Kenn Borek Antarctic Cause/Speculation Thread

[cncpc]

Flying down there is very different from what everyone is used to in the real world.......

In the real world, flying in mountains IFR below terrain without situational awareness is something that not done. I would guess that it is the same down there too.

I think that depends on how close the terrain is. IFR approaches in mountains are almost always below terrain and so is some enroute.

[glorifiedtaxidriver]

The nagging question to me is...........

If the winds and weather were as bad as they were and they were flying an unpressurized aircraft over such high terrain.............why would they depart in the first place and if they were having difficulty maintaining altitude etc would a 180 degree turn been in order?

Flame if you wish but these are always the first 2 questions asked...........

Well, I don't think there's anything that tells us that they were actually IMC at the time, or expected to be IMC anyway. The winds on the ground at their departure and destination points could very well have been calm. Heavy headwinds in flight are not a big deal as long as you're not right in the mountains. Mountain waves can be very smooth and you may not even notice it except on your altimeter. Could be they departed vfr, went to an altitude high enough to make it over the mountain range and hit cloud over the rocks. That would be expected if you've ever flown in the mountains. You would expect some cloud cover over the mountains and probably to come out the other side with no issue. Once IMC, over the mountains, getting caught in a mountain wave could drag you down at a greater rate than your a/c can climb. I don't think anyone would fly IMC over the mountains below the minimum altitude on purpose.

Also, you don't need to be pressurized to fly at any particular altitude. I go up to 16000-18000 all the time unpressurized. The only requirement is that you have the proper amount of oxygen on board for you flight.

[SkiPilot]

Flying down there is very different from what everyone is used to in the real world.......

In the real world, flying in mountains IFR below terrain without situational awareness is something that not done. I would guess that it is the same down there too.

Mr Wings - do you mean "flying IMC in mountains below terrain without SA"? Which is subtly different from flying IFR.

If you were IMC & didn't have SA you shouldn't be below the minimum height (MEA, MOCA ,MSA, whatever it may be) no matter where you are on the planet.

Anyway, who said anything about these guys flying below mountains IFR or IMC? I certainly didn't. I just said "Flying down there is very different from what everyone is used to in the real world...." Please be careful not to attach your meaning to other people's words.

[MrWings]

Ya, sorry. I think I was just caught up in what was already presented and interpreted your comments as "you wouldn't understand because the rules we fly by don't apply down there." Sounded like the physical laws are somehow violated in Antarctica.

I am eagerly waiting the investigation into this because it was an experienced crew. Although, not getting access to the aircraft could leave questions hanging for quite a while.

[SkiPilot]

No harm, no foul.

[flyinthebug]

I wasnt sure I wanted to even comment on this thread for the same reason many of us dont want to touch this one with a 10 foot pole.

There is one nagging question though for me. I wanted to point out as it hasnt been brought up here yet. It was reported and I believe mentioned in the other thread about the aircraft dropping from 13,000 ft down to 8,800 feet then climbing back up to 13,000 ft @140 kts. I think if we are going to speculate, maybe we should discuss why the aircraft descended 4,200 ft in a very short period of time...then climbed back to 13,000 but still had a CFIT accident? Was it a stall and recovery? Did he descend for some other reason? Thats going to be a tough one to figure out without having the whole aircraft to inspect.

If they ever do figure that out, it may explain why the most experienced DHC6 driver in the world drove into the side of a mountain. God, I cant even say that without feeling ill.

RIP Bob & crew.

Fly safe all.

[Cat Driver]

The answers to these questions may be in the CVR.

[Doc]

The answers to these questions may be in the CVR.

Which we won't see for at least 18 months!

[Cat Driver]

Erased.

[cncpc]

I wasnt sure I wanted to even comment on this thread for the same reason many of us dont want to touch this one with a 10 foot pole.

There is one nagging question though for me. I wanted to point out as it hasnt been brought up here yet. It was reported and I believe mentioned in the other thread about the aircraft dropping from 13,000 ft down to 8,800 feet then climbing back up to 13,000 ft @140 kts. I think if we are going to speculate, maybe we should discuss why the aircraft descended 4,200 ft in a very short period of time...then climbed back to 13,000 but still had a CFIT accident? Was it a stall and recovery? Did he descend for some other reason? Thats going to be a tough one to figure out without having the whole aircraft to inspect.

If they ever do figure that out, it may explain why the most experienced DHC6 driver in the world drove into the side of a mountain. God, I cant even say that without feeling ill.

RIP Bob & crew.

Fly safe all.

I was thinking of that, too.

I think that a starting point is to assume IMC. A turn is made in the wrong place. The belief is that an altitude at 8800 or below is safer. Terrain is seen where it isn't expected, then a WTF, then scramble for height again.

Certainly the behaviour you detail is part of the accident scenario. If the descent wasn't intentional, then it would indicate a situation of severe turbulence, mountain wave and that sort of thing. All that could take place in VFR conditions.

Does anybody know what might have been in that aircraft cargo wise?

[cncpc]

Which we won't see for at least 18 months!

You think they will be that fast doing their investigation?

And can you deep down believe the report when it is released?

This was what I said:

The answers to these questions may be in the CVR.

What we are fed from their report and what actually was on the CVR may not be the same.

I personally would have more faith that the truth will be released if the investigation were done in Nigeria.

Do you have some reason to believe, at this stage, that something is not on the up and up, Cat?

[iflyforpie]

Yeah, the investigation will be done by the Transportation Safety Board, not Transport Canada....

[Cat Driver]

Do you have some reason to believe, at this stage, that something is not on the up and up, Cat?

No I am as stunned by what happened as everyone else here, Bob was the last pilot on earth I would have worried about having such an accident.

[Cat Driver]

Yeah, the investigation will be done by the Transportation Safety Board, not Transport Canada....

True, but both deprtments are still connected at the top, sort of like which shell is coin hidden under.

[JigglyBus]

editted due above edit.

[Meatservo]

I'm going to erase mine too, since it was a response to the above, also (previously) erased.

[Cat Driver]

Once again I find I have said something that can derail a thread and for sure I do not want to ruin a thread that is about the loss of one of aviations best pilots.

So I am going to erase what I said.

[cncpc]

Do you have some reason to believe, at this stage, that something is not on the up and up, Cat?

No I am as stunned by what happened as everyone else here, Bob was the last pilot on earth I would have worried about having such an accident.

That seems to be the consensus. Highly unlikely this would result from a mistake that Bob made, or from some external event that was within his capacity and experience to recover from.

Which leaves unforseen and extreme weather event, or aircraft failure.

I asked about what was aboard the aircraft for a couple of reasons. I was thinking perhaps load shift, if there was some substantial cargo. I was also told of an incident where a Twin Otter had a jammed elevator and no pitch control, even by using the trim. It turned out that some barrels or something with a lot of snow on them had been loaded in. As the flight progressed, the snow melted and the water flowed down under the floor, where it ended up freezing the elevator cables. The crew found they had no fore and aft movement of the yoke. They did manage to get it down on power changes alone. I realize not a strong probability here, but there is some evidence for a pitch control difficulty.

I know you're not favorably disposed to the feds, Cat, and fair enough. I'm sure you have your reasons. I generally trust them, and certainly no intrigue evident in this one yet. However, something is not normal in the Resolute accident. That is under super tight wrap. Even other investigators in the TSB are not told what has been discovered. So yes, things aren't always out in the open. But, other than thinking that surely there must be some urgency to find out what went wrong and now is a better time to investigate than next October, I don't see anything suspicious in this one.

Very sad and a great loss, no doubt about that.

[pelmet]

That seems to be the consensus. Highly unlikely this would result from a mistake that Bob made, or from some external event that was within his capacity and experience to recover from.

Which leaves unforseen and extreme weather event, or aircraft failure.

I asked about what was aboard the aircraft for a couple of reasons. I was thinking perhaps load shift, if there was some substantial cargo. I was also told of an incident where a Twin Otter had a jammed elevator and no pitch control, even by using the trim. It turned out that some barrels or something with a lot of snow on them had been loaded in. As the flight progressed, the snow melted and the water flowed down under the floor, where it ended up freezing the elevator cables. The crew found they had no fore and aft movement of the yoke. They did manage to get it down on power changes alone. I realize not a strong probability here, but there is some evidence for a pitch control difficulty.
[/quote]


In reality, we have no idea whether it was pilot error or not. Any half decent investigator will not discount a mistake as you have but will instead approach the investigation with no conclusions made. He will understand that in the past, extremely competent pilots have made errors resulting in accidents but on the other hand not jump to that conclusion about the accident at hand. To discount anything based on no evidence is a diservice to the goal of learning from accident investigations.

It is important when loading freight with snow on it to remove most of the snow if the cabin will be above freezing or else you will have a significant amount of water on the floor which can lead to a variety of problems.

[Cat Driver]

The possibility exists that the CVR may not explain what happened.

One night I was flying between Inuvik and Whitehorse in a DC3 that had an autopilot, the FO was sound asleep and I was monitoring the autopilot and bored out of my skull when all of a sudden the airplane pitched nose down it took a few seconds for my mind to comprehend what was happening and find the autopilot disconnect.

The airplane pitched so far nose down before I could disconnect the runway auto pilot that we lost about the same amount of altitude that Bob and his crew apprently lost before they returned to the altitude they departed.

I am sure we were below some of the higer mountain peaks before I got the beast back under control, it happened at night in IMC.

Had we hit a mountain top during the departure from controlled flight and the airplane ended up smashed into small piecies or burnt beyond being able to trace for cause it would have been another accident that everyone would probably never figure out.

[Diadem]

That seems to be the consensus. Highly unlikely this would result from a mistake that Bob made, or from some external event that was within his capacity and experience to recover from.

Which leaves unforseen and extreme weather event, or aircraft failure.

We can't discount pilot error simply because Bob was experienced. Everyone makes mistakes. Pilots with more experience than Bob have made mistakes which caused accidents. I've flown with Bob, and I find it hard to believe he would have done something which caused this accident, but to outright dismiss the possibility because you refuse to believe it could prevent an accurate and unbiased assessment of what actually caused the crash. Being a nice guy doesn't preclude the possibility of making a mistake, and having tens of thousands of hours of experience doesn't make one impervious.

I wasnt sure I wanted to even comment on this thread for the same reason many of us dont want to touch this one with a 10 foot pole.

There is one nagging question though for me. I wanted to point out as it hasnt been brought up here yet. It was reported and I believe mentioned in the other thread about the aircraft dropping from 13,000 ft down to 8,800 feet then climbing back up to 13,000 ft @140 kts. I think if we are going to speculate, maybe we should discuss why the aircraft descended 4,200 ft in a very short period of time...then climbed back to 13,000 but still had a CFIT accident? Was it a stall and recovery? Did he descend for some other reason? Thats going to be a tough one to figure out without having the whole aircraft to inspect.

If they ever do figure that out, it may explain why the most experienced DHC6 driver in the world drove into the side of a mountain. God, I cant even say that without feeling ill.

RIP Bob & crew.

Fly safe all.

I'm not sure a heavily-loaded Twin Otter could climb back up 4200 feet in that period of time. It seems more likely to me that the sat tracking system had an error, which I've seen hundreds of times. I've seen aircraft which were at 18000 feet suddenly drop to sea level in the middle of a continent, only to pop back to 18000 when the next signal was sent. It should be fairly easy to tell whether they actually descended or whether it was just a false indication when they listen to the CVR and hear if the crew became a bit agitated at the abrupt loss of thousands of feet of altitude; if they were flying along chatting normally when the GPS shows them dropping then there might not have been any actual loss of altitude.

[cncpc]

Good post, Diadem.

I take it the assumption is that it wouldn't fly back from the South Pole without a load coming out?

[flyinthebug]

I'm not sure a heavily-loaded Twin Otter could climb back up 4200 feet in that period of time. It seems more likely to me that the sat tracking system had an error, which I've seen hundreds of times.

Thank you Diadem for that information. I was of the belief that the sat tracking systems were more reliable than that. You did though indirectly support my point about the climb back from 8800 to 13000 feet as it was noted that they were climbing at 140 Kts. There didnt seem to be any "urgency" in their climb back to 13000 or wouldnt they have went for Best rate or Best angle of climb? At 140 Kts (if we can believe these numbers) it would be a casual cruise climb at best in a DHC6, so why the lack of urgency in the climb back up if they were able to see rocks sneaking up on them?

PS... Cat, I sincerely hope you are correct and the answers will be in the CVR.

*Edit* Thanks for the PM Changes in Latitudes and I replied as well. Alls well.

[Changes in Latitudes]

fine by me.

[lostinthebattle]

I'm just going to throw this out there, no disrespect to the crew. Could they have been doing some sight-seeing and at the last minute realized they were too close to Mount Elizabeth? My closest call in the mountains came on a CAVOK day.