Aircraft Crash in Moscow
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So what happens when an aircraft lands short with EMAS present? Can you assume that in such cases the aircraft will be landing flat and not a gear first with a tendency to roll.
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SGC
Spot on - and it's not just 'at the end of the runway'. Thinking of the Spanair crash in Madrid where there was/is a ravine and a stream at the side of the runway. There was plenty of runway left but the ravine drop contributed to the breakup of the aircraft and the severity of the injuries (although paradoxically the water lessened burn severity).
Sunamer
Think of it in terms of a closed system in Newtownian mechanics and the conservation of momentum, rather than energy. If you could work out what speed the nosewheel was going, then I cant see how the speed of the aircraft at that point would be less than that, although I agree that it is likely that it would be more.
Spot on - and it's not just 'at the end of the runway'. Thinking of the Spanair crash in Madrid where there was/is a ravine and a stream at the side of the runway. There was plenty of runway left but the ravine drop contributed to the breakup of the aircraft and the severity of the injuries (although paradoxically the water lessened burn severity).
Sunamer
Think of it in terms of a closed system in Newtownian mechanics and the conservation of momentum, rather than energy. If you could work out what speed the nosewheel was going, then I cant see how the speed of the aircraft at that point would be less than that, although I agree that it is likely that it would be more.
Machinbird;
Thanks for the response. Agree, interesting topic but won't take it further as indeed it doesn't apply here.
Awaiting photos and/or the FDR to see the position of the reversers and thrust levers. Lomapaseo's photos do seem to show low rotational speed in that engine.
Also, I'm thinking of the amount of destruction of the airframe in the TAM A320 overrun accident at Sao Paulo - it was almost complete but for the empennage but here much of the fuselage remains in a single piece, looking more like the Etihad A340-600 31kt ground-test collision with a blast fence at Toulouse, though the Red Wings aircraft fractured/separated at the cockpit and empennage. The lower cockpit area and the fracturing of the fuselage dissipated much of the forward energy but the fuselage remained largely intact.
Understand the various calculations showing high speed but to me from the available photos the wreckage doesn't look like a high-speed, (=> 100kts) overrun. Perhaps the level of destruction in the TAM case was the vertical face of a concrete building while in the Red Wings overrun the ground was sloped and the same energy (about 100kts) was indeed absorbed by the undulating ground and the burm leading up to the freeway. In any case, we'll see what the speed was when/if the FDR data is eventually made available.
Thanks for the response. Agree, interesting topic but won't take it further as indeed it doesn't apply here.
Awaiting photos and/or the FDR to see the position of the reversers and thrust levers. Lomapaseo's photos do seem to show low rotational speed in that engine.
Also, I'm thinking of the amount of destruction of the airframe in the TAM A320 overrun accident at Sao Paulo - it was almost complete but for the empennage but here much of the fuselage remains in a single piece, looking more like the Etihad A340-600 31kt ground-test collision with a blast fence at Toulouse, though the Red Wings aircraft fractured/separated at the cockpit and empennage. The lower cockpit area and the fracturing of the fuselage dissipated much of the forward energy but the fuselage remained largely intact.
Understand the various calculations showing high speed but to me from the available photos the wreckage doesn't look like a high-speed, (=> 100kts) overrun. Perhaps the level of destruction in the TAM case was the vertical face of a concrete building while in the Red Wings overrun the ground was sloped and the same energy (about 100kts) was indeed absorbed by the undulating ground and the burm leading up to the freeway. In any case, we'll see what the speed was when/if the FDR data is eventually made available.
PJ2, in the Congonhas accident there was a small berm at the edge of the airfield as well, around 60cm high if I recall correctly. The fully laden aircraft traversed the road and impacted the TAM building, about 100m from the berm at the edge of the field and 10-12m lower, and head-on.
Would the fact that the TAM Airbus managed to "fly" that distance not indicate, in itself, a much higher impact speed than the 204? Or would the 204 not have bounced off the nose gear and concertinaed had it been heavy?
Would the fact that the TAM Airbus managed to "fly" that distance not indicate, in itself, a much higher impact speed than the 204? Or would the 204 not have bounced off the nose gear and concertinaed had it been heavy?
broadreach;
Re, "Would the fact that the TAM Airbus managed to "fly" that distance not indicate, in itself, a much higher impact speed than the 204? "
Yes it would and that's exactly my point.
Re-reading my post I wasn't sufficiently clear in stating that I think the 204 overrun was a low-speed accident. I think it was closer to the Etihad and (thanks, Machaca), TGU accident speeds, (30 to 50kts).
Re, "Would the fact that the TAM Airbus managed to "fly" that distance not indicate, in itself, a much higher impact speed than the 204? "
Yes it would and that's exactly my point.
Re-reading my post I wasn't sufficiently clear in stating that I think the 204 overrun was a low-speed accident. I think it was closer to the Etihad and (thanks, Machaca), TGU accident speeds, (30 to 50kts).
Last edited by PJ2; 6th Jan 2013 at 21:26.
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Braking was normal? Unless the aircraft touched down extremely late and a high-speed overrun occurred in spite of normal braking, would this indicate an attempt to take power again and go around?
Per Ardua ad Astraeus
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a flight attendant was interviewed from his hospital bed and declared that the braking was normal
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Last minute go-around attempt?
This is, of course, completely speculation, but considering the speed at which the aircrafyt departed the end of the rwy makes me think there may have been a normal landing, a deceleration/braking attempt, then a realization the aircraft will not stop, then a go-around attempt, which of course is rejected at the realization the airplane will not fly.
The Russian crews may not always have sufficient training to know exactly what to do in this kind of situation, lack of standardization, specifically with smaller operators.
The Russian crews may not always have sufficient training to know exactly what to do in this kind of situation, lack of standardization, specifically with smaller operators.
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Come on guys, you've had your fun. Reality is that none of you know what really happened. We've had enough drivel from some of you. Put it to bed and wait for the official and factual accident report to come out. 
IIRC, I remember once reading on an aeronautical site, some days after the 204 Aviastar crash out of Moscow, that RWZ CEO/President was not at all satisfied with their 204 fleet (in 2010), and was desperately trying to change it ASAP, due to a serie of no-good events and occurences...im trying to find the link.
Last edited by JanetFlight; 7th Jan 2013 at 19:34.
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On forumavia somebody from 204 make test on real plane:
a/c powered, TL on idle.
RCL unoperated, alpha TL 1-4. Move RCL to Idle, alpha TL is -18-20. Pull RCL further (with force, but they move!) - alpha TL -33!
RCL unoperated, alpha TL 1-4. Move RCL to Idle, alpha TL is -18-20. Pull RCL further (with force, but they move!) - alpha TL -33!
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Dashcam video speed information
Following the discussion of the debris speed, but without looking to check the numbers from earlier posts this is what I reckon.
The aircraft's visible diving down the bank to the right before the debris arrives, and seems to be moving quickly enough to cover its length in a couple of seconds, which would be about 20-25 m/s, about 40-50 knots. It definitely doesn't look like 100 knots. It seems to be driving not flying.
The wheel bounces off the bottom of the light gantry, crossing four lanes of the road in what looks like a bit more than two seconds - that's only about 10 m/s, so the wheel I reckon is moving slower than the aircraft was when it was released.
To correct both of these numbers, there's the factor of almost 45 degrees that the runway is angled with the road, so both should be higher by about 1.4.
I'd guess about 35 +- 15 knots for the wheel, and 60 +- 20 knots for the aircraft.
The aircraft's visible diving down the bank to the right before the debris arrives, and seems to be moving quickly enough to cover its length in a couple of seconds, which would be about 20-25 m/s, about 40-50 knots. It definitely doesn't look like 100 knots. It seems to be driving not flying.
The wheel bounces off the bottom of the light gantry, crossing four lanes of the road in what looks like a bit more than two seconds - that's only about 10 m/s, so the wheel I reckon is moving slower than the aircraft was when it was released.
To correct both of these numbers, there's the factor of almost 45 degrees that the runway is angled with the road, so both should be higher by about 1.4.
I'd guess about 35 +- 15 knots for the wheel, and 60 +- 20 knots for the aircraft.
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a flight attendant was interviewed from his hospital bed and declared that the braking was normal
I'm not saying it is in this case, just that this is another time to wait for the DFDR evidence.
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Relative Speeds A/C & dashcam car
Seems to me, the aircraft was moving significantly faster that the car with the dashcam.
Car on a steady heading, aircraft also on a steady heading, aircraft moving from the side towards the nose of the car, and would have actually arrived at the theoretical point of intersection first as indicated by the snow being thrown up in front of the car.
I don't know how fast the car was going. Looked to be around 60 mph or 50 knots but someone on this forum must have some idea of what the typical open road speed is for that stretch of highway.
Same principles apply as relative motion between aircraft inflight.
Car on a steady heading, aircraft also on a steady heading, aircraft moving from the side towards the nose of the car, and would have actually arrived at the theoretical point of intersection first as indicated by the snow being thrown up in front of the car.
I don't know how fast the car was going. Looked to be around 60 mph or 50 knots but someone on this forum must have some idea of what the typical open road speed is for that stretch of highway.
Same principles apply as relative motion between aircraft inflight.
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Hi Machinbird..
Without adding for parallax to augment rate, I still get two fuselage lengths in a bit over one second. That is wicked fast, so I go to what I think would be a very conservative value of 90 knots. Two lengths (300 feet) in two seconds is still ninety knots. It could 115+.
Anything is possible, but your take seems to affirm more velocity than 50-60 knots.
Whatever it is, the bottom line is way too fast to survive, and suggestive of added thrust or uncommanded thrust well after touchdown, imho.
Sad bad day...
Without adding for parallax to augment rate, I still get two fuselage lengths in a bit over one second. That is wicked fast, so I go to what I think would be a very conservative value of 90 knots. Two lengths (300 feet) in two seconds is still ninety knots. It could 115+.
Anything is possible, but your take seems to affirm more velocity than 50-60 knots.
Whatever it is, the bottom line is way too fast to survive, and suggestive of added thrust or uncommanded thrust well after touchdown, imho.
Sad bad day...