What PA11 said....lower angle of attack for recovery.

[Ron Blum]

GPWS is Ground Proximity Warning System (larger airplane (high $$$) equipment). But this information (through GPS data and terrain mapping) is something that we can get in a "poor man's" version. We need to use technology to bring costs down (and safety up).

[Flyfalcons]

Yes I'm aware of that, I just finished recurrent a couple weeks ago, but I was referring to issues at play at the time of the accident. Stall demonstrations are still performed to "first sign" though.

[wacoc8]

During recurrent training last month on the Hawker 900xp, we let the airplane stall, in the landing configuration with the auto-pilot on. Let the airplane fly through the shaker until we got the pusher, then recovered using full power with a nose down pitch attitude (about 7 to 10 degrees). We only lost 400 ft. Granted, we knew it was coming and were not discussing what was for dinner or what is our favorite Abita beer. Practice is good and learn from others mistakes.

[steveinindy]

If pilots of a 121 operator are inventing their own stall recovery methods, contrary to published company manuals, and contrary to how they are trained, then the training problem would be even more serious.

Actually the procedure they followed was developed by NASA during tests evaluating the issue of tailplane icing.


Didn't help being paired with a non-assertive crewmember who was still mostly disengaged (quite possibly from illness/fatigue/lack of rest).

Right. On that we agree.


In fact, no US certificated aircraft has been identified as being succeptible to "tailplane icing stall."

Um....Vickers Viscount, DC-4s, the Convair turboprops, YS-11s and Jetstream 31s all had fatal crashes as result. The DHC-6 also had issues. Non fatal incidents involved the Saab 340, DC-9/MD-80 series and the ATR-42. (http://www.skybrary.aero/index.php/Ice_Contaminated_Tailplane_Stall#Accident_History)

The following comment is made on the cited page: "Stick Shaker/Stick Pusher

It is considered possible for a pilot to confuse the stick shaker with the elevator buffet condition, followed by interpreting the stick pusher as an elevator snatch. This reinforces the requirement to be aware of airspeed, configuration and pitch control forces. Misinterpreting the shaker/pusher for a tailplane stall could be a catastrophic mistake; conversely, misinterpreting the elevator buffet/elevator snatch behaviour for a main wing stall could be equally disastrous."

I have seen that previously mentioned in NASA papers on the subject. There's a LOT of NASA research on this for something that isn't a factor at all according to you.

I agree that a disengaged crew here played a major role and the "startle factor" was what sealed their fate. My point was simply that mindset can cause bigger issues than "stupid pilots".

To back the icing issue contention up (emphases are my own):
VICKERS VISCOUNT:
4/6/1958 Freelandville, Michigan Capital Airlines Flight 67 (I have a piece of this aircraft in my garage; we found it when we went to put flowers at the site on the anniversary of the crash)

PROBABLE CAUSE: "An undetected accretion of ice on the horizontal stabilizer which, in conjunction with specific airspeed and aircraft configuration, caused a loss of pitch control."

1/29/1963 Kansas City, MO Continental Airlines flight.

PROBABLE CAUSE: "An undetected accretion of ice on the horizontal stabilizer which, in conjunction with a specific airspeed and aircraft configuration, caused a loss of pitch control."
4/14/1963 Oslo, Norway Icelandair Flugfelag Islands flight
POSSIBLE NOT CONFIRMED
PROBABLE CAUSE: "The accident to TF-ISU is assumed to have been caused by the fact that, during the approach to Fornebu, the pilot lost control of the aircraft at such a low height that recovery was not possible. From the evidence available, it has not been possible for the Commission to determine why this happened. There are possibilities, however, that the cause may have been that ice formed on the stabilizer or that the propellers went over to ground fine pitch. The Commission considers that the latter hypothesis is slightly more than the former.


1/15/1977 Stockholm, Sweden Linjeflyg Flight 618

PROBABLE CAUSE: Ice on the leading edge of the stabilizer resulted in flow separation and stabilizer stall.

JETSTREAM 31:
12/26/1989 Pasco, WA http://aviation-safety.net/database/record.php?id=19891226-0


PROBABLE CAUSE: "The flight crew's decision to continue an unstabilized instrument landing system approach that led to a stall, most likely of the horizontal stabilizer, and loss of control at low altitude. Contributing to the accident was the air traffic controller's improper vectors that positioned the airplane inside the outer marker while it was still well above the glide slope. Contributing to the stall and loss of control was the accumulation of airframe ice that degraded the aerodynamic performance of the airplane."

1/30/1991 Beckley, WV

PROBABLE CAUSE: "Flight into known adverse weather conditions by the pilot, which resulted in ice accumulation on the aircraft and subsequent loss of aircraft control (tail plane stall) as the flaps were fully extended. Factors related to the accident were: the pilot's inadequate use of the preflight briefing service, inadequate training provided to the pilots by company/management personnel, inadequate surveillance by the FAA, and icing conditions."

YS-11:
1/10/1988 Yonago-Miho Japan (icing/slush on the horizontal stab prevented rotation for takeoff causing a runway overrun)
3/15/1989 Lafayette, IN Operated by Mid-Pacific Air

Those are just the ones I found in a quick search before I got bored with the exercise....


That's interesting, because "tailplane icing stall" is not mentioned in the Comair 3272 probable cause published by the NTSB.

By the way, I got my commuter crashes mixed up. It was the crash at Pasco, WA not Detroit that I was thinking of. Sorry about that.

[Ron Blum]

Going back to stalls in the pattern (takeoff, climb and landing), we need to do something different to get pilots to notice that something is about to go bad. I find this similar to the "cyclops" brake light in cars. I am old enough to have driven before they were mandated, so I notice them as different. Younger people that I talk to don't notice them (or think that they are the only brake lights). For them it is not more noticeable or out of the ordinary. For me, the same is true with LED lights (on cars, airplanes, trains, flashlights, etc.). What can we do for airplane stalls that will bring the pilot out of his/her happy place to shout, "YOU'RE ABOUT TO DO SOMETHING REALLY BAD!"?

[PA11]

When's the last time you guys have done stalls in your own airplanes?

[Joe Delene]

When's the last time you guys have done stalls in your own airplanes?

One of my more useful things I do is 'slow flight' at altitude in different configurations. A fair amount of the time I include full stalls. Low to the ground does not leave a very wide margin for recovery. I like to back up to what lead to the predicament, usually distraction or lack of attention to the more important matters. Instead of worrying about stall recovery at 800', I'd rather focus on attention to not get one's self in that flight regime.

[Ron Blum]

When's the last time you guys have done stalls in your own airplanes?
Regretfully, we sold our airplane, and I have nothing to fly at the moment ... not even at work ... and not even a sailplane. The sailplanes I stall on every flight (sometimes intentionally and sometimes unintentionally while thermalling). I would stall the P172D we had often. Personally, I enjoy stalling rental C150s with 40 degrees of flaps at full power (they go over on their back and spin well ... for a short time ... before they recover on their own). I love to learn, but this is what I do for a living, so my experiences are a lot different than most. I'd like to build another (long story) Wright 1911 glider, and I don't plan on stalling it ... ever ... well, maybe. My day job is to make airplanes that try to warn pilots that they are about to stall and stall in a well-behaved manner when they do.

[Bob Dingley]

When's the last time you guys have done stalls in your own airplanes?
I was lucky to stumble on to an old school CFI at the tail end of the CAA era. Clyde left Embry Riddle when they got rid of their Stearmans and opened up his own school. I was 17. You can guess how my training went. Stalls & slips at hour one. Pull the pitot line off the ASI at hour two. Spins at hour four. Change from wheels to skis at hour six. Solo at 7.5.
After solo, more slow flight and now accelerated stalls. Cross control stalls. I had more time at the edge of a stall than I had X-country. Instead of letting me waste time boring holes, Clyde told me to go up to 4,000 and stall the plane. But don’t release back pressure. Keep the wings level with rudder and let it enter the next stall. Repeat down to 3,000. Remember to clear the engine. Report back to him how many stalls in 1,000. It was 10.

When the FAA replaced the CAA, the flight test standards changed. Just in time for me to get my Private. CAA called them “power on” and “power off” stalls. They wanted to see you aggressively break the stall, don’t worry too much about altitude loss. We all know the FAA method. And we know what negative habit transfer is. I eventually saw negative habit transfer come full circle in helo check rides. Helos do vortex ring state recoveries. AKA: settling with power. It must be a “positive” nose down (or side slip) recovery like 20 to 30 deg. If it’s a tepid recovery, you accelerate down at the rate of a toolbox and the ground gets in the way. You can see 6,000 fpm on the VSI. Looks just like a deep stall.

90% of everything I know about flying, I learned in the back seat of a Cub. The other 10% took decades of burning other people’s kerosene staring at glass.

The accident that started this thread happened in safe, functioning, docile airplane on a nice day. I’ve got a sneaky feeling that we will eventually find that the PIC was incapacitated and the passenger had zero training. This should not be the accident that causes us to re-invent the wheel. I know of an accident ten years ago where a passenger pulled it off. Two lived, two died.

Bob

[WLIU]

But to speak to the issue of "when was the last time you did stalls" - Once when I did a BFR, the CFI commented that statistically, the average pilot who comes in for a BFR has flown less than 20 hours a year. And his observations matched mine that a very large percentage of the pilots out there are not comfortable flying in the low speed end of the performance envelope.

So the likely answer to the question of "the last time" might well be "two years ago at a BFR".

To speak to the observations in the last post, I suggest that our current training treats stalls as scary, avoid at all cost, events. Many years ago stalls and spins were treated as routine parts of the curriculum. OK, your average pilot does not NEED to know how to spin, but preaching ignorance is equally silly. I would suggest that the curriculum include a CFI demonstration of a spin and recovery, but we now have a population of CFI's who likely have done the minimum of two spins in their entire aeronautical lives. And we continue to wring our hands over stall spin accidents.

I think that I understand that LSA standards do not require an audible stall warning, unlike Part 23 and 25 airplanes. Is that correct?

Anyway, I will suggest that the current FAA training syllabus moved too far in the direction of over simplification and needs beefing up in the airmanship area.

Best of luck,

Wes
N78PS - I spin every flight. Inverted every other.....

[Ron Blum]

I would tend to believe the 20 hours/year and stall at the last BFR for the vast majority of pilots is true. Not only is training lacking, but aircraft certification has gone the same way. If an airplane is shown to be spin resistant or have a chute on it, spins are not required for the airplane to certify. Some of the aerodynamic changes to make an airplane spin resistant also keep the airplane in the spin and make it harder or impossible to recover. LSA, ultralights and experimental aircraft are all not required to have stall warning. (this is not the full regulation, but ...) Part 23/25 airplanes must have 5 knots/7% prior warning (part 23/25) and must be able to keep roll within 15/20 degrees (part 23/25) or have a pusher to prohibit aerodynamic stall. If roll is less than 60 degrees during all stalls, the pusher must activate 2 knots before aerodynamic stall, and if roll is greater than 60 degrees during any stall, it must activate at least 5 knots before aerodynamic stall. So, not only are our pilots not shown how to recover from a spin, the airplane may not be capable of recovering.

[WLIU]

I am not sure about the current batch of Part 23, under 6000lbs, airplanes not having to have been spun successfully. Last time I looked the requirement was to be able to spin 2 turns and then recover within one additional turn with normal spin recovery control inputs. Aircraft that could not recover within one additional turn must be placarded "Intentional Spins Prohibited". So is the Cirrus placarded?

Best of luck,

Wes
N78PS

[Ron Blum]

Per current regulations, airplanes with pushers or those that are determined to be spin-resistant or those that have parachutes do not need to show compliance to the spinning regulation. The Cirrus states (I can't get this thread to accept an image), "Normal Category Airplane, No acrobatic maneuvers, including spins, approved". Ironically, the "d" in "approved" is removed by a screw.

[steveinindy]

Per current regulations, airplanes with pushers or those that are determined to be spin-resistant or those that have parachutes do not need to show compliance to the spinning regulation

There is a reason why I am kicking around a stick shaker/pusher and a ballistic parachute plus easy spin/stall recovery for my design.

[WLIU]

So the AFM statement about "including spins" is a standard statement and does not mean that the aircraft was not spun in flight test. I am not privy to the Cirrus Cirrus certification data but I can tell you that Piper airplanes have the same statement in the AFM's and they were ALL spun, even the twins. That info is straight from the retired chief designer, who is my neighbor. We have had some very interesting discussions on spinning the twin engine aircraft. Anyway, the manufacturer puts that statement in the AFM so that YOU will not try to spin the aircraft. But the flight test department likely did over 100 spins before putting that statement on the panel and in the AFM.

I should note that up through 2 turns, as spin is "incipient" and only becomes fully developed after about turn 3. So the requirement is be recoverable from an incipient spin. Now spins are an interesting topic all its own and we can go on and on for a long time.

That said, I will agree that stalling and spinning below pattern altitude hardly ever has a good outcome.

Now if Steve is looking for design ideas for spin resistant AND rugged, I would suggest looking at the Velocity canard. I think that was the one that got stuck in the nose high attitude, the pilot looked at the rate of descent, and he chose NOT to use his parachute, but rather ride it down into the ocean, where it seemed to make an acceptable boat until help arrived. Very interesting episode of both aerodynamics and pilot judgement.

Best of luck,

Wes
N78PS

[rwanttaja]

So the AFM statement about "including spins" is a standard statement and does not mean that the aircraft was not spun in flight test. I am not privy to the Cirrus Cirrus certification data but I can tell you that Piper airplanes have the same statement in the AFM's and they were ALL spun, even the twins.
Cirrus spin testing is discussed on one of their web pages:

http://whycirrus.com/engineering/stall-spin.aspx


"As a footnote, when Cirrus applied for European certification, the authorities there (initially JAA, later EASA), when first evaluating the Cirrus SR20 agreed with the principles of the FAA/ELOS approach but had further questions. A series of spins were performed on their initiative. While not a complete program they reported no unusual characteristics."


Ron Wanttaja

[WLIU]

That is interesting info in that it supports the statement that Cirrus got the FAA to agree that spin testing was not required to achieve an Equivalent Level of Safety (ELOS). Flight testing is expensive and so talking the FAA out of officially requiring that work, with the required data analysis and reporting, likly shortened the project schedule a lot as well as saved $$. I can only conjecture that since the airplane is a such very conventional configuration that conventional behavior was expected, calculated, demonstrated informally, and later demonstrated formally for EASA. Engineers use "substantial equivalency" with existing designs to justify reduced work and it sounds like the FAA will buy some of that rationalization. EASA it appears was a little more skeptical, but in my business we see the europeans similarly require more engineering data than the US.

Thanks,

Wes
N78PS

[steveinindy]

Now if Steve is looking for design ideas for spin resistant AND rugged, I would suggest looking at the Velocity canard. I think that was the one that got stuck in the nose high attitude, the pilot looked at the rate of descent, and he chose NOT to use his parachute, but rather ride it down into the ocean, where it seemed to make an acceptable boat until help arrived. Very interesting episode of both aerodynamics and pilot judgement.



Interesting but mushing into the water and nearly every common crash scenario are pretty different critters so I am not sure you can judge ruggedness by a more or less controlled ditching.

I am trying to stay away from composite designs because I do not have the money to get an autoclave for curing. It is much easier for an inexperienced designer to design a crashwothy metal design and that design is able to be executed with techniques applicable to homebuilding. The composites in my design are largely used in non-structural parts (to reduce weight) and those that are designed to attenuate energy in a crash or hard landing.

[Ron Blum]

I can only conjecture that since the airplane is a such very conventional configuration that conventional behavior was expected, calculated, demonstrated informally, and later demonstrated formally for EASA.
Be careful with your conjecture. The Cirrus wing is not "conventional" (that is what makes it more spin-resistant); look at the leading edge. And, "They reported no unusual characteristics" is not the same as "We have shown compliance to all applicable regulations." I am not doubting what you're saying about Piper and their Flight Test programs, but I know first hand that Cessna and Beech did not do that ... especially with the jets (note: twins are not required to spin). Although definitely cheaper (no flight testing is required), I don't believe that the new spin-resistant regulation is a move in the direction of safety. Evidence from this thread through the AF447 fatal accident support that statement.

[Southron]

Well I got caught in a thunderstorm that was over my airport. The rain hadn't started yet but the winds were going crazy.

On Final I ALWAYS KEEP MY EYE ON THE AIRSPEED INDICATOR, a pilot would have to be crazy to judge his speed by the way the ground was passing underneath his airplane! When I flared for landing the runway was flashing under me like I was I had never seen it do before while my ASI indicated I was at my normal touchdown speed.

I put the airplane down (a Cessna 150) because the runway was plenty long. I figure I had a 50 MPH tailwind when the wheels touched the tarmac.. Just when I taxied into the ramp, the storm broke in its full fury.

MORAL OF THE STORY-DON'T STALL OUT IN THE TRAFFIC PATTERN. I AM SORRY THAT THOSE TWO INDIVIDUALS LOST THEIR LIVES.

[PA11]

But what do you do when your ASI is broken? It's not that we all need to become super pilots who fly by the seat of their pants, it's that we need to master control of the aircraft using all the communication venues the aircraft is giving us, both directly through instruments and indirectly through the other senses.

[Mayhemxpc]

We teach stalls for several reasons, perhaps the least important of these is stall recovery. One is to exercise mastery of the craft throughout its performance envelope. Another is to recognize the signs of an incipient stall and to take action before it goes past that. ASI's are just one tool, as are stall indicators. The first is only good if you know the stall speeds throughout the envelope, e.g., at 30 and 60 degrees bank and various weights (the second not being as critical in light aircraft as the former.) Stall warning indicators may not provide adequate notification. They may also momentarily sound in turbulence, which could frighten someone inexperienced with that happening. Some airplanes seem to go from mush to a sudden break and really impressive roll if the airplane is not perfectly coordinated (e.g., tricycle Maules without vortex generators.) As someone else pointed out AOAs are not a magic bullet, especially when the pilots attention is supposed to be OUTSIDE the airplane. Being aware of mushy controls, low airspeed, or any uncommanded action is critical.

I think we are mostly in violent agreement. Is there anything else that needs to be said?

Chris Mayer
N424AF