Here’s a link to the report broadcast today on Australian 60 Minutes about the search for MH370. Part 1:
Part 2:
Discussion after the jump…
The main thrust of the piece is that an independent air-crash expert, Larry Vance, has looked at photographs of the Réunion flaperon and decided that their relatively intact state, and the lack of debris from inside the aircraft, means that the plane must not have impacted the water at high speed, as would be expected if the plane ran out of fuel as a “ghost ship” and spiralled into the water. He interprets the jagged trailing edge of the flaperon as evidence that it was deployed at the moment of impact and was worn away when it struck the water.
I find it discomfiting when people say that the mystery of MH370 is not mystery at all–that they are absolutely confident they know the answer. Vance undercuts his credibility, I feel, by taking this stance. There is indeed a strong argument to be made that the plane must have been under conscious control to the very end; to me the most compelling is simply that the plane has not been found in the current seabed search zone. However it is less clear that someone attempted a ditching. What the show does not mention is that debris from inside the aircraft has indeed been found, suggesting that the fuselage could not have survived the impact and sunk to the bottom of the ocean intact. Indeed, the program doesn’t mention the other debris at all, with the exception of the Pemba flap, which is the other relatively intact large piece. The fact that most of the debris found so far is rather small is to me indicative of a higher-energy impact. But I have no strong opinion one way or the other; I feel that proper experts must look at the debris close up to determine what forces caused it to come apart.
The program cites the recently revealed flight-sim data from Zaharie’s computer as further evidence that the plane was deliberately piloted to fuel exhaustion and beyond. For the first time, the program showed on screen pages from the confidential Malaysian report. The producers of the show reached out to me as they were putting the program together, and asked me to comment on some of the data they had accumulated. Here are the pages of the document that they showed on-screen:
It’s worth noting that these pages offer a summary of the recovered flight-sim data which are described in greater detail and accuracy elsewhere in the confidential Malaysian documents. Here is a table showing a subset of what the documents contain:
Note that the numbering systems for the two data tables do not match. (Please do not ask me to explain this.) I suggest that for the purposes of discussion, the point saved at Kuala Lumpur International Airport be called point 1; the three points recorded as the flight-sim moved up the Malacca Strait to the Andaman Islands be called 2, 3, and 4; and the points over the southern Indian Ocean with fuel at zero be called points 5 and 6.
In order to understand the fuel load numbers in the second table, I made some calculations based on the fuel loads in a real 777-200ER. I don’t know how closely these match those in the flight simulator Zaharie was using. If anyone can shed light I’d be happy to hear it.
Worth noting, I think, is that the fuel difference between point 4 and point 5 is enough for more than 10 hours of flight under normal cruise conditions. The difference between these points is 3,400 nautical miles, for an average groundspeed of less than 340 knots. This is peculiar. Perhaps the flight-sim fuel burn rate is very inaccurate; perhaps the simulated route between the points was not a great circle, as shown in the second page of the report above, but indirect; perhaps Zaharie was fascinated by the idea of flying slowly; or perhaps points 5 & 6 come from a different simulated flight than 1 through 4. Readers’ thoughts welcome.
Also note that neither the locations nor the headings of points 1-4 lie exactly on a straight line from 1 to 4, which suggest perhaps that the route was hand-flown.
@DennisW
OK, thanks.
@Tom Lindsay @others
‘catastrophic death dive says analysis’ in the Australian news.
What analysis? Not any new fact mentioned.
Just a re-stating of what the officials have suggested from early on.
Why this kind of ‘nonsens-news’?
They ought to come with a report/article of the analysis of the Pemba-piece.
That would be news.
@Ge Rijn
The ATSB are obviously being “forced” to to tow the Malaysian official line. All this talk and speculation reported the media about a conscious pilot deliberately gliding the plane to a water landing, was obviously too much for the Malaysians. Last week we had a warning of what was to come, when the Malaysian Transport Minister insisted there was no evidence the plane was intentionally flown to it’s doom in the SIO, let alone (god forbid) that one of their senior pilots was to blame.
The ATSB have been taken to one side and told not to indulge in anymore nonsense. It’s a farcical situation. Is Australia a Western-oriented democracy, or is it a dictatorship, with no freedom of speech and no dissent tolerated?
They were apparently examining the inboard flap for evidence explaining how it got separated. How are they going handle this one now? A sad situation, indeed.
Good job the French held onto the flaperon. I cannot imagine them caving in to Malaysian pressure like the Aussies.
@ROB
Technically the ATSB is briefed on finding 9M-MRO in the priority search zone only, which has sort of been decided on by the Malaysians. They are not looking into the cause of the crash.
However as an Australian the performance of the ATSB had been a bit embarrassing, as have revelations on this blog that JORN may have been switched off on the night of 8th March 2014.
We are dealing with an honour based culture where we are not allowed to talk about mistakes and say embarrassing things. So the truth suffers.
One suspects the truth of 9M-MRO will be incredibly embarrassing for some. Possibly criminal?
What if the French, and I’m purely speculating here, come out with the statement that they have evidence that the flaperon was manually removed from the wing?
http://www.theaustralian.com.au/business/aviation/mh370-in-catastrophic-death-dive-says-analysis/news-story/be03222dadaaae33c476b7ffc8b531da
Not sure if this suggests anything not already covered, but lots of interest over on the twitter.
@Susie
It’s a pay-site. Is this the same news-link as @Tom Lindsay posted yesterday?
It looks like it..
Flight simulation anomalies (2)
A discussion of Coordinate axes and sign conventions used for aircraft is given in : https://en.wikipedia.org/wiki/Axes_conventions#Conventions_for_aircraft_local_reference_frames
The table above uses somewhat unconventional conventions:
XVelBodyAxis = airspeed along aircraft lateral (pitch) axis
YVelBodyAxis = airspeed along aircraft vertical (yaw) axis
ZVelBodyAxis = airspeed along aircraft longitudinal (roll) axis
The angle of attack is then AoA = ATAN(YVel/ZVel)
and the angle of sideslip is AoS = ATAN(XVel/ZVel)
Both angles are zero for all points in the table except point #2 (FL320), where AoS = 2.32° and AoA = 1.56°.
A sideslip angle of that magnitude is highly unusual in enroute climb or cruise flight. At zero angle of attack an aircraft cannot develop sufficient lift to support its weight.
Bottom line: The FSX software was not operating correctly and needed repair.
@ROB @Steve Barrett
In this sence it might turn out fortunate the French have the flaperon still in their custody.
It’s a quite similar piece as the outboard flap section and they are independent (I think) from the countries officially involved in the search.
I mean it would be hard to bring conflicting evidence by the Malasyans and the ATSB on those peices.
If the French conclude (which they allready have suggested as the head of the ATSB stated) the flaperon was deployed thus the flight was activly piloted and ditched then the Malaysians and the ATSB will have a hard time explaining a totally different conclusion.
The French might have very good reasons why they made no official announcements on the flaperon thussfar.
P.S. A sideslip angle requires a rudder input, but the rudder and rudder trim are neutral.
@Middleton
“To depressurise, simply turn pressurisation to manual and open the outflow valves a little more. The AC pack(s) will still provide heat but the aircraft will slowly lose its pressure – you can monitor the pressure on the FMC/CDU. There might be a bit more of a breeze in the cabin, but otherwise everything might seem normal until the masks fell. ”
I thought we had just established that this is similar to what happenend on Helios 522 and in other cases mentioned in the accident report on the Helios flight.
If reports by the Greek government are cited correctly (and they have not been refuted) then the bodies on Helios 522 did suffer from hypothermia. Other cases cited in comparison confirm this.
ROB:
That sounds strait down ridiculous.
Re: French investigations into the flaperon
I have earlier cited a soure saying that Francois Grangier, judicial expert, holds the opinion that the flaperon indicates a controlled flight until the end.
But other sources, citing the BEA, are somewhat conflicting and claim there is no certainty regarding the end-of-flight scenario:
“Le scénario de la catastrophe reste mystérieux”
“Plusieurs experts estiment qu’il sera peu probable de dessiner le scénario de la catastrophe uniquement à partir de cette pièce. Pour l’ancien directeur du BEA Jean-Paul Troadec, «il ne faut pas attendre des miracles de cette analyse».”
“The scenario of the catastrophe remains mysterious”
“Most experts estimate that there is a low probability to establish the scenario of the catastrophe based on this piece only. For the retired director of the BEA, Jean-Paul Troadec, ‘you can not expect miracles from this analysis.” etc.
http://www.lefigaro.fr/international/2015/09/03/01003-20150903ARTFIG00285-le-debris-d-avion-retrouve-a-la-reunion-appartient-avec-certitude-au-vol-mh370.php
The head of the ATSB only said there is a possibility the flaperon was deployed.
@ROB @Johan @Steve Barrett
I also don’t believe at all the ATSB is ‘forced’ in anyway by the Malaysians or anyone else.
I can imagine what @Steve Barrett says there is ‘honour’ involved in this and it will be hard for the ATSB/Australians to accept if they don’t succeed now.
It would be hard for anyone after such a tremendous effort.
I still trust the ATSB and the Australian Government in the end will come forward with all their objective findings without covering up for anyone.
Guess you guys got it all wrong. This has nothing to do with alphabet soups like SDU, ACAR, or IFE., ABC or whatever And it sure ain’t got anything to do with flaps, , says, cells, logs, pings or rings .
This was a simple straight case of trespass and shoot down. Now now ….don’t get into a frenzy @jeff just yet for i aint gonna invoke SCS , missile or stuff like that
Indonesia dint spot it cos it is blind at night and Australia for sure didn’t as JORN was asleep so what happened. There was sure no glide or anything of tthat sort…. So blimey! For Pete’s sake what happened???
You see no radar detection don’t mean no flight for it just flew by on a day when they were asleep. But it got picked up,all the same, by another radar, the one at Mcmurdo manned by the Penguins of Madagascar.
They sent up two Tojos ( which they had scavenged from the retreating Japanese army post WW2) to shoo him off but he didn’t budge and didn’t even understand when they did a striptease :
“This penguin jumped out of the water and came up to me and did a little dance,” he said. “Eventually he realized I was pretty dumb and went and did the dance in front of some other penguins. I figured he was asking permission to come into the (penguin) circle.”
http://www.stripes.com/news/penguins-man-the-flightless-lines-at-mcmurdo-1.167786
So what are they supposed to do after all they had followed all guidelines including ICAO’s and yet this pesky intruder still kept coming for he wanted so badly to land atop Mt Erebus….man ….no way the Emperor Penguin gonna allow that for that’s sacred territory….so they dispatched him with Ohka or Yokosuka, I dunno which and the rest, as them Penguins say, is history .
Moral : never take them penguins for granted flightless though the may be….
Now I will be off to ladle me some alpha soup and mull a script for the above while I fly my sim …..just kidding.
@ Ge Rijn,
I didn’t realise it was a pay site, it wasn’t for me.
Sorry about that.
Yes, it looks like the same story as Tom posted yesterday – obviously my glance through the last couple of pages was a bit too quick.
As you were..
@DennisW:
And even more, it apparently has to be a demand that MAS/Malaysia could not agree to. That needed to be possible to execute within an hour or so while the plane was in the air. And that MAS could not go public with afterwards. (Or people on the plane finally tried to overcome the hijackers?)
I must admit it beats me. Any thoughts?
(btw, the coin finally dropped down on “singular integrity” — my deviate nightly associations with opposites strayed to “multiple integrity”, and couldn’t get any further. Funny isn’t it? We’d love to learn more about that, naturally)
@Johan, @DennisW, There is no evidence that negotiations took place in the hours after MH370 disappeared, and a great mass of evidence that it did not, including Hugh Dunleavy’s explicit statement to that effect and the fact that is not included in the confidential Malaysian police report that does mention the suppressed flight simulator data. Henceforth let’s file this notion under the heading of “things that were considered and rejected.”
Only 60 comments to go to 777 comments
Hm. The Petronas Twin Towers ought to have been a bit of concern when the plane headed back to KL, one would think. But by all appearances not so. I have not thought about that before. I am just thinking out loud here.
@Jeff:
Thanks. Will do. I have no trouble with that at all. I was just letting my mind chew on the piece of meat that DennisW in good faith threw at us.
@Gysbreght:
Every mathematician harbours a numbers mysticist? 🙂
@Johan
Petronas Towers.
But the plane didn’t head back to Kuala Lumpur. In the days immediately following the disappearance, I tried to go through all the possible on-board failure (mechanical or electrical) scenarios that might have made the crew fly the course they did. For example; imagine they lost all communications. Would they turn round and head back to Kuala Lumpur? Possibly they would decide against it, as the authorities might think you had been hijacked 9/11 style and were making for the Twin Towers, and would risk being shot down. So they would choose an alternative airport eg. Penang.
With hindsight, and seeing how slow the Malaysians were to react on the night, a shoot-down was probably never a serious possibility.
@Jeff
There is no basis for rejecting a political motive for the hijacking, so I will not do that.
I will, however, not discuss it any further on your site.
@ROB:
Forgive me, you are completely right. I was carried away a bit and allowed myself to think that southwestward was close enough for an approach towards KL. But it is still quite a distance.
And I vaguely remember the line of thinking, with the addition that a straight line towards the two pilot’s homebase at Langkawi would be a silent way for the pilots to state that they were harmless and had no ill intentions.
@ROB:
But Langkawi was not right either!, at least not in terms of a straight line from IGARI; the Thai border is in their way… But you could guess in that direction, and someone did, I recall.
@DennisW:
You are hereby in the wacky camp… 🙂
That is news. Did Boeing testing really indicate that? Which caveats are omitted?
That is with both engines flamed out. In a normal landing it would descend at about 700 feet a minute.
@Johan
Petronas Towers
Once at FL350 cockpit door may have been opened for pee or Tea.
Hi-jackets may entered the cockpit and told to pilot or Co-pilot whoever was still in cockpit to turn off ACARS (because of what they learnt from an aircraft investigation documentary about the 911 towards Pentagon about ACARS location and out of airspace transponder) and pilot or co-pilot told once out of Malaysia airspace to turn of transponder and turn back to KL.
Possibly the pilot or co-pilot entered UPROB (possibly left turn) instead of UPRON possible right turn. To bide time and ensure plane wouldn’t go to KL.
Pilot or co-pilot may have been told to say everything was ok (goodnight Malaysia 370) before leaving Malaysia airspace. Once out of Malaysian airspace the plane possibly turned left heading towards UPROB unknown to HI-jackers.
Pilot or co-pilot knew that this would go over military installations. Once hi-jackers realised they panicked and pilot warned we are over military installations. And asked pilot to try and avoid, so pilot adjusted heights on autopilot to bide time. Or create this as a distraction so that perhaps military would know Something’s wrong.
@ROB
I don’t think Malaysia is a likely candidate for a shoot-down, either by accident of design. Who could benefit either politically or economically from a Malaysian plane being shot down, which happened to be carrying carrying a large number of Chinese passengers?
Certainly not Malaysia, who on 28 August 2012, at their 2nd Malaysia and China Strategic Consultation in Beijing agreed to make 2014 “Malaysia-China Friendship Year”. Bilateral trade between these friends reached $106 billion in 2013, making Malaysia China’s third-largest trade partner in Asia.
Which country would benefit most if Malaysia fell out of favour with it’s best friend?
I think that statement by Boeing in the ATSB release more or less clinches it for the high impact theory given the following :
1. Boeing would have had access to data including that from the French that we don’t and modelled it accordingly to arrive at that conclusion and I don’t think they would come out with something that would embarrass them later given they have been carefully about this all along:
http://www.businessinsider.my/boeing-is-not-making-any-definitive-statements-about-mh370-debris-2015-7/?r=US&IR=T#Tl1r0d8xtj7kURlw.97
2. I have come around to the belief that no matter how inept and unashamedly sly the Malaysians might be they don’t have anything else stashed away from view. I know this might be contradictory to the transparency everyone ( including me) is seeking but I have come to the view that it is absurd that China who creates so much noise when it involves its interest or citizens is rather subdued on this one. This implies that there is nothing there to wring out despite the enormous leverage they have on the Malaysians in terms of trade investment and tourism
As for the Australians I don’t seriously entertain the notion that they would want to be involved in a coverup when it involves innocent lives. It would be inimical to their ethics and I doubt they would be interested to help out on that score particularly when they have nothing but infamy and opprobrium to gain in return.
So after eliminating those two possibilities, we have to accept the data, exasperatingly flawed, confusing and esoteric as it may be for what it is. With ISAT and the radar data accepted, one need only search for a plausible reason for a contactless bizarre flight with the contactless element explaining the bizarre nature. And this probably explains contactless adequately:
http://www.smh.com.au/world/us-warnings-on-boeing-safety-applied-to-missing-malaysia-airlines-plane-20140312-hvi0y.html
The alternative could plausibly be a lithium fuelled electronic fire knocking out comms initially before terminating other systems in a cascading manner that eventually caught with everyone on board with the flight crew being the last at FMT point. I understand both the foregoing has been examined before but they offer the best fit IMO.
Probably that what happened, minute fuselage perforation or electronic fire leading to a chain of events that culminated with ghost flight commencing on FMT onwards and ending where it was suspected to have ended and in the manner it did.
I stress to say that is all solely my opinion but it’s in my opinion at least the best fit for the available limited data in the public sphere and I suspect in official circles as well. To paraphrase @dennisW’s wise Stanford prof : don’t go there if there are too many constraints imposed
It’s mystifying alright what more troubling for the flying public out there but one has to rationalise that inexplicable shit happens and move on from there.
@DennisW
“The ATSB could not find a 777 if it were parked outside their offices.”
nor the CNN…
https://www.youtube.com/watch?v=fJOHRYhl67M
@Wasir Rozlan
Very nice resume of the situation, as you see it. However, that’s not how I would interpret the evidence. I’m not buying the inexplicable shit theory for one moment. I don’t think anyone would relish getting on a plane, with inexplicable shit waiting just off stage, ready to jump out and ruin their day.
One doesn’t need to invoke inexplicable shit to account for this.
To me, the only thing thst’s inexplicable is the behaviour of the ATSB. Imagine being the laughing stock of your professional peers around the globe. Imagine having to explain away the physical evidence of a hydrodynamically wrecked flaperon trailing edge, a similarly damaged outboard flap as the consequence of a steep, 15,000 to 25,000fps descent and impact.
If Boeing have actually signed up to this, then there must have been a serious amount of arm twisting behind the scenes. I don’t believe a word of it.
Will be interesting to see what the ICAO make of it, but I wouldnt be surprised if they had already been knobbled, into the bargain.
The real decider was the cold, deep and remote SIO. Who would want to waste any more time and money in searching it? Especially with no agreement likely on where to look next. Z will ultimately be judged the winner, the passenger and crew of MH370 and their NOK, the loosers.
If true, unconscionable lack of respect for the families.
http://mobile.abc.net.au/news/2016-08-09/mh370:-claims-malaysian-authorities-ignoring-possible-evidence/7711736
@SteveBarrett
“What if the French, and I’m purely speculating here, come out with the statement that they have evidence that the flaperon was manually removed from the wing?”
My speculation aswell. Something ain’t right here.
@Rob
I honestly see the validity of your arguments but the problem is it’s only on those pieces of debris and even then subject to much contestation too. I cannot rationalise flutter to be honest when compared to hydrodynamic damage. The only absurd compromise I can think of is flaps being extended for a landing or glide-ditch prior to fuel exhaustion and the pilot changing his mind and deciding to let the joystick and all go.
If I sound exasperated it’s because evidence regarding a ditching is not being released. Now I have come around to its not being released because they have other unreleased stuff that precludes it or they modelled it with data unavailable to us and decided high impact was it or lastly they don’t have any at all.
I know Norfolk Air and all but in my mind I don’t think ATSB are callous enough to fix things. I dunno but I don’t see that in the eyes of people like Doolan Foley or even Houston of JACC …I dunno maybe I am being naive but if the ATSB had fixed it why would China want to play along and why must the ATSB and China bend over for puny Malaysia…..unless this was not about Z or any individual but something to do with a nation state thingy.
Honestly the tell tale signs you read about the flaps is highly convincing but is probably not enough to shade things the way it plausibly could be cos of drift data, the smaller parts and log on stuff. So I guess there is only the official version to go by
And I don’t want to use inexplicable shit but I did cos I remembered @ Ge Rijn or someone mentioning every flight is fraught with risks…. I mean open aviation sites like this one below and understands the risks those who frequently fly take everyday :
http://avherald.com
Probably this incident brought it to the fore more than others but if shit’s bound to happen, it will …… sad but true.
By the way I was inclined to believe the flight sim thingy and all for it was cogently verified by FBI , not because of them per se, but their rendition of it.
But problem is I just read a couple of days that 3 other guys on that flight had flight sims in their possession including a flight steward. That was an early days piece by a reputable news agency. I forgot to bookmark and lost the link. Promise to put it up if I do access it again.
Just a passing thought. Now why would anyone aim for Antarctica unless it symbolic end of the world location. Suicide = end of the world = Antarctica = Mcmurdo
And another thing that just crossed my mind. Why would Boeing go out of their way to support that statement if it was crap. They could have easily laid off and let the Australians take the flak and all. And Boeing had more than passing interest in store in the suicide ditch theory for that would absolve equipment failure, a defo’ plus for them.
That they did come out with that statement implies two things:
a. Data points to equipment failure like the fuselage perforation and satcom antennae thingy I linked above or lith-ion battery combustion like this one:
The Economist explains
Why lithium batteries keep catching fire
http://www.economist.com/blogs/economist-explains/2014/01/economist-explains-19
Or the more cynical me says Boeing hopped on to play along because they can call in their dues anytime they want:
http://www.wsj.com/articles/malaysia-airlines-to-buy-50-boeing-jets-for-regional-refocus-1469612196
But then again, the second would be purely conspiracy mongering again, wouldn’t it?
@Susie
Yes I guess I’ve got some eye on detail in a way too. Maybe I’m somewhere on the spectrum too?
Who knows. I don’t know offcourse.. 😉
@Wazir Roslan
I think maybe it’s good to realize this is only media-news for whatever reason. And you know those reasons are often mostly commercial.
Making waves without substantial evidence or back-up.
I rather see an official report from Boeing or the ATSB themselfs.
Nothing has been officialy reported on the flaperon or the Pemba-piece yet. Nor on possible other end flight scenario.
Therefore I consider all this ‘making waves news’ inadequate for a big part of it.
It’s about gaining attention and advertisers mostly IMO.
@Johan
You said:
“You are hereby in the wacky camp… ”
Yes, I have experienced rejection throughout my life, and MH370 forensics are certainly no exception from virtually the get-go. I can take solace in the fact that I don’t have a pin in the map at 38S with my name on it.
Back on point. The notion of a lithium ion battery fire or any other cargo issue or mechanical issue is completely scuttled by the turn South on Shah’s simulator. A terminus South of 30S is not supported by a realistic interpretation of the debris finds. Draw your own conclusions.
@Gysbreght said, “Bottom line: The FSX software was not operating correctly and needed repair.”
Another possibility is that your interpretation of the variables is not correct, and the variable definition is not conventional. I observe the following:
1) The magnitude of the VelBodyAxis components is equal to the magnitude of the VelWorld components. This suggests the coordinate systems are not moving relative to each other, and are fixed relative to ground.
2) Recognizing that XVelWorld = Vew and ZVelWorld = Vne allows one to compute the track and compare that to the listed heading.
3) The track and heading are identical for all points except point 2, suggesting there is crosswind at this point.
4) Recognizing that ZVelBodyAxis is velocity (relative to ground) parallel to the body, then XVelBodyAxis represents the wind pushing the plane to the side and YVelBodyAxis represents the wind pushing the plane up relative to its flight path. (I have avoided the terms crosswind and updraft because with a non-zero FPA, they are not aligned.)
Using this convention, if there is no crosswind or updraft, then XVelBodyAxis = YVelBodyAxis = 0, independent of the FPA. The AoA is P – FPA, where P is the listed pitch, and the FPA can be calculated from the XVelWorld components.
@Gysbreght: The last sentence should read, “The AoA is P – FPA, where P is the listed pitch, and the FPA can be calculated from the VelWorld components.”
@VictorI:
Thank you for devoting such serious attention to my post. You wrote:
Yes, of course, you are quite correct, that is entirely possible.
VelWorld is the speed of the airplane relative to ground. In still air it is equal to the airspeed, the speed of the airplane relative to the airmass, which I have assumend to be represented by VelBodyAxis. In your convention you equate VelBodyAxis to VelWorld when the airmass moves relative to ground. in other words, VelBodyAxis and VelWorld both represent the airplane speed relative to ground.
The difference between heading and track could then be either crab or sideslip, and the difference between Pitch and FPA either AoA or updraft.
So if I understand you correctly, in points 1, 3, 4 and 5 there was zero crosswind and an updraft that produced the required AoA, and in point 2 there was a crosswind but no updraft?
No, that is not what I am saying. The Z axis of the BodyAxis coordinates is aligned with the flight path. The Y axis is perpendicular “up” and the X axis is perpendicular “to the side”. The YVelBodyAxis is due to upward air movement and the XVelBodyAxis is due to transverse air movement. I don’t think you can determine AoA by inspecting VelBodyAxis components alone. It’s not a conventional coordinate system, but it does seem to be self-consistent. I don’t agree with your assessment of a zero AoA and a “broken” simulator when there are other explanations that seem to properly explain the physics.
There was an interesting interview on NZ National Radio this morning, with Greg Hood and Peter Foley of the ATSB.
This clarifies a number of the issues and propaganda that have been prevalent in the media in recent days.
Here is the link . . .
http://goo.gl/zKelB0
@VictorI:
This is getting very confusing. The coordinate system you are suggesting is not only unconventional, is it even orthogonal?
The flight path is not a body axis. Is that the flight path relative to ground or relative to air? Is your YVelBodyAxis perpendicular to the flightpath (in the vertical plane?), positive upwards? Is your XVelBodyAxis perpendicular to the YVel and ZVel BodyAxes, i.e. horizontal?
“I don’t think you can determine AoA by inspecting VelBodyAxis components alone.” I first determined AoA as Pitch – FPA from the VelWorld components, before even giving a thought to the VelBodyAxis system. Brock’s comment prompted me to make sense of the VelBodyAxis values, and those produced the same value of AoA for point#2.
I understand from an earlier post that you have (access to) FSX. Why don’t you run a few “recovery” points? Otherwise any user of that software should be able to find out which ‘convention’ the software uses.
Referring to the Radio NZ interview . .
Foley tried to clarify the issue about operation of the flaperon, but didn’t quite get the message through.
He pointed out that the RAT provides sufficient power for the flaperon hydraulics [via the central system] but I’m not sure whether the central system provides hydraulics for both, or just one flaperon.
He did make it clear that flap operation requires power [and hydraulics] and someone to operate them, and was about to clarify that the flaperon is not something that can be “deployed”. It is this final point that is still widely mis-understood in the blogosphere and elsewhere. People seem not to understand that the flaperon, at all times, is operating as a roll control device, and at all times is positioned more-or-less neutral to the airflow over the wings. That means that if the flaps are deployed the flaperons droop to take up their “neutral” position, and can move upwards and downwards from that position. But, they are not “deployed”.
@VictorI: In operations FPA (e.g. as displayed on the PFD) is relative to ground. In performance work FPA is customarily defined relative to air, i.e. vertical speed = TAS*SIN(FPA). The expression Pitch = FPA + AoA is only valid in still air, or when FPA is defined relative to air.
@Gysbreght: Yes, I understand how FPA and pitch are defined. And yes, I believe the BodyAxis coordinate system satisfies the rules of orthogonality. That is why the components vectorially add to the same magnitude in the BodyAxis and World coordinate systems. That also is why I put the directions “up” and “to the side” in quotes. The reference is the flight path, not gravity.
We are left with two choices. Either the simulator is “broken” as you claimed and the aircraft wings produce lift with zero AoA. Or, the BodyAxis coordinate system is defined differently than you assumed, and we can backwards engineer that definition. I choose the latter. I am glad that you acknowledge that it is possible that FSX chooses an unconventional way to define the BodyAxis variables.
And yes, I have looked at .FLT files from FSX. Unfortunately, I don’t have the PMDG model for B777-200LR installed, and I can’t be sure the variables are defined the same way as in the “stock” version. I do see some other differences. I’ll look into this more.
I do appreciate your willingness to give this a close look. I will admit that even before your post I have been bothered by the BodyAxis coordinate system.
@Brian Anderson. Incisive interview. Clearly the ATSB is on a media blitz to persuade all that it is searching in the most likely area. The point of the article in the Australian yesterday is that they have reviewed their assumptions and data and confirmed the search area as best they are able. Personally I have no doubts as to the sincerity, integrity, high competence and innovation in their approach. I will post a dropbox copy of the Australian article, which while appearing bland does present the results of their review, and it has nuances.
Just the right flaperon is hydraulically powered by the RAT, as an aileron, via one of its two actuating PCUs, together with a mix of some spoilers and the left aileron. (Normally under aircraft hydraulic power it will ‘droop’ with the flaps to about the same angle as them and it will deflect from that as an aileron. The flaps can be deployed either hydraulically or electrically but not by the RAT).
So I think what Foley is getting at re the purported flaperon deployment could result from its use as an aileron. With the right wing down, as seems likely, it might have been down, as an aileron. It will indeed be interesting to learn of the outcome of their research into the part flap position in a “couple of weeks”.
‘Australian’ article August 9th below.
I attach some comments on it about simulator experience, one by Byron Bailey.
The first mentions in passing that the APU did not autostart, for lack of fuel. This might indicate that either the simulator was unaware that there could be residual fuel, or alternatively that there was none left or that it was inaccessible.
I note that Peter Foley referred to extensive simulation post-fuel-exhaustion by Boeing, including in 2015/16. The accuracy of simulation was qualified in 2015 by the ATSB.
“-the aircraft may have exceeded its design envelope when it was descending and experiencing
phugoid oscillations and
• the aerodynamic model used by the simulator may not be accurate when the speed was outside the flight-tested envelope.”
Leaving that aside, Foley said the ATSB “assumed” that the 7th arc logon was the result of the aircraft running run out of fuel and that, “in all likelihood” the APU restart led to the log on there.
All in all then there is still scope for doubt about the 7th log on cause, though that does not help with where to search next if that current does not succeed.
Quite incidentally I notice he said it was the Malaysian police who would be looking into what might be MH370 personal effects recovered, not their investigators.
https://www.dropbox.com/s/w3uzjtu4xh51nyh/The%20Australian%209th%20August%20article%20with%20two%20comments%20made%20on%20it.docx?dl=0