LAM Mozambique flight crashed...
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I have thought about a double engine failure also, but on the AVHerald a ROD of 6000 fpm is reported. That would fit a high level glide, maintaining a constant machnumber. I get rates of 4-5000 fpm in that regime descending on mach .80 with idle (Level change mode). If you subtract the idle power, and consider that my plane is usually loaded a lot heavier, 6000 for a light 190 (30pax) seems to make sense.
That stops, though, when reaching trnsition to IAS, then the rate reduces significantly to about 1500 fpm at IAS 250 at 10.000'. Maintaining a rate of 6000fpm would definetly overspeed the aircraft.
So maybe that information is faulty, or is an average overall or is the initial ROD.
Andrasz:
Well,... the largest TS I have seen were in Africa, cruising at FL350 the thing looks the same distance up as it does down, they dwarf our european TS.
By far the meanest, though, are the ones in NAmerica. Absolutley deadly. Just look at all the tornadoes they get over there...
I do hope they find the reasons for this crash soon, I fly the same type and am worried about anything immanent to the system. Icing of engines has made news (Boeing - GE) recently and this was no inflight breakup in a TS. It hit in one piece, as far as I can interpret the pictures of the crashsite.
That stops, though, when reaching trnsition to IAS, then the rate reduces significantly to about 1500 fpm at IAS 250 at 10.000'. Maintaining a rate of 6000fpm would definetly overspeed the aircraft.
So maybe that information is faulty, or is an average overall or is the initial ROD.
Andrasz:
...as they are in the European or US skies on any average hot summer afternoon. T-storms don't just bring down a modern jet mid-cruise
By far the meanest, though, are the ones in NAmerica. Absolutley deadly. Just look at all the tornadoes they get over there...
I do hope they find the reasons for this crash soon, I fly the same type and am worried about anything immanent to the system. Icing of engines has made news (Boeing - GE) recently and this was no inflight breakup in a TS. It hit in one piece, as far as I can interpret the pictures of the crashsite.
It is probably rather down to the fact that we know so little at this point in time and there are no 'default' ways to get a modern airliner to crash down from cruise altitude. There have been only very few such instances and they didn't follow a pattern (unlike CFIT in non-precision approaches).
So probably everyone as puzzled as myself. Here's definitely waiting for facts.
He almost sounds happy about the crash.
AVH now has some better photos of the crash site, the debris field is long and narrow, and the bulk of the burnt-out fuselage is in one compact place suggesting that it might have been an attempted emergency landing with some level of control. This makes a structural failure in a TS updraft scenario less likely.
These small aircraft are usually structurally quite strong and in the pics and vids I see serious destruction. To me it Looks more like a medium to high energy Impact.
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but on the AVHerald a ROD of 6000 fpm is reported.
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There are just a lot of questions here.
The decent rate would almost indicate a pressurization issue.
The O2 bottles for the masks could have been empty.
Hail could have damaged the windscreen until failure injuring or incapacitating the pilots, although pretty unlikely.
Fire but seems unlikely with O2 available for the pilots and few minutes to terra firma at 6,000ft/min.
I find it interesting no radio calls were made declaring an emergency and it appears there was an issue controlling the aircraft even at lower altitude even if the pilots were in conscious, the crash remains appear to be from a pretty fast speed on relatively flat ground.
The decent rate would almost indicate a pressurization issue.
The O2 bottles for the masks could have been empty.
Hail could have damaged the windscreen until failure injuring or incapacitating the pilots, although pretty unlikely.
Fire but seems unlikely with O2 available for the pilots and few minutes to terra firma at 6,000ft/min.
I find it interesting no radio calls were made declaring an emergency and it appears there was an issue controlling the aircraft even at lower altitude even if the pilots were in conscious, the crash remains appear to be from a pretty fast speed on relatively flat ground.
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These small aircraft are usually structurally quite strong and in the pics and vids I see serious destruction. To me it Looks more like a medium to high energy Impact.
Big chunks generally means relatively low speed. A ballpark guess would be around 150 knots.
Extensive breakup then means a bad ground interface, probably wing down or without a flare. Perhaps hit an obstacle. I would be surprised if it was over 180 knots worst case.
The higher the energy of impact, the smaller the chunks. Sometimes the aft pieces of the aircraft are larger because of deceleration caused by the front part of the aircraft being broken up. Fuel flowing out of fractured tanks can caused localized destruction as it tumbles parts along.
Hopefullly the recorders can be read and we will have solid data beyond my poor efforts.
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Looking at some satellite data and their most likely flight-path it seems they passed close to (or through) a Cb that was growing incredibly fast: In the space of 15 minutes the top of the Cb went from around FL295 to FL410. Unfortunately it would have been that 15 minutes that they flew near it, so it'll be interesting to see what role, if any, that played. It's one of the fastest growing (and shortest lived) storms I've seen there.
Based on past experience it also seems to be the type of Cb that produces ICI, but I can't understand how that alone would cause an accident as, in the space of about 5nm, the cloud totally disappears and the crew would've been in VMC again. They managed to continue for another 60nm or so, all in decent visibility. Is the Cb just a conicidence or did it have some effect?
In short: Haven't a clue, it's puzzling.
Based on past experience it also seems to be the type of Cb that produces ICI, but I can't understand how that alone would cause an accident as, in the space of about 5nm, the cloud totally disappears and the crew would've been in VMC again. They managed to continue for another 60nm or so, all in decent visibility. Is the Cb just a conicidence or did it have some effect?
In short: Haven't a clue, it's puzzling.
Originally Posted by henra
I fail to see a low energy Impact
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They were at FL380 which is damn near the ceiling for the Ejet at that gross weight (assuming they were carrying through fuel). Speaking from experience here, they would have been near coffin corner but not right at the edge. You do get the PLIs really quick at that altitude so plenty of time to react. Plus, it was daytime. Personally I think WX is unlikely here.
It sounded similar to the B737 problem of the rudder going hard over as they were commencing initial approach. A sudden partial or total loss of control could explain a ROD of 6000fpm and no communication from the crew
That's my two cents worth, although mind you, I REALLY hope I am wrong on this one.
It sounded similar to the B737 problem of the rudder going hard over as they were commencing initial approach. A sudden partial or total loss of control could explain a ROD of 6000fpm and no communication from the crew
That's my two cents worth, although mind you, I REALLY hope I am wrong on this one.
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mostly harmless
@torquemada60
Thank you for the link to The Villager. This article, a generally good piece of journalism, tells us a few things:
- There had been a communication from the cockpit to Botswana ATC
- The communication identified weather-related problems
- The crash site is possibly fairly close to Rundu airfield. Could there have been an attempted landing?
- The article reminds us that LAM is banned from EU airspace.
I note that, formally, the flight ban relates to issues concerning national oversight rather than any issues specific to LAM. However, casual observation at Maputo, Mozambique, reveals what, to the untrained eye, appear to be interesting landing manoeuvres.
reason for edit: correct stupid error pointed out by next poster.
Thank you for the link to The Villager. This article, a generally good piece of journalism, tells us a few things:
- There had been a communication from the cockpit to Botswana ATC
- The communication identified weather-related problems
- The crash site is possibly fairly close to Rundu airfield. Could there have been an attempted landing?
- The article reminds us that LAM is banned from EU airspace.
I note that, formally, the flight ban relates to issues concerning national oversight rather than any issues specific to LAM. However, casual observation at Maputo, Mozambique, reveals what, to the untrained eye, appear to be interesting landing manoeuvres.
reason for edit: correct stupid error pointed out by next poster.
Last edited by answer=42; 2nd Dec 2013 at 20:43.
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190 warrior:
A double flameout at cruise level could cause a pressurisation problem and justify a 6000fpm dive down to breathable air.
How well does the 190 glide one it gets down to decent air ?
How easy would a restart be, in some engines a flameout can result in temporary bearing siezure due to uneven cooling and it cannot be restarted until the temperatures in the engine equalise to free it up.
It would be interesting to know if the engines were actually turning when it crashed, this is an easy one for the investigation to determine.
A double flameout at cruise level could cause a pressurisation problem and justify a 6000fpm dive down to breathable air.
How well does the 190 glide one it gets down to decent air ?
How easy would a restart be, in some engines a flameout can result in temporary bearing siezure due to uneven cooling and it cannot be restarted until the temperatures in the engine equalise to free it up.
It would be interesting to know if the engines were actually turning when it crashed, this is an easy one for the investigation to determine.
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well, with the oxygen mask on during an emergency descent you can still communicate pretty easily. The mask has an inbuilt mic that works pretty well. If the mask wasnt on, well...that's a different story.
As for an engine flameout, it's pretty straightforward. All you do is disconnect the autothrottle and move the thrust levers to idle. The entire engine relight sequence is automatic and controlled by the FADEC. That is, provided you have at least 7.2% N2 rotation, which at 6000fpm, would not be an issue. Even the RAT deployment is automatic, so I'd be interested to know whether or not is was out at impact.
As for the glide, only ever done one in the sim (thankfully) and it may not have too much range, but it is still controllable. It can be a pain because you lose the fly-by-wire, but without extreme column movements it can be done.
As for an engine flameout, it's pretty straightforward. All you do is disconnect the autothrottle and move the thrust levers to idle. The entire engine relight sequence is automatic and controlled by the FADEC. That is, provided you have at least 7.2% N2 rotation, which at 6000fpm, would not be an issue. Even the RAT deployment is automatic, so I'd be interested to know whether or not is was out at impact.
As for the glide, only ever done one in the sim (thankfully) and it may not have too much range, but it is still controllable. It can be a pain because you lose the fly-by-wire, but without extreme column movements it can be done.
