Continental TurboProp crash inbound for Buffalo
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Add a trim warning to the FMC ?
MungoP, Chesty : good points about A/P disengaging too late.
I wonder whether an FMC knows enough about AP and PFC output commands to have a "trim becoming unusual" monitor added to it which would warn the crew of, in this case, an extreme trim and approaching AP disconnect. You probably wouldn't want the additional code in the AP or PFC cos it would be an additional fault risk in a critical system.
I wonder whether an FMC knows enough about AP and PFC output commands to have a "trim becoming unusual" monitor added to it which would warn the crew of, in this case, an extreme trim and approaching AP disconnect. You probably wouldn't want the additional code in the AP or PFC cos it would be an additional fault risk in a critical system.
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I wonder whether an FMC knows enough about AP and PFC output commands to have a "trim becoming unusual" monitor added to it which would warn the crew of, in this case, an extreme trim and approaching AP disconnect.
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The AP systems I'm aware of don't retrim in the roll axis, but simply hold the force with the servos. They monitor that servo force and pop up a series of escalating warnings if the force becomes higher than normal, before the servo has to disconnect. The pitch axis does retrim, and there's no warning from the AP if the trim has moved "a lot" - only warns if the servo is holding excess force, which usually means the trim has jammed or failed, and the servo is now doing all the work. The trim would only generate messaging if you got to the end of travel, if then.
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NASA video -- wow. Ten years old ...
two-tenths of a second, 40 degrees pitch down, 300' lost -- and that was the actual tail stall that occurred while they were in test flight intending just to creep up close to the problem! And the recovery procedure ....
Whew.
Is it time for little video cameras mounted on the tail, or something like that?
Whew.
Is it time for little video cameras mounted on the tail, or something like that?
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Mad (Flt) Scientist: right, so the monitoring software would need to look out for both extreme trim positions and unusual, near authority limit actuator commands.
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Someone earlier in the day postulated a stall spin accident due to icing and configuration change, somehow the post was removed.
The Roselawn icing accident had similar pitch and roll excursions that began on approach when flaps 15 were selected. I realize that aircraft was an ATR, not a Dash.
The Roselawn icing accident had similar pitch and roll excursions that began on approach when flaps 15 were selected. I realize that aircraft was an ATR, not a Dash.
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Assuming that tail icing is the culprit; I just wonder if there are any data's on record in respect of the tail configuration, i.e T tail Mid tail or a conventional tail.
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No! On the Roslawn accident the F/O 'deselected' flaps! He had selected flaps in the holding to stay under max holding speed (Mistake!). When he got the clearence to descend, he forgot flaps and got a flaps overspeed warning. He then reduced flaps, and the roll upset begun.
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No! On the Roslawn accident the F/O 'deselected' flaps! He had selected flaps in the holding to stay under max holding speed (Mistake!).
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Dash 8 Crash
I am extremely sorry for the loss of life. But what is it about supposed professional Pilot training? Even as a lowly and humble PPL/IR, I have read, had instilled into me, and studied the effect of ice. In as much as if you are getting iced up, dont use the flaps , you recalculate the landing distance available and if its too short, divert, unless you are certain that the tailplane is not a problem. Which must be impossible in a Dash 8. If the facts confirm this, it is another totally avoidable accident. Other causes could be a midair, but then there would be a debris path, not a entire aircraft crashed into a single house, there is not a another rational explanation No doubt I will be vilified for this comment, as usual, and told to wait for the official report, but reports of ice on approach and then a sudden fatal dive just when they went for the flaps over the OM all adds up. I am flabbergasted how this can happen, yet again and again and again, remember people died.
The lawyers have already read all the comments, so mine are not going to make an iota of difference. In fact I hope they sue the airline out of existence
The lawyers have already read all the comments, so mine are not going to make an iota of difference. In fact I hope they sue the airline out of existence
Last edited by dope05; 14th Feb 2009 at 00:40.
Good video learning about tail stall due to icing
Lots of discussion following.
But how sure are we that it's indeed tailplane stall
Are there other possibilities with the information released to date?
Lots of discussion following.
But how sure are we that it's indeed tailplane stall
Are there other possibilities with the information released to date?
I think it will turn out to be tailplane stall, but remember the ATR crash was aileron reversal, not a tailplane stall. I am nearly certain the crash is ice related, but it may not be a stab issue. I am sure in time the FDR will reveal the source.
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Airbubba!
"Anyway, the loss of control with the configuration change rang a bell when I heard that comms were lost in BUF at the marker. "
Yes! I, too, had a flashback after hearing that!
"Anyway, the loss of control with the configuration change rang a bell when I heard that comms were lost in BUF at the marker. "
Yes! I, too, had a flashback after hearing that!
dope05:
every single day around the world airline aircraft fly into ice, accumulate ice, and land safely. q400's build ice on the wings, tail and the deice system removes it and they land safely. these aircraft are approved for flight into known icing. you can't simply say "well they had ice so why did they try to land, divert!"
it is very, very likely that the crew had seen icing like that many times and had no issues with it at all, but perhaps something unique happened this time and fate arrived and luck ran out... hopefully just like after roselawn we can learn more to prevent this in the future, but it will never be as simple as avoid icing because in our environment, we can't... we can only manage the situation.
every single day around the world airline aircraft fly into ice, accumulate ice, and land safely. q400's build ice on the wings, tail and the deice system removes it and they land safely. these aircraft are approved for flight into known icing. you can't simply say "well they had ice so why did they try to land, divert!"
it is very, very likely that the crew had seen icing like that many times and had no issues with it at all, but perhaps something unique happened this time and fate arrived and luck ran out... hopefully just like after roselawn we can learn more to prevent this in the future, but it will never be as simple as avoid icing because in our environment, we can't... we can only manage the situation.
Last edited by canyonblue737; 14th Feb 2009 at 01:33.
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Is it time for little video cameras mounted on the tail, or something like that?
I would hope all new design a/c are given a good complement of cameras, long overdue.
Let us not forget the possibility of crew fatigue, it was 22:00 hrs or something, how many sectors had they flown yesterday?.
I was on a late-day/early evening commuter flight into Albany, New York 3 years ago, the one Flight attendant looked tired and I asked her how many sectors they'd had that day, and was this the last.
It was the last of seven, thats a lot !!, that possibility, and bad weather, end-of-the-day.
Whatever the circumstances, a tragedy.
f
I was on a late-day/early evening commuter flight into Albany, New York 3 years ago, the one Flight attendant looked tired and I asked her how many sectors they'd had that day, and was this the last.
It was the last of seven, thats a lot !!, that possibility, and bad weather, end-of-the-day.
Whatever the circumstances, a tragedy.
f