@fdr

Speed information is based on post from "Мамаладзэ" on forumavia ru (Link).
I don't know what is his affiliation, but judging by his forum posts he is flying for Red Wings and/or flying type that crashed.

He's saying that a/c landed approx 800m after TDZ (1700m after RWY edge?) travelling 262 km/h, crashed at >200 km/h.

FDR readout was completed already on 30th as per info from MAK Website, "Мамаладзэ" post with speeds dated late evening 1st. Not an investigator but believe it is enough time to get these basic readings out of FDR?

I stand corrected.

fdr

The first estimation I saw was of 50-60 knots. So I viewed the video probably 100 times, checked on the length of the a/c, studied the diagrams of the overrun, with LOC and downslope, pit, and then the elevated roadway. I estimated 100 knots, with numbers for fps. Mph, and standard conversions. I did accident reconstruction at Court for a time, so I think I am close, but still emphasize it is a 'soft' number. I was tempted to write 110-115 knots but wanted to leave room for the admittedly squishy metrics.

After reading forumavia, I will stand by the 100 knot value. I think it was higher, but precision is impossible. The reason I spent time on the work at all was to help establish a frame for what is obviously a very sad event. It is my opinion that "wait for the report" is just fine. If however, there are issues that are emergent, and affect the safety of the flying public, a quick ball park and early handle on the salient issues can do no lasting harm, if the data is helpful in quickly mitigating a problem that has persistence and a record of prior occurrence in its character....

@ FDR, that's why I don't even bother commenting. I'll wait for the release of the report before drawing my conclusions. The rest is speculations. :ok:

CD with T204-100 FCOM, SOP and QRH is here

PsychoKif from aviaforum who have CCTV recording wrote:

veracity of information.

The stated source of most of the "hard" figures is unattributed and looks questionable given that the posts on recovery of the recorders post dates the pages where the figures that are being espoused here start to come up in the forum, and then they are related to the THY B737-800 accident report, not the TU-204 off. Additional "distance" figures come up in between these pages, related to an assumption of worst case landing... with no evidence to justify the assumption.

Lyman may well be correct about the speed off the end, however there is a dearth of information to presuppose that the crew have acted in any manner other than attempting to deal with a critical occurrence. The images taken on the approach (sequentially by the same photographer) do not indicate an aircraft that is outside of normal flightpath parameters.

Wait for the actual data before hanging the crew.

I completely agree. The velocity off the runway and into the obstructions was not compatible with survival. The runway's length cannot be published as it is; better to publish a shorter value, and mitigate a worst case with EMAS.

To expect an overrun to be of lowest velocity rather than highest creates a problem, and serves no one. Exaggeration of any kind must err on the side of survival, not appearance. In a strange way, the runway was too long, for its performance the a/c needed much less than what was represented as being available.

I am sorry if my estimates have caused rumors of unwarranted accusations.

Not just in Russia - I've seen cameras in cars in Singapore and the States - people have them so they can prove who'se fault it was in an accident

I'm in the UK and use my mobile phone to record when driving any distance with a windscreen mounted bracket. One touch on the screen saves the last 2 minutes of video, or if an impact is detected by the shake monitor, the phone will autosave the last 2 minutes of video. I do this after 2 insurance claims that were not driver fault took far too long to finalize due to unreliable witnesses or false claims from those responsible.

There are now a few UK insurance companies offering cheaper insurance to drivers who agree to have a "driving monitor" in the car, normally for 17 to 25 year olds. The box is installed and the GPS data is sent to the insurer who will set your premium based upon how safely you have been driving and how much/when you drove.

Sorry for the thread deviation......

Were the pilots and the F/E in their designated seats?

Where is this CCTV footage (link) ?

Which taxiway exit is B4? The one towards the end of the TDZ or the rapid exit one well beyond the last marker?

Lyman, and for anyone reading this who is interested, if you are traveling at
100 kts, your kph is 185 (well, 185.2 ...)
At 100 kph, speed in knots is 54 (well, 53.99 ...)


EDIT:
Thanks, mm43, for you catching my error.

B4 is the third 90 exit and B5 is the 01 HSE

It's not circulated, by the posts of this guy it's security CCTV of VKO and he doesn't want it to be in open access.

The amendment to the FCOM mentioned earlier re turning off reverse if it does not kick in and leaving it alone point to the possibility IMO that instead of reverse they ended up with uncommanded forward thrust instead. The amendment is "temporary" pending a technical fix the way I read it

Thanks BOAC - there seem to be conflicting reports as to where the plane touched down (posts 250 and 253) - if it was at B4 then that is within the TDZ but even the late touchdown would still have given 1300m of runway and 200m of overrun before the fence.

- if you read a post by Kulver on one of the other overruns it is said that crew 'broke' the reverse levers and that gave 86%N1 forward thrust!

Something to be said for the Boeing way for thrust and T/R levers. But, even that didn't work for AAL at KJAC.

NB We still do not have clear idea of how the 204 reverse selection is made/controlled.

That leaves less than 5000 feet before disaster. If the CCTV is accurate, that there were 30 seconds between TD and impact, that is an average velocity of approx. 115 mph. Allowing some velocity at the impact zone means there was little if any deceleration. Since the a/c obviously had residual velocity at the impact, the numbers suggest strongly the speed was higher than any survivable value. Assuming the impact speed was zero, post impact, (obviously) the average speed was far higher than 115 mph. Thanks to Doors to Automatic for the relative distances involved.

I am with vovachan in proposing uncommanded forward thrust. Unfortunately, there is the possibility also of commanded forward thrust. The Pitch of the a/c off runway did not follow the contour of the terrain. Rather, it suggested at least to me, there was a serious component of aerodynamic lift at the end of the runway.

Any low speed excursion would have the nose in the video lurch vertically. I did not pick that up. The "settling" I perceived could also be to the inertia of trajectory, so that wants a dash of salt.

RT seem to have hold of the story of the 204 making 2 approaches which has been one of the claims. I guess we will know soon.

Another media already published "interview with surviving stewardess" with claim that a/с "landed after second attmpt and before for a hour circled around to consume fuel"... :mad:

More RCL photos:

http://cdn-www.airliners.net/aviatio.../3/0780343.jpg

http://cdn-www.airliners.net/aviatio.../4/1969421.jpg

Surely if this were true, then after one attempted landing and an hour spent dumping fuel, they would have been diverted to one of Moscow's three other airports which presumably did have full fire cover? :confused:

For me, this a very strange accident/crash....

- a very light, modern jet didn't come to a halt on a +3 km runway, not snow covered, not icey
- no tech problems, at least not told to ATC
- between TD and impact, the AC lost only 20 kts (if true...)
- it is yet still not known, who was on the controles
- it is yet still not known who was in the cockpit and on which seat...

Could I ask some of you Boeing and Airbus drivers something about a comment made previously in this thread criticizing the Tu-204's "Russianess" in that it's a "poorly" layed out cockpit with clunky nobs etc.

Is this really so? The cockpit looks like a nice place to be and doesn't look very cluttered to me. I am not an airline pilot (yet) so I can't judge the ergonomics of it all but I am curious to know the answer to this question.

hetfield

one question I can answer for you (info from VKO rescue team member):

Everybody was at their places in cabin and CC was at seats. CPT was at his seat which was completely destroyed by impact, 2P and F/E was at their seats BUT they buckle only lower belt, not the shoulder belts :( Same with CC - they were not on theit seats with shoulder belts. :ugh:

Circling 'burning off fuel' - more puzzles rather than less.

BOAC, forget it. There was nor circling nor second attempt. I heard ATC recording (and posted link there) from radioscanner. Till touchdown there was not any hint of emergency situation. Also you can see track at flightradar24.

If there had been a previous attempt to land, we would by now have had some information about it especially as it seems there was CCTV footage of the final attempt.

If there had been a failed attempt to land followed by circling to reduce the fuel load, it would then make no sense to try to land at an airport with no fire cover when there were three others so close.

@kulverstukas

thx.

No reason to headbang, that's BOAC's job:ouch:

Well, I read those comments as well, and as I never had even heard of a Tu 204 before this crash I had already seen the cockpit fotographs while researching.

And I have to say, just as you, seems pretty organized, a well structured station. I have seen a few concepts in my life, and this doesn't turn me away like the pic of a 742, wher new developed screens (like TCAS) have been stuffed to whereever there was room to hold one.

Looks ok to me, even if somebody else might think the switches are "cluncky", they are still switches.

I am probably wrong, but I thought Boeing has an iron in the 204 fire, and that it is basically a Russian version of the B-757....

Definitely a "Concordski" flavor at the helm.....

EMAS and Runway End Safety Area (RESA)
 

The role of the RESA and the use of EMAS has been raised by several people here – first by SGC. Thanks to the excellent diagrams/photos posted by Kulverstukas, I was able to look at what effect an EMAS would have had at Vnukovo Airport.

What an EMAS really does
Firstly let me clarify what an EMAS really does because there are sometimes misconceptions about what it can do. It is not a physical arrestor like the aircraft carrier arrestor cable, nor is it a barrier net or barricade like the military use.

It can be simplistically thought that an EMAS effectively adds 525 feet of runway with guaranteed maximum braking which is 160 metres.

Effectively because the deceleration in an EMAS varies due to several factors which can be correlated to aircraft weight – heavier aircraft do not slow down as quickly. EMAS design adjusts for this by providing longer EMAS beds for heavier aircraft to ensure it still effectively adds 525 feet of maximum braking.

guaranteed maximum braking because the EMAS does the braking for you. Regardless of brakes, tyres, systems, pilots, runway surface, or weather, EMAS gives you that guaranteed maximum braking. Staying with my simplistic 525 feet analogy, it gives a deceleration of 13 ft/s2 (which is 0.41g or a typical Boeing "Autobrake Setting MAX). The actual aircraft deceleration in the EMAS bed varies with weight and other factors from 0.38 g to 0.78 g for aircraft from the 747 to the CRJ-200.

Simplistic because there are many more factors at work, but there is a consistency in the results which suggests that simple works here.

Design EMAS for Vnukovo Airport
A standard EMAS design will stop the design aircraft at a runway exit speed of 70 knots; it has a paved 75-foot set-back, assumes no reverse thrust, and a 0.25 braking friction coefficient.

Assuming that the EMAS for Vnukovo Airport was designed with the Tu-204 as the design aircraft. Assume that the Tu-204-200 design aircraft has a MTOW of 244,115 lbs (110,750 kg). The designed EMAS structure would typically be a bed length of 375 feet (115 m) and a paved setback of 75 feet (23m); a total of 450 feet (137m) from the runway end which would easily be fitted at that end of the runway at Vnukovo.

If the aircraft left the runway at 70 knots, then it would be stopped at the end of this EMAS bed.

Performance of EMAS in actual accident
The performance of the EMAS in the actual accident would be very much affected by the speed at which the aircraft was travelling when it left the runway. The standard EMAS design assumes a runway exit speed of 70 knots, but for Vnukovo, Lyman has given us some reasoned estimation that the speed was 100 knots.

At 100 knots exit speed, a MTOW Tu-204 would leave the paved 75 feet area and enter the bed at 165.17 ft/sec (98 knots). It would leave the EMAS bed still travelling at a high 71 knots. From there it is about 123m to the first significant drop-off. Assuming very poor braking on the snowy ground, it would be travelling at 64 knots or more when it reached the first significant drop-off. The actual aircraft was light, so its deceleration in the EMAS bed would be slightly higher but the effect on speed would only be 5-6 knots lower. All this assumes no forward thrust, which would only have made matters worse.

So would the EMAS have saved the day or even mitigated the accident? Unfortunately in this case it appears not.

I think you are wrong in that conclusion, OverRun.

The assumption the aircraft left the runway at 100kts, is just that - an assumption at this stage. Might be faster, might be slower. Lets concentrate on what we know for sure.

If we go by known facts, I think that EMAS would most certainly have saved lives. Being that some of the injured died at hospital or after the crash, we can deduce that the impact speed was right around the threshold of survivability for these circumstances - regardless of what that actual speed was.

That is all that matters in a crash really - how quickly you come to a full stop. Speed is not the killer. If you hit the ground at 250kts but use up 3 miles to stop, then you will most likely survive the impact. But if you hit an unforgiving obstacle at 50kts and take only 1 foot to stop, then you will probably die or at least end up severely injured.

The overrun did not kill in this instance, it was the unforgiving obstacles that killed the occupants. EMAS would have certainly shaved 10 or 20kts of their speed, and that might have been enough to bring them within the threshold of the restraint devices and within the energy absorbing limits of the airframe. Remember that as speed increases, the chances of dying go up exponentially.

Either way, by FAA standards, this runway is illegal unless it has EMAS. The RSA is simply not long enough. And with obstacles so unforgiving like the dirt embankment they hit, IMHO, I would exceed the FAA limits and put EMAS all the way up to the highway shoulder (or even shorten the runway a bit to extend the EMAS strip). This time it was an empty repo flight, next time it might be a full IL96 with Russian vacationers.

Hopefully the Russian authorities, as tragic as this was, take this accident and look at it as a warning of how bad it could have been.

Unless there is a bit of M²/V² involved, I don't understand why if,

it would, assuming an entry of 100kts,

especially given that it was virtually empty.

I must be not understanding, overun. you suggest that EMAS' mechanism for energy dissipation is 'braking'. If a 125 meter bed 'effectively' provides 175m of 'additional runway braking', then the efficacy of its use is barely marginal.

The mechanism as I understand it has fibrous and frangible concrete installed as an 'arresting bed'; as the material decomposes with the passage of the landing gear, it provides greatly enhanced arrestment due friction and non uniform crumpling of the supporting material. My guess is that the landing gear is destroyed, the EMAS install is most definitely destroyed. But the sacrificial nature of the installation is a design consideration. Better to save lives than landing gear and lightweight frangible 'runway'?

Better than runway braking, surely?

I have to concur with Sqwak 7700, the EMAS system will attenuate velocity better than runway. It would have slowed the subject Tu204 markedly, perhaps saving everyone. The Runway is definitely non compliant per FAA, not that FAA regs should obtain here.

I would repeat my observation that 01 is "too long". Runway that should be overrun is not runway. It is overrun, and cannot (should not) be represented as usable runway for purposes of flight planning....

With great respect.