Over the last three years, Inmarsat, the ATSB, and the DSTG have been commendably proactive in explaining the mathematical process by which they deduced MH370’s most likely endpoint from the Inmarsat data. The most recent installment, “The Use of Burst Frequency Offsets in the Search for MH370″ by Ian D. Holland, continues that tradition by shedding light specifically on the BFO analysis. All told, it reinforces the impression that the team had good reasons for thinking that the plane would be found in the 120,000 sq km search box. This, of course, only deepens the riddle of why it wasn’t.
Holland’s paper gets into some pretty dense math but a couple of points stand out. On page 6 we read:
Since the mean of the BFOs from the 18:39- 18:41Z call attempt are in broad agreement with the linear trend observed in the BFOs from 19:41Z to 00:11Z (for which the BTOs themselves were consistent with straight and level flight [1]), this supports the finding in [1] that there were most- likely no major turns after the unanswered call attempt (see ([1], Fig. 10.5)).
This is a familiar idea: that the BFO value at 18:40 indicates that the plane, if flying level, was already heading south at that time, and that the FMT had already occurred. This was long accepted as being almost certainly true. But as Victor Iannello recently pointed out on his newly started blog, if the plane turned before 18:40, then its wreckage would have been found in the SIO search area. Therefore, he proposes an alternative that originally seemed less likely: that the plane was in a steady, 2900 feet per minute descent.
Why would whoever was flying MH370 want to descend in such a fashion? Iannello proposes that they might have been setting up for a landing at Car Nicobar airstrip in the Andaman Islands. Perhaps the plane descended for a while — at this rate, getting down from 35,000 o 20,000 would take about five minutes — and then the pilot changed his mind and flew south into the SIO instead.
However, as I’ve pointed out before, if the plane flew straight after 18:40 then the geometry of the BTO rings itself suggests what speed the plane was flying at. The reason is that the 19:40 and 20:40 rings are quite close together, and so there is a small angular distance between, say, a 400 knot path and a 500 knot path. This small angular distance means that the intersection of these paths with the 22:40 and 00:11 rings are spaced at very similar distances. The upshot is that the BTO rings themselves imply a speed of about 480 knots. This is not dissimilar to the speed seen on the radar track, about 500 knots.
To fly this fast without burning all its fuel before 0:11, 9M-MRO must necessarily have been flying at or close to normal cruise altitude.
What Iannello is effectively proposing, then, is that MH370 flew fast and high, then descended, then climbed and flew fast and high again. It is not easy to see what such a dive-and-climb might have accomplished. That is not to say it didn’t happen. But it does run counter to the behavior that the plane otherwise exhibited, which seems to have been geared toward getting where it was going rather quickly.
Another thing I found interesting about the paper was the amount of attention given to the question of the anomalous BFO value at 18:25:27. Apparently a body within the official search effort called the “MH370 Flight Path Reconstruction Group – SATCOM Subgroup” produced a whole paper on this topic; it has not been released to the public but Holland refers to it no less than 7 times, as sk999 has pointed out. We’ve known for some time that the ATSB was unable to find a reason for this value. This struck me as suspicious and I wondered if it might be evidence that the SDU has been tampered with. In this paper we learn for the first time that a study of 20 previous 9M-MRO logins found that one similar anomalous value. (Previous reports have stated that login requests in mid-flight are extremely rare, so we can assume these occurred during normal power-up sequences on the ground.) Unfortunately, Holland doesn’t say anything about what the circumstances were. The implication however is that this kind of anomaly can arise innocently.
Finally, Holland also touches upon the issue of the rate of acceleration implied by the final two BFO data points: 0.68 g. Again, we’ve discussed this before on this blog, but since Holland revisits it I think it bears repeating. This is an extremely high rate of acceleration — two-thirds of what the plane would experience if it was free-falling in a vacuum. With no engines to hasten its descent, the plane must have been pointed nearly vertically down. With its velocity increasing at such a rate, the plane must have impacted the surface quite soon after, therefore it couldn’t be very far from the 7th arc.
My overall impression upon reading this report was: Wow, this is extremely solid work. The DSTG’s analysis of the Inmarsat provides a very compelling case for where the plane went in the southern Indian Ocean. I wouldn’t want to bet against this, I thought.
Then I remembered that their predicted area has already been searched and nothing was found.
@JeffWise
…”of 20 SDU logins from previous 9M-MRO flight”. Should this be flights?
I presume it was the first BFO value with the plane sitting on the ground. Is this just oscillator warm up as discussed by @DennisW?
Good analysis!
We should be clear about “one” thing; that is we need to know two factors associated with the BFO in order to find the third. Why? Because the aircraft is flying in a three dimensional medium.
With reference to the Ian Holland DSTG analysis; its sole purpose was to establish that ‘ipso facto’ the final logon comprised factors that led to the assumption of a rapid descent. In all probability that assumption appears to be correct, which then begs the question of why the other logons on the “P Channel” or non “P Channel” telephone call BFO’s were not questioned.
This may be a case of “after the fact” self justification in relation to a nil result in the recommended Search Area. Though not meaning to impune/impugn the work of the author, it seems that similar importance should also be placed on determining all possible outcomes – be they variable or not, on other determinate BFO’s.
This work needs to be done and reviewed.
@DennisW, @ventus45, @Jeff Wise, @Barry Carlson
Many feel that it was part of the plan to embarrass specifically the Malaysian military/ATC. This is why I feel a diversion en route to, say, Europe would not have done the job.
Regardless of the risk of an actual interception, at the very least there was the risk of someone raising an alert, had MH370 flown directly through various territories. Malaysia did not raise any international alert until several hours after the disappearance, notifying its neighbours via AFTN (FI:100-101). Had MH370 on the other hand been tracked by Indonesia while intruding own airspace and heading south towards Australia, that could have triggered international suspicion and communication. MH370 was later flying within JORN radar range. It could have been tracked all way long.
Whatever the original intention of that diversion was, I find it more logical that MH370 attempted to avoid any interference from third countries (e.g. a plane apparently hijacked and tracked all way long until it crashed in the SIO would not be such a mystery, a plane showing up at a completely different landing site would not be such a surprise and so on).
In the weeks following the disappearance several media reports indicated that MH370 was skirting Indonesian radar, and I am unaware of any specific information overturning this assumption (other than the 18:40 BFO, but since the search area has come up empty, the assumption of it indicating a southern turn by that time appears to be flawed – and imo a descent makes sense only if the aim was to reduce line of sight with Sabang/Aceh radars; it does not make so much sense in a loiter scenario where MH370 later passed through Indonesian territory at cruising altitude).
@Jeff
“Finally, Holland also touches upon the issue of the rate of acceleration implied by the final two BFO data points: 0.68 g. Again, we’ve discussed this before on this blog, but since Holland revisits it I think it bears repeating. This is an extremely high rate of acceleration — two-thirds of what the plane would experience if it was free-falling in a vacuum. With no engines to hasten its descent, the plane must have been pointed nearly vertically down.”
I caution the conclusion from this value alone. The following is based on the asumption, that the figure of .68g is measured acceleration or easier understood loadffactor. 1 g is the normal loadfactor for an unaccelerated fligt, again simplified flying straight and level at steady speed. 0.68 g then resembles a reduction in acceleration by .32g, which would be a reduction by 1/3 of normal acceleration.
Now whatever it was, this measurement could be a momentary snapshot of the loadfactor at the time of the measurement, I can see no prove that it existed over a prolonged time. It could be more or less, the value could vary over time. It can not be necessarily asociated with a pitch attitude. During transition from a climb to a descent the pitch could still be positive, the aircraft could even still be in a climb.
There is no basis for the assumption that the BFO values for a straight and level flight produce a linear trend line versus time:
https://www.dropbox.com/s/ygml1kf4uw8e2r4/BFOtrend.pdf?dl=0
@SteveBarratt, Yes, thank you, I’ve changed the wording to clarify that though not specifically described as such, the 20 previous logins must have occurred on the ground. I presume that, yes, these transient effects are due to oscillator warmup.
@StevanG, Thank you!
@Barry Carlson, Holland covers a number of topics but the validity/meaning of BFO values generated immediately after an SDU logon is the biggest one, as this is both difficult to understand and important in trying to understand what happened at two critical junctures in the flight. The other BFO values seem fairly cut and dried, though I’m willing to be convinced otherwise.
@Nederland, Australia has said that MH370’s path did not bring it within ranger of JORN.
Also, you wrote, “In the weeks following the disappearance several media reports indicated that MH370 was skirting Indonesian radar.” Worth bearing in mind, I think, is that at the moment of its final appearance on Malaysian military radar at 18:25, 9M-MRO was just 74 nm from Sabang. A well-informed pilot might have expected that he’d be tracked well past this time.
I haven’t looked into the matter in detail, but I don’t think that anyone has proposed an FMT that would put the plane’s track outside of range of potential Indonesian radar detection. I don’t think we can say, therefore, that Zaharie (it seems to me that any SIO scenario is essentially a Zaharie scenario) was trying to avoid being seen by Indonesia; the most we can say is that he was trying to avoid overflying Indonesian land. The point presumably being not to avoid detection, but interception.
Even this is odd, however. If he really was motivated to avoid interception by Indonesia (having already flown 300 nm up the Malacca Strait instead of keeping his southerly heading at Penang for this reason), why not just fly on another 100 nm or so before turning south?
@Jeff Wise
Australia actually said that JORN was not operational that night and that it is “unlikely” it would have tracked MH370 given “lack of information on MH370’s possible flight path towards Australia.”
https://www.airforce.gov.au/docs/JORN_FAQS.pdf
Sounds like some amount of criticism to me: Had Australia been given that “information”, chances are JORN would have detected MH370 especially if it was going further north than assumed (and there seems to be some consensus on that now). Their indicated range (p. 3 on that sheet) would seem to suggest that.
I don’t think there was a real issue with MH370 being tracked by Sabang in general, as long as it was not flying through Indonesian territory (which it wasn’t at that time). It would have appeared to be a commercial plane flying in Malaysian territory.
I have earlier posted a proposed flight path in which MH370 would not have been detected by Sabang/Lhokseumawe radar (flying through Indonesian territory) and which works with the BTOs/BFOs (in the v.4 YFF BFO calculator) and a further waypoint route to McMurdo, taking into account the descent rate posited for the 18:40 phone call in a direction to IGOGU/APASI. MH370 would have disappeared/been out of range by the time it had descended to ~20,000 ft and keeping a distance of 200nm from Sabang while going south. I am currently trying to update it to make clearer the discussion on loiter around Car Nicobar versus route bypassing Indonesian radar.
@RetiredF4, I think you’re misinterpreting the meaning of this number. It’s not talking about the load factor experienced by the plane, it’s talking about a rate of change of velocity. If you drop a ball in a vacuum, it goes from 0 feet per second to 32 feet per second in 1 second. That’s a rate of acceleration of 1g. The load factor experienced by the ball is 0g. Similarly, between the last two BFO data points 9M-MRO’s vertical speed component (aka rate of descent) went from about 7,000 fpm (70 knots) to 17,000 fpm (170 knots) in eight seconds. If we assume (for simplicity’s sake alone) that there were no components of acceleration in either the x or y plane, a person on board the plane would have experienced a load factor of 0.32g.
@Jeff
Thanks for the clarification, so the figure is computed aceleration. But please recheck your numbers.
Using this calculator
http://www.engineeringtoolbox.com/acceleration-d_1393.html
I come up with :
100 to 170 in 8 sec = .4
100 to 150 in 8 sec. =.28
From this figures It seems clear to me that the figures are change of aceleration. A person on the plane would feel .6g in case one, .72g in case 2.
Once the descent rate is established and stable, this person would feel 1g again.
This calculator might be off by some rounding figures though.
Here is a partial list of possible reasons for descent at 1840
1. Landing approach
2. Getting out of air traffic EK343 close coming up MH370 from rear, maybe another flight too
3. Drop out of (Sabang) radar
4. Closing off lateral offset (temporary southern move)
5. Repressurization of cabin
@Spoofies
Holland paper
Its really consolatory to see how dedicated excellent science is done on the highest performance level possible to help with this dreadful mystery.
I go with Mr. Wise here to say that just this excelling standard is also further mystifying the disapearance, because the only conclusion can be in my view, that the data are wrong.
So it would break down the search for a discussion of what kind of spoof might have happened. A public discussion of the possibilites of spoofing would be very helpful to develop effective defense mechanisms against data attacks.
I would outright dismiss the possibility of the data being fabricated after the act. Sure it would have the advantage of knowing the offset bias, but it would require a very complicate and clandestine operation within the Inmarsat domain, and even if one of the key Inmarsat employees died in the course of events, i think the mathematics necessary to fabricate consistent data points with the right offset and a reasonable route into completely uncharted territory was just not there.n The data are not fabricated after the fact.
Also use of a decoy or use of a spoof ship within the first ping ring would require a complicate on the spot (at GES Perth?) listening operation, to get the actual offset bias of the specific SDU. That makes it quite unlikely that that happened.
The spoof, if at all, must have been done aboard the plane with the genuine SDU. Mr Ianello suggested a good idea how this could have been done, but i think he is not a specialist for a combat situation. If a spoof was done on the plane, it was either by access to the E/E-bay or directly in the passenger compartment. Both are typical combat situations, because people must be held in check to allow someone else to tamper with the SDU or E/E bay. If you plan for a combat situation, you would not go for altering parameters in the SDU but you would provide a tool like a device to the commando that merely needs to be placed between the SDU and its data source, therefore only requires the removal of the cable for the data stream for a short time. The power for the spoof device would come from a battery. The wiring must be intersected in the passenger compartment, because its too complicate to find the right wire in the E/E-bay.
I think , if this kind of spoof did not happen, there was no spoof at all.
@Jeff Wise
With all respect but it’s becoming a repeat of moves like in a chest game in away.
The final BFO’s were rejected by Inmarsat for being unreliable.
The great majority of debris shows it could not have been a nearly vertical high speed dive into the ocean. The whole plane would have been smashed into unrecoqnizable smitters. There won’t be left a clearly identifiable and complete monitor mounting or a clearly identifiable ~80x60cm piece of a closet.
Let alone a 2.40m flaperon with nearly undamaged leading edge and overall condition and an over 3 meter outboard flap section that shows the same lack of high speed impact damage.
Then most of the other pieces found. Also all wing/engine/trailing edge surface control related pieces. Most of them around or over ~70cm dimensions and identifiable too.
All confirmed and very likely MH370 debris found to date show the signs of a relatively low speed horizontal and level entry in the water.
Why dismiss this evidence and keep holding on to this final BFO’s as prove? Prove that was rejected by Inmarsat in the first place?
Those BFO data or not more than data. But this debris shows facts that cann’t be denied or interpretated in many different ways. One way only IMO obviously.
Where ever this debris seperated from the plane remains an open question.
Maybe an SDU-spoof disguised a flight to the Maldives and than to Diego Garcia. Or a flight to Kasachstan or whatever place.
But it definitely made no nearly vertical high speed dive into the ocean.
The debris tells this story better than any other Inmarsat or radar data (that even is not public yet to be verified).
But still you and many are still crunching your heads on this data which seems to serve as a religious believe in data sometimes.
While the debris and drift analizys are telling a much more reliable story in between.
Default of conspiracies and unreliable, even dismished data.
I’m confident the debris holds the key to what happened and where. Not the BFO data or the radar data. They proved themselves to be unreliable definitely by the failure to find the plane in the search area.
I think that 18:40 and final BFO’s have to be discarded as evidence of anything. Too much room for interpretation which make them practiccaly useless IMO.
Focus should be on real existing evidence now. The debris and what it tells.
It’s ignored obviously and shamelessly by the Malaysians, ISDG and the ATSB. Many parts arent even collected and studied.
Why not? Do they allready knew what happened so it had no use anymore?
They at least create this suspicion to me.
Anyway they deflect any attention to the debris by this attitude. And if this is a trap we should not fall into it and focus mainly on the data.
The debris has a lot more to tell than those final BFO’s I’m sure.
@Ge Rijn
I wouldn’t be so sure about that. How likely is it that a plane descending at 0.68g could keep its wings and would not break up in-flight altogether?
Then you have some parts much better preserved than others, particularly wing parts (and an explanation for the incomplete handshake).
@Nederland: “How likely is it that a plane descending at 0.68g could keep its wings and would not break up in-flight altogether?”
According to JW “a person on board the plane would have experienced a load factor of 0.32g”, i.e. the loads on the wing are only 32% of the loads supported by the wings in unaccelerated flight.
😉
@Gysbreght
OK, got it, but it’s just an 8 seconds window.
@Gysbreght, Jeff Wise. You are confusing load factor with vertical acceleration. The two would be identical only if aircraft were horizontal. At the other extreme, vertical, the load factor is independent of vertical acceleration, which would be drag dependent, including induced. The load factor could be anything.
http://home.anadolu.edu.tr/~mcavcar/common/Loadfactor.pdf
Besides, to change vertical speed like this in eight seconds does not need, and quite possibly cannot be explained in realistic terms by, vertical acceleration. An increase in nose down pitch will do it, any acceleration just lessening the amount somewhat.
You are confusing load factor with one minus vertical acceleration…..
@David: Did you notice the smiley?
Starting from a condition of unaccelerated flight, there are basically two ways to achieve a vertical acceleration of 0.68 g:
The first is to push the nose down to a low angle of attack, to reduce the lift force to 32% of its initial value. That would correspond to Jeff’s arithmetic. I submit that the airplane would only do that in response to a pilot input on the control wheel.
The other is to bank the airplane to an angle of 71 degrees at constant angle of attack, to reduce the vertical component of lift to 32% of its initial value. If you look at the Boeing simulations shown in the ATSB’s report, then perhaps two or three of the ten simulations may have achieved or exceeded that bank angle near the end of the trajectory. However, none of the simulations comes anywhere near 71 degrees of bank at the 7th arc (the point in figure 6, Nov.2, 2016 where all ten trajectories have been aligned to). Therefore, I submit that the airplane would only bank to a large bank angle near the 7th arc in response to a pilot roll command.
Of course combinations of those two ways are are also possible, but I maintain that it is highly unlikely that the airplane would be accelerating downwards at 0.68 g at the 7th arc without pilot inputs.
@Gysbreght. Pushing the nose down to reduce AoA, resulting in a transient centripetal acceleration upwards of 0.68g while leaving .032g, is not what I believe Holland or Jeff Wise have in mind.
As collateral it would get the nose down but it would be very coincidental if that pitch rate proved even roughly right. In any case, outcome would be the result mainly of the pitch down. Banking the aircraft steeply when unpowered will get the nose down too. Your 71deg, based on the vertical component of lift, overlooks the vertical component of drag and that bank’s almost unloaded main effect would be to get the speed vector pointing down as descent caused yaw.
What I believe Holland at least had in mind was not a rotation of the speed vector but an acceleration along that vector. Jeff Wise also says as much, “With no engines to hasten its descent, the plane must have been pointed nearly vertically down.”
What prompted my input was your response to Nederland, which did not get at what he was implying generally; that in a steep dive a wing could come off; which indeed it could, given enough ‘g’, or load factor. That might have resulted in large wing debris, those bits then fluttering down.
The Boeing simulations result from no pilot and any spiral surely is more likely without a pilot. In that case I maintain that differential flaperon lift under RAT will make a tight spiral and high g more likely. It also could well contribute to your initial roll to high bank, unpiloted.
Piloted, the envelope might have been exceeded also, again allowing Nederland’s general point.
@David: My response to Nederland was of course somewhat provocative and that’s why I put in the smiley. Yes, if the 0.68 g vertical acceleration is maintained beyond the 8 seconds, the speed and loadfactor could become so high that the wings could come off. We discussed that earlier.
In my response to you I wrote “basically two ways”. By “basically” I meant to say that I skipped a few details, such as pitch rate, roll rate and thrust-minus-drag. What I wrote is still “basically” correct.
Your comment on the Boeing simulations misses the point. The Boeing simulations should include the effect of differential flaperon, among other things. Yes, a tight spiral could eventually develop, as I mentioned, but did not occur as soon as the 7th arc in any of the simulations.
I have demonstrated that an uncontrolled descent is characterized by an approximately constant angle of attack. For any given angle of attack the turn radius is a function of airspeed and bank angle. ATSB’s Nov.2, 2016 Figure 6 shows only radius of turn for ten simulations conducted by Boeing. However, rougly speaking, it can be said that a small radius of turn indicates a high bank angle, and a large radius a low bank angle. At the time of the final BTO transmission which defines the 7th arc, all ten trajectories exhibit a large radius of turn, consistent with a low bank angle. At the very end of some of the simulations a small radius can be observed, indicative of a high bank angle.
@Gysbreght.”The Boeing simulations should include the effect of differential flaperon, among other things”.
Maybe they did though the ATSB made no mention of this after the initial simulations, where just RAT operation applied initially. Some of the turns of those more recent start to the right, though the flaperons under just RAT turn the a/c left. Others are at a high turn radius as you say, with little left bank.
Even with other electrical configurations I suppose that RAT-only initially still is part of their 7th arc theory.
@David: “Some of the turns of those more recent start to the right, though the flaperons under just RAT turn the a/c left.”
Unfortunately, the various scenarios ATSB specified for the Boeing simulations are veiled in secrecy.
you can also achieve a vertical acceleration with a stall…
@Marc: The airplane left to itself doesn’t stall.
@Nederland
“Many feel that it was part of the plan to embarrass specifically the Malaysian military/ATC. This is why I feel a diversion en route to, say, Europe would not have done the job.”
Exactly, possibly getting idea from embarrassment of swiss military just two weeks before.
Someone who has done something extraordinary like that would LOVE to see consequences, his serotonin levels would skyrocket and suicide/murder would be last on his mind.
@JeffWise
“I haven’t looked into the matter in detail, but I don’t think that anyone has proposed an FMT that would put the plane’s track outside of range of potential Indonesian radar detection. I don’t think we can say, therefore, that Zaharie (it seems to me that any SIO scenario is essentially a Zaharie scenario) was trying to avoid being seen by Indonesia; the most we can say is that he was trying to avoid overflying Indonesian land. The point presumably being not to avoid detection, but interception.”
That’s good reasoning. Now it would be nice if we could find what happened later that would be compatible with such flight path.
@StevanG
“Many feel that it was part of the plan to embarrass specifically the Malaysian military/ATC. This is why I feel a diversion en route to, say, Europe would not have done the job.”
My own take on it is that Z picked a flight whose diversion was obvious and would be known early in the flight. A flight to Europe or say Jeddah would not have served that purpose.
The date might also have had some significance in the flight selection.
A motive was talked about earlier of MH370 being used as political leverage.
The scenario was that it flew well out of radar range into the Andaman Sea with Shah knowing he was going to eventually land in Indonesia. This meant there was no need to avoid Indonesian radar as he came back towards Indonesia.
With Indonesia admitting they knew what happened to MH370 together with all the other evidence, inconsistences, omissions, errors and confusion that seem to tie in with the motive surely it is time to take this motive seriously.
DennisW “The date might also have had some significance in the flight selection”
The 8th of March is a significant historical date for the opposition party that Shah supported.
@TimR
“With Indonesia admitting they knew what happened to MH370”
What did Indonesia say? Nobody seems to admit knowing what happened to MH370 except that it changed course and went up the Malacca Sts.
@Nederland
Coming back on your comment about possible wings ripping off and an in flight breakup of the plane during a high speed dive.
China Airlines Flight 006 made the kind of vertical dive Jeff suggests in the topic. It descended 30.000ft in ~2.5 minutes nose down vertically to pull out on 3100Ft.
During the dive nothing broke off nor by flutter or other loads. The plane stayed together.
Only during the pull-out parts of the elevetor broke away due to excesive G forces exceeding 5G’s.
No other wing parts came off. And the plane landed safely.
https://en.wikipedia.org/wiki/China_Airlines_Flight_006
It seems highly unlikely to me a B777 would loose his wings and break up in flight under same kind of circumstances.
If MH370 really made this vertical nose dive and did not pull out in time it would have hit the water nearly intact like Flight 006 would have done.
Only it would have been smashed into millions of small unreqocnizable pieces.
A break up in flight would have caused larger pieces but also an enormous amount of debris over a wide area. There is no indication this happened. On the contrary.
The ~30 pieces found so far indicate a rather small debris field. Drifter based studies calculate around 30 pieces of debris from a debris field of around 170 pieces will land on African shores and Islands after ~2 years.
This is what we see till now.
I see on the new started blog of VictorI the focus is on the Inmarsat-data again too. Which offcourse is not a bad thing at all.
I only still miss the attention on the debris also in relation to this (BFO)data.
I think both must be brought to more congruenty with eachother and not contradicting as they do now IMO.
@Ge Rijn
It may or may not happen that one or two wings come off, or the whole airframe breaks apart. In the incident you quoted, the pilot was eventually able to regain control before coming anywhere close to sea level. Just another example is this one…
https://en.wikipedia.org/wiki/Lauda_Air_Flight_004
… where the Boeing disintegrated at 4,000 ft altitude and the largest piece found was 5 by 2 m (crash on ground).
I agree it’s different, but so is your example as the present assumption (by the ATSB) is that of a spiral dive, so I assume the forces are similar to the ones you describe when the aircraft was levelling out from the dive.
Imo the most obvious piece is the presumed vertical stabliser, which is pretty much damaged. That is unlikely to happen at controlled ditch/low speed impact.
If the plane breaks up at high altitude (in the case of an explosion), debris would be scattered over a large area, but the BFO suggests it could have broken up at low altitude, and this reduces the extent of the debris field.
Source: common sense.
@Nederland
Thanks for the link. Mach 0.99.. Who knows he also tried to pull out of that dive at about the same altitude but the plane broke apart unlike Flight 006.
Did something like this could have happened to MH370?
A debris field of 1km2 from around that altitude and big pieces of debris make a good point.
Although I think we are still left with the small amount of debris and kind of pieces (wing related) found to date. A mid air (fuselage) break up would have caused a tremendous amount of debris from all parts of the plane. Not ~90% wing surface related parts.
Still I think your ‘common sence’ creates an option I did not consider yet which could both explain the final BFO’s and the (kind and amount of) debris found.
This scenario though requires one crucial factor: an active pilot trying to pull the plane out of the dive. Which then succeeded probably better than Air Flight 004 but worse as China Airlines Flight 006.
@Ge Rijn
Just from a complete amateur perspective:
The plane was uncontrolled and entered into a spiral descent (with increasing forces from one sinus to the other).
At low altitude, and with incresing speed, the right wing comes off, flutters down. The pieces most vulnerable (the flaps) break up separately or on impact with water. The left wing may have stayed, but the outboard flap came off. The rest came down in one piece.
So, you have well preserved parts from the right wing, just one piece from the left wing (pending future finds) and tiny pieces from the interieur, including the heavily damaged vertical stabiliser (the one piece that would stay intact at any botched ditch). A couple of identifiable pieces from the cabin inside, but no identifiable pieces from the fuselage (although some of the tiny pieces found by B. Gibson et al. could be from the fuselage).
No pilot needed in that scenario.
@Nederland
Me the same. If I could make money out of this I would become some kind of professional (start a blog f.i.;)
It’s hard to image the right wing seperating and fluttering down and then trailing edges of the flaperon and outboard flap section breaking off before those pieces break off completely. Also those trailing edge wing panels, engine cowels and flap fairings breaking and the only pieces found to date.
Made that right wing a perfect level ditch in the water on its own with the engine still attached?
And till now only a trailing edge of the left outboard flap. Why only this trailing edge if the rest of the plane entered the water with great speed?
This makes no sence to me.
Indeed the vertical stabilizer part is disturbing in this view but it also is quite big.
I think a combination of factors is in play here.
@Ge Rijn
Obviously, the wings as a whole or vulnerable parts of them (like flaps) are most vulnerable to in-flight break up once the plane recovers from a phugoid motion at grater air density and winds close to sea level. Flap sections may also separate on impact, but are then much better preserved. The engine would drag down the wing and hit the water first.
If only parts of the right wing came off, that would explain why there more pieces from the left wing.
…why there are more pieces from the right wing.
GeRijn: “The 30 pieces found so far indicate a rather small debris field. Drifter based studies calculate around 30 pieces of debris from a debris field of around 170 pieces will land on African shores and Islands after ~2 years.”
I know you’ve consistently argued for a small debris field, but: what we don’t know is the recovery rate of beached debris. I’d guess that it’s reasonably high for larger pieces that look like some part of a plane. For small shards, if Blaine Gibson is for real, the recovery rate of beached debris has obviously been very small.
So, your math works for the most informative debris [still suggesting there is more than half at sea], but doesn’t tell us much about the size distribution of debris or energy/speed of impact.
@ TBill “What did Indonesia say?”
The Indonesian police chief at an aviation seminar said he knew what had actually happened with MH370.
http://www.news.com.au/…mh370-indonesian-police-chief
Sep 18, 2014 – Flight MH370: Indonesian police chief General Sutarman says he knows what … I actually know what had actually happened with MH370.”.
@TimR
Surely, he did not mean they saw it flying through their airspace (it’s not even within the remit of the police chief to say such things; he may or may not know more about the police investigation, though).
“The scenario was that it flew well out of radar range into the Andaman Sea with Shah knowing he was going to eventually land in Indonesia. This meant there was no need to avoid Indonesian radar as he came back towards Indonesia.”
Surely, he did not attempt or intend to land anywhere in North Sumatra, and if he did not, why would he fly straight through Indonesian radar in that region?
@DennisW
“My own take on it is that Z picked a flight whose diversion was obvious and would be known early in the flight. ”
hmm not sure, why’d he turn off the tranponder then, and choose the perfect moment between malaysian and vietnamese airspace to confuse ATC(s)?!
To me it looks like he wanted a surprise factor to play the role.
@TimR
“The scenario was that it flew well out of radar range into the Andaman Sea with Shah knowing he was going to eventually land in Indonesia.”
I doubt he would skirt indonesian airspace if he wanted to land there. At least not from the north.
@TimR
OK you got me there, but all we have is controversial remarks behind closed doors that the police chief may or may not have actually said.
@ StevanG “I doubt he would skirt indonesian airspace if he wanted to land there. At least not from the north”
To show the seriousness of their negotiations they had to give the Prime Ministers office time to see the radar track out into the Andaman Sea, then time for the negotiations. Going out into the Andaman Sea and coming back towards a landing at Banda Aceh gave some time. With no confirmation Shah then went round below Sumatra at a loiter to give more time.
@StevanG
“To me it looks like he wanted a surprise factor to play the role.”
Then a flight to Jeddah or Europe would have been perfect. He would have been all the way to the FMT before hanging a left into the SIO. My take is that he wanted it to be known that the fight was diverted, but not necessarily where it was being diverted to.
My hint: disappearance of MH370 was masterminded by Noshir Sheriarji Gowadia, chief designer of B-2 Spirit bomber’s stealth systems. He is currently in SuperMax prison, because USA convicted him in a pre-arranged trial of selling top secrets to the chinese military. The MH370 event punished USA (maker of B-777 airplane) and China (most of the pax onboard were chinese persons), so it could be his personal revenge. He is an acknowledged excentic genius, so I wouldn’t exclude a chance he found to run a conspiracy out of even the most locked down kind of prison in the world.
There is a new ebook by James Nixon, “The Crash of MH370”.
It gives some views on the theory of deliberate depressurisation, which the author rejects.
He thinks cabin altitude would rise by no more than approximately 500 ft/min (seems to be somewhat consitent with earlier observations on an FSX trial and comparison with other air accidents). This means it will take more than 15 mins for masks to drop down (still at a safe level) and much longer until the cabin altitude reaches a critical level.
He also says that passengers could have used different oxygen supplies and there were plenty available, each lasting 22 mins. The portable oxygen bottles in the cabin could have lasted for hours. He therefore thinks it is unlikely everyone in the cabin could be killed.
He does not, however, discuss issues such as altitude sickness, pressure breathing and 100% oxygen flow.
@Nederland
I have done depressurization studies with the FS9 PSS777 model (reported here a month or two ago). I see 2500 ft/min max. initial depressurization rate. It does start slowing down as the pressure falls. So I was seeing maybe 20-30 minutes to get pressure all the “down” to FL350.
Of course, I am not claiming PSS777 model to be accurate.
I will take a look at Nixon’s book, but he is obviously contradicting a lot of pilots who wrote prior MH370 books saying depressurization may have been realistic expectation.
@TBill
On an FSX simulation reported to me the figure was 2000 ft/min initially. Overall, at the very least 20 mins, probably much longer.
It is basically correct to say that the oxygen bottles could sustain one or several persons for hours. The actual questions seem to concern oxygen flow and pressure breathing and how big the advantage of the indivual(s) in the cockpit would be over those in the cabin. Seems to depend very much on individual fitness. There are reports that Z was not only a long time smoker but also suffered from asthma, probably a massive disadvantage in that scenario.
@Nederland
Pilot(s) O2 is special pressurized mask so that is good for high altitude. Cabin masks are low pressure and not effective at altitude. Immediate and rapid emergency descent to low altitude is the premise upon which the cabin O2 masks are designed.
I would think there is no doubt the PAX are at serious disadvantage at altitude. FI states a number (approx. 15) of 11-ft3 O2 bottles for flight attendants, so that is a lot of total O2, almost as much as the pilot’s full O2 cylinders, but only if it is bio-available.
@TBill,
An extract from a previous post below; consider that the portable O2 cylinders can be fitted with continuous flow mask or medical mask.
The passenger oxygen masks are continuous-flow units. As the name implies, a continuous flow mask always flows oxygen. Continuous flow oxygen masks are simple devices made to direct flow to the nose and mouth of the wearer; they fit snugly but are not air tight. They are designed to be sufficient for passengers in a decompression and subsequent decent scenario to survive.
Continuous flow masks contain a mask which connects to a plastic bag and then a tube that connects to the oxygen supply. Often the tube connecting to the oxygen supply will contain an inline flow indicator. Oxygen will flow through the tube and inline flow indicator, then to the bag and finally into the mask.
Between each inhalation by the mask user, oxygen continues gathering in the bag. The bag never fully inflates between inhalations. The mask has an inlet valve to pull in atmospheric air and an outlet valve. When the user takes a breath, air is pulled in through the inlet valve as well as from the oxygen bag. When the user exhales, air is pushed out through the exhalation check valve.
The altitude limit for continuous flow masks will be around 25,000 feet. Operation above 25,000 feet should be limited to very brief time intervals (2-3 minutes). Above 25,000 feet, continuous flow masks are unable to provide sufficient oxygen.
OZ