Aircraft Crash in Moscow
Per Ardua ad Astraeus
Join Date: Mar 2000
Location: UK
Posts: 18,579
Likes: 0
Received 0 Likes
on
0 Posts
I have no idea what you are talking about. What pitch attitude do you see? What would you expect?
I find the English instructions on the headrests of more interest.
I find the English instructions on the headrests of more interest.
Trusting souls?
dsc
Yes I do agree even though they were from different sources. I got confused when the one mis-labled as left was in the background of the TV person and they jumped to a closeup shot apparently of the RH one.
So I guess we are back to square one, only pics if one engine so far
Those pictures look to me like they are of the same engine, the first one after the fire has been dowsed and the second prior to this happening.
The are taken from slightly different angles, but there are number of almost identical pieces of debris in front of the engine and the angle at which they are resting is the same.
The are taken from slightly different angles, but there are number of almost identical pieces of debris in front of the engine and the angle at which they are resting is the same.
So I guess we are back to square one, only pics if one engine so far
Guest
Posts: n/a
in other words, too fast, too light, too long
Looks like many pilots like this "know" to land an airplane ONLY if same weight every day every flight. Yes ?
Join Date: Jul 2009
Location: Not far from a big Lake
Age: 82
Posts: 1,454
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Green Guard
You add 15 kts or more (even when on Max Landing Weight)...in same wors, too fast, too heavy, tooooooooooo looooong.. Why don't you solve problem with your Chief Pilot and adjust Vref to factory values, and not be scared to use them on low weights ?
Looks like many pilots like this "know" to land an airplane ONLY if same weight every day every flight. Yes ?
Looks like many pilots like this "know" to land an airplane ONLY if same weight every day every flight. Yes ?
But first you would need AOA indicators in the cockpit and would need to learn how to use them. (Not hard to learn since very intuitive).
If it ends up that non-activation of the WOW switch is one of the big holes in the cheese leading to this accident, you can probably add low gross weight, a gentle touch down, and general cold weather stiffness of seals in the struts as contributing factors to such non-activation.
Machinbird;
Re, "Now if you ran your approach using AOA for speed control and simply cross checked it against Vref to be sure it was reasonable, this could all be avoided. Right speed every time. No additive factors to foul up."
Not commenting on this accident but as a general observation on AoA indication, bear in mind that AoA indication does not compensate for a contaminated wing but additives, (when employed where such contamination is suspected), do.
Re, "Now if you ran your approach using AOA for speed control and simply cross checked it against Vref to be sure it was reasonable, this could all be avoided. Right speed every time. No additive factors to foul up."
Not commenting on this accident but as a general observation on AoA indication, bear in mind that AoA indication does not compensate for a contaminated wing but additives, (when employed where such contamination is suspected), do.
Last edited by PJ2; 4th Jan 2013 at 20:05.
Per Ardua ad Astraeus
Join Date: Mar 2000
Location: UK
Posts: 18,579
Likes: 0
Received 0 Likes
on
0 Posts
No-one to comment on the vastly different speeds of the two RedWings at touchdown?
(I do appreciate that the time sampling may be part of the story, but......?)
(I do appreciate that the time sampling may be part of the story, but......?)
AoA
Not commenting on this accident but as a general observation on AoA indication, bear in mind that AoA indication does not compensate for a contaminated wing but additives, (when employed where such contamination is suspected), do.
while that is true in most cases, there is one system that this is not true for, which has been tested and is being promoted by a Canadian R&D company, which assesses the boundary layer development, and can identify a contaminated wing on the takeoff roll, while on the ground. Pretty neat trick. Not germaine to the event in question, but a clarification of the comment on AOA application.
(So far, the OEM's even those with wings that are critically sensitive to contamination - read no LE devices... have shown the usual level of apathy in the uptake, probably will take a number of additional catastrophes before gaining some acceptance).
In relation to the wind additions, the move towards gust/steady wind components rather than the use of a minimum ground speed/reference ground speed is lunacy, particularly in strong crosswind conditions, where the usual outcome is a destabilised aircraft attitude and flightpath and loss of touchdown precision in a case where these factors are most beneficial.
Last edited by fdr; 4th Jan 2013 at 21:22.
Join Date: Jun 2010
Location: USA
Posts: 245
Likes: 0
Received 0 Likes
on
0 Posts
As I understand it, the present theory is that the wow switch presented the system logic with a false negative (the switch said the plane was not on the ground when it was) so the TR never deployed when commanded by the crew.
So why would the the system logic in that situation apply significant thrust such that the PF has to send TL back to idle?
So why would the the system logic in that situation apply significant thrust such that the PF has to send TL back to idle?
Join Date: Jul 2009
Location: Not far from a big Lake
Age: 82
Posts: 1,454
Likes: 0
Received 0 Likes
on
0 Posts
There are indications that excessive approach speed may be relevant to this accident. For that reason, I mentioned the possibilities of using AOA indicating systems to properly control approach airspeed. It works, and is darned simple to interpret and use.
Discussions of contaminated wings are not relevant to this accident (it appears) so I suggest we not go beyond tidying up the immediately previous discussion, no matter how interesting.
Thank you for that comment PJ2.
When your wing is contaminated, you are flying with a poorer airfoil than originally designed. No one really knows at what AOA the airflow might break loose, but we have SWAGs (Scientific Wild @ss Guesses) by the manufacturer that provide a pretty good estimate based upon their actual experience.
You can achieve a conservative AOA by either looking at GW and configuration and coming up with an additive airspeed, or you can reduce the approach AOA by flying deliberately at a lower angle of attack (using an AOA indicator). Almost the same thing. All you need are additional AOA target tick marks on the indicator.
If you are in a turn though, flying constant AOA will compensate for the additional g that results. The airspeed additive approach has to build in a safety factor for reasonable maneuvering.
Interesting fdr! Would that be an acoustic system of detection?
Discussions of contaminated wings are not relevant to this accident (it appears) so I suggest we not go beyond tidying up the immediately previous discussion, no matter how interesting.
Originally Posted by PJ2
Not commenting on this accident but as a general observation on AoA indication, bear in mind that AoA indication does not compensate for a contaminated wing but additives, (when employed where such contamination is suspected), do.
When your wing is contaminated, you are flying with a poorer airfoil than originally designed. No one really knows at what AOA the airflow might break loose, but we have SWAGs (Scientific Wild @ss Guesses) by the manufacturer that provide a pretty good estimate based upon their actual experience.
You can achieve a conservative AOA by either looking at GW and configuration and coming up with an additive airspeed, or you can reduce the approach AOA by flying deliberately at a lower angle of attack (using an AOA indicator). Almost the same thing. All you need are additional AOA target tick marks on the indicator.
If you are in a turn though, flying constant AOA will compensate for the additional g that results. The airspeed additive approach has to build in a safety factor for reasonable maneuvering.
Originally Posted by fdr
......there is one system ........... which has been tested and is being promoted by a Canadian R&D company, which assesses the boundary layer development, and can identify a contaminated wing on the takeoff roll, while on the ground.
Prof. Airport Engineer
Join Date: Oct 2000
Location: Australia (mostly)
Posts: 726
Likes: 0
Received 0 Likes
on
0 Posts
EMAS and Runway End Safety Area (RESA) (part 2)
In an earlier post, I looked at what an EMAS might have done if it was installed at Vnukovo Airport (but there was no EMAS there). Now I'll look at RESA and Runway Safety Area. This discussion is hypothetical and based on assumptions which are noted; these must be verified when facts become available.
I'll start by clarifying the difference between ICAO and FAA on the matter. The FAA "Runway Safety Area" is sort of equivalent to what ICAO gets by combining their "Runway Strip" and "Runway End Safety Area". In FAA terms, the total distance of this safety area from the runway end is 1000 feet (305 m), and if you haven't got it, then it is non-standard and you must work towards a solution. In ICAO terms, the total distance of this safety area from the runway end must be 60m + 90m = 150m (500 feet) and ICAO recommend it to be 60m + 240m = 300m (1000 feet). I have rounded the conversions slightly for the reason of common sense. See the diagram below:
SGC's post first got me thinking about ICAO's 240m RESA. I am now going to look hypothetically at Vnukovo Airport to see what the effect of RESA and FAA Runway Safety Area might have been. For clarity, I do not know what is actually present at Vnukovo Airport, but my look at Google Earth suggests that there was more than an ICAO 90m RESA. There was not an ICAO 240m RESA. There was not an FAA 1000 feet Runway Safety Area. It appears from the Google Earth and the information so far that Vnukovo Airport likely had about 160m of ICAO RESA (which, after adding the ICAO 60m runway strip length, makes it about 720 feet of FAA Runway Safety Area).
Would this be enough?
It depends on exit speed and deceleration. I used the reasoned estimation from Lyman that 100 knots was the runway exit speed of the Tu-204 at Vnukovo. There is no data on deceleration or friction over the snowy ground past the runway end. The FAA EMAS design assumes a poor braking action with 0.25g deceleration on the paved area between the runway end and the EMAS. Tom Yager did a winter friction assessment in 1999 (report: NASA-99-tm209142), suggesting to me that an effective braking friction coefficient of 0.25 would be reasonable for 2-3 inches of snow at 80 knots. I used 0.25g deceleration in my analysis.
I assumed nil forward thrust even though there is speculation that there was some; forward thrust would obviously reduce deceleration and make things worse. I ignored slope, which was downhill and would make things worse.
If the aircraft exited the runway at 100 knots, the stopping distance would be 540m (1771 feet).
Hypothetically if a 90m RESA was present, it finishes 150m (500 feet) from the runway end and the aircraft would be travelling at 85 knots as it left the RESA.
Hypothetically, if a 240m RESA was present, it finishes 300m (1000 feet) from the runway end and the aircraft would be travelling at 66 knots as it left the RESA.
Hypothetically, if an FAA Runway Safety Area was present, it finishes 300m (1000 feet) from the runway end and the aircraft would be travelling at 66 knots as it left the Runway Safety Area.
Neither the 240m nor the 1000 ft RSA were present. The first ravine that the Tu-204 encountered was located 257m (843 feet) from the runway end and hypothetically the aircraft would be travelling at 72 knots as it hit it.
I can't comment on the relative mitigating effect of the various safety options on accident severity, but I reckon that the speeds are all very high to hit a concrete fence and fall into a ravine with.
So would an ICAO 240m RESA or a 1000ft FAA Runway Safety Area have saved the day? Would an ICAO 240m RESA have saved the day compared to the 90m RESA? Would an EMAS have saved the day? Unfortunately in all three cases, it appears not.
I'll start by clarifying the difference between ICAO and FAA on the matter. The FAA "Runway Safety Area" is sort of equivalent to what ICAO gets by combining their "Runway Strip" and "Runway End Safety Area". In FAA terms, the total distance of this safety area from the runway end is 1000 feet (305 m), and if you haven't got it, then it is non-standard and you must work towards a solution. In ICAO terms, the total distance of this safety area from the runway end must be 60m + 90m = 150m (500 feet) and ICAO recommend it to be 60m + 240m = 300m (1000 feet). I have rounded the conversions slightly for the reason of common sense. See the diagram below:
SGC's post first got me thinking about ICAO's 240m RESA. I am now going to look hypothetically at Vnukovo Airport to see what the effect of RESA and FAA Runway Safety Area might have been. For clarity, I do not know what is actually present at Vnukovo Airport, but my look at Google Earth suggests that there was more than an ICAO 90m RESA. There was not an ICAO 240m RESA. There was not an FAA 1000 feet Runway Safety Area. It appears from the Google Earth and the information so far that Vnukovo Airport likely had about 160m of ICAO RESA (which, after adding the ICAO 60m runway strip length, makes it about 720 feet of FAA Runway Safety Area).
Would this be enough?
It depends on exit speed and deceleration. I used the reasoned estimation from Lyman that 100 knots was the runway exit speed of the Tu-204 at Vnukovo. There is no data on deceleration or friction over the snowy ground past the runway end. The FAA EMAS design assumes a poor braking action with 0.25g deceleration on the paved area between the runway end and the EMAS. Tom Yager did a winter friction assessment in 1999 (report: NASA-99-tm209142), suggesting to me that an effective braking friction coefficient of 0.25 would be reasonable for 2-3 inches of snow at 80 knots. I used 0.25g deceleration in my analysis.
I assumed nil forward thrust even though there is speculation that there was some; forward thrust would obviously reduce deceleration and make things worse. I ignored slope, which was downhill and would make things worse.
If the aircraft exited the runway at 100 knots, the stopping distance would be 540m (1771 feet).
Hypothetically if a 90m RESA was present, it finishes 150m (500 feet) from the runway end and the aircraft would be travelling at 85 knots as it left the RESA.
Hypothetically, if a 240m RESA was present, it finishes 300m (1000 feet) from the runway end and the aircraft would be travelling at 66 knots as it left the RESA.
Hypothetically, if an FAA Runway Safety Area was present, it finishes 300m (1000 feet) from the runway end and the aircraft would be travelling at 66 knots as it left the Runway Safety Area.
Neither the 240m nor the 1000 ft RSA were present. The first ravine that the Tu-204 encountered was located 257m (843 feet) from the runway end and hypothetically the aircraft would be travelling at 72 knots as it hit it.
I can't comment on the relative mitigating effect of the various safety options on accident severity, but I reckon that the speeds are all very high to hit a concrete fence and fall into a ravine with.
So would an ICAO 240m RESA or a 1000ft FAA Runway Safety Area have saved the day? Would an ICAO 240m RESA have saved the day compared to the 90m RESA? Would an EMAS have saved the day? Unfortunately in all three cases, it appears not.
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,074
Likes: 0
Received 0 Likes
on
0 Posts
J.O. 3Jan 22:15...
The video demonstrates a test of EMAS with a 727. From text elsewhere, the entry speed is 70 knots, and the aircraft stops in roughly 3+ fuselage lengths.
The nose gear collapses, but the hull is intact. From video, actual humans are aboard for the deceleration....the test is impressive.
The parameters and applications are a long discussion...
Thank you Overun, for a great foundation....
The video demonstrates a test of EMAS with a 727. From text elsewhere, the entry speed is 70 knots, and the aircraft stops in roughly 3+ fuselage lengths.
The nose gear collapses, but the hull is intact. From video, actual humans are aboard for the deceleration....the test is impressive.
The parameters and applications are a long discussion...
Thank you Overun, for a great foundation....
Join Date: May 2004
Location: 3.5 from TD
Age: 47
Posts: 1,042
Likes: 0
Received 0 Likes
on
0 Posts
I'm not sure what figures you are using there overrun. I'm also not sure what you mean by "save the day". Would EMAS prevent a hull loss in this instance? Probably not. But would it have reduced the speed at final impact? Most certainly.
As Lyman has already suggested, you should look at the video of EMAS stopping a 727. I think it most definitely have made this accident less deadly. Until we know the actual speed of the end of the tu204 we won't know for sure.
As Lyman has already suggested, you should look at the video of EMAS stopping a 727. I think it most definitely have made this accident less deadly. Until we know the actual speed of the end of the tu204 we won't know for sure.
Join Date: Jan 2013
Location: Shangrila
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Wheelbarrowing
The combination of excessive forward pressure on the control column during the ground run and high speed can cause the main wheels of some nosewheel aircraft to leave the ground, allowing the aircraft to run along on its nosewheel only. Brakes are out of equation.
Join Date: Oct 1999
Location: UK
Age: 70
Posts: 288
Likes: 0
Received 0 Likes
on
0 Posts
Velocities
It would be instructive to cross-check KC and OverRun's posts with how fast that nosewheel was travelling (the one shown on the dashcam hitting the car on the elevated section of road). Although not in a straight line if you know the width of the road and use a bit of trig it should be possible to estimate the velocity. If you are conservative with the numbers it would provide a comparison. Or we could just wait for another leak from the FDR readout.
Sqwak7700: I dont think OverRun needs to do that. He designs runways and does runway incident analysis for a living 
.
you should look at the video of EMAS stopping a 727
.
Join Date: Aug 2012
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
It would be instructive to cross-check KC and OverRun's posts with how fast that nosewheel was travelling (the one shown on the dashcam hitting the car on the elevated section of road). Although not in a straight line if you know the width of the road and use a bit of trig it should be possible to estimate the velocity.
that wheel bounced from some obstacle before going into the frame. + part of AC could transfer to that wheel more energy that it had before the impact, thus making the speed of that wheel more than (or less than) the speed of actual AC.
Ek = 1/2 * mV^2...
That means that the only thing that could be changed during that energy transfer is V (in order to accommodate difference in Ek). Mass is the same before and after, since that wheel is more or less intact and in one piece.
So, could you explain, what we need speed of that wheel for?
Guest
Posts: n/a
There's no such thing as a normal overrun, but there are overruns that can be exceptional due to factors not normally present in the majority.
These come to mind as having 'extra factors' as well as a high numbers of deaths.
There are 2 issues which I think should be thought about. Firstly, does the airport sign up to 90m or 240m RESA. Secondly, if a high energy overrun were to happen is there anything beyond the RESA provided which could create an additional hazard.
The Air France overrun at Toronto in Aug 2005 and the Iberia at Quito in Nov 2007 both highlight the effect of less than ideal topography beyond the end of the runway.
However, ICAO have seen fit to require all certified airports to provide a 90m RESA but recommended 240m.
Question is, how many airports that only provide 90m RESA are satisfied with their level of safety not only for high energy overruns but also 'normal' ones?
If there are physical obstacles beyond the end of a runway limiting the provision of RESA one option is to reduce the Landing Distance Available (LDA). Doing this might have a commercial impact on operators performance calcs especially the Max Landing Mass.
So regardless of any particular accident, should airports re-apprise their declared distances to meet ICAO's recommended 90m RESA or bite a potentially bitter pill and redeclare LDA?
Also, should airlines train their crews' differently wrt landings which could become overruns? Is it an HF vs Just Culture issue?
These come to mind as having 'extra factors' as well as a high numbers of deaths.
09/07/2006 A310 S7 Airlines Irkutsk, Russia Landing 125 F
17/07/2007 A320 TAM Congonhas International, Landing 187F +12F
22/05/2010 B738 Air India Express Mangalore, Landing 158F
17/07/2007 A320 TAM Congonhas International, Landing 187F +12F
22/05/2010 B738 Air India Express Mangalore, Landing 158F
The Air France overrun at Toronto in Aug 2005 and the Iberia at Quito in Nov 2007 both highlight the effect of less than ideal topography beyond the end of the runway.
However, ICAO have seen fit to require all certified airports to provide a 90m RESA but recommended 240m.
Question is, how many airports that only provide 90m RESA are satisfied with their level of safety not only for high energy overruns but also 'normal' ones?
If there are physical obstacles beyond the end of a runway limiting the provision of RESA one option is to reduce the Landing Distance Available (LDA). Doing this might have a commercial impact on operators performance calcs especially the Max Landing Mass.
So regardless of any particular accident, should airports re-apprise their declared distances to meet ICAO's recommended 90m RESA or bite a potentially bitter pill and redeclare LDA?
Also, should airlines train their crews' differently wrt landings which could become overruns? Is it an HF vs Just Culture issue?