Commuter plane crash

[dusty IV]

The Commuter plane crash in Feb. just got a lot of PR. Blamed on ice on the wing. Last words were Gee,look at the ice on the wing as they were coming in for a landing. er something like that .

So how do you recover from a stalled wing covered with ice? The inquiry indicated it could be done. Can it?

[MCarlton]

More to the point, why was there such significant ice on the wing,why was it only noticed on the approach and why, in that scenario, was a normal approach pattern adopted without taking account of the effect it might have on the aircraft?

[Thomas B]

The Commuter plane crash in Feb. just got a lot of PR. Blamed on ice on the wing. Last words were Gee,look at the ice on the wing as they were coming in for a landing. er something like that .

So how do you recover from a stalled wing covered with ice? The inquiry indicated it could be done. Can it?

It depends on how much ice and how it accumulated and how much it changed the airfoil on the wing and the deicing and anti icing gear the plane has.....a little ice can be dealt with, but a lot can make the aircaft much harder or impossible to recover from an upset....

I would not agree that an aircraft could be recovered for sure from a stall/spin on approach in a major icing situation. The best percentage effort for not crashing would be to do all possible to avoid the stall at all costs.

Aircraft on autopilot have had issues dealing with icing...this is well known.

The famous Ju-52 had a major flaw that caused a real need to avoid icing conditions...ice would accumulate in between the trailing flap and aileron and the wing, locking them in place. Due to the venturi effect of this setup, ice would accumulate there sooner.

[JetPlaneFlyer]

Had they known about the ice problem earlier i guess they would have increased their approach speed to avoid stalling in the first place. If they were at low altitude when the stall occured then it was probably unrecoverable.

[Work in Progress]

The direct cause of that accident was airframe icing, but almost certainly tailplane icing rather than wing icing was the actual killer, leading to a non-recoverable tailplane stall and uncontrollable pitch-down. Tailplane icing can be pernicious because it is not as well understood by pilots as wing or prop icing, and because in most cases it cannot be seen from the cockpit.

A reduced flap setting would have helped as it would have reduced the required down-loading on the tailplane.

There is a very good NASA video available on the issue here, which explains it all in full.
http://video.google.com/videoplay?docid=2238323060735779946

[CloudyIFR]

I realize you're looking for info on stalls related to icing but if you're talking about the recent crash in Buffalo by Colgan Air, I think icing was not the issue. The Dash-8 airplane can carry a butt load of ice, it's a great design.

There's a lot of aspects to this accident but a quick summary:
1) Too much unrelated cockpit conversations during critical phase of flight
2) Ignored for 6.7 seconds the stick shaker telling the pilot a stall was imminent
3) Failure by either pilot to notice the airspeed reduction
4) Once the plane stalled the pilots incorrect stall recovery (difficult in IMC conditions) but it's something we train for, called unusual attitudes.
5) Crew rest will be an issue

It's important to note that the crew should have never gotten into the position of stall that needed excellent piloting skills to recover. The airplane warned them, then the plane tried to save them but sad to say it didn't happen.

I'll save my thoughts on cockpit automation i.e. A/P useage.

The Final 7 minutes CVR.
http://online.wsj.com/article/SB124214197938010949.html#printMode

FDR Animation
http://www.ntsb.gov/Events/2009/Buffalo-NY/AnimationDescription.htm

Curtis
Montana
Commercial Pilot. 6,500 hours.

[nmasters]

2) Ignored for 6.7 seconds the stick shaker telling the pilot a stall was imminent


How could anybody ignore a stick shaker? :eek: :censored:

--Norm

[vintage1]

How could anybody ignore a stick shaker? :eek: :censored:

--Norm
That's probably a question for your wife. ;)

[MCarlton]

Are there pilot induced stick shakers? ;)

[nmasters]

It's that kind of talk that drove the puritans to migrate to the colonies. :rolleyes:

[Dan Baldwin]

I realize you're looking for info on stalls related to icing but if you're talking about the recent crash in Buffalo by Colgan Air, I think icing was not the issue. The Dash-8 airplane can carry a butt load of ice, it's a great design.

There's a lot of aspects to this accident but a quick summary:
1) Too much unrelated cockpit conversations during critical phase of flight
2) Ignored for 6.7 seconds the stick shaker telling the pilot a stall was imminent
3) Failure by either pilot to notice the airspeed reduction
4) Once the plane stalled the pilots incorrect stall recovery (difficult in IMC conditions) but it's something we train for, called unusual attitudes.
5) Crew rest will be an issue

It's important to note that the crew should have never gotten into the position of stall that needed excellent piloting skills to recover. The airplane warned them, then the plane tried to save them but sad to say it didn't happen.

I'll save my thoughts on cockpit automation i.e. A/P useage.

The Final 7 minutes CVR.
http://online.wsj.com/article/SB124214197938010949.html#printMode

FDR Animation
http://www.ntsb.gov/Events/2009/Buffalo-NY/AnimationDescription.htm

Curtis
Montana
Commercial Pilot. 6,500 hours.

The NTSB seems to aggree with your assesment that the icing had little to do with the crash.

Preliminary airplane performance modeling and simulation conducted by the NTSB show that icing had a minimal effect on the stall speed of the Colgan Air Bombardier Q400 that crashed outside Buffalo on February 12, killing all 49 occupants and one person on the ground, the Safety Board said today.



It appears that Marvin Renslow, the pilot on the flight, was at the controls, and Rebecca Shaw, the copilot, was handling gear, flaps, throttles, communications, etc. Within 1 second after the stick shaker began, miss Shaw immediately advanced the throttles (the correct action), and Captain Renslow immediately pulled back on the yoke, which is the opposite of what should be done when the stall warning goes off. He continued to hold back pressure throughout the stall, and all the way to the ground. The stall actually occured at almost 1700 ft AGL, and it was another 18 seconds before the plane contacted the ground. If he had relaxed the back pressure after the stall, he might have had enough altitude for the plane to recover from the stall.

I'm not a commercial pilot, but I do have a private pilot license, and I can't imagine ANY pilot pulling back on the yoke when faced with a stall warning.

Dan

[vintage1]

The NTSB seems to aggree with your assesment that the icing had little to do with the crash.


It appears that Marvin Renslow, the pilot on the flight, was at the controls, and Rebecca Shaw, the copilot, was handling gear, flaps, throttles, communications, etc. Within 1 second after the stick shaker began, miss Shaw immediately advanced the throttles (the correct action), and Captain Renslow immediately pulled back on the yoke, which is the opposite of what should be done when the stall warning goes off. He continued to hold back pressure throughout the stall, and all the way to the ground. The stall actually occured at almost 1700 ft AGL, and it was another 18 seconds before the plane contacted the ground. If he had relaxed the back pressure after the stall, he might have had enough altitude for the plane to recover from the stall.

I'm not a commercial pilot, but I do have a private pilot license, and I can't imagine ANY pilot pulling back on the yoke when faced with a stall warning.

Dan

If you look at WIPS link, an ice stalled tailplane would push the nose down hard. The natural thing to do would be to pull back hard.

Its not clear as to whether the stick shaker is an indicator of a stalled tailplane though.

[JetPlaneFlyer]

If you look at WIPS link, an ice stalled tailplane would push the nose down hard. The natural thing to do would be to pull back hard.


Stall of the wing also causes the nose to drop...but I'd hope that the 'natural thing' for a competent pilot to do was NOT to pull back on the stick, quite the opposite in fact. If the stick shaker was shaking then surely there can be no possible excuse or reason for pulling back on the stick?
Looks to me like he panicked and forgot all his training :(

[vintage1]

Stall of the wing also causes the nose to drop...but I'd hope that the 'natural thing' for a competent pilot to do was NOT to pull back on the stick, quite the opposite in fact. If the stick shaker was shaking then surely there can be no possible excuse or reason for pulling back on the stick?
Looks to me like he panicked and forgot all his training :(

Stall of a wing that causes the nose to drop and speed to build up can be recovered by pulling the stick back once the wing is unstalled.

However the opposite is required with stalled tailplane where the aircraft is trimmed with a lot of negative lift on the tailplane.

The video makes the point that training in this area is not good: That's what the video is for. The correct action is in fact to reduce flaps, lowering the tailplane load, and reduce stick until the tailplane comes out of stall.

The point being he would have found himself in a steep nose down attitude with plenty of airspeed,and not in a wing stall at all, but the aircraft not responding to up elevator.

The only action that would have worked would be to pull the flaps off.

[CloudyIFR]

I'm not a commercial pilot, but I do have a private pilot license, and I can't imagine ANY pilot pulling back on the yoke when faced with a stall warning.

Dan

Dan,

I fly single and twin engine Cessna's and at the first indication of a stall you are correct that you apply full power, apply forward pressure to the yoke to decrease the AoA, lower the nose below the horizon to gain airspeed then recover once the plane has regained flying speed.

I also fly Piper Cheyenne's turboprops and the recovery is similar except there is quite a bit more power and you only apply enough forward pressure to lower the nose to the horizon i.e. maintain altitude and power your way out of the stall.

Lastly I fly a Learjet 24D and with this plane there is so much excess power you hold the nose level and it'll power itself out of the stall.

I have a checkride next week in the Cheyenne and Learjet and the lear is so amazing that when the boss will fail a motor on departure at 400' AGL I'll have to reduce power on the operating engine to keep the airspeed below 200kts in Class D airspace! :) Now is that fun or what!

You are correct though, the pilot pulled too much aft without the addition of power. You'll also notice in the video the application of flap and gear while maintaining level flight without the addition of power.

Curtis
Montana
www.TailwindGliders.com

[Dan Baldwin]

Dan,

I fly single and twin engine Cessna's and at the first indication of a stall you are correct that you apply full power, apply forward pressure to the yoke to decrease the AoA, lower the nose below the horizon to gain airspeed then recover once the plane has regained flying speed.

I also fly Piper Cheyenne's turboprops and the recovery is similar except there is quite a bit more power and you only apply enough forward pressure to lower the nose to the horizon i.e. maintain altitude and power your way out of the stall.

Lastly I fly a Learjet 24D and with this plane there is so much excess power you hold the nose level and it'll power itself out of the stall.

I have a checkride next week in the Cheyenne and Learjet and the lear is so amazing that when the boss will fail a motor on departure at 400' AGL I'll have to reduce power on the operating engine to keep the airspeed below 200kts in Class D airspace! :) Now is that fun or what!

You are correct though, the pilot pulled too much aft without the addition of power. You'll also notice in the video the application of flap and gear while maintaining level flight without the addition of power.

Curtis
Montana
www.TailwindGliders.com

While I was working on my license, one of the exercises I practiced was flight at minimum controllable airspeed, where you fly around with the stall warning going off the whole time. Another exercise was to pull the yoke all the way back to my gut, and try to hold the airplane level by dancing on the rudders. The hardest thing about that was fighting my natural tendency to relax the back pressure when the plane started to mush or drop a wing. Apparently the pilot on this flight did not have that natural tendency.

As soon as the stick shaker went off, the copilot did apply nearly full power, but it wasn't enough to compensate for the herculean pull on the yoke by the pilot. The pilot applied 25 lbs of backforce resulting in a 1.42G pullup. The pilot was not compensating for a nose drop. The nose was high when he pulled on the yoke, and ended up at something like 30 deg above the horizon. Unfortunately, that plane doesn't have enough power to 3D.

I haven't flown in many years now (except RC, of course), and I really miss it. It helps to read about your flying experiences, although it does make me jealous.

Dan

[JetPlaneFlyer]

The direct cause of that accident was airframe icing, but almost certainly tailplane icing rather than wing icing was the actual killer, leading to a non-recoverable tailplane stall and uncontrollable pitch-down.

I just dont see that in the evidence or the video reconstruction. Looks to me like gross pilot error. The pilot let the airspeed fall, the stick shaker went off, correctly indicating that the WING was approaching stalling AoA (but not yet stalled). Then for some inexplicable reason the pilot hauled hard back on the yoke :( .
The aircraft responded as you would expect with a fully functional 'non-stalled' tail.. the nose pitched up and the wing stalled. Even then it was probably recoverable if he's even took his hands of the yoke and let the stick pusher do it's job.. but he just kept it pulled back!... inexplicable and tragic.

Steve

[vintage1]

How accurate is the video reconstruction?

Why would a pilot, in a stall, keep the nose up?

Its the inexplicability of the thing..that suggestss the investigation didn't cover all the bases.

[JetPlaneFlyer]

How accurate is the video reconstruction?

Why would a pilot, in a stall, keep the nose up?

Its the inexplicability of the thing..that suggestss the investigation didn't cover all the bases.

It was produced by the US National Transport Safety Board for the public hearing into the crash.. It was reconstructed from the planes black box recordings which would show control input, aircraft attitute, altitude, airspeed etc.. plus data from ground radar and voice recordings etc..

I'd say it should be highly accurate... Do you think they are trying to cover something up?

As to why the pilot would pull the yoke back and keep it back.... incorrect decission made under stress in a split second, followed by sheer blind panic? Even pilots are human.

Steve

[Work in Progress]

I crashed my Formosa last year (fairly gently) in a stupid stall accident. Just as I was taking off, the TX battery ended its life, and the voltage sagged, making my transmitter low voltage alarm bleep out with the aeroplane climbing through about six feet height. Obviously I needed to land within seconds while I still had some sort of control, and chopped the throttle (good decision) but instead of letting it float down straight ahead and probably land harmlessly in the long grass or the hedge, I tried the "impossible" turn back to the mowed strip, and stalled it in. i can still remember seeing the nose drop in the turn, and pulling the stick back further instead of unloading and rolling the wings level. I have no idea why I did that - I would never do it in a full size aeroplane, and have had plenty of EFATO practice and plenty of actual cable breaks winch launching in sailplanes. For some reason, probably because I had not adequately self-briefed about possible problems and solutions before take-off, I panicked completely and stuffed it in.

A trivial matter in comparison to this accident, of course, but it does show that people do strange things on the spur of the moment. Ideally, sufficient training ensures that the instinctive reactions of various situations are safe ones. A lot of current airline pilots have not experienced a full stall for a very long time - unless they are the select few who also fly Cubs or Tiger Moths on their weekends off.

[Flight Engineer]

This isn't the only pilot failing to recognise approach to stall and failure to correctly recover from stall accident this year. The Turks put a 73 in too!

[CloudyIFR]

This isn't the only pilot failing to recognise approach to stall and failure to correctly recover from stall accident this year. The Turks put a 73 in too!


I rarely do Autopilot coupled approaches as I'd rather hand fly. Perhaps this is why but when I do A/P coupled approaches it's very tough to keep my head in with what's going on, much easier to just fly the plane myself.

I believe I notice diversions from airspeed, glideslope or localizer sooner than with the electrons flying.

Curtis
www.TailwindGliders.com

[Flight Engineer]

I was at a very interesting Head Up Guidance Systems symposium last week hosted by Rockwell Collins and Lufthansa (our parent company). One of the major threads of conversation throughout the day was how HUGS encourages man machine integration rather than interface, and that this active integration significantly reduces excursions.

[StevenatorLTFO]

In that video, there is a huge airspeed decrease when the condition levers go from min to max. Is that similar to prop pitch on a recip powered airplane?

[JetPlaneFlyer]

In that video, there is a huge airspeed decrease when the condition levers go from min to max. Is that similar to prop pitch on a recip powered airplane?
I believe that the condition levers set the RPM of the constant speed props. In cruise they are set to min which equates to about 850RPM. On landing approach they go to MAX which is about 1200RPM which is to allow for reverse thrust on landing or to give maximum thrust should a go-around be needed.

Pitch adjusts automatically to suit power and RPM

Steve

[invertmast]

I believe that the condition levers set the RPM of the constant speed props. In cruise they are set to min which equates to about 850RPM. On landing approach they go to MAX which is about 1200RPM which is to allow for reverse thrust on landing or to give maximum thrust should a go-around be needed.

Pitch adjusts automatically to suit power and RPM

Steve


Unless its different in the dash-8 "condition" levers in the king-air 90's i fly, equate to N1 idle rpm. So min (low idle) is approx. 52% N1 and high idle (max) would be around 85% (if my memory is correct) n1 idle rpm.

The "high idle" condition, makes the reverse thrust on landing more effective, as the engine is already spooled up.

[CloudyIFR]

invertmast,

I'm not sure about the percentages, but they are quite close. During flight you'll most likely see no change at all when moving the condition levers from low to high.

At least that's how it is in the Cheyenne's with PT6-135's.

Curtis
Montana

[Cap_n_Dave]

How accurate is the video reconstruction?

Why would a pilot, in a stall, keep the nose up?

Its the inexplicability of the thing..that suggestss the investigation didn't cover all the bases.

Because turboprop fliers are on the "ladder" on their way to jet certification. Accordingly, they aren't paid very well, and have little experience when compared to pilots of similar age in the military and those who command larger jet aircraft.

Bit of a "dirty secret" IMO.

[groundfx]

Because turboprop fliers are on the "ladder" on their way to jet certification. Accordingly, they aren't paid very well, and have little experience when compared to pilots of similar age in the military and those who command larger jet aircraft.

Bit of a "dirty secret" IMO.
Not much of a secret anymore.
http://new-yorkpost.org/seven/05142009/news/nationalnews/co_pilot_was_paid_just_16g_169217.htm

Among the revelations:
* Co-pilot Rebecca Shaw was paid $16,254 a year, lived with her parents in a Seattle suburb and worked part time in a coffee shop. She'd gone 36 hours without proper bed rest prior to the fatal flight.
* Capt. Marvin Renslow earned $55,000 a year. He commuted from Tampa on Feb. 9 and was in the middle of a two-day assignment. It is unclear where Renslow slept the night before the fatal flight, but on Feb. 12, he checked in at Newark at 3:30 a.m., then idled in the break room.
* Renslow did not tell Colgan about his previous flight check failures.
* There are no checks on preflight pilot fatigue, nor are proper sleeping areas provided.
Unbelievable.

Executive's of Colgan Air setup a situation where bad things were more likely to happen. I don't understand why there isn't a criminal investigation going on looking into whether there was a level of criminal negligence.

Also, where is the government oversight? First lack of oversight of banks and now this.

Unbelievable. If I was an American tax payer I'd be furious and be demand answers from my local rep.

Maybe airlines should have to disclose to the public a bio (including salary, years of experience, discipline actions in last 5 years, etc.) on the pilots before you fly and offer you a full refund if you decline to fly.