quote:

Originally posted by Balzé Halzé:
I certainly understand that sentiment, and normally we tend to criticize people who during tragedy have an inclination to do nothing but stand around and record the event with their phones. But in a case such as this, clear and abundant video recordings will be immensely helpful for the crash investigators.

During my career as a military imagery analyst, especially during my last five years when I was Chief Instructor of the school here at DISC Chicksands, I was involved in three investigations carried out by the AAIB here at Farnborough. #1 was the Mosquito crash at Barton airfield in 96 and #2 was the loss of the P38 Lightning at IWM Duxford - both of these relied very heavily on both still and moving images from the huge crowds present on each occasion. The most poignant, however, and most upsetting for those of us closely involved, was #3 -examination of imagery taken from a camera belonging to a little girl who, with a sister and her friends had been taken on her birthday treat flight around Derbyshire back on 1996. She had taken most of a 36-exposure reel of film in her simple pocket camera, clearly showing ground details of her flight, including passing low over a farm, with the man on the ground apparently waving at the 'plane. Three minutes later she was dead, with her friend and daddy as he misjudged the ground height and flew into the nearby hillside field.

Her photos, and the undamaged lens of the recovered camera, still blood-stained from her hands, provided the flight evidence that assisted with the conclusion of the AAIB.

https://www.independent.co.uk/...ne-trip-1337252.html

https://assets.publishing.serv...afety_pdf_500101.pdf

This message has been edited. Last edited by: tacfoley,

That looked very tail heavy.

Those poor people. I can only imagine their terror. Very sad.

^So any of you pilot types think the pilot mishandled the stall recovery?

quote:

Originally posted by kkina:
^So any of you pilot types think the pilot mishandled the stall recovery?

A few things, this ATR has some checkered history dealing with ice. Even in another part of the globe, these pilots would be aware of that.

Going back to the Roselawn IN accident, I seem to recall they were operating rather slow, flying. That was a serious contributor.

These pilots don’t just sit there and let events unfold, they need to do some of that pilot shit. Any icing event takes a few moments to ramp up. Even before any real icing starts, one has OAT & upcoming clouds to consider, before even a hint of moisture, or icing.

I don’t buy they didn’t have an out. If ATC didn’t grant them a descent, if needed, take a vector, get down, or start some after the may-day call.

I didn’t delve into every detail, I did see a very erratic flight path near the end. I back it up before any stall, the stall & flat spin shouldn’t of happened.

I just don’t think the average operator will let events transpire without serious mitigation protocols. They will know more with the flight data recorders. Of course there’s the human element, potentially a tad short at times.

quote:

Originally posted by kkina:
^So any of you pilot types think the pilot mishandled the stall recovery?

It seems that once in the stall, or at least the flat spin, they were fucked. As pointed out by others, it's the fact that they allowed themselves to get into that situation (assuming of course this is what it was) that brings into question the pilots' actions.

But yeah, way too early to know anything.

OK, interesting. Wow, these aircraft are not even certified for spin. That tells me that the best way to recover from one, in these types of planes, is not to get into one in the first place.

quote:

Originally posted by kkina:
^So any of you pilot types think the pilot mishandled the stall recovery?

Not necessarily. It could be that icing caused an asymmetrical stall which tossed them right into a spin. It could be that they did not realize the situation that was developing, perhaps flying on autopilot (flight data suggests that is the case), and the aircraft entered a high angle of attack where the tail airflow was blanked out.

I have not looked in detail at any flight data, but from what I saw on one analysis video the airspeed was stable until shortly before the spin. Which leads to some questions about power management and the icing. Drag increases as ice builds up. With autopilot on in level flight, the airspeed will bleed off as the ice accretes.

Back in the last century, the official procedure for the EMB-120 was to wait until we lost 10 knots, then run the boots to clear the ice. The rational was "ice bridging", which is where the ice expands when the boot inflates but does not break off. Subsequent activations of the boots will be ineffective and the ice will grow. So the thought was to wait until ice was thick enough that it must break, not bridge. I would expect worldwide this old procedure would be gone, and they would be instructed to run the boots if entering potential icing.

However, keeping that in mind, if they did not run the boots or if the ice accreted at an extreme rate, the drag could have slowed them down in that last minute and then a stall could have occurred with the autopilot on.

Normally the autopilot disconnects when a stall happens, but not necessarily when the stall is caused by icing. The stall warning is activated by angle of attack, and with substantial ice on the wing the stall could happen at a low angle of attack which does not trigger the stall warning. Thus the admonition to turn off the autopilot when in severe icing.

So they may have gone into a stall with the autopilot trying to deal with pitch, bank, and yaw all over the place. That would possibly make things very much worse.

Another factor is p-factor. The ATR has big props which develop more thrust on the right side (downward moving blade) than the left. As power is added, the airplane yaws left, requiring quite a bit of right rudder to compensate. In cruise there is always some right rudder being applied. As the aircraft entered a stall, if the tail were blanked out the rudder would become ineffective and the nose would yaw left. That could be part of the mechanism for them ending up in a left turning spin.

Finally, extreme icing is very rare, but it is possible ice went on so quickly they were not able to keep flying. I have only been in ice like this one time, where you could literally hear it freezing onto the airplane. The encounter lasted less than about 30 seconds, and we were fully loaded up beyond the capability of the deice system. If we had stayed in those conditions another minute we would not have kept flying. If this ATR crew ran into something like that it may have quickly overtaken them.

All of this is conjecture. It could be the crew did everything correctly but some other unknown problem caused the accident.

quote:

Originally posted by kkina:
OK, interesting. Wow, these aircraft are not even certified for spin. That tells me that the best way to recover from one, in these types of planes, is not to get into one in the first place.

No multi-engine aircraft should ever be taken close to a full stall, and should never be spun! Many flight instructors have been killed by students who somehow put a twin engine aircraft into a spin.

quote:

Originally posted by Pipe Smoker:
I would’ve guessed that a twin engined plane could counter a flat spin by reversing the prop pitch on one engine.

Or by simply stopping one engine and max throttle on the other.

Nobody commented on my suggestion, but it seems like a reasonable course of action to me.

If not, why not?

quote:

Originally posted by Pipe Smoker:

quote:

Originally posted by Pipe Smoker:
I would’ve guessed that a twin engined plane could counter a flat spin by reversing the prop pitch on one engine.

Or by simply stopping one engine and max throttle on the other.

Nobody commented on my suggestion, but it seems like a reasonable course of action to me.

If not, why not?

If I were in that situation, I would certainly be willing to try differential thrust! There is no downside that I can think of. Stopping rotation is the first step in spin recovery, which then is a simple deep stall to recover from.

Prop pitch cannot go into reverse without being on the ground. Gear has to be down and the struts compressed before pitch will unlock and allow reverse.

But pulling one engine to idle, the right engine in this accident scenario, and increasing power on the left engine would counter the spin. It would certainly be something to try.

quote:

Originally posted by kkina:
OK, interesting. Wow, these aircraft are not even certified for spin. That tells me that the best way to recover from one, in these types of planes, is not to get into one in the first place.

Most (nearly all) airplanes are not certified for spins.

quote:

Originally posted by jeffxjet:

Most (nearly all) airplanes are not certified for spins.

True. Also, most pilots have not had spin recovery training in flight.

My airman certificates (Commercial Pilot, Flight Instructor) were issued in the 1960s. Pilot certificates (Private, Commercial, ATP) did not require spin training.

For Flight Instructor, I was required to demonstrate entry to, and recovery from, a spin. Definitely NOT my favorite maneuver! I used a rented C-150 (legal for spins) for that demonstration, the rest of the checkride was done in the Beech 23 that I owned at the time.

quote:

Originally posted by V-Tail:

quote:

Originally posted by jeffxjet:

Most (nearly all) airplanes are not certified for spins.

True. Also, most pilots have not had spin recovery training in flight.

My airman certificates (Commercial Pilot, Flight Instructor) were issued in the 1960s. Pilot certificates (Private, Commercial, ATP) did not require spin training.

For Flight Instructor, I was required to demonstrate entry to, and recovery from, a spin. Definitely NOT my favorite maneuver! I used a rented C-150 (legal for spins) for that demonstration, the rest of the checkride was done in the Beech 23 that I owned at the time.

My only spin experience was in a C152 Aerobat, and was done at about 5k AGL, and with a certified aerobatic instructor.
We did about 2.5 spins & recovered, wasn't as much fun as the other aerobatic maneuvers we did that day.

quote:

Originally posted by V-Tail:
Also, most pilots have not had spin recovery training in flight.

My airman certificates (Commercial Pilot, Flight Instructor) were issued in the 1960s. Pilot certificates (Private, Commercial, ATP) did not require spin training.

For Flight Instructor, I was required to demonstrate entry to, and recovery from, a spin. Definitely NOT my favorite maneuver! I used a rented C-150 (legal for spins) for that demonstration, the rest of the checkride was done in the Beech 23 that I owned at the time.

My private pilot training in 1979/1980 included spins in a C150 or 152, and in a Tomahawk. I never enjoyed spinning but wasn't scared of them. For CFI, my instructor was terrified of spins, so we only did incipient spins, no more than 1/2 turn, using just modest rudder input to initiate the spin.

As a CFI, I always trained my students in spin recovery using a simulated spin. Flaps down, engine idle, steep descending turn. Recover with rudder, then ease out of the nose down with elevator. I also had the student in slow flight with the stall horn sounding, then hold wings level with rudder only, ailerons held centered.

Imho, spin training should be required for private pilots. In a suitable aircraft it is a safe maneuver.

Here’s an event from 2016 with an ATR that ‘potentially’ could be related to events with this crash. The flight data recorder should reveal a lot once it’s made public.

https://www.flightglobal.com/s...upset/140138.article


If icing was a leading contributor, the setup could be similar to this close call.

quote:

Originally posted by Fly-Sig:
Imho, spin training should be required for private pilots. In a suitable aircraft it is a safe maneuver.

I agree wholeheartedly.

However, I believe reason that the requirement was dropped was because too many people were getting killed doing the training. The spin training required of CFIs is absolutely minimal at best. Someone who just got through that minimal requirement has no business teaching spins. Really, much more training and competence in spins is necessary for the vast majority of CFIs before they should be teaching spins to anyone.

I was absolutely delighted when my son came to me after he had gotten his license in a Bellanca Super Decathon (an airplane certified for aerobatics with inverted fuel and oil systems) and asked me to take him out and teach him spins. He had been extremely uncomfortable with stalls during his training and didn’t want to even talk about spins. However, once he got his license, he wanted to take his best friend for a ride and felt he owed it to his passengers to know how to handle a spin. We talked about them on the ground, then went flying and climbed to a safe altitude. I demonstrated one, I talked/followed him through one, then he did several more. Before we were done, he was much more comfortable with the idea of spins, had the recover (PARE) down, and more importantly, had a better feel for what an entry felt like and how to avoid a spin before it started.

Understanding how to fly the airplane through the whole envelope and knowing what it feels like as you approach the edges is important. Not all instructors have enough of that understanding to safely teach it though.

News reporting that the aircraft had been traveling at around 200 knots leading up to the crash, but at the moment it crashed it had slowed to 40 knots, hence the stall.

What would make an airplane slow down that much?

^I wonder if the auto-pilot reacted to the loss of lift from the ice build-up by gradually increasing the angle-of-attack until the inevitable stall.