If you were leading a high-profile international aircraft investigation, in command of the world’s most qualified technical experts and in possession of all the relevant data, would you bother listening to a rag-tag band of internet commenters, few of whom actually work in the space or aviation industry, and none of whom have access to all the data?
Most likely, you’d say: certainly not! But as time goes by, and the puzzle remains curiously impenetrable, you might find it worthwhile to pay a listen to what the amateurs were saying. You might even abandon some of your own conclusions and adopt theirs instead.
This appears to be the case in the search for Malaysia Airlines Flight 370, which disappeared en route from Kuala Lumpur to Beijing back in March. From the beginning, the authorities running the investigation — first, Malaysia’s Ministry of Transport, and later the Australian Transportation Safety Board (ATSB) — held their cards close to the chest, releasing very little information about the missing plane and maintaining a posture of absolute conviction. The investigators’ self-confidence reached its apex in April, when their methodology led them to an area of ocean where underwater accoustic signals seemed to be coming from pingers attached to the plane’s black boxes. Officials assured the press that the plane would be found in “days, if not hours.” But then it wasn’t. A scan of the seabed found nothing; the pingers were a red herring (perhaps literally!). Back to square one.
Meanwhile, on the internet, a group of amateur enthusiasts had come together from all around the world to trade ideas and information about the missing flight. The group, which came to call itself the Independent Group (IG), emerged from various online comment threads and eventually grew to about a dozen individuals. This was a truly spontaneous, self-assembling crowd: there was no vetting of credentials, no heirarchy of any kind. (Full disclosure: I count myself among this group.) Basically, if you seemed to know what you were talking about and could comport yourself in a collegial fashion, you were accepted into the crowd.
While the mainstream press was reporting the ATSB’s pronouncements as received wisdom, the IG was raising red flags. IG members were among the most vocal critics of the ATSB’s contention that the accoustic pings probably came from black-box pingers. And later, after a public outcry led Inmarsat to release a trove of data received from the aircraft, and the ATSB issued a report explaining how it had come to identify its current search ear, the IG dove into the new information with abandon, quickly identifying holes in the data and weaknesses in the official approach. In a pair of papers, the group recommended its own search area, hundreds of miles to the southwest of the ATSB’s officially designated zone.
Today, the ATSB has released an update to its earlier report, explaining why it has decided to reassess its conclusions and move its search zone to a new area — one that overlaps, as it turns out, with the IG’s recommended area. (In the graphic above, the white bracket shows the ATSB area; I’ve added a yellow dot to show the IG area.) Needless to say, this has caused elation within the ranks of the IG, who see the move as vindication of their methods, and indeed validation of their combined efforts over the last few months.
A few observations on the new report:
— One of the reasons the ATSB gives for the shifting of the search area is the recognition that Inmarsat data related to an unsuccessful ground-to-air telephone call attempted at 18:40 indicated that the plane had already turned south at that time. The IG had been basing its analyses on this data point for months.
— Since the June report, the ATSB has improved its BFO model by taking into account various factors — such as temperature shifts caused by the Inmarsat satellite passing through the Earth’s shadow and the mis-location of the Perth ground station in an important Inmarsat algorithm — that IG member Mike Exner has been working through in detail for months.
— The ATSB has fundamentally changed its approach in how it is assessing the plane’s likely path. In its June report, the focus was on what I call the “agnostic” approach: it generated a large number of flight paths based on as few initial assumptions as possible, then graded them based on how well they fit the timing and frequency data received by Inmarsat. This resulted in a population of potential flight paths that fit the data well, but did not make any sense in terms of how a plane might be flown. Some of the routes, for instance, involved multiple changes in heading and airspeed. Today’s report explicitly excludes such flight paths. The ATSB and the IG alike now assume that the last several hours of the flight were conducted without any human input — the crew were presumed to be incapacitated by hypoxia or other causes, so the plane flew on autopilot until it ran out of fuel and crashed. This has been the IG’s starting point for ages, and the fact that the ATSB has now adopted it is a major reason for why the two group’s search areas have now converged.
— You can see in the graphic above how an emphasis on matching the Inmarsat data will tend to lead you in one area (“Data error optimisation”) while an emphasis on routes that comport with real-world autopilot functioning will lead you to another (“Constrained autopilot dynamics”). To be sure, they overlap, but the peak area of one is far from the peak area of another. I think it’s important to realize this, because it helps us to understand why it has been so hard to get a handle on where MH370 went, why the official search area keeps moving, and why knowledgeable people have been furiously debating possible flight paths for months: the BFO and BTO data just do not match up that well. In order to arrive at its recommended area, the IG has been willing to accept much wider deviations from Inmarsat data points than the ATSB has been comfortable with.
— Finally, it’s worth nothing that the ATSB approach is superior to the IG’s in one important regard: it is at heart statistical, looking at families of potential routes rather than proposing and assessing one at a time. There is a tendency, as an individual–and I have fallen into this myself–to cook up a solution, run an analysis, and to be so impressed with the result that one wants to shout about it from the rooftops. (Ask me about RUNUT some time.) The IG has come up with a search area essentially by pooling together a bunch of individual solutions, each of which is generated by a different set of procedures and different set of assumptions. It’s a herd of cats. To really move the ball forward a more rigorous approach is needed, one that takes each procedure and sees how it would play out if the assumptions are methodically modified.
The upshot is that, since the early days of the investigation, the attitude of search officials has changed radically. Once dismissive of amateurs’ efforts to understand the incident, they have clearly begun to listen to the IG and to turn to it for insight and ideas. Indeed, you could say that since the release of Inmarsat data and the issuance of the ATSB report in June, the search for MH370 has become effectively crowdsourced: a de facto collaboration between the professionals and a spontaneous assemblage of knowledgeable experts.
UPDATE:
The overlap between the ATSB’s analysis and the IG’s is more evident in the image below, courtesy of Don Thompson. It shows the fan of values calculated by ATSB to match likely autopilot settings.
Ugh, apologies for the distracting misspelling of staticky and crotchety and whatever gnomes of illiteracy are likewise lurking in my last missive. iPads, scribbling on the fly in an effort to keep up…we are all doomed to watching nothing but cartoons in 20 years or so.
@Matty-Perth
“And would I be right in saying that with AF447 they didn’t need satellites to find debris?”
Yes, Matty, debris within 5 days I believe, the black boxes 2 years I think.
But 447 ended thusly……
likely due to the aircraft’s pitot tubes being obstructed by ice crystals – caused the autopilot to disconnect, after which the crew reacted incorrectly and ultimately led the aircraft to an aerodynamic stall from which they did not recover.
A “stall” is not a dive, nor is it a low bank angle descent. IMHO, MH370 may have been ditched, and that’s as far as I’ll go for now.
Matty
Actually, 447 never would have been found if it was not for Inmarsat and ACARS. That search team had it much easier because, in the case of 447, frequent ACARS reports continued to be relayed by the AOR satellite up to the very end. So there was no need for BTO and BFO analysis. They effectively had what we now call ADS-B…GPS positions transmitted as messages via Inmarsat. That is why they found the wreckage so quickly (5 days). And they found wreckage in that case because, unlike 370, 447 was effectively flown (stalled) in to the water such that it made a hard “belly landing”. The crew was “in control” until the end, although they were holding the elevator so far back that they were stalling the aircraft. It is very likely that 370 hit the water nearly vertical at high speed, causing far more instantaneous destruction, leaving little to no debris on the surface.
Ugh again, my reference to 1nm was general rather than specific and quite obviously included a harried, iPad derived syntax error.
As for your exchange with Mike Exner, strike two…
@Rand
“As for your exchange with Mike Exner, strike two…”
LOL! Now you know why everyone boos the umpire………. 🙁
John: Actually, the role of umpire falls to the barkeep; this is entirely another issue.
I hope you don’t find me intrusive, but given a previous reference to your diabetes, I would like to share something with you.
My father developed diabetes at age 27 as a pilot in training in the USAF. He was heartbroken to be forced to leave the skies that he loved.
He is now 78 and a tough old bastard, given that he is a ‘fragile’ Type I. When I was growing up – and this is not synthetic irony – he had a rule that he and acutallly we all rather adhered to. The rule was that he did nothing but eat plus or minus one hour from 7:00pm, given that his blood sugar was prone to wild fluctuations at this time. He did not offer opinions on anything more important than the weather during this period each day, and he most certainly did not berate me regarding my struggles with homework involving polynomial equations, which I loathed, as would any self-respecting high verbal.
There you have it.
@Rand
Say hello to Dad
Always revere and cherish him
Mine passed in 1963 and I still cry when I think of him.
“Don’t bother to examine a folly – ask yourselves only what it accomplishes.” — Ayn Rand
So, what did misinforming the air traffic controllers that the plane was in Cambodian airspace accomplish?
Mike,John etc – Where they are searching now was the focus of a much earlier sea search, aided by satellite meaning there were programmes scanning millions of km2 for a skerrick of anything and all they got was sea junk – and plenty of it. I struggle to get around that still.
A general poser: if there is no plane, meaning it’s to the edge of a search area, it simply got missed/osbcured, or it isn’t there at all – will this enduring situation where Inmarsat still hold some cards pretty close blow up on them?
To Matty & All…
Once found….not being a doubting Thomas, if 4-5 miles deep…what about retrieval of the box’s?…
Luigi – it sounds like it might have been panic stations over there at that point. And I don’t think there is anyone over there who would have the ticker in peace time to shoot down anything.
Chris – from what I read the boxes won’t be much use…
Another day, no news.
Gotta hand it to HH, the Cambodian airspace thing was clever. The guy doesn’t miss a trick. “Tell them it’s in Cambodian airspace — yeah, that’s the ticket!”
airlandseaman Posted October 10, 2014 at 10:33 PM:
” The significant rudder trim required to hold a B777 on a constant heading (or track) with one engine out (an automatic response of the autopilot when one engine flames out) results in a very large unopposed yaw force once the second engine flames out, and the autopilot disengages. This cause a turn that quickly turns into a very steep spiral dive. The -2 Hz BFO value at 001937 indicates a vertical speed of >150 kts at that time, consistent with 370 spiraling in very close to the 7th arc, and within +/-100 NM along the arc. ”
You are perpetuating a myth that has absolutely no foundation.
The TAC (Thrust Asymmetry Compensation) is a function of the FBW (Fly-By_Wire) FCS (Flight Control System). It is completely independent of the autopilot. It monitors the thrust of both engines continuously and trims out any asymmetry instantaneously. Small asymmetry – small trim. No thrust asymmetry – no trim. There is no instantaneous total loss of thrust and hydraulic pressure when an engine flames out, the spool-down is slow enough to maintain the airplane in trim. The airplane remains perfectly in trim whether the autopilot quits or stays engaged. A steep spiral dive does not develop without pilot inputs.
Watch the variations of heading and bank angle after the first and the second engine shut-down in this video:
https://au.news.yahoo.com/thewest/wa/a/22235213/flight-recreated-in-777-simulator/
@Gysbreght
Spot on, and also as I described in my response to the IG and as posted by Jeff Wise on his blog.
I will just not give a great rating to that particular video.
@John Fiorentino:
“I will just not give a great rating to that particular video.”
The video is not representative of a double engine flame-out with inactive pilots – the airplane stalls because the autopilot is kept engaged in altitude-hold mode after the second engine flame-out.
However, as I said, the TAC is independent of the autopilot, and the video correctly represents the operation of that system.
@Gysbreght: Thank you for that link. I had not seen the video before. Most interesting to me was the demonstration that different simulations produce different results.
The following excerpt is from the video:
*******
“What would it be like at the end? I am about to find out. The serenity of the moment is shattered as I cut the fuel to one engine.
The 777’s systems cut in with some urgency and compensate for the lack of power from one engine as the flight continues. But all hell is about to break loose as I cut the fuel to the second engine.
The result, I am told, is unpredictable. And it is. It is also utterly terrifying. We try it three times. The first gives a nose-up situation into an aerodynamic stall and then a dive followed by another nose-up. We are on the roller-coaster from hell.
Bells and alarms ring out. It is chaos and suddenly we hit the sea.
On another attempt, I find myself in a flat spin with alarms shattering the eerie silence of engines without power. The control column is shaking violently, the altitude read-out a blur and the forward speed non-existent. I forget I am in a simulator – this is real and I am sweating.
The third is a spiral dive at near supersonic speed. This time the speed tape is to the red. It takes seconds to bring the flight to a ghastly halt.”
*********
As I have said before, simulations will produce different results for the behavior at the last flame-out with different assumed conditions. Until proven otherwise, I’ll believe the BFO value indicating a steep descent of greater than 15,000 fpm.
One might say it is prudent to ignore the results from any single simulation.
@Gysbreght
Yes sir, Agreed.
Thanks
@VictorI:
“Until proven otherwise, I’ll believe the BFO value indicating a steep descent of greater than 15,000 fpm.”
AF447 exceeded 15,000 fpm in its stalled descent from FL380.
For the rest of your post – look at the airplane instruments, they tell a different story than the journalist’s penchant for drama.
The fuel is not “about to run out” – they shut down the engines.
The airplane does not “gyrate around the sky” – it wobbles a few degrees in roll and yaw, as one would expect of a decent airplane in a stall.
@Gysbrecht. The narrator says that they ran several simulations each with different results, including one with a spiral dive at near supersonic speed. The video does not show the spiral dive scenario, so the instrument display is irrelevant.
It is surprising to me that anybody could use this video as evidence that the spiral dive did not occur since the narration and accompanying text suggests that a spiral dive is certainly possible.
VictorI,
As I said, I’d take the narrator with a large pinch of salt – his ‘story’ is not evidence of anything and normal cruise speed is “near supersonic” anyway. On the other hand, the ‘only B777 simulator in Australia’ can be trusted for fidelity.
Yes, a spiral dive is certainly possible, but I cannot it happening in the absence of pilot inputs or system malfunction.
Apologies for a missing word in “cannot see it happening”.
Hi Lauren,
This is in response to your questions posted in the “What We Know Now” thread.
From 17:07 (last ACARS data) to 00:16 (second engine flameout), my MH370 route includes 3,541 ground miles at an average ground speed of 495 knots. During this same period, MH370 flew 3,591 air miles at an average true air speed of 499 knots. At 17:07 the aircraft dry weight was 174,000 kg and the remaining fuel on board was 43,800 kg. The average fuel burn rate would have been 6.13 metric tons per hour.
Can you (or anyone else) comment on the reasonableness of this fuel burn rate?
The Skyvector plot in my Figure 6-1 was only intended to show the route relative to land masses. I did not use Skyvector numbers for any calculations.
Good catch on the second dot in my Figure 5-1 (the one on the 20:41 arc). It should not be there.
@Gysbreght & ALL
There’s plenty more, but this on the “fidelity” of the “simulator” in the video.
Dear Sir,
Many of my fellow pilot’s and I would appreciate if Geoffrey Thomas reported on the news rather than trying to make judgements and commentary on Malaysian Airlines flight. The fact remains Geoffrey is not a pilot and has no aviation expertise other than sitting in business class of QANTAS. I have read many newspapers but this does not make me a journalism expert. He is not trained on the Boeing 777 and allot of the information he portrays as an “expert” is simply not accurate. The information he provides is misleading and dangerous. The most obvious case being that his recreation in the “only simulator” in Australia is wrong. The aircraft he used is called a fixed based trainer and is not a simulator. The only Boeing 777 simulator in Australia is in Sydney that is used by Virgin Australia.
jf
@Frank (Rand) – about Duncan as the game show host – that cracked me up. A fitting analogy.
@John – I think we’ve covered the search area controversy. I’m not following the nuances of the IG’s language the way you are, but I understand that the IG generally believes the flight ended in a dive, rather than a glide, and you believe the opposite. If I’ve misstated either position, I apologize.
However, the only downside to you being right is if the search is never expanded beyond the IG (or anyone else’s) suggested search area. The downside is the opportunity cost. But I just don’t see that happening – the search will expand until it runs out if money or it finds a plane. So what is the point of this?
@Matty – as the sand goes through the hourglass, I have to believe that by now, the starting point of the IG’s search area, which is probably common to most of the SIO theories, has been fully searched. There is no news, that I’ve seen, detailing how much of the area was covered, but by now, they must have covered what most of us would agree is the highest probability area. No plane, no news. I share what appears to be your skepticism.
I find it odd that Tim Clark’s comments are now at the top of the news. I don’t believe he has a scientific basis for them, but I believe he is “placing a bet.” His comments come well-timed, just as the highest priority search areas have apparently failed to yield results. It is definitely a fourth quarter bet, but good bets are often driven by insider knowledge.
@John Fiorento,
whether the simulator is ‘fixed base’ or ‘full motion’ is somewhat irrelevant to our discussion. In both cases, to be acceptable as a substitute for the real airplane for the purpose of professional pilot training, it has to demonstrate very stringent ‘fidelity’ criteria. But your comment does add a few grains of salt to the discourse.
@Gysbreght
Yes, actually I shouldn’t have directed my post to you.
I understand completely your intent in trying to visualize re TAC.
I was hoping to aid others to see it, but admittedly didn’t do a very good job.
@JS
“…the search will expand until it runs out if money or it finds a plane. So what is the point of this?”
First, I agree the search area controversy is getting a little long in the tooth.
But, the “point” is, the IG recommendation to “narrow the width” of the search area, brings up the cost factor of the search.
Obviously, there isn’t an unlimited budget. However, “narrowing” assumes we perhaps know more than we really do.
It also (it is stated) would assure funds are available to extend the search where?
Not eastward, but North up the arc in the IG’s narrowly defined (width) corridor?
Of course at that point, it would mean the IG had already been proven wrong about it’s “most probable” location as well as ATSB, etc.
So, here we go climbing North, based on input from those who at that point would have already demonstrated their best guesses were wrong.
Now, I hope they search the IG area first, and I hope they find the plane!
But personally, I don’t think it’s anywhere near where the IG says it is. (Just my opinion)
@Rand:
After arriving home from a party this am having imbibed generous amounts of sangria — and a bright pink, vodka-infused something (for breast cancer awareness) — I read your comments and laughed for a long while.
The game-show analogy was funny enough, but “gnomes of illiteracy”? Platinum. LOL
To the barkeep: I’ll take one of whatever he’s having.
Back to the phugoid.
If one includes all second-order and third-order effects, and the characteristics of the FBW system control laws, it is probably a bit more involved, but the basic characteristics of phugoid motion are expressed in two very simple differential equations:
dV/dt = (sinFPAe – sinFPA)*g
dFPA/dt = ((V/V0)^2-cosFPA)*g/V
where FPA and FPAe are the momentary and steady flight path angles, respectively,
V and V0 are the momentary and initial values of true air speed, respectively, and
g is the acceleration of gravity.
Take for example a steady flight path angle of -3,3 degrees (100 NM range from FL350), an initial condition of level flight at 400 kt TAS, the phugoid motion will have a period of 93 seconds, the airspeed will cycle between 385 and 415 kts, and the rate of descent between zero and 4500 fpm.
Yap’s BFO calculator gives 4029 fpm for location 37S 90E at 00:19, 400 kt south, BFO=182 Hz, and FFB=150 Hz.
I hate asking for directions as much as the next man, but (1) can anyone point me to a substantive critique of Bobby’s response to the IG that goes beyond the dive v. glide question? If not, his solution seems to me to represent the state of the art, and to render the ATSB/IG convergence pretty much meaningless.
(2) Can anyone point me to an actual simulation of the end of MH370 (as opposed to an account of one)? The only one of which I am aware was prepared and published by Dave Whittington, who is a retired Boeing engineering simulator developer. The link and some discussion is at http://www.duncansteel.com/archives/826#comment-7052
JS – “placing a bet” is about right. It’s what I did ages ago. This is oceanic pin the tail on the donkey where you need a fair bit of luck despite all the refinements in the world. If this is fruitless does that pressure Inmarsat to share a bit more? Because there is no more money after this and they will be open to some finger pointing. I have the same feeling now that I had when they were excitably trawling for those acoustic pings and being right won’t be a great feeling.
@JS, Matty
“I find it odd that Tim Clark’s comments are now at the top of the news. I don’t believe he has a scientific basis for them, but I believe he is “placing a bet.” … It is definitely a fourth quarter bet, but good bets are often driven by insider knowledge.”
A telling quote from Clark that appears in the Spiegel piece (http://t.co/9pw74aKsvW), but does not appear in the SMH piece Matty posted that references the Spiegel article:
“We need to know who was on the plane in the detail that obviously some people do know.”
Watch this space.
The computational part of the two planes theory (TPT) is slowly improving and it becomes more readable:
https://plus.google.com/102683253990040028382/posts/YuamykWxhdw
This is a kind of a MH370 research newsletter:
https://plus.google.com/102683253990040028382/posts/UfFjJ8nYmGd
On the Aussie officer heading Peninsular Malaysia air defense:
https://plus.google.com/102683253990040028382/posts/T7UAMbdVBKm
Nihonmama – Regarding Tim Clark, I like this bit: “Disabling it is no simple thing and our pilots are not trained to do so. But on flight MH 370, this thing was somehow disabled, to the degree that the ground tracking capability was eliminated.”
And it was indicating a lot of technical proficiency – the the the SDU comes on…..
Re Gysbreght
Posted October 11, 2014 at 11:43 AM
Sorry to ruffle your feathers so. You are correct, of course. It is the TAC, not the Autopilot that controls rudder trim when one engine flames out. But you could have simply corrected that minor misstatement and addressed the main point. A spiral dive is not only likely, your video reference confirmed that it happened in at least test case they ran. That was a simulation, but as Victor notes, the 001937BFO=-2 Hz is hard data that cannot be explained by any mode of flight other than a very high speed descent. That is factual evidence, not a simulation.
Via my bud Dr. Helene Lavoix (@HLavoix):
“Ukrainian CyberBerkut hacktivists claim that they have penetrated the internal network of Ukraine’s Defense Ministry and found proof that Kiev is getting secret data from MH17 crash investigators, including information which implies its involvement.”
https://twitter.com/HLavoix/status/521204122796584962
Happy Sunday.
SECOND ATTEMPT
@Matty:
“And it was indicating a lot of technical proficiency – the SDU comes on…”
I referenced the email (below) a couple of days ago. Note the three points from my cousin the T7 pilot.
From: j. judice
Date: Thu, Apr 24, 2014 at 3:10 PM
Subject: Victorl’s comment today and E&E hatch
To: @duncansteel.com
Dear Duncan:
Have been a avid follower of the MH370 mystery from day one and got a tip from a Twitter friend about your blog and analysis, which has been simply superb, along with many of the informed comments there.
This comment by Victorl today (specifically #5) http://t.co/K7Ua8mPTyf
is, I believe, related to what can best be described as a flaw on the 777. Don’t know if you’ve seen this, but a video re the vulnerability of the electronics bay (aka E&E hatch) was posted on pprune shortly after MH370 vanished. It appears to have been moved or deleted, but here’s link http://www.youtube.com/watch?v=mLmzvF2qkDY
One of my cousins, a long-time commercial pilot who also has much experience in the 777, shared the following with me a few weeks ago:
1. The 777 can be disconnected from SATCOM via E&E hatch.
2. Not every 777 pilot understands the intricacies of the satellite system (or knows how to disconnect it).
3. Easy accessibility of the E&E hatch is not something Boeing (or airlines) want the public to know.
Victorl’s point that removing the CPM would also prevent SATCOM from getting speed and position updates from the AIMS appears to be very the point my cousin was making.
The E&E hatch issue has been on my mind for weeks and given that we can’t yet rule out foul play, I just wanted to bring this to your attention.
Thanks for all of your fantastic work! I’ll continue to follow your updates. The only thing I regret in reading it all is that I never took physics. 😉 Maybe there’s still time…
All good things!
Julie
@Matty:
I’ve attempted a response to your last TWICE, but it’s not appearing. But my last (re #MH17) did post
Looks like there’s filter on…
@airlandseaman posted October 12, 2014 at 2:10 AM
Two points:
First, if there has been a spiral dive, then it was not the autopilot, nor the TAC, nor the empty fuel tanks that caused it. You have to come up with another explanation that causes the airplane to end up in a tight spiral dive as you describe it.
Second, the 001937 BFO of -2 Hz is not evidence of a high speed descent, nor of a high rate of descent at low airspeed. There may be other explanations for that value, and therefore the Inmarsat experts consider it prudent to disregard it.
@airlandseaman posted October 12, 2014 at 2:10 AM
Further to my last post, about simulators and evidence.
A professional flight simulator embodies everything that is known about an airplane and its systems, how it performs in conditions that span the entire flight envelope, and how it responds to changes in those conditions as well as to pilot inputs. A test in a suitable simulator is evidence of that rsponse.
The video of Geoffrey Thomas’ simulator session shows the response of the airplane when the two engines are shut down by the pilots in a particular manner – by shutting off the fuel supply to each engine, then moving the thrustlever to the idle position, while the airplane is controlled by the autopilot in HDG SEL and ALT modes, and the autothrottle in SPD mode, both remaining engaged after shutdown of the first and the second engine. The video demonstrates that there is no rudder mistrim at any point until the airplane stalls. There is no turning or spiral dive, not even after the airplane is stalled.
According to the ATSB’s Flight Path Analysis Update, Boein and MAS have done tests in their B777 simulators:
“The recorded BFO values indicated that the aircraft could have been descending at that time. Aircraft systems analysis, in particular the electrical system and autoflight system, has been ongoing. In support of the systems analysis, the aircraft manufacturer and the operator have observed and documented various end-of-flight scenarios in their B777 simulators.
The simulator activities involved fuel exhaustion of the right engine followed by flameout of the left engine with no control inputs. This scenario resulted in the aircraft entering a descending spiralling low bank angle left turn and the aircraft entering the water in a relatively short distance after the last engine flameout. However when consideration of the arc tolerances, log on messages and simulator activities are combined, it indicates that the aircraft may be located within relatively close proximity to the arc. Whilst the systems analysis and simulation activities are ongoing, based on the analysis to date, the search area width described in the June report remains reasonable with the underwater search to commence at the 7th arc and progress outwards both easterly and westerly.”
John Fiorentino has been permanently banned.
Jeff – I shall miss his general crankyness.
Nihonmama – Every now and then someone on board a plane does something ridiculous like attempt to open the door, or attempt to enter the cockpit. What if some unstable soul went to town in the E/E bay? The main computer is sitting right there. Including oxygen cylinders.
jeffwise
Posted October 12, 2014 at 7:01 AM
Hi Jeff ~
Good call. I could say more but a simple and much appreciated “thank you” will suffice.
~LG~
John: Hey, tough stuff. I did attempt to warn you by way of metaphorical baseball references, an allegory involving erratic blood sugar levels, etc. I even went so far as to tell you directly that there were all sorts of nasties out there that were deserving of a good beating, and that you should turn your attention to them, rather than heckle members of the peanut gallery. It seems that our mob ethos is yet evolving, and thus does our space require people such as our good barkeep to keep things reasonably safe & sane (not to mention well lighted – thanks, Jeff). Look at it this way: at least you will still be able to follow the exchanges between others here, which is, in fact, and then to a large degree, a central function of this site.
OK, let’s carry on. Just don’t tell my wife, as she is beginning to grow suspicious.
Was the plane really travelling at normal cruising altitude (35000 ft) when it returned to Malaysia, or was it travelling much lower, as indicated by the cell-tower reconnect uncovered by Malaysian police investigators and pointedly endorsed by US intelligence officials?
Eyewitnesses reported seeing an airliner flying at well below normal cruise altitude near Kota Bharu at 1:30 AM, heading west. Months later, we now have confirmation that the plane was in that particular location, at that particular time, and on that particular heading. What about the plane’s altitude?
We have a clear conflict here, with the IG/ATSB saying one thing, while eyewitnesses, police investigators and US officials say something quite different. Who should we believe?
http://abcnews.go.com/International/fishermen-plane-sighting-tip-false-lead-mh370-hunt/story?id=22954793
Gysbreght: Please correct me if I have misunderstood, but is not the larger point of whichever sort of spiral dive scenario that it is now (after a number of analyses) reasonable to assume that the aircraft did not glide for any sort or real distance? From here, the arguments for a spiral dive beyond a low bank(ed?) angle turn are solid and not specious, while they certainly can be countered, as you have demonstrated. Regardless, it seems that the present search area has tightened up, which is a good thing, as it can always be enlarged once again – with adequate resourcing, of course. As it is, this thing has ‘budget creep’ written large all over it; the continual refinement of the location science is necessary to keep the kids on the ships from quite literally going on fishing expeditions. Finally, I would imagine that Mike or Victor would be among the first to ditch the concept of a spiral dive, if it were not indicated. I really don’t see them wedded to anything but the process.
BTW, I flew Tokyo-Shanghai via Seoul today on a Korean Air 777. The aircraft had a four point security detail on the tarmac in Seoul, but then they do have a rather kooky neighbor to the north. After the Tokyo-Seoul leg, I spoke with the Captain as he deplaned. I queried him as to what would happen upon one engine sputtering dry and the other flaming out, and his only response was that he would go from programmed “memory” and initiate a restart (he gestured down with one hand and up with another). When I added the assumption of no human input (i.e., no pilot), he got a bit flustered – as if he had never thought of the situation previously – and he clearly had no idea what would actually unfold in terms of the flight dynamics. It was, really, yet another demonstration of that ‘MH370 thing’: there are very few elements of the mix that make much sense to anyone, even a pilot.
I gave the Captain my card and asked him to email me, but I doubt he will. I don’t believe he very much enjoyed envisioning an aircraft flying sans a pilot. In truth, me neither.
@Matty:
“What if some unstable soul went to town in the E/E bay?”
Well, instability is certainly a central theme in this entire tale, isn’t it?
And despite the fact that many people looking at MH370 (up until fairly recently) appeared unwilling to acknowledge it, technical sophistication (and aviation skills) appear to be key features too.
So again, from an investigative perspective (and assuming a “taken” scenario), you’re left with two choices: the known qualified persons on board (the Capt and or 1st officer. Or the unknown – and qualified.
Recall Tim Clark’s comments in June:
“this aircraft was disabled in three primary systems. To be able to disable those requires a knowledge of the system which even our pilots in Emirates don’t know how to do. Somebody got on board and knew exactly what they were up to.”
https://twitter.com/nihonmama/status/474364105109696512
(My MacBook Pro just crashed so I’m trying to make do using a PC and without my saved files or spellchecker)
Dr. Ulich – A few things:
While, it was expected the ACARS data should include the remaining fuel, this is the first time I have seen your 43,800 kg value. I didn’t think they had released any of the 17:07 information to the public. If it is correct, it would mean the a/c burned 5,400kg of fuel from the 49,200kg Jeff Wise reported at the 16:41 takeoff to 17:07. My calculations yield a burn rate of a little more than 17,000kg/hr. I believe that is high, even for a plane on it’s initial climb. I have found a table that uses 1,635kg from brake release to FL100 but I cannot find data on the amount from takeoff to FL350. Interestinly enough, the Delta Airlines B777 manual that can be found online, says when doing fuel load estimates for a given trip, you can approximate that almost all the extra fuel used while climbing is gained back when descending (i.e. just like perpetual motion). Unfortunately, unless you postulate a gradual glide after fuel exhaustion, that probably does not apply to MH370.
It appears that your 6.13 mt/hr burn rate supports your TAS and distance. But, rather than give you my crude fuel burn calculations, I’ll give you selected values from two different fuel burn tables so you can compare them:
From Boeing Data for B777-200ER.
Long Range Cruise. Engines RR Trent 892
All up Weight at start of distance, 200.0 Tonnes.
Time in hours and minutes, fuel burn in 1,000s kg. (I took this to mean that 1.5 hours is not 1h30m but 1h50m and interpreted the table, for example, on a 1200nm trip at FL300, 15,600kg was burned over 2h52m.)
Distance ————– Flight level
(nm)_______100__________200___________300____________400
_________Fuel Time______Fuel Time_______Fuel Time________Fuel Time
_600_____11.5 1.50_______9.1 1.37________7.5 1.28_________6.6 1.22
1200_____23.3 3.18______18.8 3.12_______15.6 2.52________13.9 2.38
2000_____38.5 6.08______31.2 5.21_______26.4 4.45________23.5 4.19
From the Delta Manual (Be careful, the below rates are PER ENGINE):
FL300, 440kts TAS, 7,200PPH
FL360, 473kts TAS, 7100PPH
Is the 50nm (3,591-3,541) difference between air miles and ground miles you used due the extra air miles travelled while climbing and that the diameter of the air travel sphere is 70,000ft larger than the earth? I never thought it was such a large value. I guess I haven’t even yet made it up to the kludge level.
@ LGHamilton – very nicely put indeed!
@Nihonmama
>> “this aircraft was disabled in three primary systems. To be able to
>> disable those requires a knowledge of the system which even our pilots
>> in Emirates don’t know how to do. Somebody got on board and knew
>> exactly what they were up to.”
I can think of a senior 777 pilot, remote-control enthusiast and all-around technical wizard with a pimped-out flight simulator in his man cave who might have been able to offer some insight into this mystery. Unfortunately, he happened to be flying the plane at the time it disappeared and is therefore unavailable for comment.