TBM Icing analysis video.

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rookiepilot
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TBM Icing analysis video.

Post by rookiepilot »

Again few years back. This one freaks me out a bit.

https://m.youtube.com/watch?v=0JkLR_xgayM
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Re: TBM Icing analysis video.

Post by digits_ »

Lots of unnecessary drama in that video.

Moderate icing should not be a problem, they glanced over the second part of the definition that said that anti icde should be used. This airplane had proper anti icing. Climbing in icing doesn't mean certain death either. You don't *need* to raise the nose if you accept a slightly lower climb rate.

The video is strongly hinting the pilot brought it upon himself by not checking the weather and going. I don't think there is anything in the displayed weather reports that should have prevented him from leaving in such a machine.

Letting it stall/spin due to icing, that's where the trouble starts of course, but that seems to be only an aftertought. Focussing on the pre flight stuff for this accident is irrelevant imho.
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Re: TBM Icing analysis video.

Post by challenger_nami »

In my opnion, this accident like many other accidents was the end result of multiple seemingly manageable issues which in combination turned into one big disaster.
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Re: TBM Icing analysis video.

Post by pelmet »

I disagree with the TBM manual for the first three things to do when it comes to severe icing(Request priority handling from ATC, avoid abrupt/excessive maneuvering, do not engage the autopilot). The first three things should be SPEED, SPEED, SPEED.....as in maintain an airspeed which will be significantly higher than what is safe with a clean wing.

I used to fly a twin turboprop that had a really bad record of many accidents and incidents in icing conditions. It actually has what we called icing bugs to use as a reference for a minimum speed in icing conditions.

If severe icing is encountered there are memorized actions for the pilot to follow, which are in the following order(not written word for word)......increase that minimum icing speed by specified margin, increase the power, disengage the autopilot, escape the severe icing conditions and then advise ATC. And if there is an uncommanded roll....push the control column firmly forward.

In this case, he had very good options because he had no significant terrain and warm weather below. Ensure you have plenty of speed when encountering severe ice and don't worry about ATC.

I suggest that if you don't have icing bugs or a published minimum speed for ice, choose an increased minimum speed and if you can't maintain it, take action to do so, such as deciding not to climb.
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Last edited by pelmet on Fri Sep 04, 2020 3:43 am, edited 3 times in total.
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Re: TBM Icing analysis video.

Post by Heliian »

pelmet wrote: Thu Sep 03, 2020 7:14 pm I disagree with the TBM manual for the first three things to do when it comes to severe icing(Request priority handling from ATC, avoid abrupt/excessive maneuvering, do not engage the autopilot). The first three things should be SPEED, SPEED, SPEED.....as in maintain an airspeed which will be significantly higher than what is safe with a clean wing.
Yes, aviate, navigate, communicate.

This is classic Swiss cheese though, it was a chain of events that led to it. Doesn't help that the TBMs are just a newer fork tail, the pilot was very confident at the start.

The only way out of that would be to not get into it in the first place. That one pilot who said it was "the worst he's seen in 38 Years" is enough to convince me it was pretty frickin bad.
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Re: TBM Icing analysis video.

Post by digits_ »

Heliian wrote: Thu Sep 03, 2020 7:53 pm That one pilot who said it was "the worst he's seen in 38 Years" is enough to convince me it was pretty frickin bad.
Statements like that are hardly ever accurate, for various reasons. The main one being that people like to tell tall tales be it intentionally or subconciously. It makes you look like an ace. In one statement you get to flaunt your experience (38 years), get to tell people you flew through an exceptional condition (worst ever) and you had the skills to survive (the person you're talking about crashed).

It is highly likely that this pilot would report the same if you put him in slightly better conditions in 5 years. It's just how the brain works.
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Re: TBM Icing analysis video.

Post by Heliian »

digits_ wrote: Thu Sep 03, 2020 8:04 pm
Heliian wrote: Thu Sep 03, 2020 7:53 pm That one pilot who said it was "the worst he's seen in 38 Years" is enough to convince me it was pretty frickin bad.
Statements like that are hardly ever accurate, for various reasons. The main one being that people like to tell tall tales be it intentionally or subconciously. It makes you look like an ace. In one statement you get to flaunt your experience (38 years), get to tell people you flew through an exceptional condition (worst ever) and you had the skills to survive (the person you're talking about crashed).

It is highly likely that this pilot would report the same if you put him in slightly better conditions in 5 years. It's just how the brain works.
Sure, but the other dozen pireps would also make me believe there was some bad icing.
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Re: TBM Icing analysis video.

Post by iflyforpie »

There must have been something else. An airplane overcome by icing simply descends. If it stalls, with lots of altitude, you recover. You don’t go into a spiral. Death is slow as you run out of power, altitude, airspeed, and ideas.

I believe this was a roll or a pitch upset that this pilot wasn’t trained or prepared for, and he continued to perform the wrong actions until the plane over stressed.

That’s what the “rattle” was. The elevator or aileron going in and out of stall and trying to “snatch” the controls from you as a result of flow separation ahead of the control surface.

Roll or pitch upset is almost impossible to diagnose with the autopilot engaged and if it disconnects it is only after your aircraft had departed controlled flight.

If your controls are being moved in roll.. you have the potential for roll upset and you need to reduce the angle of attack and maintain configuration (or reverse it if it was brought on by a configuration change).

If your controls are being moved in pitch, you have the potential for a pitch upset aka tail stall. The corrective action—besides maintaining or reversing a configuration change— is the opposite for a conventional stall or roll upset.. you need to increase the angle of attack by pulling on the elevator.

Given that the tail plane generally has a finer airfoil and increased rate of accumulation in icing conditions, it’s very likely that this was a pitch upset followed by a complete loss of control of the aircraft.

The recovery is very counterintuitive when your plane suddenly nosedives when the tail stalls. Even more so these days with the legacy of AF447 and Colgan 3407 which enforce the need to push forward when encountering a stall. The only cue you have is what the controls were doing before it happened.

But it’s only a theory of mine. Lack of CVR/FDR data and the descent, crash, and post impact fire certainly destroyed all of the evidence.
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Re: TBM Icing analysis video.

Post by pelmet »

iflyforpie wrote: Sun Sep 06, 2020 8:22 pm Given that the tail plane generally has a finer airfoil and increased rate of accumulation in icing conditions, it’s very likely that this was a pitch upset followed by a complete loss of control of the aircraft.

The recovery is very counterintuitive when your plane suddenly nosedives when the tail stalls. Even more so these days with the legacy of AF447 and Colgan 3407 which enforce the need to push forward when encountering a stall. The only cue you have is what the controls were doing before it happened.

But it’s only a theory of mine. Lack of CVR/FDR data and the descent, crash, and post impact fire certainly destroyed all of the evidence.
I think a tail stall due to ice typically happens when flaps are extended for approach when the airflow is deflected downward exceeding the critical AoA of the horizontal stab.

In this case, the increase in AoA would have been on the wing due to the climb.
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Re: TBM Icing analysis video.

Post by iflyforpie »

There’s no saying what would happen first for what reason.

That’s why this video seems a little off.. like previous posters said, emphasizing preflight planning and vertical autopilot modes rather than more immediate situations.

No plane should be climbed in pitch or vertical speed mode for any extended periods of time. It should be climbed at a speed, or at the very least the airspeed monitored. Airspeed at 1G = angle of attack for all practical purposes. Nothing much changes as you get higher. Your climb rate gets slower, pitch attitude gets lower, but you aren’t—or shouldn’t be—increasing angle of attack.

Both roll and pitch upsets can happen at any time depending on the amount and type of ice accumulation even without a configuration change. In the case of the stabilizer and elevator, it’s not based on a critical angle of attack.. or at least not the critical AoA for a clean airfoil. The AoA is still very low.. it’s just that the ice has created turbulence much like a spoiler has that greatly reduces lift coefficient.

But you can still positively change that lift coefficient by pulling on the elevator. That little bit of ice has no chance against such a large and lightly loaded control surface.
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Re: TBM Icing analysis video.

Post by pelmet »

iflyforpie wrote: Mon Sep 07, 2020 10:09 am That’s why this video seems a little off.. like previous posters said, emphasizing preflight planning and vertical autopilot modes rather than more immediate situations.
Thanks,

It is always good to bring up pre-flight planning as it can be extremely important in many ways. But it is also important to emphasize the immediate situation as proper pre-flight planning can be invalidated by faulty forecasts or perhaps other unexpected events.
iflyforpie wrote: Mon Sep 07, 2020 10:09 am Both roll and pitch upsets can happen at any time depending on the amount and type of ice accumulation even without a configuration change. In the case of the stabilizer and elevator, it’s not based on a critical angle of attack.. or at least not the critical AoA for a clean airfoil. The AoA is still very low.. it’s just that the ice has created turbulence much like a spoiler has that greatly reduces lift coefficient.
Thanks,

Perhaps I should have called it the new lesser critical AoA(or whatever term the aerodynamic engineers might use for it).


As a note, this is what the FAA has to say on tail stalls......

Tailplane Stall Symptoms

Tail stalls usually occur during an approach when flaps are at full extension and/or the aircraft is being flown near the upper speed limit for flap extension. There may be few or no symptoms prior to flap extension. Symptoms include:

Abnormal elevator authority, vibrations, and or/effectiveness.
Sudden uncommanded nose down pitch
Autopilot performing excessive pitch trimming.


https://www.faasafety.gov/gslac/ALC/cou ... eview=true

Therefore, I say that this was a loss of control due to the wings stalling at a higher than normal stall speed due to contamination.
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Last edited by pelmet on Tue Sep 08, 2020 5:41 am, edited 3 times in total.
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Re: TBM Icing analysis video.

Post by photofly »

Here’s a paper that measures the effects of ice contamination on various factors.
https://www.sciencedirect.com/science/a ... 611630019X

Here’s the graph of Cl vs alpha for various forms of contamination in the experiments:
4F4A6C11-2064-4C1C-AE11-7B37166A2A58.jpeg
4F4A6C11-2064-4C1C-AE11-7B37166A2A58.jpeg (31.48 KiB) Viewed 912 times
Note that the graph runs to negative alpha, so the reduction in lift available is more severe than it looks at first sight.
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Re: TBM Icing analysis video.

Post by valleyboy »

I look at accidents like this, obviously a pilot with the means to acquire this type, and ask myself how much actual flight time hand spanking in actual IMC. I have witnessed the tendency for low time pilots to depends on automatics. The TBM is glowing example of this and while it has fancy avionics they are not airline standard because of cost.

As we have seen over and over again, low time professionals with high performance aircraft ending with tragic results. I have even seen non ifr rated pilots filing and flying ifr and totally depending on the auto pilot to keep them alive.

Sadly they always seem to take friends and family with them. In many cases perceived stick and rudder skills or lack there of trumps experience. This pilot's mindset was that the TBM could handle any enroute ex and never took the icing reports seriously.
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Re: TBM Icing analysis video.

Post by digits_ »

valleyboy wrote: Tue Sep 08, 2020 7:29 am I look at accidents like this, obviously a pilot with the means to acquire this type, and ask myself how much actual flight time hand spanking in actual IMC. I have witnessed the tendency for low time pilots to depends on automatics. The TBM is glowing example of this and while it has fancy avionics they are not airline standard because of cost.

As we have seen over and over again, low time professionals with high performance aircraft ending with tragic results. I have even seen non ifr rated pilots filing and flying ifr and totally depending on the auto pilot to keep them alive.

Sadly they always seem to take friends and family with them. In many cases perceived stick and rudder skills or lack there of trumps experience. This pilot's mindset was that the TBM could handle any enroute ex and never took the icing reports seriously.
If you were flying that airplane, would you have cancelled your flight based on the weather reports?
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Re: TBM Icing analysis video.

Post by valleyboy »

How can I answer that unless I had first hand information and was there at the time but likely not. There were back doors available like altitudes above freezing, possibly the fact of 50 years of flying experience as opposed to his. I might have even decided to delay the flight but detailed wx I don't have so the question is really mute.
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Re: TBM Icing analysis video.

Post by digits_ »

valleyboy wrote: Tue Sep 08, 2020 9:54 am How can I answer that unless I had first hand information and was there at the time but likely not. There were back doors available like altitudes above freezing, possibly the fact of 50 years of flying experience as opposed to his. I might have even decided to delay the flight but detailed wx I don't have so the question is really mute.
They showed some of the weather reports in the movie.

If you don't have enough information to decide if you would do this flight, then how do you have enough information to state that the accident pilot did not take the icing reports seriously?
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Re: TBM Icing analysis video.

Post by valleyboy »

hen how do you have enough information to state that the accident pilot did not take the icing reports seriously?
Likely from the end result but if he did and then found himself in a situation above his level of confidence (not competence but experience) he was lulled into a state of overconfidence because of the aircraft's performance.

Who can know what is going through his mind but evidence I see points to experience and with that the power of decision making. I'll bet pushing the nose down and declaring an emergency never even entered his mind. I'll even go out on a limb to say he possibly could have been oblivious to the severity of the situation until it came all unglued. The scan of the "new" generation of pilot is for the most part a lost art. I have trained pilots falling back to no auto pilot aircraft that the first few hours was all about teaching them to hand fly instruments. This is mostly because of poor instrument and flight deck scans while flying at the same time.

Tragic accident that really should never have happened and who can truly judge the mindset of the pilot at the time. As I said before low time private pilots flying high performance aircraft has always had the higher potential for disaster. At my level I for instance would never consider flying a single engine aircraft over the North Atlantic, even one like a TBM.
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Re: TBM Icing analysis video.

Post by pelmet »

valleyboy wrote: Tue Sep 08, 2020 11:25 am
hen how do you have enough information to state that the accident pilot did not take the icing reports seriously?
Likely from the end result but if he did and then found himself in a situation above his level of confidence (not competence but experience) he was lulled into a state of overconfidence because of the aircraft's performance.

Who can know what is going through his mind but evidence I see points to experience and with that the power of decision making. I'll bet pushing the nose down and declaring an emergency never even entered his mind. I'll even go out on a limb to say he possibly could have been oblivious to the severity of the situation until it came all unglued. The scan of the "new" generation of pilot is for the most part a lost art. I have trained pilots falling back to no auto pilot aircraft that the first few hours was all about teaching them to hand fly instruments. This is mostly because of poor instrument and flight deck scans while flying at the same time.

Tragic accident that really should never have happened and who can truly judge the mindset of the pilot at the time. As I said before low time private pilots flying high performance aircraft has always had the higher potential for disaster. At my level I for instance would never consider flying a single engine aircraft over the North Atlantic, even one like a TBM.
I probably would have departed based on the weather reports. I have flown a TBM and it was across the Atlantic(but not as PIC - it was both of us who delivered two piston singles to Europe flying back in a new TBM delivery aircraft) and it is quite happy at FL 290 where icing won't be a problem. The weather at departure was great. It could be difficult in the NYC area but why not work out something with ATC(even the flight plan filing) to see if the climb can be done before the cold front. According to the video, ATC was well aware of the difficulties of singles in ice and appears that they may have been willing to accommodate where able.

Just keep your speed up if you get significant ice in a plane like that and then take further action.
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Re: TBM Icing analysis video.

Post by anofly »

He could have flown south at 4500 or 6500 feet a few hundred miles (an hour?) in VFR! conditions. There was no pressing need to get up high other than saving fuel, as it was a turboprop.
I am often boggled by the refusal to fly vfr when thunderstorms and or ice are present.
It does not make you a lesser pilot , it is another tool in your toolbox along with your ifr.
There are many thunderstorm days i will fly vfr that I would not fly ifr, or embedd myself in cloud.You lose some freedom to maneuver with ifr, and sometimes you need it.
I would indicate that vfr done well actually often has a higher workload, watching for airspace, obstructions, and traffic along with digging out frequencies you may want that they do not always offer....
of course most ifr fellas in vfr conditions are rarely looking for traffic as much as they should...
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Re: TBM Icing analysis video.

Post by valleyboy »

I have flown a TBM and it was across the Atlantic(but not as PIC - it was both of us who delivered two piston singles to Europe flying back in a new TBM delivery aircraft) and it is quite happy at FL 290 where icing won't be a problem
I'm old and half brit so I'm still of the school more is better when it comes to engines. 3 is way better than 2 and 4 is better than them all :smt040 and single is day vfr with landing gear applicable to where you are doing that flying.

Even my boat has 2 engines -- lol
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