May 10, 2019, ©. Leeham News: An Aeroflot Sukhoi Superjet 100 crash-landed Sunday at Moscow Sheremetyevo Airport and burst into flames.
We shall look closer at the likely cause of the accident, which involves the SSJ100 Fly-By-Wire (FBW) control system working in Direct law.
The flight, Aeroflot 1492, started from Sheremetyevo for a flight of two hours to Murmansk, 800nm away. During climb out the aircraft was hit by lightning at 6,900ft and leveled off at FL100.
Normally an airliner recovers after a short hiccup after a lightning strike, but this time the aircraft’s radios and autopilot would not function after the strike. The crew, therefore, turned back to land on the runway they departed, Runway 24 at Sheremetyevo airport.
As the crew had intermittent radio contact with ATC on the emergency frequency 121.5 MHz (probably over the standby radio) they decided against long time circling over Moscow to dump fuel due to the heavy traffic in the area.
Instead, they prepared to land with an aircraft which was over Max Landing Weight but not more than a couple of tonnes. In normal landings, this creates no problems on runways the length of Sheremetyevo’s runways (shortest runway of three is 10,500ft, longest 11,650ft).
The lightning strike had put the FBW in its backup mode, Direct law. This is an emergency mode which bypasses the aircraft’s flight law computers and controls the aircraft’s control surfaces directly. One can say the aircraft is controlled by electrical wire instead of steel wire.
A FBW aircraft like the SSJ100 has a sophisticated digital feedback based FBW. This means the Pilot commands the aircraft movements he wants by sidestick and pedals. The FBW computers then move the aircraft’s control surfaces to achieve the commanded movement.
If the Pilot commands a pitch up to flare during landing, the aircraft pitches up at an adapted rate for the flare situation which is the same regardless of center of gravity or flap setting. The aircraft is nice and predictable to fly.
When such a system is forced to backup mode, Direct Law, in this case by a lightning strike, the aircraft becomes more difficult to fly. The movements of the sidestick and pedals are now moving the control surfaces directly. There is no damping nor any adaptation of stick sensitivity to different flight phases.
Full deflection of the stick must command full deflection of the control surfaces in case it’s needed to control the aircraft. This makes for a sensitive stick when making the small corrections needed for normal flight. Large movements of the stick and the aircraft can run into a Pilot Induced Oscillation, PIO.
Having watched the video of the landing I guess this is what happened. The Crew conducts an ILS approach on RWY 24 (the Nav receivers worked apparently). As they approach the runway the Pilot prepares to flare the aircraft.
The aircraft is about 15 to 20 knots over normal landing speed according to FlightRadar24 traces, which is plausible. They are overweight, on backup systems and might even be on backup instruments. A padding of the approach speed when landing overweight on a long runway is then natural.
As we only have video when the aircraft has started the flare over the runway it’s difficult to say if the PIO had started on short final. I would not be surprised if it had. When one sees landings with a runway gallop like for the SSJ, the PIO normally start before the runway threshold, on short final when the Pilot starts the flare.
Either he flares too little or too much initially. In both cases, he must correct and now he is stressed. His feel is, the aircraft is not responding to his commands. This pumps adrenalin into the muscles which get stiff. Stiff muscles increase the PIO and the over corrections further.
The gallop gets worse and worse until at the third touchdown the main landing gears, attached to the rear spars, ruptures the wingbox and with it the wing’s fuel tanks. Now fuel sprays out into the engine exhaust and the rear of the wing and fuselage is quickly engulfed in flames. The catastrophe is a fact and 41 of 78 onboard the aircraft perish in the smoke and flames.
I refrain from commenting on the evacuation with all its facets, I want to focus on why the aircraft burst in flames. One can talk of Pilot error but there are reasons for what happened. Direct mode is a certified flight control mode but it’s not certified to the same standards as full FBW mode.
I would be interested to hear others opinions about the decision to land early and not dump fuel. Am guessing there is no vent option so dumping would have required a couple of hours of scenic flying. You mention heavy traffic but given Moscow’s proximity to nothing and it’s multiple airports it can’t be as busy as many. To me if the controls are working at some level then getting the aircraft light and low on fuel is a no brainer.
As a pilot, landing an aircraft over its MLW is a no brainer, you add a bit of speed and done. Totally uneventful. If it’s a hard landing you need to inspect the aircraft afterward. Better than stay on top in IMC conditions around an airport for a long time, anything can happen.
The high weight was not the problem, the PIO at landing was. He should have made a go-around after the first bounce however if you are on partial systems you want to stay down.
You are the pilot Bjorn! I was comparing it to the Qantas A380 incident where they flew for 50 minutes assessing controls, did they vent fuel in that instance (beyond the leaks that is)
No problem Bob, just my 2 cents.
There isn’t the pilot which hasn’t overcorrected and bounced on a flare and got stressed sometime in his career, it’s common when learning the feel of a new type. Direct law essentially makes it a new type for the pilot.
If control was an issue then landing ASAP would be the right move.
If not, dumping fuel when flying a new aircraft that the Super Jet became would have been the best course for a lot of reasons.
The lading issue wight full fuel not the weight as well as the ability to do a go around which should have occurred if the approach was not stable.
Any idea how much they practice in Simulator in direct?
Bjorn, Your 2 cents are really worth a dollar. Your analysis is measured, deliberative, authoritative and informative. I for one am very thankful for your “2 cents.”
One would think that they had to pass simulator training for landing overweight in direct law with degraded systems.
This for different windspeeds/directions, rain/snow, darkness and degraded Airport systems, Aircraft mass, c.g. and different faults like only standby instruments available, single engine landing, bus bar error, loss of hydraulics…
I was told that the SSJ is landing normally quite fast. Do you have some facts.
MLW is 41t so assuming 29-30 BOW + payload, they should have been quite far from the MTOW even for the -B version and not far from the MLW
I was told the Earth was flat.
Or we can stick with facts?
If so list the source.
How could this lightning strike be different from others, that it failed the Autopilot and radios. Is it because of different standard of certifications specs ? Or a random event. What could be learnt from this tragic event?
You can only test so much and you have to make interpretations from the data you get.
Time will tell. Random, Maintenance, a deficiency unknown?
The SSJ seems to have a very small wing area (84m2) compared to a similar 5 abreast seating plane like the A220 (112m2)
A very extensive interview about the SSJ where a surprising amount of detail of aerodynamics and the development process are covered. Even the FBW redundancy is covered which may be useful in current context.
“The world’s first fully remote system without a mechanical backup, having the side stick as the main control lever”
They claim the aspect ratio for wing is very close to that of the 787(11) while they have 10!!
The perfect aerodynamics – interview with A.Dolotovsky
(Deputy Chief Constructor for Aerodynamics for Sukhoi)
I’ve read it, it’s good. The key parameter is wingloading, at 550kg MTOW/Wing area it’s the same as for the E190 and CRJ900. So nothing special. Landing speeds should be similar to these types.
Very nasty incident, I really feel for the victims and their families. From an aerospace perspective everyone will have a good look on this specific emergency situation and see if more general lessons can to be learned here.
Yea the sad thing is who gets affected are the victims not the causers (if any in this case)
FBW training in direct would be one for sure.
No idea how good the Russian system is for training and standards and not one we can affect regardless (well maybe Trump can whisper sage advice in Putins ear)
Any idea what percentage of pilots might make a mess of things when presented with direct law for landing?MCAS killer mode looks quite challenging to me but I really hope that next time I board a plane that 99% of pilots would be able to cope with what is thought to have happened here.
Well that is the crux of the issue.
A lot are screaming how much a killer the MAX is, and then we see how much a killer the FBW can be as well in direct.
My guess is no one is training much for it and now it will be a BIG deal.
«they prepared to land with an aircraft which was over Max Landing Weight but not more than a couple of tonnes.»
Are you sure? The trip to Murmansk has a length of approx. half of the range of the Superjet 100. So the tanks were probably not filled to the max. There were just 73 passengers on board (of max 98/108 for the Superjet 100). And the specified maximum landing weight for the SSJ100/95B of 41 tonnes is just 4.9 tonnes below the maximum takeoff weight of 45.9 tonnes.
So I think the landing weight was for sure below the specified maximum landing weight.
They were most likely gassed up for the outbound and return journey. So fully fueled at departure.
You alwyas have to take into account the cost of fuel at the far end as well as the time to fuel up.
That would drive to a top up in Moscow, it would balance out burn rate wise.
Thin route, who wants to go to Murmansk in the spring?
Moscow Murmansk 7 flights per day currently, around 2 hrs and 40 min
Some of other flights are A320 or 737.
The train, most likely only alternative is about 30 hrs …give me the plane !
Which would you like?
FBW that kills you
MAX that kills you
787 with RR engines that fail?
Who wants to go to Murmansk anyway?
This is the most insightful comment – and a professionally observed comment – that I’ve seen about this disaster. Thank you, Bjorn.
“Either he flares too little or too much initially. In both cases, he must correct and now he is stressed. His feel is, the aircraft is not responding to his commands. This pumps adrenalin into the muscles which get stiff. Stiff muscles increase the PIO and the over corrections further.”
It is almost as if full computerized FBW, manual + computer augmentation, and full manual controls each have their strengths and weaknesses, and each design philosophy and the pilots trained in using it will perform better in some circumstances and worse in others. Huh.
Thank you for a very insightful analysis. It is worthly to note that the crew was unable to communicate, and was squaking 7600 and 7700 just before the landed, so perhaps there had a “black out cockpit” situation. If several electronics were failing, then it will be very awful situation for the pilot to be.
Regarding the aircraft, the only thing that could be improved would be to study a better way to isolate the electronics from the body of the aircraft, if possible. Nonetheless, high voltages are always very dangerous. 300.000 volts and 200.000 amperes are more than enough to vaporize many things, including isolating material.
Sorry for those who suffered from this accident, and I think that it should be stressed on the security briefing before flight: DO NOT TAKE ANY PERSONAL BELONGINGS DURING EVACUATION!!!!!!!
If people take possessions during these emergency evacuations, they should be some sort of huge fine or punishment. This was also apparent with the 777 crash landing in San Francisco.
This is about the ops and what happened not the evacuation per the heading.
However I fully agree on the fact that not adhering to the rules – do not take along personal items during evacuation – during evacation should have (newsworthy) consequences. Currently the punishment for smoking in the lav is more severe… ridiculous!
Regarding: “If people take possessions during these emergency evacuations, they should be some sort of huge fine or punishment.”
As a math/science type I tend more towards engineering solutions than attempting to win over hearts and minds. If I am worried about someone stealing something, I place more faith in a good lock than in changing the penalties for theft. Might be that I am just gravitating towards the type of solutions that I understand better and am better at.
As far as I am concerned the ideal solution to the problem of passengers retrieving their carry on baggage during emergencies would be to remove the damned baggage bins from the cabin.
Since in the real world it probably isn’t going to happen that the baggage bins are going to be removed from the cabin, next best might be locking the bins via a remote controlled locking system during takeoff and landing, or whenever emergency exits are open.
Even better, but also not likely to happen in the real world, would be electrifying the baggage bin latches so they give a painful but non-lethal shock if touched when an emergency exit is open.
Kids, do not try this at home! (like I did when I was a teenager)
Thanks for the remarks on electronics system. I am hardware designer and I wonder what exactly happens when lightning strikes the plane. Electronics systems must be immune to stresses like this. Thsles, that supplies avionics, is renowned company. They should know this.
The underlying problem is much more fundamental: how did a lightning strike disable the airplane? This is quite uncommon: aircraft are designed and certificated to handle lightning routinely (most strikes are not noticed by crew).
The Superjet appears to have a design or manufacturing flaw in this respect. If so, the airplane will not fly again in the West.
I guess we need to retest all the FBW types eh?
Aircraft operators or autopilot manipulators of planes like the SSJ or the Airbus will always be at a disadvantage when it comes to actually flying the platform, that is, being asked to perform the role of pilot. When your day to day job is making requests of the autoflight systems, you are unprepared for the reality of flying.
It is the new paradigm for sure and we just have to live with it.
I was reading an AW story about pilots who aim for the threshold of the runway and some make a mistake and the wheels impact the ground before the runway itself. There was such a scenario in 2015 with Air Canada A320 AC624 at Halifax ( all survived) and the story said the Air Canada company policy was for pilots to only manually control the aircraft ( from the FMC and auto throttle) once the 100ft minimum was reached in the landing phase.
The story and the accident investigation had the primary cause as the pilot procedures but the airline has sued Airbus saying “”failed to identify shortcomings of the Airbus A320”, which included uncommanded descent below the pre-programmed glide path.
Any thoughts as to why the landing gear ripped open the wing box? All design cases that I know of have landing gear breakaway scenarios. Most have fuse pins attachments to the wing beam precisely to avoid this kind of event
Perhaps poor manufacturing or a very unusual landing condition?
Do you have an links to scenarios?
If you punch the gear hard enough, links and break away is irrelevant as the stuff of the gear goes up through the wing.
I don’t know if there is fuel above the gear but there is adjacent.
Once it keels over the engines drag and none of that is something you can design for or around (nor should you)
One way or the other the wing will break apart and open.
Dump the fuel and not an issue other than the wrecked aircraft
Most of the break away design cases are IP’d by the primes, since it is inherent to their design methods. I was just reacting to the comment made that the landing gear ripped away the wing box. The cases that engineers plan is a break away aft, for hard landing or obstructed landings. But given the energy and the bounce and tilt that the ship took, it is possible that there was a break away but somehow the landing gear got snagged in the wing box and the subsequently perforated the wing, where the fuel tanks are located. I hope some detail of this comes available. Many thanks for the fine work you do for our industry!
It is supposed that they hit ground so hard that when fuselage hit ground wings were not able to hold it. So it wasn’t gear ripped fuel tanks, but heavy strike to ground of airplane itself. Stress might be too high.
For all those that won’t fly the MAX they should add this to the list.
The Superjet is a killer that should not have been certified.
You can’t trust FBW. Direct Law is a killer. So lets rule out the A380/A350/A330/A320/A220/787/777. (is the 767/757 FBW?)
Darned, if that doesn’t leave us the MAX after all.
The 767/757 are not fly by wire aircraft. Flight controls are hydraulically actuated and control of the actuators is through cables and rods.
Well, calling it an act of God these days gets a lot of eye rolls, and considering the outcome that’s not the God most people claim… But, I dont think it can be anything other. From all the news I’ve seen, heard, read this was a great plane, in good condition, suffering from a typical malfeasance and under standard operator protocols. The landing gear broke, the backdoor wouldn’t open, the only thing I think could have affected anything sooner is a rearview mirror out the side of the windshield so the crew could have assessed the incredible speed of situation deterioration. I’m trying to be cheeky about the mirror, this was a tragedy and extremely sad for many families. I’m not a pilot, but I am a welder/ metalurgist/blacksmith. In my expertise, that’s where I see the flaws, and I don’t believe man or machine could have prevented this disaster. So, is there anything to learn. I don’t know that, looked like an act of God. You don’t take the invention of the wheel back to the drawing board because you lost a spoke and a tire went flat.
Leaving religion out of it, random events maybe.
I don’t get the back door reference. How do we know it was stuck and why would anyone be evacuating into a ball of flame.
You have it right, families have been impacted in the worst way possible.
And under that system no one will get anything.
While it may not have any aspect here, the Superjet has been bedeviled by reliability issues. Air Mexico is dumping their and they got a bargain.
How much that is work build issues vs spare parts and early wear out is unknown.
This is pretty good in so far as where it discuss Sukoi, Russian Training.
Bjorn’s post, knowledgeable and informative, as always, reminded me of the FedEx flight 80 and flight 14 MD-11 accidents, in which there were no flight control failures, but in which the end result of bad hard landings with bounces were similarly a fire and total loss of aircraft, and in one case. similarly fatal results. The passengers in the Aeroflot accident are fortunate that their SSJ100 didn’t flip upside down when the landing gear collapsed. as FedEx flight 80 and Flight 14 did.
FedEx flight 80.
FedEx flight 14.
It was amazing that the MD-11 pax did not have the disasters that the F model (and converted did)
I understand FedEx has instituted some serious remedial training to stop that.
UPS (another big user) has not had any problems.
LuftH wreaked one in the desert a few years back, same lack of being able to fly it well.
Another MAX type killer obviously (or badly trained and or operating of the pilot in those hot dog freighter types)
I understand its quite the rush when you cob all 3 engines.
A new training module for Aeroflot pilots? Perhaps too simplistic at the airline transport level or for jets, or not? I suspect that it will be very difficult to find the carb heat on a jet aircraft.
Colin Cutler has a somewhat different opinion than the instructor whose video I posted a link to above.
“Many bounced landings can still end with a smooth touchdown.
If you bounce, the first thing you should do is hold back pressure to keep the aircraft in a nose-high landing attitude. You might need to release some back pressure on the yoke or stick if your nose is too high, but don’t push the nose down. If you force the nose down, you could land even harder than the first time, or worse, land on your nose gear.”
However, if you start to porpoise …
“A porpoise landing is a bounced landing that, if not recovered, results in your plane touching down nose first. If you let it continue, it will set your plane off into a series of “jumps” and “dives”, like a real porpoise. Porpoise landings can happen when you are flying too fast during touchdown, or if you have too high of a descent rate at touchdown.
Immediately executing a go-around is the safest thing to do. Because porpoise oscillations occur so rapidly, flight control inputs to correct the oscillations are difficult, if not impossible to accomplish.”
I know, I know, I know …. hindsight is always 20/20 and being an armchair quarterback (or pilot) is the easiest job in the world, unlike being a real world quarterback (or pilot), nevertheless, I thought these links added some interesting information to the discussion.
Oh my god! The instructor in the MzeroA Flight Training “How to Recover From a Bounced Landing” video that I posted a link to above, is flying his airplane by directly moving the control wheel, throttle and flap switch with his hands, instead of by pressing buttons on an autopilot or autoflight system. I suspect that if one of this instructor’s students wrecks a plane, he won’t be impressed by the excuse that when you pressed some combination of buttons on the autopilot, it didn’t work like you wanted it to, so the wreck was the airplane or autopilot manufacturer’s fault.
Some airlines procedures mandate use of FMC and auto throttle until just before touch down…..so it’s a stable configuration and and hands off till you are 100 ft from touchdown!
Regarding: “Some airlines procedures mandate use of FMC and auto throttle until just before touch down…..”
I believe that almost all major airlines now have this as their standard procedure, although I believe that most US airlines allow additional hand flying at the Captain’s discretion. May God help their passengers if the autopilot or FBW computers malfunction and the pilots are required to hand fly their airplane and they have not acquired hand flying skills somewhere else (US military* or started out flying training or low budget freight operator airplanes without fancy autopilots).
Regarding: “so it’s a stable configuration and and hands off till you are 100 ft from touchdown!”
On a crystal clear day with mild winds, the pilots in the Asiana Flight 214 crash found a way to use the autopilot and auothrottles to make a highly UNSTABLE approach, culminating in a crash onto the runway, when they had to make a visual approach due to the instrument landing system being down for maintenance. Prior to Asiana 214 crashing, dozens of other airplanes had made successful normal stabilized approaches and landings under the same conditions. In the case of the US carriers, due to the instrument landing system being out, most of these approaches were probably done by the method of looking out the windshield, and moving the controls by hand as necessary to maintain a proper and stable glidepath towards the touchdown point, instead of the method punching buttons on the autopilot to make the plane go up or down, or change speed.
*There is no “auto-dogfight” button on US military fighters.
From the NTSB report on the Asiana Flight 214 accident.
From page 62.
“The Asiana 777 chief pilot stated in an interview that the airline recommended using as much automation as possible. He agreed with the statement that Asiana pilots obtained most of their manual flying practice during approaches below 1,000 ft agl. He stated it was permissible for Asiana pilots to disengage the A/P above 1,000 ft, but turning the A/P off at 8 nm from the airport and at 2,800 ft, for example, would not be recommended.”
From page 99.
“The accident flight was the first time he had flown a visual approach without an ILS glideslope in the 777 outside the simulator. During a postaccident interview, the PF expressed a lack of confidence in his ability to fly a stabilized approach without an ILS glideslope, saying he was “stressed” about having to do so.”
From page 100.
“As noted above, to fly a visual approach, a pilot must possess a broad array of skills, including the ability to accurately judge the airplane’s height, speed, and distance from the runway; anticipate the airplane’s altitude and speed changes in response to configuration changes; and make the necessary adjustments to remain stable. However, these skills can atrophy through lack of practice. Throughout his training, the PF used the A/P regularly and typically relied on the ILS glideslope as a cue to proper altitude and flightpath. Thus, he did not have an opportunity to practice the skills necessary to anticipate and control the airplane’s flightpath while making a straight-in speed-restricted approach with no ILS glideslope.”
From pages 74 and 75. (I wonder if Aeroflot’s training syllabus includes recovery from a bounced landing with all autoflight systems inoperative?)
“The FAA issued Safety Alert for Operators (SAFO) 13002, “Manual Flight Operations,” on January 4, 2013, encouraging operators to promote manual flight operations when appropriate. It stated that a recent analysis of flight operations data (including normal flight operations, incidents, and accidents) identified an increase in manual handling errors. The SAFO acknowledged that autoflight systems are useful tools for pilots and have improved safety and workload management but cautioned that continuous use of autoflight systems could lead to degradation of the pilot’s ability to quickly recover the aircraft from an undesired state. It
encouraged operators to take an integrated approach by incorporating emphasis of manual flight operations into both line operations and training (initial/upgrade and recurrent).
The FAA issued a revision to 14 CFR Part 121, titled “Qualification, Service, and Use of Crewmembers and Aircraft Dispatchers,” on November 12, 2013, intended to enhance US air carrier pilot training programs by emphasizing the development of pilots’ manual handling skills. Among the changes was a new section, 14 CFR 121.423, “Pilot: Extended Envelope Training,” which states, in part, that pilots must receive training that includes the following maneuvers and procedures: manually controlled slow flight, manually controlled loss of reliable airspeed, manually controlled instrument departure and arrival, upset recovery maneuvers, and recovery from bounced landing. Operators’ compliance with this section is required no later than March 12, 2019.”
I have read in another journal that the SSJ does not fuel dropping or dumping capabilities. The regional nature of the jet (lower fuel capacity) was provided as a reason. Any comment on that?
The video at the link below shows one of the landing bounces that Mr. Fehrm discusses in his post about the Aeroflot Flight 1492 accident.
The video at the link below shows the FedEx Flight 80 hard landing/bounce/gear collapse accident on 3-23-09, that I mentioned in a post above, from a similar camera angle.
As far as I know fuel dump capability is only available in long range aircraft like f. ex. B747. Definitely not in B737/A320-families, so I doubt the SSJ can dump fuel.
Looks like you are right, have to say I never saw one dump fuel and have seen the big ones do that half a dozen times.
Mentour says this plane doesn’t even have the ability/function to dump fuel! So they couldn’t dump fuel even if they wanted.
Thank you, had not a clue on that one.
Still could burn it off
I don’t get its a busy airport. Who care? Its an emergency.
>As we only have video when the aircraft has started the flare over the runway it’s difficult to say if the PIO had started on short final.
Bjorn, here is approach video before the flare:
Approach, bounces and crash captured by different cameras (synchronized in time):
From a contact who was onboard (and lost his wife):
“Half of overhead bins were opened during landing and some of luggage fell down to aisle. Some paxes took luggage during time, when people stayed in the aisle, waiting for activating of emergency slides.”
-> maybe overhead bins should be certified to remain close in case of hard landing
“all paxes, who seated in their seats at the end of aircraft were simply fainted because of the smoke at the time, when evacuation began. And anybody, who remained conscious, left the plane.”
-> cabin furniture releasing toxic fumes ?
My condolences to your contact on the loss of his wife.
The bins should be lockable on a command from the flight deck.
Regardless they should not fly open on a survivable landing (it was) so that is a cert issue and or a failure to test right issue.
Materials should no longer be toxic per se, but smoke kills you regardless so its an open issue (the Superjet is sold in the West and assume it meets those standards)
” cabin furniture releasing toxic fumes ?”
The fire was fed from the fuel tanks- it gives off a very black smoke
Murmansk seems like an interesting city. More the 300000 inhabitants , several theatres and even a philharmonic . But you probably be interested to visit a submarine ( WW2 vintage ) and if you are lucky the northern fleet will set anchor there when you visit. Never been there but seems pretty interesting place.
May have my views shaded by Purdhoe Bay. Been there, open, flat, wind blows the snow from one end of the slope to the other.
Murmansk probably survives as the major base for the Russian fleet and support there of.
Barrow the only “town” up there has all of 4500 people and they get large amounts of money from the Oil Field Taxation.
Pretty major population drop, what I sleuthed reminds me of St Marys AK on the Alaskan West cost. Hills and bushes no real trees.
Spent more than a few years up in the high Arctic, happy to be further South!
Murmansk is a cool place. Lived there for many years, still enjoy visiting.
Not sure if anyone has seen this video, which show the full landing. I’ll leave it to the experts to comment. https://youtu.be/fwQIZWs1ZWA
Hello Holger – Thanks for posting the interesting video. I’m no expert, but I won’t let that stop me from commenting.
Does the approach looks stable until just before landing but perhaps fast? Does the following excerpt from the FAA safety course at the link after the excerpt describe what happens after the airplane contacts the ground, except that it is the main gear rather than the nose gear that fails first?
“In a bounced landing that is improperly recovered, the airplane comes in nose first, setting off a series of motions that imitate the jumps and dives of a porpoise.”
“Porpoising can also be caused by improper airspeed control. Usually, if an approach is too fast, the airplane floats and the pilot tries to force it on the runway when the airplane still wants to fly. A gust of wind, a bump in the runway, or even a slight tug on the control wheel will send the airplane aloft again.
The corrective action for a porpoise is the same as for a bounce and similarly depends on its severity. When it is very slight and there is no extreme change in the airplane’s pitch attitude, apply power to cushion the subsequent touchdown, and smoothly adjusting the pitch to the proper touchdown attitude.
When a porpoise is severe, the safest procedure is to EXECUTE A GO-AROUND IMMEDIATELY.
In a severe porpoise, the pitch oscillations can become progressively worse, until the airplane strikes the runway nose first with sufficient force to collapse the nose gear. Pilot attempts to correct a severe porpoise with flight control and power inputs will most likely be untimely and out of sequence with the oscillations, and only make the situation worse.
No attempt to salvage the landing should be made. Full power should be applied while simultaneously maintaining directional control, and lowering the nose to a safe climb attitude.”
Here is what I see at the indicated times in the video that Holger posted.
20 seconds: Final bounce starts.
20 to 21 seconds: Aircraft is ascending from final bounce with nose up.
21 seconds: Aircraft levels out at top of final bounce.
22 seconds: Aircraft is descending rapidly nose down towards runway.
23 seconds: Nose is rising and aircraft hits runway descending rapidly with with nose level but not raised (or perhaps just very slightly raised), i.e., flare was too late and too little to give soft nose up landing on main gear. Main gear collapses, fire starts.
Here is an excerpt from FlightGlobal’s analysis of the video that Holger posted a link to above. See the link after the excerpt for the full FlightGlobal article.
“The aircraft oscillates again, from nose-up on the second bounce to nose-down as it strikes the runway at around 1,100m, before pitching up into a relatively high third bounce which carries it over the A7 taxiway intersection.
Images then suggest the aircraft pitches nose-down before partially recovering to a flatter attitude just before the final hard impact at about 1,300m, appearing to be banked slightly to the right resulting in a touchdown on its right-hand main landing-gear.”
Got a draft of a preliminary report:
FAC: 1976 …
The co-pilot: born in 1983
Cabin crew: 3 people.
The nature of the task: the commercial transportation of passengers …
Last point of departure: Sheremetyevo Airport (RF).
Target landing point: Murmansk Airport (RF).
The number of passengers, their citizenship: 73, including: 72 – citizens of the Russian Federation, 1 – a citizen of the United States.
The consequences of the incident, including for surrounding objects: 41 people (40 passengers and 1 crew member) died, 9 people (6 passengers and 3 crew members) were injured. There are no consequences for surrounding objects.
The nature and weight of the cargo: cargo 292 kg ….
A brief description of the circumstances of the event: according to the records of the onboard recorders, at 15:03 the crew of the aircraft took off from runway 24C. The take-off mass of the aircraft was 43545 kg, which did not exceed the maximum allowable value set by the RLE of the RRJ-95B. Automatic thrust was turned on before takeoff. At an altitude of 700 ft (215 m), the crew turned on the autopilot. At 15:08 at an altitude of about 8900 ft (2700 m) at a standard pressure of 760 mm Hg. Art. and a distance of about 30 km from the Sheremetyevo airfield, when the aircraft was on the standard output circuit KN 24E, a malfunction of the electronic units was registered on board with the control system switching to / (manual control) mode and automatic autopilot off. At this moment in time, the plane was in the zone of thunderstorm activity. After 30 seconds, the automatic shut-off device was registered. Piloting the aircraft in manual mode was carried out by the FAC until the completion of the flight. Prior to a power failure, radio communication with experts of the ATS unit was conducted using a VHF station ± 1. Later, the crew was unable to contact the approach controller at the set frequency. Radio communication was restored using the VHF station ± 2 at the emergency frequency of 121.5 MHz. At 15:09:32 the crew set the responder code 7600 (loss of radio communication). PIC decided to return to the departure aerodrome. Return to the departure aerodrome was performed by the vector method. The landing approach was carried out on runway 24L on ILS in manual mode. By the time of entry into the glide path, the mass of the aircraft was about 42,600 kg, which was 1,600 kg higher than the maximum permissible landing weight. The wing mechanization was released in position 3 (flaps 25 °), which corresponds to the recommendations of the RLE for the conditions: (DIRECT MODE) and.
At 15:26:31 the crew set the responder code 7700 (the main emergency code). The glide path reduction was carried out without significant deviations at a speed of 155 … 160 knots (287 … 296 km / h). According to the RLE, the approach speed for the existing conditions is 155 knots. The entry was made in the conditions of a side wind with a force of up to 30 knots (16 m / s) and a direction of 190 °. In the range of true heights of 1100 … 900 ft (335 … 275 m), five cycles of wind shear warning (Predictive Windshear Warning) were recorded.
From a true altitude of 260 ft (80 m), the aircraft began to go below the glide path, at the true altitude of 180 ft (55 m) a TAWS warning was triggered. In the range of true heights of 180–40 ft, the engine’s operating mode was increased — the engine control levers moved in the range of 18–24–20–24 °, which by the time of the runway end reached 40 fg (12 m) led to an increase in instrumental speed to 164 knots (304 km / h), and to a height of 16 ft (5 m) – up to 170 knots (315 km / h).
After setting the throttle to , at the command of TAWS , KBC performed several alternating deviations with a large amplitude control knob (up to maximum values), which led to alternating changes in the pitch angle (+6 …- 2 °) .
At a distance of 900 m from the runway inlet and a speed of 158 knots (293 km / h), the aircraft first touched the runway by with a vertical overload of at least 2.55g followed by separation to a height of about 6 ft (2 m). In the mode / automatic release of brake flaps (interceptors) is not provided, the crew did not produce manual release. After 2 seconds, at the instrument speed of 155 knots (287 km / h), the aircraft again landed ahead of the front landing gear with a vertical overload of at least 5.85g, after which the aircraft again separated from the runway to a height of 18 ft (6 m). The third landing of the aircraft occurred at a speed of 140 knots (258 km / h) with a vertical overload of at least 5g. There was a destruction of the structure with fuel spillage and fire.
The first fire alarm (in the rear luggage compartment) is registered at 15:30:18 at a speed of 100 knots when the aircraft is moving along the runway. At 15:30:34 registered alarm of the fire APU. The plane stopped at 15:30:38. The first use of fire extinguishing systems is registered at 15:30:58 in the APU compartment. The engines of the aircraft worked until the recording of the parametric recorder was stopped (at 15:31:05).