In an earlier post I described research conducted at the GEOMAR-Helmholtz Institute for Ocean Research in Kiel which suggested that, based on reverse-drift analysis of the Rénion flaperon, its starting point most likely lay in the tropical latitudes of the southern Indian Ocean, far north of the current seabed search area.
Today the same scientists published an update of their research, with a press release available here and the full report here. The upshot can be seen in the chart above, which shows the probability distribution of where the piece likely began its journey to Réunion island. Once again the authors have concluded that the greater part of the probability (98.7 %) lies far north of the seabed search area, shown as a white rectangle. The study’s authors suggest that their results might justify a shift of the search area:
The Australian search authorities are aware of this report. “Whether or not these new results will be used to facilitate the last few months of the ongoing search for MH370 is not clear,” Arne Biastoch summarizes.
One of the refinements included in the new study is that while the authors continued to assume that there was no direct wind effect on the flaperon (it being presumed to be floating essentially flush with the surface), they have included for the first time an effect called Stokes Drift, which results from wind-generated waves:
“In our recent calculations we included more physical processes in order to simulate the drift more realistically,” Prof. Biastoch explains. “In particular the drift induced by wind generated ocean waves is now included,” Biastoch continues. “Even though we use state-of-the-art modelling systems, representing the ocean currents in the Indian Ocean quite well, all simulations naturally contain limitations. Our investigation is one important piece of the puzzle in finding MH370.”
As a result of the new calculations the possible source region of the flaperon was refined, and “While it is shifted a bit southward from the initial study done last September, our basic result that most particles originate from a region north of the current search area remains unchanged,” states Dr. Durgadoo.
So should Australian search officials call a halt to the current search and relocate its ships further north? Actually, I don’t think they should. If the GEOMAR scientists are correct and MH370 did crash into the ocean west of Exmouth, the plane must have been following a low and curving trajectory of the kind that is not supported by any simple autopilot mode. That is to say, the plane would have been either conscious control the entire time or flying along a series of arbitrary user-defined waypoints.
The latter seems extraordinarily unlikely. First, we would have to surmise that whoever was in control of the plane decided to fly a basically random path, and to choose a cumbersome way of doing so, entering by hand pairs of latitude-longitude coordinates. This would be bizarre behavior, to say the least. Furthermore, as explained in the DSTG report issued last December, it is extremely unlikely that a randomly chosen set of slow segments would happen to match the ping rings. Instead, random sequences are only likely to match if they conform to a fast-and-straight flight to the south: in other words, if they end up in the current search area.
The former is problematic for the same reasons, and for an additional one as well. If the plane was under conscious control until the bitter end, then we cannot assume that, as in the unpiloted scenario, it spiraled into the sea once its fuel ran out. Instead, the conscious pilot might have chose to hold it into a glide far beyond the seventh arc. We have no reasonable expectation, therefore, that a narrow search along the seventh arc would yield the wreckage.
Warren – the bloody towelette again. Hundreds of these things arrive here in Perth weekly. Cervantes is a tourist spot. Since we started on this business 27 months ago thousands of these things have arrived here by air incidentally. What chance this one is from MH370 when nothing else has shown up. Not even a vertical stabilizer. Cordially that is.
Rather than some specific setting, such as “LRC”, is it possible that the engine throttle was simply set to “MAXIMUM”, generating the maximum amount of thrust ?
Dennis – I posted Bailey this time because it looks like he has flamed out. He’s maintained the strut and the disparaging mount of authority but it’s evolving slowly, and not in a way he would really want, not that he would care – yet? He’s wedded to a view and he’s put his credibility on the line. Sound like anyone?
BTW – you have always sounded a lot more independent than the ‘Independent Group’. It (IG)started out independent of the ATSB but that distinction was voided by the proximity of the hotspots and the lack of debris. Nowadays it’s independent of what?? Certainly not each other. Skin in the game. I can only think of one who comes across as independent and I won’t bore him with a massage.
When I first poked my nose in here, I remember discussing SLDMB’s and met conditions around the IG predicted point. Some good data was forthcoming from Guarded Don, Mu one and Gysbreght. It was suggested sea surface conditions were light at the time. I don’t think this point was ever pinned down, however, Mu one provided a gem that I reproduce below that may be good as a reminder, and even moving forward:
earth.nullschool.net/#2014/03/08/0000Z/wind/surface/level/grid=on/orthographic=90.09,-36.26,1024
@Matty-Perth:
Bailey cracks me up. He is continually bitch whining about aviation experts being nothing more than consultants in every piece he writes (as one should). But for a guy of his supposed experience, all his pieces are littered with stuff that makes me cringe. The latest being that the wing root sits at the juncture of business class/economy. That’s some business class MRO must have had:
bradleywest.net/media/2015/05/1.jpg
When it comes to aviation, he should just stick to flying. Engineering is obviously not his forte. Which is a shame, cause he makes some interesting points, only to be let down by his own inaccuracy.
Insert usual protocol prior for the links.
@Matty
I agree with you about Byron. Seems he’s a spent force now. I doubt if the ATSB will even bat an eyelid.
clicking on the earth nullschool link at around the predicted IG point, surface winds are shown around 25Km/h @ 235 degrees. Whilst the accuracy of this information could be argued, and it doesn’t provide total wave height (sea + swell), it does show it wasn’t as dastardly as it sometimes can be down there.
For what its worth?
Latest report from ATSB is with the finding of the cabin piece on Mauritius island. It looks like the planes cabin/ fuselage torn apart on impact. Personally I don’t there was a conscious pilot or hijacker at the controls right till the end. Also I believe immarsat data has been wrong from the beginning.http://www.duncansteel.com/archives/507
JS wrote Posted May 13, 2016 at 2:17 AM “@Ken Goodwin, …..But this one is a decal, not a stencil, isn’t it?”
Possibly either; stencils were going out and decals were coming in; in terms of popularity; decals are easier to replace in the field. Very hard to tell from pictures; must look very close to see decal lines.
Note: MAS decals/stencils that match debris even though it is not unique to that airline still provide evidence that the debris fits MAS configuration.
From BYRON BAILEY article: “Some pieces of debris — confirmed as coming from MH370 — have been turning up. The first was a right flaperon that I suspect was due to the right engine being shorn off, as they are designed to do, in a heavy impact with the sea.’
Very plausible.
I am not big on the pilot ditching scenario. If so, what happened to the passengers and the life rafts with emergency locators onboard? If a slow speed landing; the passengers would get out and deploy the life rafts.
Buyerninety wrote Posted May 13, 2016 at 4:24 AM “@Ken Goodwin ……did you get to see how the wiring that goes to the cockpit is routed? ………………. Is there any video showing the building of a 777 in e.g. speeded up time? ………………….. Do you know of any source, (besides the purchaseable maintenance manuals)
that shows the wiring routing in a 777….”
Overtime, I have been all over the airplanes during all phases of construction. The wiring on a Boeing plane will take the shortest distance between two points, for weight purposes, with few exceptions. Exceptions: Safety of the wiring, available space and redundancy. Wires are routed on the inside of the airplane structure away from the fuselage surfaces for safety, routed in the overhead due to space and routed along the floor beams for space and safety. If there are two systems, one main, one backup, they will be separated to support redundancy. Hydraulic lines are similar.
The cockpit wiring will run under the floor to the E/E bay below and behind the Cockpit; in general. Wires will run aft down the center of the overhead and down the floor beams depending on their destination for shortest distance.
There are videos showing the building of a 777; speeded up. Various copies on the web of manufacturing Boeing airplanes. I don’t think any of them will show the installation of wires just the hooking up of major sections; mostly of final assembly moving lines.
The CATIA 777 dataset contains all the detail you need.
@Gysbreght.
Thanks for that graphic. So it’s not all rubbisch afterall I guess..
Interesting. And you see the point on 23:11 with the deviation starting through the 5th arc in the curve?
@gysbreght.
..forget to ask; what does/can it mean in your opinion?
@Sharkcaver
No, probably just a gentle swell, but enough to catch the right hand wing tip as he settled in.
And what was Byron doing when he said the weakest part of the airframe was where the wings join the fuselage? It’s just the opposite in fact. A salutory message to us all, I think; never write copy when under the influence.
@Oleksandr.
Yes I agree. I said this earlier. Why would a hijacker/pilot wait till flame out of the second engine? To have power would indeed certainly have its advantage to prepare a glide and a lowest speed possible ditch.
34S would be too far south I agree also. But with a deviation to the left starting around 30S and a max long glide from the of 125miles from the 7th arc 100E would be in reach I think.
Matty,
Re: “Warren – the bloody towelette again. Hundreds of these things arrive here in Perth weekly.”
Have you found any litter related to the aviation? I think it has been around 2 months since I proposed to conduct a little semi-scientific experiment. Nothing so far, right? Not talking about MAS.
Re: “What chance this one is from MH370”
Given all the information we have, I would say more likely yes than no, i.e. >50%.
Do we know if the pilot had any idea who was aboard his plane?
If the towelette came from MH370 their still is no way to proof it did I understood.
Imo that makes it useless for the investigation anyway.
@Ge Rijn: The rubbish is this:
Whether the apparent trend ‘break’ at approximately 77000 seconds could be significant is another matter entirely. I’m currently looking at a path which turns to the SE near waypoint BEBIM at about that time.
@Aaron: 777 doors have imploded before. Cf. Asiana crash in San Francisco, the 4L door imploded, and there wasn’t even any water.
This is the best view I’ve found of the Rodrigues fragment:
[img]http://i.imgur.com/rldsrkM.png[/img]
Note the little tab of metal at the top center: it’s bent back in the opposite manner of the main left to right bend. That tells me there were to events: the first crash, and then probably the door imploding and probably the danged emergency slide deploying, that tore off the top part of the bulkhead.
There is nothing about the interior fragment per se that indicates fuselage rupture. Yes, it is extremely deformed indicating very violent impact, but there is no evidence that the fuselage separated right where the 1R door is. That is in the middle of the 41 section; it is a relatively protected place to be.
Also, if the aircraft concertinaed, the piece shouldn’t be bent forward the way it is.
However, the fact that the piece is right by the 1R door is quite consistent with the 1R door imploding. So it could easily have escaped the fuselage even if the fuselage was not separated or concertinaed.
Re: Byron Bailey, the man is spot on IMO. Sure, he gets a few details wrong, but the main thrust of his argument is probably correct: there probably was a glide at the end. This hypothesis has not been falsified by the underwater search by any stretch of the imagination.
The search area should not be moved to the north (as DS is already trying to do). Dolan is right: if we reject no-controlled inputs, then we must consider controlled inputs. So before we go moving the search area way north, or poking around Kazakhstan, we ought to look to the south of where straight-line, cruising speed paths lead. That is by far where the best Bayesian location is IMHO.
@Warren Platts
I’m sorry but that Asiana 4L door did not implode.
Enlarge the picture and you’ll see it lying just outside the plane (the red door) near the 4L door opening relatively intact.
http://q13fox.com/2014/06/23/asiana-airlines-crash-whos-to-blame/
@Warren
“best Bayesian location” ?? There is nothing Bayesian about your suggestion. It is based solely on ISAT data, and a random assumption relative to the flight dynamics. If you want Bayesian then include the debris finds which clearly support moving the search North of 30S.
You continue to beat on a very dead horse.
@Ge Rijn: Wow, thanks for that picture. That sure likes like the door laying on the ground. But what I said was based on the NTSB final report:
“19. Passenger 42A was likely restrained for landing, and the severity of her injuries was likely due to being struck by door 4L when it separated during the airplane’s final impact.”
http://www.ntsb.gov/news/events/Pages/2014_Asiana_BMG-Abstract.aspx
The passenger in 42A was supposedly wearing her seatbelt, and was not ejected from the aircraft as far as I know. That would seemingly require that the door was imploded to the interior. Perhaps the rescuers grabbed it? Maybe I’m missing something (as I have done before, cf. Coriolis HDG HOLD).
@ Dennis: Don’t make me laugh… The straight-line, glide hypothesis is not only a very much alive horse, it’s the horse favored by the Bayesian odds to win this race. Dolan and Bailey are finally on the same page, thankfully. My “suggestion” was never based on “random assumption relative to the flight dynamics”. It was based on my own analysis based in turn on behaviorism. I predicted the current search box long before DS/IG/ATSB did simply by applying the behavior of the initial phase to the latter phase: cruise speed, cruise altitude, LNAV waypoints. It’s that simple. It leads you to the POVUS ISBIX MUTMI RUNUT corridor. After that, there are several options, but if cruising speed is maintained, you wind up right where they have been intensively searching–except for the fact they haven’t taken into account the possibility of a glide well beyond the 7th arc.
The dead horse is your Christmas Fantasy Island “theory” that’s about as likely as your theory of evolution.
And @ROB: “I agree with you about Byron. Seems he’s a spent force now. I doubt if the ATSB will even bat an eyelid.”
Rilly? Dude, he has been the one guy with some traction to advocate for “your” pet theory…
Amateurs!
@Warren Platts.
Yes when you read it like that it looks like the door hit the passenger while seated.
I rather think they meant hit by debris from the L4 door when it seperated during the final impact. Seperation is in my view coming off the aircraft, not getting in the aircraft.
Anyway it’s interesting, for it also shows a door can seperate on impact leaving the hull intact.
So this could have happened too on impact on the surface with MH370.
Leaving a wide open gap to wash debris like the Rodrigues piece out.
Who knows maybe someone even finds a door on a beach someday..
@Warren
You and Dolan and Bailey on the same page coming at it from three different “disciplines”? Maybe time to contact Springer about book possibilities.
@ Ge Rijn: Would a door float? That would be interesting!
@ Dennis: By golly, you may not be the best evolutionary biologist on this planet, but you do have a business acumen about you that I do highly respect! I had not thought of the book possibilities…. Maybe your are on to something! 😉
@Warren Platts.
I stored the picture and zoomed in further.
It’s clear the outer white edges of the door are intact. They cover the hull-opening when closed.
So, no way the door entered the cabin.
Maybe see for yourself like this. Also compaired to the other doors and the visible line around the door opening which shows where the door covered/closed on the fuselage.
But I think it could be an important clue a B777 door can separate like this without damage on the fuselage around it first (and after).
So, meant differently you came up with another possibility which could explain how the Rodrigues piece came out of the aircraft.
One way or another it’s a nice way of finding possible solutions imo 😉
@Warren Platts.
Anything with some honeycomb in it seems to float on a B777?;-)
Oleksandr – I doubt anyone out there knows how prevalent towelettes are in litter surveys and I’m not about to go looking. But they are items that tend to have long lives sitting at the bottom of handbags, glove boxes, bathroom drawers etc and often get discarded with time. Why would they have to be present in a litter survey? I suppose it’s just inconceivable to me that all we got was a towelette. If that is all we have then we have nothing – in my opinion.
@VictorI:
You constructed a BFO-derived vertical speed diagram for the 7th arc here:
https://www.dropbox.com/s/r0ozzivz0vxiajn/BFO%20vertical%20speed%20on%207th%20arc.png?dl=0
If there *was* a landing/takeoff/paraglide in the area of Banda Aceh (the ‘loiter’) you might expect the 2nd arc ping / login to occur at some point during takeoff, at least before 10,000ft.
If it’s possible to calculate, it might (?) be interesting to see if the BFO-dreived vertical speed would be consistent with a minimum climb speed for the weight at that time (~ 200 knots?) and a low rate of climb (~ +1000ft/min?).
@Middleton: At 19:41, for a given value of BFO, increasing the vertical speed would require a higher southerly component of speed. There are infinite combinations of speed, track, and vertical speed. That said, there is plenty of time between 18:25 and 19:41 to regain cruise altitude and speed if there was a descent in that interval.
@VictorI Further to the path calculations.
My reason for suggesting IPKON as the final waypoint was that it was a straight extension of the flightpath when travelling at a constant speed from 19:40 right round to 00:11
Because it was late in the flight Shah would still be listening for a broadcast from his team on the ground that the deal had been accepted and that Indonesia was aware of the need for MH370 to make an emergency landing at an airfield in Java, preferably Bandung as had been prearranged.
While waiting for a communication from his team he would probably hedge his bets on which airfield the Indonesians would be confirming for his landing so he would head up to a position such as waypoint IPKON, the closest waypoint to the coast putting him within range of a number of airfields.
@Warren
Amateurs indeed! I got a bit mixed up there, I admit. What you might call friendly fire. I’m not proud admitting it either.
But as for it being my “pet” theory… Slightly inaccurate description there. It’s the most plausible theory out there, no less. Modesty forbids me from going any further.
And I’d be in the market for a copy of that book too. Guaranteed to become a collectors item.
@ROB: Well if it’s any consolation, it’s my pet theory too. And I agree that it’s the most plausible theory out there, and will remain so until our search area is searched.
As for collector’s items, there’s a lot of competition amongst all the other MH370 books. Time for a MOVIE!!
I was wondering, could any of the debris have drifted to Cocos Island or New Amsterdam / Amsterdam Island ?
@Warren
You should get ROB to write the intro to your book. If it becomes a collector’s item perhaps you can both move out of your parent’s homes.
@VictorI:
You constructed a BFO-derived vertical speed diagram for a stationary aircraft on the 7th arc here:
https://www.dropbox.com/s/r0ozzivz0vxiajn/BFO%20vertical%20speed%20on%207th%20arc.png?dl=0
If the aircraft was not “stationary”, but in “the flare to ditch” at 00:19:29 ?
Could you constuct a series of similar graphics, but for a range of vertical speeds from zero to 600 feet per minute descent rate, (say in 100 feet per minute increments, ie, produce 7 graphics), that presumably should show the horizontal speed vector for the recorded BFO at 00:19:29z ?
The reason for this request, is that if the aircraft was “ditching” at that moment, the final descent rate would be low, ie between zero and 600 feet per minute down.
Examination of these plots should then allow us to “home in” on a segment of the arc that produced “sensible” or “plausible” horizontal speed vectors for an attempted ditching.
Title of book: Wrong field, but search this adjacent haystack
According to the Inmarsat JON article, only the 00:19 BFOs are anomalous, and the satellite-velocity component of the same was only about +52 Hz, near 35S 93E.
The first 00:19 BFO, the only one I understand Michael Exner to advocate using, is about -75Hz below expected trend. The most obvious culprit and prime suspect is negative climb, of something like -5000fpm, which is slightly extreme. Are there other ways of dropping the BFO down a few more points, besides high rate of descent ?
If satellite blue-shift changes from +50Hz in the SIO to +0Hz in China, then it changes at an average rate of vaguely -5Hz per 2000nm towards the NE, ie if the plane veered NE between the 6-7th arcs, that would reduce the satellite blueshift slightly… the a/c traversed <100nm, and so reduced satellite blueshift < -5/20 = -0.25Hz. So even if the a/c veered hard to port, it could only "defray" a fraction of a Hertz of BFO. That's well within the noise of the data, and so is hard to justify for further consideration. Note that i acknowledge that i myself was confused about this particular data point, sorry to possibly contribute to other's confusions, so best to clarify this issue once-and-for-all.
Next suspect, a/c velocity. Inmarsat computed the compensation error due to a/c velocity as -9Hz on a 180-ish heading at about 455kts. So, with the satellite slightly NORTH of the equator, that's actually the deepest drop in BFO possible, at that speed. If the a/c was travelling 500kts, +10% more, then the MAGNITUDE of the BFO would increase +10%, dropping down to -10Hz. If the a/c was heading E/W, perpendicular to the satellite position error, then the BFO would be about 0Hz. And if the a/c was heading N, the BFO would have been positive, up to +10Hz.
So, any change of heading, from the Inmarsat due-south heading, would actually have made the BFO less negative… i.e. more positive… i.e. even harder to explain it being -75Hz too low. Again, if we want to explain the -75Hz too low below trend value, we want to find all the ways to drop the BFO besides negative climb. If the a/c veered NE from the 6-7th arcs, then the BFO would have dropped… but imperceptibly, magnitude << 1Hz.
But, if the a/c veered NE, then the compensation error would have changed, from approx. -10Hz, to 0Hz or up to +10Hz… that's the wrong way, the wrong sign change, that would make the observed BFO value of 182Hz appear to be up to -85Hz below expectations… if that actually occurred, then the a/c was falling out of the sky even faster than ~5000fpm.
So, if Mr. Exner is actually correct, that the first 00:19 BFO value is valid, then any change of course, from 6-7th arcs, would actually make the BFO anomaly more (in magnitude) than -75Hz too low, up to -85Hz too low, on northerly headings. Note, only fairly-high-and-fast more-or-less straight southwards to the SIO, is consistent with the first 7 BFOs, from the first Sat-Phone call at 2:40am, to the 8:11am ping.
So if the first 00:19 BFO value is valid, then the minimum rate of descent is already very high, more in magnitude than minus 2000fpm, the expected rate of descent for the 1st 5 min. after 2nd engine flameout. That would imply that the a/c was already about 5 minutes after second engine flameout… which would be more consistent with the original estimation, of 1 minute for APU to start, +3 minutes for system reboot… and less consistent with the revised estimates of 1 minute for APU start, +1 minute for system reboot.
And if that is true, then that would affect the timing estimate of the first reboot at 2:25am.
Middleton,
“it might (?) be interesting to see if the BFO-dreived vertical speed would be consistent with a minimum climb speed”.
Everything depends on assumptions you made with regard to what happened between 18:25 and 19:41. For example, I have a batch of trajectories, which resemble missing approach at Car Nicobar. On the other hand, they can also be consistent with what Kate Tee saw (but then inconsistent with Car Nicobar). In summary, there are many ways to fit BTO/BFO data; IG, ATSB and Bobby use geometric approach to connect two sections, which is the simplest but illogical.
Ken Goodwin,
The “The wiring on a Boeing plane will take the shortest distance between two points”
This is exactly what I thought. A long while ago Don posted schematic diagram of VHF and HF antennas. Based on it, two VHF cables and one HF cable would likely be routed along the centerline on top of the fuselage, and central VHF coaxial cable would be placed on the belly.
What is a chance for these cables to be simultaneously cut by debris or damaged in case of a blast/fire around EE-Bay area (I mean nose landing gear tire blast, oxygen tanks blast, flash fire, etc)? It appears that the area behind the cockpit is the most vulnerable.
Two silly questions with regard to Mikes’ simulations. Could someone pls remind:
– Aren’t AP and essential flight instruments supposed to stay engaged/functional after the flameout of the second engine, using battery?
– What is a reason for the spiral dive to progress when APU is on and RAT is deployed, so that hydraulic power is available again? Inability to recover?
@Oleksanda.ATSB Definition of
Underwater Search Areas Dec 15 Update p9, “Following the loss of power on both the left and right AC buses:
• the autopilot and auto-throttle would disconnect”
Hope they have it right.
My understanding is that the autopilot would have to be manually reconnected after AC was restored and absent that, the spiral, even with AC and some hydraulic power being available.
David,
That is exactly a point of my question. Why AP is getting disconnected on the second flameout? Why can’t it be temporarily powered by the battery at least in some degraded mode, till APU kicks in? Design limitations?
“Why AP is getting disconnected on the second flameout?”
That has been explained earlier. With all generated power lost, the pitots are not heated. That causes the flight control system (FCS) to go into secondary mode, without envelope protections. The autopilot needs the FCS to be in normal mode, so it disengages.
Starting the APU restores Pitot heat, the FCS returns to normal mode, and the AP can be re-engaged.
The FCOM doen’t say whether the RAT provides AC power for Pitot heat.
@Geysbreght
You know what circuits the RAT energizes. Are the pitots powered by those circuits?
@Oleksandr.
What I read about it, AP is disengaged for Auto Throttle is disengaged (with engines out there is no throttle left to engage anyway).
With engines out pilot intervention is required. Thats why the AP shuts off I understand. I guess backup battery power will keep the pitot tubes heated at least until the APU kicks in and even on the RAT.
They don’t consumme that much energy.
Concerning redundancy it would be very risky to allow also the pitot tubes to fail in case of an all engines flame out.
So I hardly can imagine Gysbreght’s explanation.
To take a risk of failing crucial pitot tubes in circumstances like this would be a major design flaw imo.
Gysbreght,
So the issue is only in Pitot? Does its heating require too much power to be powered from the battery for 1 to 2 minutes? I find it somewhat strange that there is virtually no protection against dual flameout or dual IDG failure. Why can’t AP with the data sourced from ADIRU glide in such conditions in contrast to a human pilot?
Also, in Mike’s simulations bank angle reached 35 deg only by the time when APU kicked in. 35 deg is the bank protection limit. In other words it looks like the envelope protection was functioning before APU started. Is it just a coincidence?
Ge Rijn,
What I am trying to understand is why the “Cornfield bomber” could land without human input, but a sophisticated B777 cannot even glide given availability of the power from APU/RAT. Of course, if APU kicks in when it is too late, then it is too late.
Also, the rudder must be deflected after the flameout of the first engine to compensate for the yaw moment. Will it stay deflected after the flameout of the second engine? Based on Mike’s simulations the rate of turn remains zero, again until APU kicks in. What does control yaw moment after the flameout of the second engine, and why does APU have adverse impact on the stability in terms of the bank angle and the rate of turn?
For comparison; Helios flight 522, although a B737, did not bank or spiraled out of the sky after engines flame out and then disengaging AP with unconsious pilots who thus could not intervene.
It made a gradual wings level descent untill crashing.
@Ge Rijn; @Oleksandr: Read the FCOM.