At a press conference earlier this month, Australian officials released a new report updating the scientific rationale for their continuing search of the southern Indian Ocean, which is expected to wrap up no later than June, 2016 after the expenditure of an estimated $130 million. “We have a high level of confidence that we are searching in the right area,” declared Assistant Minister for Defence Darren Chester.
As a result of this new analysis, the width of the area to be searched has expanded: from 20 nautical miles inside the 7th arc and 30 nm outside, to 40 nm inside the arc and 40 nm outside.
The key piece of data deployed to justify this reassessment was the newly announced finding that that the satellite data unit (SDU) requires only 120 seconds from fuel exhaustion to first log-on attempt, rather than the 220 seconds cited in earlier reports.
Assuming that the plane was operating as a “ghost ship” without a conscious pilot at the controls, its final moments played out like this:
- 00:11:00 Transmission from SDU to [ground station]. Hourly ping as previously described.
- 00:17:30 Approximate APU start time. APU requires approximately 60 seconds to provide electrical power.
- 00:18:30 Approximate time of SDU power restoration. SDU required approximately 60 seconds after power application to begin transmitting a log-on request.
- 00:19:29 SDU initiated log-on request. SDU began log-on process to satellite system.
- 00:19:37 Log-on request complete. SDU successfully logged onto satellite system.
- 00:21:06 Expected IFE [Inflight Entertainment System] set up of first ground connection. IFE set up request did not occur.
Here’s a nice visualization, from page 11 of the report:
A shorter log-on time for the SDU means that the plane must have run out of fuel later than originally believed, and therefore would have been higher and/or faster at time of the 7th ping. The important question is: what are the implications of this new timeline for how far the plane could have traveled after it sent the final ping? Here are a few different ways of looking at the problem.
#1: Historical data. On page 14 of the ATSB report we read: “A large sample of previous accidents was reviewed including the results of an analysis commissioned by the French investigation authority the Bureau d’Enquetes et d’Analyses (BEA) during the search for flight Air France 447… The BEA found that in the case of an upset followed by a loss of control, all the resulting impact points occurred within 20 NM from the point at which the emergency began.” Of course, by the time MH370 reached the 7th arc, its loss of control had been underway for two minutes, so the impact distance should be even less than this.
#2: Simulator data. From page 13 of the ATSB report: “The aircraft behaviour after the engine flame-out(s) was tested in the Boeing engineering simulator. In each test case, the aircraft began turning to the left and remained in a banked turn… The final position of the
aircraft was within a region defined by 10 NM forward and 10 NM left of the position where the flame-out occurred. Therefore, relative to the arc location, it was determined that 10 NM forward and 10 NM behind the arc would encompass the simulation impact area.” To take into account various uncertainties, the ATSB felt justified in adding an additional 10 nm in either direction, resulting in, once again, an endpoint no more than 20 nm in either direction.
#3: Stochastic Analysis. Back in May Brock McEwen conducted a stochastic analysis of MH370’s final path using the data current at the time. Asked to rerun his numbers using the new SDU reboot time, he produced the chart below (note that the label “Distribution DESCENT RATES” should actually read “Distribution of DISTANCE from impact point to 7th arc (FL0), in nmi.”
The key rectangle to look at is the light blue one, which refers to the area shown marked off in the thick baby-blue line below. As you can see, it encompasses the core “fried egg” of the probability distribution published in the ATSB’s report:
According to Brock’s calculations, the number of paths that hit the 7th arc and have endpoints 20 nm beyond the arc is invisibly small. Similarly few paths hit the 7th arc and wind up 5 nm within the arc.
#4: Assumption of functioning IFE. All of the above methods assume no more than a second-engine flame-out two minutes before the 7th ping. There is, however, a constraint that can be considered. The new ATSB report says on page 10 that an IFE system transmission was expected at 0:21:06, or 97 seconds after the 7th ping. But that never happened. That means that either someone turned off the IFE after 18:28, or the plane had hit the water by then (or was in a very unsual attitude, which let’s assume would be bad enough that the plane was about to hit.) Traveling at 500 knots, a plane can go no further than 13.47 nautical miles in 97 seconds.
#5: The ATSB Approach. In addition to #1 and #2 above, the ATSB paper considered what it calls “basic trajectory analysis of an uncontrolled but stable aircraft…. this analysis included constant and increasing bank angles, but did not include variations in speed or pitch angle.” It is not clear what exactly this analysis exactly entails, or how valid it might be; one would expect that increasing speed and downward pitch would naturally be part of a terminal spiral. At any rate, this methodology produced scenarios in which the plane wound up as far as 40 nm from the 7th arc. The ATSB acknowledges the inherent weakness of this approach: “ Due to the generic nature of this analysis it was given a lower weighting” in calculating the final probability distribution.
Putting all of the above together, the ATSB concluded that in all likelihood the plane hit the water within 20 nm of the 7th arc, yielding a total width of 40 nm. It calls this area the “highest priority width.” In addition, it designated a “secondary priority width” extending out another 20 nm based on “possible uncertainty in the simulation results and the trajectories from the turn analysis.”
The official search area has been redefined to match the results of the ATSB analysis; three ships are now tasked to search a box that stretches nearly 400 nm along the 7th arc and 40 nm on either side.
This strikes me as a remarkable state of affairs.
The report issued by the ATSB on December 3, 2015 is 28 pages long; its data and reasoning were further explicated in a densely erudite book by analysts at Australia’s Defense Science and Technology Group that is 128 pages long. Yet the broadening of the search area, which will entail the expenditure of tens of millions of dollars, is justified only by a fleeting invocation of “possible uncertainty.” This is hand-waving.
Continuing the search beyond the 40 nm “highest priority width” is not justified by the ATSB’s own analysis. Most of this region has already been searched; a remaining 5 nm-wide strip on the inner section of the 7th arc could be accomplished in short order. The ATSB should fulfil its duty to search the area suggested by its analysis. If the plane is not there, then the ATSB’s initial assumptions were incorrect. This will be a crucial piece of information guiding future efforts to solve the mystery of MH370.
My sincere appeal is the mh370 is NOT AT ALL IN SEA WATER!It is inside a hills cavity in north SUMATRA only.I am following mh370 from july2014.I studied all relevant data’s, news,radar plot& psychological background.
Great piece, Jeff, as always.
My update factored in not only the later flameout time for engine 2, but an earlier flameout time for engine 1 (had been 00:11:00 previously). These work together to…
1) lower the starting altitude (and speed) at point of engine 2 flameout. This lowers the potential energy of the plane at the starting point of the stochastic process, and compresses the impact distribution (i.e. reduces the SIZE of the fried egg).
2) translate the entire distribution 100 seconds worth of (one-engine) flight time in the direction of pre-fuel exhaustion bearing (i.e. shift the POSITION of the egg 10nmi or so further south)
Even before these updates, the stochastic model was suggesting there was little point searching more than a dozen or so nmi inside Arc7. After the update, it seems even more pointless.
Yet that it what they plan to do: if you subtract the area already searched from the latest priority area, you find that the vast majority of remaining time and money will be spent searching significantly inside the arc.
I will listen to those arguing for searching outside the Arc to points accessible only via controlled glide (I’ve yet to be convinced this is a plausible scenario, but I will at least listen).
But nobody – nobody on Earth – has ever argued that we should search out to points only accessible via the COMBINATION of
a) 135 +/-25 degree RIGHT turn at/near Arc7, and
b) straight-path controlled glide back ni the direction +/-25 degrees of northeast.
What would the argument for this scenario even look like?
Either the ATSB is clutching at straws, or executing an entirely different game plan altogether.
@DWARAKANATHAN
this is no place for conspiracy theories, flaperon was confirmed to come from B777 so it hit the water
@Brock
“Either the ATSB is clutching at straws”
they are clutching at straws for a while already… doesn’t bother them and why should it when it’s other people funding it
@StevanG: re: ATSB: agreed.
Re: “confirmed to come from B777 so it hit the water”: even laying Jeff’s barnacle/algae analysis aside – as you do, in making that statement – I must, with respect, point out that it was PRECISELY this attitude which led to media/expert silence whilst Tony Abbott’s “confirmed” acoustic pings caused several months and millions to be utterly wasted.
What say we VERIFY official “confirmations” from here on in?
@DWARAKANATHAN
Do you have any evidence to back up your statement about Sumatra? Somebody must know what happened to MH370…any crumb of real information would be useful.
@All
Correction to my much earlier post: I was referring to the original GEMS study with the claim that debris might land up on the shores of Sumatra (not Java as I said).
The flaperon was confirmed to have come from 9M-MRO and “the date of manufacture of Flaperon matched that of the plane, built in 2001 and delivered to Malaysia in 2002.” (from Florence de Changy’s 4th Sept report in Le Monde via Google translate). But, was that flaperon later replaced? With maintenance records lost this presumably cannot be verified.
@StevanG: You might be onto something with the lack of IFE log-on due to contact with the water. Many reasons are given why the IFE didn’t log on but the final crash isn’t one of them — it should be.
This means MH370 was airborne for somewhere between 2 and 3.5 minutes after fuel exhaustion. Oleksandr, in his treatise on abnormal BFO values, shows the final descent rate to be on the order of 20 meters per second (about 4000 feet per minute). This puts MH370 at 8000 to 14000 feet just prior to fuel exhaustion.
Since March 2014, I have held that MH370 left the Malacca Strait area at an altitude of 10k – 12k feet. The IFE log-on behavior at 18:25 and 00:19 further support this scenario. See mh370site.com for further.
Let me preface my first ever response here by saying I am in no way, other than extreme interest in aviation, I am not an expert in anything related to MH370 and have just followed closely.
@AM2 “But, was that flaperon later replaced? With maintenance records lost this presumably cannot be verified.”
It is so great that you pointed this out! I’ve wondered this myself, but dismissed it, assuming they’d have such documents. Clearly, I should have oboe better. Now I’m really hesitant to accept this theory and not just because logic and my gut say it’s inaccurate.
Something new on the subject?
http://acdemocracy.org/malaysian-airline-downing-a-terrorist-operation/
How Wide Should the MH370 Search Area Be?
Obviously it needs to cover 100 NMi beyond the 7th arc.
do we beyond doubt know what exactly has caused 7th ping?!
@Ed: There are many problems with this account. For one, what evidence is there that the “entire electrical system was blown out” by a large explosion? In fact, the log-on of the SATCOM at 18:25 and the flight until 00:19 would suggest the electrical system was functioning and there was no explosion as suggested.
His statement about the Uighur resident with pilot training is also false. There was confusion in the early days (prior to March 15, 2014) between a university professor living in Turkey who was not on the flight and a Chinese Uighur painter who was, both with the same name.
Look at the picture at the start of the article. The author does not even know the difference between a B747 and a B777.
Gysbreght,
Plus ~10 nm to account for the possible deviation of the 7th arc from the nominal 7th arc…
Anyhow, I think it is more important to understand how and why MH370 did fly to the middle of nowhere rather than how it fell down…
There were so little comments on the CTS model and a number of weird coincidences it features that I have decided to send the last revision to ATSB and Malaysian team. Both have aknowledged reception. Let’s see if anything useful comes out of it. There is still plenty of work that can be done, particularly with regard to the end-of-flight scenario, and understanding how electronics of B777 may function (or mulfunction) in case of certain damages, which is beyond my expertise.
I am posting this message in connection with Bruce’s note as the modelled terminal altitude of CTS-based models is around 7 km, as opposite to 11 km of the AP-based models.
Gysbreght,
What would be your rough estimation of the maximum terminal (settling) velocity of MH370 filled with seawater? I came to the figure of ~8.5 m/s on the conservative side. This is if it sunk strictly vertically, with no trapped air inside.
@VictorI: It might be best to consider the electrical system as not an “entire electrical system” but rather a large collection of smaller systems. The biggest subdivision in the electrical system is between the power side and the control/data side. While there is great redundancy for the power and flight controls, much of the rest doesn’t have the same level of redundancy. Considering the near simultaneous loss of data and control (transponders, ACARS, comm, …), there is a good probability that the data and control lines were compromised in a flash fire. Photos of the B777 equipment bay shows many cables draped from one side of the bay to the other with no protection from fire.
As we know MH370 made a turn to the west as a result of some great emergency, it would make sense to also descend in order to get to the safety of an airport. If the left engine controls are severed, the only thing is to cut its supply lines: fuel and power. Flying on just the right engine, the B777 can easily make a landing back in Malaysia.
At both 18:25 and 00:11, the B777 automation brought power back on line through various means.
@Bruce Robertson: Exactly which “B777 automation brought power back on line through various means”?
So the pilot turns back west to fly to an airport, descends, and passes near two airports before heading out to the Malacca Strait, where it turns first northwest after Penang and then south. All the while flying around 500 knots. I am sorry, but I view that as quite unlikely.
Victor,
On contrary, this is one of the two most plausible scenarios. How would you land with 30+ tons of kerosene and malfunctioning electronics, possibly smog or fire onboard? Midnight, no emergency service on duty at these airports, no communication means. This attempt would definitely end up in a crash and inferno. What would you do if you were a pilot?
@VictorI: The B777 has quite a few computers that work together, including the flight management system, auto-throttle, fuel automation, and others.
The fire was fed from the pilots’ breathing oxygen, just topped up at KL after an unexplained 40% loss. Between the left engine being shut down and the oxygen depleted, the pilots have no breathable air and lose consciousness prior to the Malacca Strait.
MH370 flew slower than 500 knots.
@Bruce Robertson: If MH370 flew slower than 500 knots, the radar data is false. I have looked at this quite closely. Is this really what you are proposing?
As for a pilotless, seriously crippled plane following waypoints and making turns and then flying for hours into oblivion, I still maintain this as unlikely.
@VictorI: What has made finding MH370 so difficult is that so many have assumed so many constants. Instead, MH370 changed direction, speed, and altitude so often. Most of the time, MH370 flew slower than 500 knots. Westbound from IGARI, it’s probable the plane was put into a rapid descent due to the nature of the emergency. That rapid descent would certainly result in a high airspeed.
With the data lines severed, there is no navigation, no routes, and certainly no waypoints. This is the definition of a seriously crippled plane.
@Bruce Robertson: You said the plane flew slower than 500 knots for most of the time. Please read this report I wrote and then explain how the radar data would allow speeds less than 500 knots for most of the time.
https://www.dropbox.com/s/zh9rfqa6rxy582m/2015-08-18%20Radar%20Data%20for%20MH370.pdf?dl=0
@VictorI: I meant for the 4+ hours heading south into the Indian Ocean, MH370 was flying well under 500 knots. Sorry for the misunderstanding.
QUESTION …@VictorI, Oleksander, et al.
The radar data is pretty unambiguous about speed, so hypothesized speeds of about 500 knots for the segments under radar coverage makes sense.
But what about speed after radar coverage beyond waypoint MEKAR?
What if the aircraft descended to, say 12000ft, and flew at slower speeds?
Would the aircraft still hit the 7 arcs at the times they were recorded?
@Gysbreght, In order to fly as far as 100 nm (indeed, in order to fly any distance beyond 20 nm, I’d argue) the plane must have had a conscious pilot at the controls. But if that’s the case, we have to admit the possibility of step-climbing, which allows faster flight and hence endpoints further to the southwest, as well as a turning course to the left that would bring the endpoint further to the northeast. In other words, the search area grows significantly in every direction. Time and cost required would rise accordingly. I would be surprised if anyone bankrolling the current search area will have much stomach for this.
@Jeffwise:
I would limit the length along the arc to the range that VictorI has recently calculated. That calculation follows the BTO and BFO data exactly as recorded, without ‘a priory’ assumptions, the only unknown being the timing of the turn south between 18:28 and 18:40.
@jeffwise:
The Bayesian Ornstein-Uhlenbeck method also admits changes of heading, speed and altitude, but assumes that these occur randomly in terms of location, frequency and magnitude. What is the logic behind that?
Ed – putting the theory to one for a moment side it’s sobering just to look at all the malevolent players out there just bobbing around. Then look at this-
http://www.theaustralian.com.au/news/world/egypt-claims-no-terror-link-to-russian-plane-crash/news-story/0115d532895540afd6c7455689ac2b16
Total rubbish. Egypt aren’t the only ones out there trying to play down terrorism though. Obama said ISIL were Junior varsity, and even more recently said they were contained. He has been brought to the table by uncomfortable reality.
CliffG,
Re: “But what about speed after radar coverage beyond waypoint MEKAR?”
It is unknown past 18:22, but subjected to BFO constrains.
—
Re: “What if the aircraft descended to, say 12000ft, and flew at slower speeds?”
My opinion is the same as before: it could. Moreover, I think dual flameout 18:23 explains a lot of things. Perhaps it was done on purpose to knock down the whole electric/electronic system to repair something, as with one engine “on”, the power would be automatically provided by cross-IDG, while with both the engines and APU off, they could have 1 minute or so.
—
Re: “Would the aircraft still hit the 7 arcs at the times they were recorded?”
Yes. But this implies a curved trajectory.
@Oleksandr
“Anyhow, I think it is more important to understand how and why MH370 did fly to the middle of nowhere rather than how it fell down…”
spot on, however good luck persuading any official to even think about that…
StevanG,
I don’t expect much from the authorities… whether they are democratic or not. But I am quite surprised with the reluctance of a number of other enterprises and institutions to collaborate on this matter: Boeing, Inmarsat, Curtin University, NOAA, NASA.
In reviewing my end-of-flight stochastic model, a potentially huge issue popped up, on which I seek an aviation specialist’s opinion.
For any given straight-line track, the arcs are separated by a very specific distance.
If, as the ATSB now asserts (per excerpt in Jeff’s article, above), MH370 ran on one engine from 00:04:00 UTC (+/- 2 minutes) until 00:17:30, then MH370 had to be slowing down significantly, yet maintaining track.
Back when engine 1 was supposed to be flaming out at 00:11:00, the deceleration @airlandseaman documented (0.315kts/sec) didn’t commence until MH370 was within 50nmi or so of Arc7. Even under reasonable further deceleration, Arc7 was attainable.
Now, engine 1 flameout is more like 100nmi north of Arc7. When I fully update all parameters (including my estimate of POSITION at point of engine 1 fuel exhaustion), I find the model as calibrated cannot reach Arc7 under ANY end-game scenario – including a pilot making a beeline straight at the arc.
@IG members (and others doing similar work): are you experiencing similar difficulties? Any assistance offered would be keenly appreciated. Thanks.
@Brock:
What is the problem? At 93°E the radial distance between 6th and 7th arcs is 43 NMi. To cover that distance in 8 minutes the groundspeed must be not less than 322 kt. At FL300/ISA 322 kTAS corresponds to 202kIAS, close to the maneuver speed at a 174t of 206 kIAS, which is probably the minimum speed that the A/P will allow.
@Brock: A very interesting issue. According to page 3.3.6 of the 777 Flight Planning and Performance Manual (available at http://www.piac.com.pk/technicalbulletins/b777/777-200er-fppm-rev-02_27122010.pdf) with one engine out and the other operating at max continuous power, at standard temperature and approximately 174,000 kg, a 777 will fly about 390 knots at 27,000 feet. Assuming that at first engine flameout MH370’s autothrust powered up in an attempt to maintain altitude, the plane would have slowed, and then begun to sink until it reached this speed and altitude. As it crossed the 6th arc at 0:11 it would already have been traveling at 390 knots and flying straight, so we can say with a fairly high degree of confidence where it was (that is to say, we can draw an accurate ping arc.) Google Earth tells me this line is 19 nm from the 7th arc on its current heading, which would require a ground speed 570 knots to reach in two minutes. If the plane turned to the left and headed for the nearest point on the 7th arc, the distance is 14.5 nm, requiring a speed of 435 knots.
Bear in mind that so far I’ve been mixing apples and oranges here: the 390 knot speed deriving from the FPPM is airspeed, and the speeds I’m calculating off Google Earth are ground speeds. According the Nullschool, the wind at altitude would have been about 45 knots from 235 degrees, meaning that a plane on a straight-ahead bearing (~185 degrees) would have faced a headwind of about 30 knots. So getting to the 7th arc would be even more problematic: at second-engine flameout the plane would be 23 nm from the 7th arc on a straight-on heading and 18 direct to the nearest point, requiring ground speeds of 690 and 540 knots, respectively. Against a headwind!
There is a potential way out of this problem. The 7th arc I’ve been referring to is that calculated for 35,000 feet. If the altitude at 0:19 is less, the ring will be closer. According to a kmz file I borrowed from someone a long time ago, the sealevel 7th arc will only be 17 nm on a straight-ahead bearing, and 12 nm direct, requiring ground speeds of 510 knots and 360, respectively. So if the plane turned left after second-engine flameout and accelerated as it plummeted toward the 7th arc, it might just about get there.
And of course all of the above is predicated on the idea that I’ve correctly characterized the plane’s behavior after first-engine flameout. I’m checking with some 777 experts to see if I can nail that down.
@jeffwise:
THX for the link to the FPPM for the GE engine. Do you have one for the RR engine? I believe it provides a few % more Maximum Continuous thrust.
@Gysbrehgt, Ah, the age-old question! We’ve been looking for a Rolls-Royce FPPM for over a year now. Some tables have turned up but not the whole thing.
@Gysbreght: the problem lessens if I change max sustainable speed on 1 engine from the 325 KTAS you just gave me yesterday to the 390 to which Jeff refers above. Do you retract your 325?
But 43 nmi is, as you say, the radial distance; the paths leading to where they are searching cut across the arc at an angle; the straight-line track distance between arcs with which I’ve been working is 56 nmi. I believe the IG uses the same.
Any theory that assumes cruising speed until engine 1 flameout will need to cover this greater distance – a major turn into a track perfectly perpendicular to the arcs is not rational: if piloted, it is arbitrary, and a fluke; on auto-pilot, it is not even possible.
This problem is not lessened in cruising speed scenarios which impact further NE due to path circuit around Sumatra (circling, landing, etc.). That angle is a function of assumed speed.
Gysbreght, would you be so kind as to reconcile Jeff’s 390 at FL270 (above) to the numbers you quoted me a couple days ago? Just trying to improve my understanding of the variables affecting the max sustainable vel/alt for a 174t 777-200ER on 1 engine.
@anyone: what is a, say, 90% confidence interval for the BFO-indicated horizontal component of aircraft speed, assuming it is experiencing a constant drop in velocity per the 1-engine dynamics Jeff quotes above?
Thanks.
There are a few problems with that. We are assuming that the airplane is flying controlled by A/P and A/T without an active crew, right? The response to a first engine failure depends on the initial speed and altitude and the active thrust limit. The active thrust limit in normal cruise is CLB. With one engine inoperative that could change to Maximum Continuous Thrust (MCT), but I’m not sure that would change automatically, because the deceleration of 0.315 kt/s observed in ALSM’s simulator test is higher than would be expected at MCT. (Extrapolating FCOM OEI ceiling data to FL350 I get about 0.2 kt/s). If the airplane at the first engine failure was at FL270 and the active thrust limit changed automatically to MCT, then the A/P would maintain FL270, the A/T would move the thrustlevers to MCT, and the airplane would decelerate to and maintain 390 kTAS (or a few knots more for the RR engine). The rate of deceleration at FL270 would be much less than at FL350.
On the other hand, if the airplane had the first engine failure at FL350, M.80, the A/P would also initially maintain altitude, the A/T would move the thrust levers to the active thrust limit (CLB or MCT), the airplane would decelerate to the minimum speed allowed by the A/P (which I think is the ‘flap maneuver speed’), the A/P would then automatically change mode from ALT hold to SPD hold, and the airplane would start to descend at constant IAS until it reached the ceiling for the active thrust limit (CLB or MCT), and then maintain speed and altitude.
@Oleksandr
“But I am quite surprised with the reluctance of a number of other enterprises and institutions to collaborate on this matter: Boeing, Inmarsat, Curtin University, NOAA, NASA.”
Those are engaged for the technical part, it probably wouldn’t be professional from them to comment on the possible motivation especially because they’d likely touch malaysian politic situation and it would be meddling in malaysian internal problems…
however ATSB should be allowed to assume all sorts of possible scenarios that would lead to the plane and up to date not a single word from them
@Gysbreght: sorry, I was unclear: I was asking you to help me either ignore (if they were wrong) or understand (if they were right) your posts of Dec.10 (prior thread), in which you gave me a max sustainable 1-engine vel/alt of 325KTAS/FL295.
To my (admittedly untrained) eye, you referred to neither in your response.
StevanG,
I am talking about technical aspects. Take for example Curtin University. Why do they refuse to publish details of their investigation? I got in touch with Dr Duncan, and I hope to receive a reasonable explanation from him: mysterious 3rd station, some mumbling from ATSB about incompatible timing. Same about NOAA: a long time ago I have made request to them with regard to Suomi NPP 18:55 images – no response at all. As about Inmarsat: they have not published entire logs. For instance strength of signal could possibly be useful in understanding if satellite dishes were properly oriented. That would likely eliminate or confirm attempt of BFO spoofing. So it is not only Malaysian military, who withheld essential data…
@Gysbreght & @Brock, It seems like this should be a fairly well-defined aspect of the flight control system what we can nail down definitively. Seems important. I’m working on it now. All help welcome.
@Brock:
I’m not sure I you still want confirmation/verification of data I posted earlier.
That was based on the B777-ER, Trent engines FCOM, Performance Inflight section giving the One Engine Inoperative Max Continuous Thrust Driftdown Level Off Altitude with 100 ft/min residual rate of climb at 174000 kg, optimum driftdown speed 219 kIAS (345 kTAS), ISA + 10° C & below as 29500 ft pressure altitude.
Although the 206 kIAS maneuver speed maintained by the A/P is slightly less than the optimum driftdown speed of 219 kIAS, I guessed that the residual rate of climb of 100 ft/min would cover that difference. After doing further work, I’m not so sure that Max Continuous Thrust is selected automatically, and that the sustained level flight condition is reached within 15 minutes. Depending on the initial speed and altitude and the selected thrust limit, it may take longer. Does that answer your question?
Regardless of what has been reported and calculated, how can we be sure that the first engine flameout did not occur closer in time to the second? Can we be sure that the plane was not flying with two engines at 00:11?
@Victor: is your argument that the ATSB may well be searching in a place rendered impossible by their own (PDA-based) flameout data, but that we should not fuss over this, because their data could well be dead wrong?
(Shades of the fuel fiascos. Or the acoustic pings. The list is long, and depressing.)
I don’t know what happened to MH370, but it is time to call time of death on the credibility of search leadership.
Oleksandr,
I would have to agree with what you said also about the greater importance of “why” MH370 got to the SIO in the first place as opposed to “how it fell.” Although the “how it fell” inclusive of the SDU/AES performance and logon time, speed, spiral dive or not, all contribute to the “where” it fell. And in all likelihood the determining of the “where” it fell and finding it may be the only key to the “why.”
You said two key things on this page that touched on what I have been harping on for a year. One was that an 18:23 dual flameout may mean the 18:25 reboot was indeed “engine” related (AES being on the whole time), and the second was that they were in the vicinity of several airports near the Straits yet they don’t land. One of the things I had said was perhaps they just can’t land, or the situation was so dire onboard that a landing en terre would be catastrophic. So whoever the ‘conscious” pilot was (those that are assuming there was a conscuious pilot after 18:40), did he choose to attempt a sea landing instead? Why so many hours of it though?
@VictorI:
You’re quite right. The ATSB report of 3 December says: “… it is estimated that the left engine could have continued to run for up to 15 minutes after the right engine flamed-out.”
@Gysbreght: Thank you for reminding us exactly what is in the ATSB report.
@Brock McEwen: My point is only that some are trying to apply precise calculations to an end-of-flight scenario in which there are many unknowns, such as the exact time of the inoperative engine, and then using those results to somehow call the search leadership into question.
The best evidence we have that the current search strategy is incorrect is that the hot spot was searched with no success. There is no alternative strategy, as the DSTG is incorrectly being used to confirm the current search strategy (with some minor modification) as the only one to consider. That is the real story, in my opinion.
I believe we should not wait until June 2016 to consider alternative scenarios, be it end points in the SIO or elsewhere.
@Victorl
if I understand it, latest report considers possibility that there was enough fuel to reach more southern area, but in case we mirror their effort, it also means posibility to reach more northern area; cause I believe big players are in fact cooperating closely for years back, despite media clashes; just to force the bads to make mistakes; and all we see is relaunched analytical power
@Victor: were this the only instance of the search group’s own data appearing – quite emphatically – to contradict its own conclusions and decisions, I would give them the benefit of the doubt.
It isn’t, so I don’t.
Telling us the first engine flamed out 5-9 minutes before Arc6 is just the latest in a very long series of analytical fails. The search group needs to be audited – rigourously. When the time to demand this action arrives, I dearly hope your voice joins the chorus.
The search group’s reports have, in fact, become an “unanswered question machine”. Perhaps this is by design. I am going to shift focus. I am going to stop wasting my time arguing with folks who are zealous in their determination to trust search officials – no matter how many times their story changes, or doesn’t add up – and increase my focus on some of the key unanswered questions already on the table.
Such as: if the latest official explanation for the Maldives’ mass sighting – that it was actually DQA149, course-correcting in prep for landing at Thimarafushi – is authentic, then why is this magic flight…
– absent from all available online historical flight schedules?
– not documented in Maldivian Airlines flight records (as far as they’ve been able to show)?
– 30nmi (or more) off course on a 119nmi flight leg, in a light wind?
– claimed to have been beyond reach of Maldives radar* (reason given for 16 month delay in this story’s arrival)?
(* this same radar was cited in Mar/’14 as definitively ruling OUT any flight near Kudahuvadhoo…)
In my opinion, this is where strong independent minds should focus.