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.
@Ge Rijn: If you increase the downhill slope the truck will accelerate, but the orientation of the pendulum relative to the truck will not change provided the drag is constant. The orientation of the pendulum relative to the truck changes if you change thrust or drag, e.g. if you step on the brakes or start the engine and step on the accelerator.
@Gysbreght
This started with the question if an in descent (by gravity) accelerating aircraft, fuel in the tank would move forwards, backwards or stay where it is.
In the Zero G movie you see everyone and everything staying or floating without moving backwards or forwards (if not by choice) not in the climb, in Zero gravity, or in the accelerating/’falling’ descent.
This suggests to me the fuel would also not move forward or backwards in the tanks in such a situation.
@Ge Rijn: in the Zero G movie the thrust and drag are carefully controlled to avoid people moving forward or backwards until they are firmly back on the cabin floor. The pitch is controlled to provide Zero G.
@Ge Rijn
Good question…
Answer is that the wing ribs act as baffles to prevent fuel slosh and two of the baffles in the #1 and #2 fuel tanks have check valves to prevent fuel flow away from the boost pumps.
A description of the fuel tank design can be found here: http://digilander.libero.it/andreatheone/fueltks.htm
@Gysbreght
So if thrust and drag are carefully controlled in a steep accelerating descent I can conclude fuel in the tanks will not move forward or backwards?
(I appreciate your patience by the way, this will be my last question on the subject)
@George Tilton
Thank you. I think it could be important for what @David brought up about how long the APU could have worked under such circumstances (steep accelerating descent) on residual fuel in the tank(s).
But as a matter of fact the subject of a possible log-on at 0:19 due to right engine flame out and left engine AC isolation (yes I listen David) triggering an auto start of the APU I consider a lot more interesting.
Hope discussion on this subject will continue!
@Ge Rijn: Yes, that is correct.
@Ge Rijn, on further reflection, the thrust may not need much controlling provided it is set correctly at the start of the zero-g maneuver. Zero-g is essentially zero-lift, so the drag is essentially the zero-lift drag which is proportional to airspeed-squared. For constant thrust setting, airspeed and thrust both reduce during the climb and increase on the way down, so perhaps it is not particularly difficult to maintain thrust equal to drag in that maneuver. But obviously the maneuver needs to be planned carefully in advance and requires precise execution.
@David
Re questions iro cabin emergency oxygen: I agree, the passengers do appear to be short changed, with only 15 minutes approx. worth of oxygen available in the event of depressurization.
As I understand it, in the event of a sudden depressurization at altitude, the standard procedure is for the flight crew to initiate an emergency decent to 10,000ft. normally taking less than 15 minutes.
As you point out, one purpose of the portable oxygen cylinders is medicinal, meaning they could be used on a routine basis. So a large capacity makes sense, if these units are routinely checked/replenished after a certain number of flights, rather than before each flight.
Factual Information gave the flight crew oxygen availability as at least 18 hours, if my memory serves me rightly. I read somewhere that if a civil airliner is flying at 43,000ft, standard procedure is for one of the flight crew to be on oxygen, as a precautionary measure in case of unexpected depressurization. Not because the cabin altitude at 43,000ft is less that at 39,000ft, because it isn’t. I think it’s required because the time of useful consciousness at 43,000ft altitude is so short.
If I’m wrong on this, doubtless someone will correct.
@Gysbreght
Thanks. I think I’ve got my anwser on that one now.
There is only one subject in this regard I still question.
Someone (David?) brought up vapor-lock could occure during a steep/fast descent.
IMO vapor-lock will not occure with increasing air-pressure but only with fast decreasing air-pressure (in a fast steep climb maybe).
What is your opinion on this?
@Ge Rijn: I have no opinion on vapor-lock.
@falken
Zero G must be awesome but after a while I think also this becomes boring and you start longing to feel the earth pulling at your feet again.
We where not born to be space-creatures.. 😉
@falken
..and not to fly ourselfes either. That’s a risk we all take everytime we step into an airplane in denial of everything that could go wrong and went wrong in the past.
It’s a risk millions of people take every day. Consiously or unconsiously.
But without taking risks you wont have the opportunity to live anymore as you intend to.
@Rob, David
Time of useful consciousness at 40000 feet is about 18 seconds and at 45000 feet is about 10 seconds…
Also SOP during cruise if one crew member needs a bathroom break the other dons a mask until he gets back.
A slight relapse from me:
Is there anyone here knowledgeable in the flight control system, the aircraft computer?
Would it be possible for the Captain, Shah, to hook up his (never-retrieved) laptop to the flight controls?
That would take an auxiliary port or something similar.
I would expect that to be blocked by the manufacturer, and giving away notices, but one the other hand, in testing and training it would be conceivable to have that opportunity.
I have never seen it mentioned at all in any discussions.
My train of thought is that Shah could have prepared some application at home, and had the flight system retrieve that from his laptop. It would not necessarily have been sinister, but something that e.g. would make underway navigational inputs (of waypoints) unnecessary — to make life easier and show off. But for some reason it “backfired” or messed up everything.
I don’t find it very likely, but as a kind of bridge between his fsim interests and personality traits. He might have had chatfriends or belonged to a gang of likeminded through the internet who might have supplied him with something one otherwise would not expect him to have the capacity, if you will.
But is that at all possible? I hope not.
Capacity for…
and a little more.
Perhaps somebody has already pointed this out, but from the original table something jumps out at me.
All of the values for point 6 are very close to round numbers.
To me, while the four decimal precision on the other points suggest they are simply random save points, point 6 looks like an END point.
These values look like the gas pump, when you ask for $20 and it shuts off at 19.99.
So, while I previously felt that the precision ruled out the possibility that these points were hand-entered, I take it back with respect to point 6. Point 6 looks like something entered as 45 07′ 39.6″, 104 08″ 27″, 4000 feet, which was reached within a few hairs.
I’d also point out that the likelihood of three numbers being so close to round by random chance must be fairly low, but I’ll let Brock tell us how low if he doesn’t mind.
@George Tilton
“Time of useful consciousness at 40000 feet is about 18 seconds and at 45000 feet is about 10 seconds…
Also SOP during cruise if one crew member needs a bathroom break the other dons a mask until he gets back.”
Small, but important adition: Those are the numbers for a gradual increase of cabin altitude like encountering a leak.
During a rapid decompression the times are considderably smaller.
http://www.abag.org.br/noticias/images/Times_of_useful_consciousness.jpg
In reality it wont matter for the average passenger wether TUC it is 5 or 30 seconds, as he would not recognize his individual symptoms of hypoxia.
@Ge Rijn
ya, while I dont like any adrenaline adventures, todays regular flying is still far more safer than driving a car or walking over roads; sad but true; I really predict that driverless cars can be quickly safer – but then its more about psychology (again, what isnt), thats the hard part…
Back to ditching procedures.
There seems to be a view that a ditch is done in or against the direction of the swell. That is not the case – a ditch should be done 90 degrees to the swell so essentially flying along the crest or the trough of the waves.
Going with/into the swell risks the plane nosing into the backside of the next wave and that highly stresses the top of the fuselage. The French did some tests on this (was on the internet but I cannot now find it) they found that typically the fuselage would be breached and as that is where the overhead bins are not a good thing to do if the pilot is determined not to leave a debris trail.
Flying across the swell usually crushed the aft lower fuselage and worse case the cargo hold is breached. But in there is little that floats, heavy suitcases, packing cases so the breach just allows the cargo to get on its way to the ocean floor.
If you look at Pilot Charts (“Pilot” as in navigating the ocean not flying a plane) for the SIO for March you finds that an area around 30S 95E is a sweet spot for ocean swells. The prevailing wind is from the SE with less wind direction variation than typical in other areas and the swell is less than many other places. Typically 4 to 5 ft. swells, 200 to 400 ft. between crests’ and 10 kts speed of advance.
So to ditch the pilot would head SW or NE. You can see swell direction from 30,00ft on a clear day – not to measure crest height but who cares – nothing you can do to change that. You do not look at the crests but at the distance between crests.
So assume the pilot is flying south as the sun rises and the swells can be seen and a choice made of SW or NE (assume typical applies) Which turn? Assume the pilot has spent many, many hours in command from the left seat. Turning left is then natural even though it is a greater heading change. The other point in favour of left turn is that it takes a path back close to where the plane has flown just minutes before so any shipping could have seen from the same left seat.
So the plane reaches its furthest point south and then heads back to the NE. When is the turn made – when ditching all attention is needs to control plane attitude (roll pitch) so you would the major heading change done well before that preoccupation … so 10,000 ft, 15,000 ft perhaps.
ATSB has mentioned a spiral in the last few minutes .. spiral or was it just a heading change. Was it left hand. What does a course change to the NE with slowing descent reflect in the ISAT data?
Going NE flies MH370 toward the drift analysis origin.
Thoughts?
Mike Gibbon
@Aaron,
“@all I’ve just been informed that the supposed flight path found on Zaharie simulator was fabricated or a hoax.
My source told me that Zaharie actually used X plane ten sim. And X planes software does not permit asymmetric combinations of latitude and longitude 10- 11 digit co-ordinates are invalid entries in x plane.
Can anyone here shred some more light on this?”
I notice your “hoax” story is getting some legs on other forums. It was intriguing at first and was looking forward to see what pops up and how it develops. Then I saw someone’s circles around the offending datapoints in a retweet, and now to me it looks like the hoax is the hoax story itself.
All the data points have 4 decimal precision for the seconds. So there is no asymmetry there. The minutes and seconds together all have 8 digits for all lat long data points. Now add the degree portion and you end up with either 9, 10 or 11 digits, depending on whether you are close to the equator (or Greenwich meridian), eg. 2N for KLIA, or far away from it (them), eg. 101E vs. 98E.
In fact to cover all Lat you need 10 digits (max +/- 90 at poles) and to cover all Lon you need 11 digits (max +/- 180 on opposite of Greenwich meridian). I’d say, any software providing Lat/Lon in the deg-min-sec format with 4 decimal places precision on the seconds would have coded such a 10 vs 11 digit “asymmetry” in.
@Mike Gibbon
“thoughts”
Found an interesting exchange on NPR (National Public Radio here in the US) after the Sullenberger ditching about the lack of simulator training by airlines for “water landings”…
BLOCK: You mentioned you don’t get trained on flight simulators for something like this.
BERMAN: Yes, it’s true. And the main reason is, the flight simulators are programmed based on the data that the manufacturers and the operators have about how the airplane really performs and behaves. So, the simulator is made to behave and perform just like the real airplane. Well, they don’t test ditching airplanes, so there’s really no experience for most aircraft types on exactly what the airplane will do when it touches the water, and therefore, it’s impossible to program a flight simulator for it. I think if we had data to program the simulators for, we might do well to practice ditching and practice multiple engine failures more often.
There is much to be said about this possibility, but what comes instantly to mind is…pathetic
@Jeff
Time for another article/reset. This thread has run out of gas about 300 posts or so ago.
@MuOne
I don’t know why anybody would enter 4 decimal places in the seconds for a way-point…
Nobody is going to enter a way-point with precision to 1 mm.
Converting to decimal degrees we have:
45 + (7/60) + 39.6/3600 = 45.12766667
6 decimal places will get you to 10 cm at the equator…the limit for surveying…
5 decimal places to 1 meter.
4 decimal places in the degree is good enough to locate the position of a plane that is ~100 meters long to within 10 meters.
@David said:
‘@Middleton. You were curious about shutting down of the cabin oxygen system.
Oxygen generation is activated by pulling on masks but the mask overhead release relies on 115VAC from the standby bus, that solenoid selected by 28VDC from the Captain’s Flight Instrument bus. The cabin oxygen can be selected on from the flight deck but not off, either in prevention or while generating.’
The cabin oxygen masks are released automatically when the cabin altitude exceeds a set level. Yes, the pilot can also release them using a switch in the cockpit, but it’s primarily designed to be automatic in case of a sudden depressurisation.
If the left bus and tie *were* intentionally selected ‘off’ after IGARI then there would be a specific reason for doing so.
To shut down the SDU? But why would you need to do that? You can select ACARS to voice and turn the IFE off on the overhead panel.
To avoid being tracked by SAT pings? No point – they only happen once an hour and you’re likely being tracked by several primary radars anyway.
According to the FI there wasn’t any SAT phone capability for the passengers, so that’s not a reason either – unless the cabin crew had a SAT phone? The FI doesn’t mention a cabin SAT phone, only that incoming calls would ring in the cockpit.
So why turn off the left bus and tie?
Is the cabin altitude sensor (that releases the oxy masks) powered by the left bus?
That is, if you disable the left bus & tie, is the altitude sensor that releases the masks disabled?
Does the left bus also power the Captain’s instruments?
Does anyone (even if just reading but not posting) have access to a 777 maintenance manual that will list what the left bus powers on a 777, that isn’t provided in any other way if that bus and tie are disabled?
Obviously, if it does (power the cabin altitude sensor, Captain’s instruments) then that could be a reason for it being turned off and then back on later.
@ George Tilton, RF4. Thanks for the explanation as to why flight crews might need extra oxygen, though the amount ‘looks’ excessive for occasional uses right up high. Older manuals indicate earlier models of the 777 had just the one bottle (same size) for the flight deck so there was a change somewhere.
Given that getting masks on can take 15 secs and there can be a delay while pilots figure that they are needed and possibly cope with an errant aircraft, the 10-18 secs consciousness, dropping to 5 at 43000 (RF4) in a rapid decompression, makes it sound as though one should be worn continuously up there, particularly at night (mist and disorientation, some instruments failing) though uncomfortable I suppose. And maybe that was the envisaged requirement.
@Rob. On p3 I said that if the flaps are housed the flaperons will operate as ailerons from 2 to 8 degrees. This part is wrong and describes aileron droop at flap housed and take off positions. With the aircraft in the air, in normal mode the flaperons droop as flaps much as I said earlier, the maximum being 31 deg, that droop generally being a few degrees in advance of the flaps.
@Ge Rijn, Kenyon. Further on EK521 and the left flaperon up position, as a flap the flaperon should be down with the others. It may be that its up position reflects its aileron use, overriding that as a flap but I have not substantiated that its range of movement is that much.
@Richard: thanks for replying. We’re not THAT far apart – you say “not impossible”, I say “nearly impossible”. No incompatibility beyond tone, really.
Under a piloted end-flight assumption, what is your best-guess assumption for each of…
1. time of engine 1 flameout,
2. speed, altitude, & bearing (relative to Arc direction) at time of 1st engine flameout,
3. change in speed & altitude per unit time whilst on engine 2 only
4. time of engine 1 flameout, &
5. change in speed & altitude per unit time after engine 2 flameout?
Feel free to express any or all as ranges, if you feel it better describes your sense. Thanks much.
I will compare your assumptions to those in the Anderson paper, so you can save us a back and forth by explaining major differences between the two sets, if any.
I am particularly interested in your sense of Anderson/Exner’s remarkably consistent reported deceleration rate of 19 knots/min whilst on 1 engine – a state the ATSB’s Dec/’15 report claimed MH370 was in for as many as 9 minutes PRIOR to crossing Arc 6.
http://www.duncansteel.com/archives/1461
@ Middleton. My earlier addressed whether the flight deck could turn off cabin oxygen and not the cabin Pressure Sensor Monitor therefore. 13,500 ft and 80 knots. Yes it is on the same circuit, 28V Capt Flt Inst bus and 115AC from the standby bus.
“You can select ACARS to voice and turn the IFE off on the overhead panel.” I do not think selecting IFE off would match indications, that is that the SDU was unresponsive at 18:03:11. IFE log-on follows.
I think others will answer your other power distribution system queries better than I.
@Johan. Plugging in a laptop. Do not know but I would like to piggy back a related thought, quite possibly raised earlier. The aircraft had flown up the Straits to Europe and I wonder if those waypoints can be retrieved easily by anyone flying manually, on the hop or under instruction to head that way.
I agree DennisW 🙂
I’m sure Jeff is working on our next topic-o-the-day.
So until then, as I watch the Opening Ceremonies, I’d like to wish all of the countries represented on the forum here Good Luck and Goodwill during the Olympics.
@JS
For me, the point 6 data of 3999 feet in the original table is
interesting. (Incidently, why would this value not be repeated in
the supposedly more accurate table, while other values such as 40003
and 37651 are repeated?)
3999 feet is a possible indicator that point 6 was used by Shah for
for testing purposes. What testing? Well, we know Shah carried out
tests to find why his flight simulator was crashing, to try to find a
set of conditions that would cause the sim(computer) to predictably
and repeatably crash.
A method to ‘stress’ a flight sim could be to fly a long flight (and
flying till fuel exhaustion = long flight…) while trying differing
conditions – such as setting different backgrounds or topography
colouring.
FSX can apparently colour the topography of terrain acording to what
multiple of 1000 Feetaltittude the sim is at. If there’s no topography,
because the sim aircraft is over ocean FAR from land, you could test
if topography was a factor in the crashes by increasing the view(zoom) outwards until topography becomes a factor because your ‘zoom’
outwards eventually includes land.
“…ElevationXColor variables are available only at
1000’ intervals, so the same color band applies for an aircraft flying at 3999’ altitude –
the TAWS map colors cannot change until the aircraft reaches 4000’ altitude.”
http://www.fsdeveloper.com/forum/attachments/taws-17a-pdf.13322/
Anyway, for me these tables don’t provide evidence of anything, that
can’t be just as likely attributed to usage of his flight sim, and possibly as merely a fragment of his testing régime to find a reason
for his sim/(computer) crashing.
@VictorI,
I have been exploring 180 degree True Track routes through BEDAX. Here are three examples:
https://drive.google.com/file/d/0BzOIIFNlx2aUcDZ4VWJ6WGpyY1U/view?usp=sharing
All of these routes have FMTs well after the 18:40 phone call. In order to match the 18:25-18:40 BTOs and BFOs, it appears necessary to invoke at least 4 turns or 3 turns and a descent ongoing at 18:40.
Pages 1 and 3 are two essentially identical routes except that Maximum-Range Cruise is used post-FMT in Page 1 and Holding LRC is used in Page 3.
Page 1 is a route with a post-FMT speed of Maximum-Range Cruise at FL377. There is a lot of information on my route summary pages, and you can find just about everything there by enlarging the page and scanning around. All three routes I am showing in this file have “textbook” BTO error statistics and RMS air speed errors ~1 knot. The Page 1 route does not make a significant descent at FMT. Because my route fitter currently only handles 3 turns at FMT, It does not show a match with the 18:28 and 18:40 BFOs, but this can be done with a turn North, a turn ~South, a turn ~West, and a FMT South. This turn sequence will satisfy the 18:40 BFO when traveling ~South, and the total distance travelled during the turn sequence can be the same as shown for this route, so the fuel consumption is the same. So it is possible to generate a route that satisfies all the satellite data – except for the fuel used. As shown on Page 1, the PDA needed to produce fuel exhaustion at 00:17:29 is -0.8%. Page 3 has a PDA also equal to -0.8%. That is, you need engines that are more efficient than factory new ones to fly until 00:17:29 at these speeds and altitudes. I can say that these routes are very unlikely be correct because the fuel is inadequate to match the known endurance.
The Page 1 route (MRC) averages 482 knots TAS over 3,457 powered air miles at FL377. The Page 3 route (Holding LRC) averages 480 knots over 3,446 powered air miles at FL405.
Obviously higher-speed options such as ECON with Cost Index = 52 (the flight plan value), or Long-Range Cruise will have even shorter endurance and will also fail that PDA test.
Page 2 shows a Holding LRC route also through BEDAX and at 180 degrees True Track, just like the others. The Page 2 route averages only 454 knots over 3,224 powered air miles at FL406. It has an interesting turn sequence. The first turn is to due North (0/360 degrees). The second turn is to due West (270 degrees), and the FMT is to due South (180 degrees). At the end of Turn 2 (to the West) a descent is made down to FL100 at ~1,650 fpm (at 18:40) and the speed is also set to Holding LRC. The descent ends around 18:44. The FMT begins at 18:50. BEDAX is reached at 19:11. Ten minutes later the climb up to FL406 begins and is completed at 19:40, just prior to the 19:41 SDU transmission. This turn sequence involves only 0, 270, and 180 degree tracks, so it could be done, in principle, by a non-professional pilot such as a cabin crew member. I recall reading they have some rudimentary training in setting direction and altitude using the Mode Control Panel. The Page 2 route could be flown after the radar track by 3 directional commands (TRUE TRACK HOLD), two altitude commands (FL CHANGE), and one speed change (to Holding). However, the PDA for the page 2 route is -1.4%, and this also indicates the fuel is inadequate to match the known endurance. So this route fails also to match all the satellite data.
In summary, all 180 degree True Track routes (whether or not they pass exactly through BEDAX or just nearby) appear to have insufficient endurance.
I have also found True Heading and Magnetic Track routes that pass close to BEDAX and satisfy all BTO and BFO data. Because these routes both curve toward the southeast, the air miles travelled will be reduced compared to True Track, and one of these may have sufficient endurance with a PDA typical of used engines (roughly 1.5% to 4%). I shall have more to say about this possibility later.
@Middleton
@David
Middleton, you asked why the need to de-energize the SDU after passing IGARI? I will step up to the plate.
There were no passenger satellite phones, but the business class seats had email and Text (SMS) connectivity. These had to be disabled. If he (the pilot) had simply switched them off by switching off the IFE/Seat power switch, he would also have disabled the video surveillance system, as this is also powered through the IFE switch.
He needed to be able to monitor what was going on the other side of the cockpit door, while the depressurization was taking effect.
So, the only way round the problem was to either isolate the LH main AC bus, or switching over to backup generator and so make the electrical load management system (ELMS) automatically shed non essential load, including the SATCOM (SDU).
Then, after an hour of depressirization, he was able to dispense with the surveillance cameras, and switch back to normal electrical power. But evidently, he forgot to switch off the IFE power switch, because the IFE logon was transmitted 90 secs after the 18:25 logon. I think he punched the IFEswitch off, as soon as he realized this, and kept it off for the rest of the flight.
The LH main ac bus also powers the cockpit door lock. If this had been de-energized, it would have failed-safe to unlocked position, but it can be locked manually.
Sorry if this is long winded, but it cannot be explained in a sentence.
@Ge Rijn, Gysgreght. Aircaft acceleration effects. I hope this simple proof will be sufficient.
https://www.dropbox.com/s/80snphi23vc54wq/Forward%20forces%20from%20aircraft%20internals%20in%20aircraft%20acceleration.pdf?dl=0
@ Ge Rijn. All the same I do not think pursuing end of flight is likely to be fruitful since it is so unlikely to lead to a search hot spot – as distinct from an impractical area.
As to vapour lock, fuel just in the line will not be pressurised at the inlet end by the APU fuel pump but will need to be sucked through by the APU. This is feasible on the ground but up high with air pressure low and against the force of teh “proof” above (say around 10% of its weight) the APU may suck large bubbles of vapour. It is likely that a reason like this is why the ATSB makes no mention of this fuel being available.
@David
Thanks.
And aproved by Isaac N himself. I’ll say no more on this 😉
@Ge Rijn
Yep, Isaac Newton was a clever old kiddie.
@David: “Aircaft acceleration effects. I hope this simple proof will be sufficient.”
What you are showing was never in dispute.
When thrust is less than drag, non-constrained objects in the aircraft will move forward, and fuel in the tanks will also move forward. That applies not only in a steady descent, but on any flight path, including level flight.
So what are you trying to prove?
@DennisW, @Billy
Agreed too, move on. And Olympic ideals arent mad. Something “transcendent” around, no doubt. I am not mad either (not sure if you agree, but thats ok), maybe only linking things to create imaginations and dreams. Learn to fly.
https://www.youtube.com/watch?v=QheoYw1BKJ4
@ROB, Isaac Newton was the Last Sourcerer 🙂
We do need more possible explanations why the SDU might’ve been powered down around IGARI – and why it came back to life again at 18:25 UTC. It could’ve happened because someone pulled the left bus for some reason. Victor suggested that by pulling the left bus the voice recorder could’ve been deliberately de-activated in order to stop it from recording the mayhem which ensued after the captain locked himself in. In such a scenario the deactivation of the SDU was just a by-product. If someone restored power to the left bus again, the comeback of the SDU would’ve been a by-product as well.
But there are other possible explanations and while Victor’s explanation has merit, we can’t be sure if the SDU was really de-activated because someone pulled the left bus or if it was by some other course of action entirely. We also do not know if the de-activation of the SDU was deliberate or a by-product.
Newton was the Last Sorcerer.
Sorry for the spelling mistake
@David:
You mean if an old/previous/last entered/common/standard flightpath already in the syStem from previous flights would pop-up to select from in one way or the other?
I have a vague sense that was brouhgt up a long time ago, in the columns of IG. I am quite sure you can find that out looking / googling for images/manuals for the entering of waypoints into the machine (beats me right now how it is referred to and abbreviated in English).
There will be such a manual out there (or was until someone made us pay).
I mean the way that system appears is pretty imoprtant so it is certainly worth to look for. I remembered it as a bit dull, but I can be wrong.
(This typing would have been a little bit easie if I had not had to teach My cell Phone how to spell in English at the same time. You might think there could have been somewhere out there better equipped for that than me. Tusan. )
@Littlefoot
I don’t go with the CVR proposition, simply because it only records the last2 hours of the flight, and erases everything that goes before. The pilot had planned a flight lasting until fuel exhaustion, imho, so hw wouldn’t have had to worry about what was on the voice recorder.
My explanation is still the front runner, Imo, but that’s just me, obviously 🙂
@David
I’ll give another one back at you. Is it established if the infamous inflight system reboot happened directly before or after the FMT?
Is it also known if the pilot / rebooter very well might have realised that this could give away the plane’s position? Or at least give away that the plane was still in the air? (As in contrast to the other “handshakes”).
You understand what I am getting at?
@Johan
Interesting twist on the reboot.
@DennisW:
Are you making fun of me, or are you serious?
That is a staple ingredient of movie thrillers, and/but the interpretation will vary with whom is performing it.
I have feeling it has been discussed before, though.
@littlefoot
“We do need more possible explanations why the SDU might’ve been powered down around IGARI ”
The SDU when you get near the edge of the satellite footprint will logon to the next satellite. The switch can be triggered by GPS position, S/N ratio or increased errors in the link.
Footprints overlap a bit. The edge of inmarsat 3 coverage is ~132E degrees and the the pacific satellite covers to ~105E degrees. The pacific satellite is likely serviced by a different ground station than Perth…I haven’t found that out yet…
That gives us the scenario that the SDU logged on to to the Pacific satellite after 17:07 and switched back to the India Ocean satellite after the turn-back when it left that satellite’s coverage around 105 degrees.
Second observation about powering down the SDU…
The Thales SDU is mounted on rails adjacent to the Flight Data Recorder in the tail. It is unlikely that it is not powered by the same power that is supplied to the FDR. Inmarsat is proposing that FDR data be streamed in the future which would suggest that the SDU is on an un-interruptable supply as is the FDR already.
Isolating the left AC bus alone doesn’t shut down the SDU per ATSB (August 2014, 33):
“The SDU was powered by 115 V AC from the left AC bus which was normally supplied by the left IDG. If power from the left IDG was lost, then a bus tie breaker would close and power would be automatically transferred from the right AC bus. Similarly, if power was lost from the right AC bus, power would be automatically transferred from the left AC bus. This power switching is brief and the SDU was designed to ‘hold-up’ during such power interruptions. To experience a power interruption sufficiently long to generate a log on request, it was considered that a loss of both AC buses or, a disabling of the automatic switching, would be required.”
So, it seems it was very much a deliberate decision to shut down the SDU, possibly in order to prevent communication.
Also, per various accident reports the portable oxygen bottles for the cabin crew would normally have lasted c. 2 1/2 hrs. And it seems to take several minutes to depressurise the aircraft manually until masks drop down.
@DrBobbyUlich: First, thank you for taking the time to evaluate the BEDAX-SouthPole path. In the past, you have claimed that this path does not satisfy the satellite data. I am glad we now agree that it does. It also looks as though your routes include the “sidestep” manoeuver to the right at 18:25 that I proposed many months ago.
I question whether we can rank reconstructed routes based on such small differences in fuel consumption, considering the uncertainty we have based on:
1) The exact route flown before 19:41. For instance, it is possible that after 18:28 the plane flew at low speeds on N571 until 93.8E longitude and turned directly south. The low speed would reduce fuel flow, making more fuel available later in the flight.
2) The possibility of changing altitude to maximize fuel efficiency.
3)Uncertainties in temperature and wind fields.
4) The possibility of a (low thrust) descent in the later portion of the flight, which would reduce fuel consumption.
I should add that the BEDAX-SouthPole route was proposed only as a possibility. There are still so many unknowns that it is difficult to propose any reconstructed route with any reasonable level of certainty.
That said, I do value the fuel analysis that you performed.