dtuuri
Final Approach
Then how could all three control surfaces get jammed in neutral, especially the rudder?Shifting load makes most sense given limited info.
Then how could all three control surfaces get jammed in neutral, especially the rudder?Shifting load makes most sense given limited info.
Exactly.Here's a drawing of the L-19 Birddog gust lock. It is quite ingenious since it locks everything, including the brakes. I found it almost impossible to access the front seat with the gust lock in place. If the gust lock for the SIAI Marchetti 1019 is anything like this, it would be impossible for the pilot to miss. I understand that the SM 1019 is basically a highly-modified Birddog, but I'm unfamiliar with the SM 1019 and don't know how much of the L-19 was adopted, modified or re-engineered; consequently, I don't know if the gust lock shown in Juan Brown's video is anything like the L-19's. The photo of the gust lock that Juan Brown posted, does not look like the L-19's. I have been hoping that someone with access to an SM 1019 could post a video or photo of its gust lock, so that we can either pursue the gust lock as a factor or put it to bed.
View attachment 99200
It isn't. He has his mind made up and ruled out the control lock on the basis of not being able to taxi with it engaged. What if it wasn't engaged during taxi? Why couldn't the pilot have used it as a parking brake and forgot to release it? Looks like his legs could have straddled the latching mechanism, but he doesn't address it at all. In my experience, parking brakes are not reliable under much power.Exactly.
Here’s a good video on it.
You seem to have things figured out before the rest of the crowd, so I’ll leave you with it.It isn't. He has his mind made up and ruled out the control lock on the basis of not being able to taxi with it engaged. What if it wasn't engaged during taxi? Why couldn't the pilot have used it as a parking brake and forgot to release it? Looks like his legs could have straddled the latching mechanism, but he doesn't address it at all. In my experience, parking brakes are not reliable under much power.
Then he launches into the electric trim system, saying it could have been wired backwards. Well, why isn't the elevator deflected to compensate for that? Not a well thought out analysis, IMO.
I have nothing "figured out". I think Brown should keep more of an open mind to possibilities. If you look at the one minute frame on the video posted here the plane is in knife edge flight and the pilot is not able to deflect any of the three control surfaces. That isn't explained by trim system malfunction. Controls locked for takeoff isn't dismissed by the ability to taxi to the runway either. I've engaged the control lock in windy conditions while awaiting takeoff and I'm sure I'm not the only one who ever thought of it. However, I'd keep my hand on it as a reminder in addition to the design feature that blocked the throttles from advancing.You seem to have things figured out before the rest of the crowd, so I’ll leave you with it.
As should we all… It’s nothing but speculation and theories at this point.I think Brown should keep more of an open mind to possibilities.
It’s nothing but speculation and theories at this point.
That is what's known in engineering circles as a "glaring contradiction." Well, technically it isn't because you really haven't figured it out, but you seem to think you have.I have nothing "figured out"...the pilot is not able to deflect any of the three control surfaces.
Anyone have METAR or other wind data at the time of the accident?
Personally, I think the notion of engaging a gust lock while waiting to take off is the second most bonkers thing I have seen on the internet today. Most days it would win, but today our incompetent withdrawal from Afghanistan takes the prize.
I've been staring at the film in slo mo on a large monitor. It's hard to tell and admittedly there is confirmation bias at work, but I think you can see significant down elevator deflection in the video from the time the aircraft begins to pitch up until the wing over. Take a close look at 0:56 to 0:57.
View attachment 99205
Y'know, you seem to think you know what I'm thinking, but you don't. All we have is what we can see (and hear) and our experience. I spent two years doing nothing else but rigging flight controls. It wouldn't be the first time someone ever took off with the rigging pins left in, so that's just one more possibility. If you can believe what you see at 1:00 in the video none of the controls are deflected and there's a highly experienced pilot at the controls with his hand on the stick and finger on the mic button and he knows he's going to crash. Is he trying to disable the trim and has the wrong button? Why no rudder then? Why is the plane descending, not climbing, if he intentionally rolled in the bank to pull the nose down? All he'd need do is let off some forward pressure and bank less. Etc, etc,.That is what's known in engineering circles as a "glaring contradiction." Well, technically it isn't because you really haven't figured it out, but you seem to think you have.
Nauga,
with cause and effect
How do you feel about a parking brake?Personally, I think the notion of engaging a gust lock while waiting to take off is the second most bonkers thing I have seen on the internet today.
All I have is your words in your posts describing what the pilot could and could not, was and was not doing. You're not involved in the investigation and you weren't with him in the cockpit, so you don't have facts, only opinions. Yes, from your own words I know what you are thinking, unless you're being deceptive.Y'know, you seem to think you know what I'm thinking, but you don't.
How do you feel about a parking brake?
I'm pretty sure if he could move the controls he would have saved his own life. If that's an opinion not a fact, I'm guilty. Other than that, I have no opinion on the cause of this accident, but I've thrown out some possibilities that theorists here haven't seemed to consider.All I have is your words in your posts describing what the pilot could and could not, was and was not doing. You're not involved in the investigation and you weren't with him in the cockpit, so you don't have facts, only opinions. Yes, from your own words I know what you are thinking, unless you're being deceptive.
The reason you don't trust them is the same as me, no doubt. But this plane had a powerful (I presume) turbine engine and if the prop can't be managed to render zero thrust or reverse there could be a lot of residual thrust making brake holding uncomfortable. I don't know if it would be a factor, but then how many here know better? So, it is conceivable to me, in the absence of actually knowing how the power management on the ground really is, that a pilot might use the control lock to hold the brakes. Maybe it isn't needed or isn't recommended, I don't know. But it is something to be considered as possible.On a plane? Never use 'em, don't trust 'em.
I had considered that also ..... engaging the gust-lock-brakes once he was lined up on the runway ... presumably to to an extended run-up of his engine or something.The reason you don't trust them is the same as me, no doubt. But this plane had a powerful (I presume) turbine engine and if the prop can't be managed to render zero thrust or reverse there could be a lot of residual thrust making brake holding uncomfortable. I don't know if it would be a factor, but then how many here know better? So, it is conceivable to me, in the absence of actually knowing how the power management on the ground really is, that a pilot might use the control lock to hold the brakes. Maybe it isn't needed or isn't recommended, I don't know. But it is something to be considered as possible.
Sherlock Holmes - Sir Arthur Conan Doyle When you have eliminated the impossible, whatever remains, however improbable, must be the truth......Yes, that's rare, but when you eliminate the other possibilities, rare can become the most likely option.
I watched the video and it appears to me that there may have been an attempt to lift the tail as power was first applied. Perhaps, like others, I'm seeing things (or wanting to see things) that aren't there. It may just be an illusion from the lighting and shadows.
It also appears that the initial pitch up was near normal before suddenly increasing. This may indeed indicate a cargo shift that left the plane too tail heavy.
I also wonder why the power wasn't immediately pulled back. I know that things were happening in a hurry and he would have had a great startle factor but he is also a highly seasoned & professional pilot. Keeping the throttle covered during take offs was taught early in my training.
Regardless of the reason ... this is such a horrific tragedy!
I watched the video and it appears to me that there may have been an attempt to lift the tail as power was first applied. Perhaps, like others, I'm seeing things (or wanting to see things) that aren't there. It may just be an illusion from the lighting and shadows.
It also appears that the initial pitch up was near normal before suddenly increasing. This may indeed indicate a cargo shift that left the plane too tail heavy.
I also wonder why the power wasn't immediately pulled back. I know that things were happening in a hurry and he would have had a great startle factor but he is also a highly seasoned & professional pilot. Keeping the throttle covered during take offs was taught early in my training.
Regardless of the reason ... this is such a horrific tragedy!
That you are pretty sure of it is a fact, that it is true is an opinion. Using that opinion to develop scenarios to investigate is a valid technique, basing conclusions on that opinion is not. There is way too much of the latter in these accident threads.I'm pretty sure if he could move the controls he would have saved his own life. If that's an opinion not a fact, I'm guilty.
I know pulling power wouldn’t have been my reaction with the nose high.
That you are pretty sure of it is a fact, that it is true is an opinion. Using that opinion to develop scenarios to investigate is a valid technique, basing conclusions on that opinion is not. There is way too much of the latter in these accident threads.
Nauga,
after the fact
Whatever. In my opinion he didn't want to die, but couldn't save himself. Most would probably say that's a fact. I have not made any conclusions, despite your insistence to the contrary, and stand by what I said the other day:That you are pretty sure of it is a fact, that it is true is an opinion.
Knowledgeable opinion and speculation has a place in accident investigation. We may differ on where that place is, and we certainly differ on what constitutes 'knowledgeable.' I think trying to learn from sheer conjecture based largely on "what I would have done" or "What I've seen in a completely different airplane' is akin to studying for a written exam using an answer key with wrong answers for all the questions. It might make you think, but there's no assurance that there's any validity in what you're thinking about and no assurance that you aren't missing something even more important.Knowledgeable opinion and speculation (as found on this forum for example), can be very useful and can even save lives.
Nauga's corollary: Don't be offended when someone calls you on your BS. Try to learn from it.To shorten an overly long and wandering narrative: "Keep it up with the opinion and conjecture guys".
Hmmm...maybe someone who has access to the wreckage will do that. I wonder who that might be....?It seems like an examination of the wreckage or even a report by someone who saw the wreckage intact would quickly indicate whether here was a large cargo load that might have shifted.
Hmmm...maybe someone who has access to the wreckage will do that. I wonder who that might be....?
Nauga,
methodically
You appear to have reached a conclusion that the controls were not deflected. If you agree that they may be deflected and that you just can't discern it from your sources then I am in error, as is your 'analysis' that follows.I have not made any conclusions, despite your insistence to the contrary, and stand by what I said the other day: [...] "You'd think something would be deflected if it was at all possible.
Knowledgeable opinion and speculation has a place in accident investigation.