Last week we discussed what we know about the first hour of MH370’s disappearance, based on primary radar data and the first Inmarsat BTO value. Today I’d like to talk about the BFO data and what it can tell us about MH370’s fate.
As longtime readers of this blog well know, the Burst Frequency Offset (BFO) is a type of metadata that measures how different the frequency of an Inmarsat signal is from its expected value. It is an important value to a communications satellite operator like Inmarsat because if the value gets too large, the system will be operating outside its approved frequency limit. One cause of such a change would be if a satellite begins wandering in its orbit, which indeed was the case with MH370. The fact that the Satellite Data Unit (SDU) aboard MH370 did not properly compensate for drift in the Inmarsat satellite overhead is the reason the BFO data contains a signal indicating what the plane was doing.
While each of the BTO values recording during the seven “pings” tells us fairly precisely how far the plane was from the satellite at that time, the BFO data points taken individually do not tell us much about the plane was doing. Taken together, however, they indicate three things:
- After the SDU logged back on with Inmarsat at 18:25, the plane took a generally southern course. If we didn’t have the BFO data, we wouldn’t know, from the BTO data alone, whether the plane followed a path to the north or to the south (see above.)
- The plane had turned south by 18:40. The BFO value at the time of the first incoming sat phone call at 18:40 indicates that the plane was traveling south.
- At 0:19:37 the plane was in a rapid and accelerating decent.
However, as I’ve previously described, if all of these things were true, then the plane would have been found by now. So at least one of them must be false. In the course of my interview with him, Neil Gordon said that the ATSB is firmly convinced that #3 is true, and that as a result he suspects that #2 is not. Specifically, he points out that if the plane were in a descent at 18:40, it could produce the BFO values observed. Thus it is possible that the plane did not perform a “final major turn” prior to 18:40 but instead loitered in the vicinity of the Andaman Islands or western Sumatra before turning and flying into the southern ocean. If this were the case, it would result in the plane turning up to the northeast of the current search area. An example of such a route has been described by Victor Iannello at the Duncan Steel website.
It is worth nothing that such a scenario was explicitly rejected as unlikely by the Australian government when they decided to spend approximately $150 million to search 120,000 square kilometers of seabed. The reason is that it was deemed unlikely that the plane would just happen, by chance to be descending at the right time and at the right rate to look like a southward flight. For my part, I also find it hard to imagine why whoever took the plane would fly it at high speed through Malaysian airspace, then linger for perhaps as much as an hour without contacting anybody at the airline, at ATC, or in the Malysian government (because, indeed, none of these were contacted) and then continuing on once more at high speed in a flight to oblivion.
Well, is there any other alternative? Yes, and it is one that, though historically unpopular, is becoming imore urgent as the plane’s absence from the search area becomes increasingly clear: the BFO data is unreliable. That is to say, someone deliberately altered it.
There are various ways that we can imagine this happening, but the only one that stands up to scrutiny is that someone on board the plane altered a variable in the Satellite Data Unit or tampered with the navigation information fed back to the SDU from the E/E bay. Indeed, we know that the SDU was tampered with: it was turned off, then logged back on with Inmarsat, something that does not happen in the course of normal aircraft operation. It has been speculated that this depowering and repowering occurred as the result of action to disable and re-enable some other piece of equipment, but no one has every come up with a very compelling story as to what that piece of equipment might be. Given the evident problems with the BFO data in our possession, I feel we must consider the possibility that the intended object of the action was the SDU itself.
When I say BFO tampering has been “historically unpopular,” what I mean is that almost everyone who considers themselves a serious MH370 researcher has from the beginning assumed that the BFO data was generated by a normally functioning, untampered-with SDU, and this has limited the scenarios that have been considered acceptable. For a long time I imagined that search officials might know of a reason why tampering could not have occurred, but I no longer believe this is the case. When I questioned Inmarsat whether it was possible that the BFO data could have been spoofed, one of their team said “all Inmarsat can do is work with the data and information and the various testings that we’ve been doing.” And when I raised the issue with Neil Gordon, he said, “All I’ve done is process the data as given to me to produce this distribution.” So it seems that the possibility of BFO spoofing has not been seriously contemplated by search officials.
If we allow ourselves to grapple with the possibility that the BFO data was deliberately tampered with, we quickly find ourselves confronting a radically different set of assumptions about the fate of the plane and the motives of those who took it. These assumptions eliminate some of the problems that we have previously faced in trying to make sense of the MH370 mystery, but introduce new ones, as I’ll explore in upcoming posts.
@Nederland
“The ghost flight is still possible if …” – I was only noting what Jeff had said that a ghost flight had been largely debunked as a theory (see his comment today at 10:15 above). If that is right and someone was alive, then I don’t see why everyone was not still alive. It certainly looks to me as if someone was alive for many hours after IGARI.
As I see things, the ‘depressurisation theory’ (is there any evidence at all or just speculation?) would be great for Hollywood but not in reality. Too unlikely and too many things that could go wrong – like everyone ending up dead. Without it though, the murder/suicide theory is also on thin ice.
RetiredF4: “No, it would not happen that way. But you are free to believe otherwise.”
Actually, a colleague of mine experienced nearly the exact scenario posited by Matt Moriarty, and guess what – it did happen that way. It was night. The plane developed a fuel leak 5 hours out over the Pacific. The captain reversed direction, turned off the in-flight tracking system, and didn’t tell anyone. Their first clue was when he announced they were landing back at their starting point.
Did Malaysia Airlines give the passengers mileage credit? My colleague did not get any, which is the only thing that annoyed him.
@RetiredF4
At what altitude is pressure breathing strictly required and how long could you stay conscious on oxygen bottles at around FL300?
@Lauren H
The BFO “fudge factor” of ~ -150HZ @L1 derives from measurements made at KL when the aircraft was at essentially zero ground speed. It simply states that with no correction applied the BFO was low by 150Hz. This bias is due to the oscillator in the AES not running at exactly 10MHz. Instead of running at 10MHZ it was running slow by about 1Hz. A very small error indeed. Something on the order of a part in 10 million. This error would change for two primary reasons:
1> The oscillator will continue to age – that is migrate away from its nominal frequency with time. This change is extremely gradual and is probably negligible over the time of the flight.
2> Errors due to temperature variations which will not be negligible over the time of the flight. The cut of the oscillator crystal in the AES has the property that the frequency decrease as the temperature rises and vice versa. The temperature sensitivity is a function of the accuracy of the crystal cut.
We do not have ISAT data along with the ACARS data for the previous flights of 9M-MRO. However, the DTSG was given this data and compiled some statistics relative to the actual BFO measurements of 9M-MRO. This summary data is provided in Table 5.1 of the DSTG book.
An interesting figure in the book is Figure 5.4 which illustrates the BFO error of 9M-MRO on a single flight from Mumbai to Kuala Lumpur. BFO errors (I assert related to drift) are on the order of 20Hz for this flight. My assumption is that the data of Figure 5.4 was selected as an extreme case. It would be interesting to see plots of BFO error for several other flights. It would be even more interesting if we had the data provided to the DSTG so we could compile our own BFO statistics, but we don’t.
Getting back to your question. The best estimate we have for the BFO bias is the bias derived on the ground at KL. We know that this bias will not be perfectly fixed, but we do not have any information which would allow us to predict how the bias might change. We can recognize the imperfections by allowing BFO residual errors to deviate from zero by an amount subject to the discretion of the analyst.
It should be noted that any errors made in estimating ground speed and track will make there way into a BFO error as well.
@Johan
(1) I had a similar question to yours, can the pilot divert warmer air to cockpit? to keep warm. If you look at Nederland’s Helios report from last 2 days, there is possibly a separate vent to the cockpit. I was assuming the cockpit is not air tight for pressure.
(2) Cloud contrails: Here is the presentation I have seen…I first heard about it on Blaine Gibson’s site, he said it was not definitive but supporting evidence. I would like update on it too.
https://drive.google.com/file/d/0BzOIIFNlx2aUWEtvSjBVS2JWX0E/view
@Retired F4
Thanks for that. I am aware that the O2 systems are different and that the FAA requirement for one or both pilots to continually use the mask is probably the most disregarded regulation in the book!
The cabin O2 system is a simple chemically generated system which delivers oxygen at a constant flow, irrespective of the pressure altitude. From the extract you quote, concerning the crew system, how does that result in any crew surviving but all the passengers dying?
@PaulC
There is definitely no hard evidence that the aircraft was depressurised at IGARI. It is purely conjecture. That all started when the NYT reported that military radar showed the plane ascending to FL400 or above just after IGARI. That was seen as indicating that the “suicidal pilot” wanted to kill everyone on board to prevent passenger resistance as normal oxygen bottles don’t work any longer at those altitudes. The whole construction has since been debunked and it has been established that MH370 was, in fact, descending to FL300. The whole reasoning behind that was that the passengers wouldn’t keep quiet during a seven hour flight off route and were likely aware the plane was hijacked.
The ATSB then found out that the satellite data after the FMT suggest no further pilot inputs. Obviously, there were quite a few pilot inputs up to that point and that has always been clear and announced to the public. The ATSB then came up with the possible conclusion that this could be because of hypoxia during the latter stages of the flight.
Following this, there was a heated debate and some said the ATSB is completely nuts to assume a hypoxia event even though it is plain clear that MH370 was piloted until the FMT, something they obviously never said in the first place. Byron Bailey keeps on publishing articles that pursue this simplified version of the MH370 case on a monthly basis on average.
@Johan
PS…if I understand, Bobby Ulrich’s 2015 cloud contrail predicted end-point is southerly at 85/-40 (see above link) which is in close agreement with Simon Hardy’s YouTube presentation using a different logic (further above link).
@Paul
The crew has pressure breathing available the cabin does not. Atbaltitudes where ambient air pressure is not enough the cabin would drift to unconsciousness pretty quick, the cockpit crew would be able to operate unrestricted.
Wether this will lead to the death of some or all passengers depends on the altitude, the time of exposure to hypoxia and the individual physical condition of the respective person. With malicious intent a culprit could use this time of unconsciousness to make sure, that passengers are no factor anymore.
Point to remember is, that the cockpit crew will not be affected by hypoxia due to pressure breathing equipment, while the cabin occupants are.
DennisW,
Nice writeup on oscillator drift and the DSTG BFO analysis. I also was thinking that Fig 5.4 was picked to be a worst-case situation, but how often does it happen? Unfortunately the book is way too thin on details.
Regarding flight paths that best-fit the BTO/BFO data assuming that the BFO data for this flight do not suffer major drift, my best end-point is at latitude -32.4, longitude 95.8, obviously with some error ellipse around it. It meets all three conditions of the parent article, but is outside the currently searched zone. It is not entirely consistent with an uncommanded autopilot scenario. Caveat emptor.
@All
New Russian slant on MH17.
Cheers Tom L
http://www.news.com.au/world/europe/russia-reveals-news-conspiracy-theory-over-mh17-on-eve-of-final-crash-report/news-story/11f0147add37ee4246cf1d008f9b478b
@SK999
I remain annoyed by the fact that we were not given ISAT plus ACARS for a half dozen or more flights. It would have been enormously helpful. As it is people got very close to the DSTG results which benefitted from this data. Said another way, we did a lot of things right without any truth checking as a guide. The IG has been a beacon in this regard.
While the computations are not over-the-top complex, there are a lot of places to stub your toe without a sanity check.
@ at all dead
The flight on MAS from KUL to Beijing is 5 to 6 hours but the plane is flying 1 hour and 40 minutes longer than the schedules flight, at that time, sunrise on the passengers left rather than where is should have been on their right.
@Jeff and Shadynuk, technical chops-
USIsrael, Russia, China, Iran, UK
…North Korea ?
@MH17 If US is telling the story it was Russian backed rebels
(#too much rabble there)
If Russia is telling the story is was the US backed and armed Ukrainian military.
@Depressurisation
Been following this scenario since the event, posted about this two topics ago.
The issue of air pressure at altitude is an important consideration, as Netherland points out. Even though passengers (drop down) air allowance is much less than pilots the critical factor is air pressure, hence need for rapid decent in an emergency.
An aside, the record for underwater (greater external pressure) is 22 minutes while most people can only hold for under a minute or more likely underwater, under 30 seconds.
Holding your breath does not work at altitude with low air pressure, death is rapid, your diaphragm pressing against your lungs as stomach gasses expand.
“Altitude – Moderate Activity – Sitting Quietly
25 000 feet – 2 minutes – 3 minutes
28 000 feet – 1 minute – 1.5 minutes
30 000 feet – 45 seconds – 1.25 minutes
35 000 feet – 30 seconds – 45 seconds
40 000 feet – 18 seconds – 30 seconds
At most altitudes these masks do little more than keep an unconscious person alive. That’s why the Emergency Descent is so important.”
http://code7700.com/rapid_depressurization.html
@Hijacking demands, circa 1970s style hijacking while intent more likely.
@Specialist pressurized oxygen gear, see aviation and mountaineering supplies…http://www.mhoxygen.com
How do you get specialist gear on a night flight if you are a passenger intent on hijacking.
Pretend a medical condition, sleep apnea, chronic emphysema or other requiring you to travel with the oxygen in the cabin.
Who is going to check what style or type of oxygen tank or equipment.
What is left of the CCTV footage of the passengers at the terminal, passenger records, medical information on the passenger manifest?
Depressurization is the way to kill all passengers, even if only one or two were the intended targets, then the plane/passengers was disposed of.
Professional, planned, military action.
Traveling with oxygen
https://www.vitalaire.com/home-healthcare/home-oxygen-therapy/travelling-with-oxygen/
https://beta.aircanada.com/ca/en/aco/home/plan/medical-mobility/travelling-with-oxygen.html?acid=beta%7Credirect%7Caircanada.com%7CDispBar
@Tom Lindsey
Good update on MH17 above but
Doubtful the Dutch will find anything other than what the strong arm of NATO want them to find.
@Tbill “ocean mountain expert comments” what does he mean can you give me of an explanation?
Mr crackpot Gyson, that does not surprise me that he got his theory from someone else but is branding it as his own..
@Jeff wise
In regards to broken ridge as a possible location… You said the plane would have had to loiter..The previous topic on Mh370 military radar and speeds the plane might been going… Can the scenario using more fuel equate to short distanced traveled due to fuel exhaustion?
As mentioned in Duncan steel site http://www.duncansteel.com/archives/date/2016/06
@Jeff
OT… our local news tv is airing your presidential debate – quite cool for them I hope ))) you ma think its not related to lost plane, but, you know … everybody here knows what is happening around precisely, especially if its related to Russia, yet… without hard evidences mostly; everywhere only opinions, shared by some weird channels; crazy ))
@Aaron I am in reference to Peter Lee’s book MH 370: By Accident or Design where there is some input from a NOAA scientist suggesting (back in 2014 before the final search area was defined) the just looking at the underwater terrain might provide a clue to flight path, assuming intent to hide wreck in the difficult terrain. Note that many suggested flight paths basically go down the 90East Range and end toward the Broken Ridge.
There are many other possibilities. Just saying if it is not a ghost flight, then what would be the possible thinking? Mountain burial would be consistent with suicide premise.
Now we got another premise lurking I may have to move over to DennisW side. If it was a botched plan of some other type, then the flight south was less planned.
as a reminder of VictorI’s analysis of BFO/BTO that meet the northbound theory:
http://www.duncansteel.com/wp-content/uploads/2015/05/VI_Fig1.png
I find it striking how it easily fits all ping rings and fuel range.
@RetF4
“No, it would not happen that way. But you are free to believe otherwise”
Jolly good answer. A close second to “I know you are but what am I?”
@Nederland
I have no idea why FI would state 13 hrs at FL360. No idea at all.
“So, “at or below FL410” means in a pressurised cockpit? The FI says crew oxygen supply would last for 13 hours (for two pilots) at 36.000 ft (unpressurised), why is it then required to do an immediate emergency descent?”
Yes. 121.333 pertains to pressurized jets only. And why the descent? Because you’re only required to supply full O2 to 10% of the pax. (ICAO regs should be identical, just with different wording)
From the book: “When an airplane is operated at flight altitudes above flight level 250, oxygen must be available at the rate prescribed by this part for not less than 10 percent of the passenger cabin occupants for the entire flight after cabin depressurization, at cabin pressure altitudes above 10,000 feet up to and including 14,000 feet and, as applicable, to allow compliance with § 121.329(c) (2) and (3), except that there must be not less than a 10-minute supply for the passenger cabin occupants.”
@PaulC
Your aeromedical data is just great, but the fact is crew quick-donning masks allow pilots to operate perfectly well up to FL410 for as long as the supply holds out (meaning a really long time). As I said above, the reason emergency descents to 14,000′ are required is because the pax are on a continuous flow system with only 10% of them being covered under the law.
The standard for a fully pressurized cabin, btw, is 8,000′ at any altitude flown, so everyone in the sky is hypoxic to a small degree.
@SK999
“Actually, a colleague of mine experienced nearly the exact scenario posited by Matt Moriarty, and guess what – it did happen that way.”
Imagine that!
@Jeff – It was my assumption that ISAT BFO analysis was unchartered territory in 2014. As such it is hard to conclude that any of the PAX would have the expertise to do so. And why would someone go through such great lengths to “spoof” the BFO data on this particular flight rather than just disabling the SDU permanently? If you possess the ability to do the former, the latter would be a walk in the park, IMO.
@DennisW – You said “Errors due to temperature variations which will not be negligible over the time of the flight. The cut of the oscillator crystal in the AES has the property that the frequency decrease as the temperature rises and vice versa. The temperature sensitivity is a function of the accuracy of the crystal cut” – Could BFO data have been “spoofed” unintentionally? Could temperature changes (if this could create errors) have occurred other than through purposeful manipulation?
@sk999: turning without telling
That is pretty interesting. It means the pilot 1) wouldn’t want to wake all passengers, 2) worry them for x hours 3) get into a discussion with all of them.
@SK999/@Johan, It is highly inconceivable that crew/PAX would not have noticed a radical turn, or even a normal turn for that matter. Practically living on aircrafts, I can assure you that “turns” do not go unnoticed especially by crew and PAX who fly a lot. Also, many people do not sleep but watch movies/read books and typically dinner/drinks are served starting 20/25 minutes into the flight. Flights of 6 hours or so, is just sufficient to get an owls nap, tops. IMO, it rarely happens that passengers don’t notice the leaning movements a plane makes when turning, especially an aggressive one.
TBill:
Re cloud contrails.
We have discussed it in great details around April 2015 (you may search Jeff’s site). It is extremely unlikely that what you see in these images are contrails due to their size, unfavorable weather conditions, etc.
Generally, I think only the IR images taken by NPP Suomi 18:55 deserve attention. Most of us agreed that in the visible spectrum you can see whatever your imagination draws.
@Jeff,
I enjoyed reading “how MH370 got away”, although I thought your conclusion was based on rather flimsy assumptions. But in this post, you’ve totally missed the mark.
Now you make the case (I believe, -again-) that some of the data was manipulated, in this case the BFO.
This is a totally unnecessary, and highly unlikely.
Unnecessary because you yourself recently interviewed Neil Gordon in which he clearly explained that from the outset it was clear that there was only a 70% chance of finding the plane in the current search area.
The fact that it didn’t turn up yet poses no new information whatsoever!
It certainly doesn’t warrent your extraordinary claim that BFO data was somehow spoofed. Extraordinary claims require extraordinary evidence…
And it is also very unlikely because, unlike VHF radio, the SATCOM is clearly designed to work with a single pre-existing satellite network with fixed operational parameters. The VHF radio you can tune, but why would there be any tune-able or tweak-able setting in the SDU? Let alone such a tiny engineering detail as a programatically applied frequency offset. Even if it exists at all in its design, it is likely hidden deep in the bowels of the millions of lines of firmware that make up the SDU system, and not accessible to the outside world.
@All
On SDU related topics, there is a point about which I wondered if there is any information available.
If you look at the FI, Appendix 1.9A, you’ll see that while on the ground, the SDU logged on without flight number at 15:54.
Presumably at that time someone entered the flight plan, because at 15:56 the logs show the valid flight number again.
It is also mentioned in the FI that SATCOM after the 1720 event never showed the flight number again.
Has any analysis been done under what circumstances the flight number can reset? Isn’t this information stored in non-volatile memory? (i.e. impervious to power cycles)
Matt Moriarty
“Your aeromedical data is just great, but the fact is crew quick-donning masks allow pilots to operate perfectly well up to FL410 for as long as the supply holds out (meaning a really long time). As I said above, the reason emergency descents to 14,000′ are required is because the pax are on a continuous flow system with only 10% of them being covered under the law.”
One should consider though, that despite pressure demanded oxygen for the cockpit crew the problem of decompression sickness(DCS) still exists. the required emergency descent is for both reasons, Hypoxia and DCS.
https://www.faa.gov/pilots/safety/pilotsafetybrochures/media/dcs.pdf
@Keffertje
“It is highly inconceivable that crew/PAX would not have noticed a radical turn, or even a normal turn for that matter.”
An aggressive turn, sure. But a normal turn? You’re totally wrong. Check out this famous video of Bob Hoover pouring iced tea DURING a 1G barrel roll without spilling a drop.
https://www.youtube.com/watch?v=V9pvG_ZSnCc
@Keffertje
“IMO, it rarely happens that passengers don’t notice the leaning movements a plane makes when turning, especially an aggressive one.”
There might be a probability, that most passengers themselves would not notice an unplanned turn. The Cabin crew however would notice and would challenge the cockpit bout such a great course change. The diversion explanation would be acceptable to them, but again, they know that when they turn around 1 hour after takeoff it is something severe and they had to prepare the cabin for the oncoming landing / emergency landing in the next hour. After 911 they even have a responsibility to monitor the integrity of the cockpit crew. They would be critical, ask questions and request explanations from the crew.
When flying I always book the front seats and can observe, how intense the information exchange is between the cabin crew and the cockpit including the personal contact when pilot or copilot visit the toilet or when the cabin crew serves meal and bevarages to the cockpit.
Meandering around off from original planned course and flying for further 6 hours to the opposite direction without notice by the cabin crew is unlikely to happen.
@Matt Moriarty
But a normal turn?
Gysbreght computed the outbound track in relation to the following inbound track resulting from a 25° bank turn. During normal cruise flight at FL350 such a bank angle is not normal, at that altitude the usual bank for course changes would be between 5 and 10 degrees.
The duration of such non normal bank would again be much longer than one would expect for normal course changes enroute.
@ RF4, “There might be a probability, that most passengers themselves would not notice an unplanned turn”. I don’t know about “most” but am sure there are those that do not notice. Agreed that cabin crew would notice and challenge such a maneuver. Because I am spoiled rotten, I always sit in front and am very perceptive as it relates to reading body language of crew and pilots an attribute acquired from hours of sheer boredom.
@Matt, “An aggressive turn, sure. But a normal turn? You’re totally wrong. Check out this famous video of Bob Hoover pouring iced tea DURING a 1G barrel roll without spilling a drop”…You don’t have to spill drops of your drink to notice (or not notice) a turn. Apples and pears.
Dennis,
Thanks for the reminder on Fig. 5.4 and 5.5 of DSTG report. A couple of observations:
1. Fig 5.5 is sufficient to say that the exceedances of 10 Hz absolute BFO errors are rare: roughly 50 in 3392 samples, meaning 1.5%. It could be expected that 98.5% of BFO should be within 10Hz errors.
2. Fig 5.4 looks to me like a superposition of a deterministic component and stochastic. The stochastic component appears to be in the range of 5 Hz. The deterministic component is interesting. I recall previously Gysbreght associated Schuller oscillations with this effect. DSTG has suggested some mysterious geographic dependence. In my understanding you are suggesting the oscillator drift. So, what is it?
3. The other thought I have is again with regard to the ADIRU: it numerically integrates acceleration, so if the groundspeed is fed “as is” from ADIRU into the SDU/AES, the magnitude of errors associated with the Doppler compensation term would grow over the time of a flight, as possibly evidenced by Fig 5.4. On the other hand, the magnitudes of MH370 BFO deviations from the “trend line” do not exhibit such a behaviour. It can be due to the lack of samples, but it could also be due to the failed ADIRU: in such a case the ground velocity could be sourced from GPS, which is more accurate than ADIRU. Just an another possible ‘symptom’ that the ADIRU was malfunctioning.
@Keffertje,
“@SK999/@Johan, It is highly inconceivable that crew/PAX would not have noticed a radical turn, or even a normal turn for that matter……..I can assure you that “turns” do not go unnoticed especially by crew and PAX who fly a lot. Also, many people do not sleep but watch movies/read books and typically dinner/drinks are served starting 20/25 minutes into the flight.”
Exactly
Catching the KL to China flight with MAS for six years on a regular basis. On the red eye, for 1.5 hours the crew go through the protocols of drinks, satay, meals and duty free as if it 2 pm in the afternoon and not 1 am in the morning.
What was happening on the plane at 1 hour 30 minutes into that flight? Only a few people sleep, certainly not the majority of passengers. Lights are not turned off until after the aisle run with the duty free. A flight leaving at 12.42 am, it would have been 2 am by the time the lights were dimmed in the cabin.
MAS standard routine, includes an excessive number of in flight announcements, no matter the time of night. On KL to China flights they make every announcement in Bahasa, English, Chinese which takes an inordinate amount of time.
Sometimes the pilot makes the announcement, then a crew member will repeat the same announcement another three times in the three languages.
Sleep is a myth on those flights.
Lights go on on 1.5 hours before the flight is due to land at what would have been 5 am Beijing time or Perth time.
Any turns and changes in altitude are definitely felt.
KL to Beijing red eye is a computer flight, lots of expats working in Asia.
@Keffertje
You don’t get it, huh? Hoover flies UPSIDE DOWN and yet his pitcher keeps pouring tea into a glass. A 1G turn. Understand?
Absolutely identical to the forces exerted on you while you’re sitting there typing into your keyboard. Anybody posting on an aviation-related comments thread should know very well what I’m talking about. You apparently don’t.
1G is 1G. A 25 degree bank turn at mach .84 is 1.1 Gs. Hardly any different as far as the human brain is concerned. The point being: at night, on an airliner, you can make make turns all over the place without the passengers sensing anything more than normal flying – just as the guy said 30 comments ago when he landed back in LA unbeknownst to him.
Go get a pilot’s license and do a coordinated standard rate turn at night and then you’ll understand.
@RetF4
The bank angle limit is whatever the pilot sets on the MCP. You mention some analysis by Gysbreght and then take it nowhere. Is a 180 deg turn at altitude normal? Is it rational to assume that a guy who doesn’t want to check in with Ho Chi Minh would go for a 5 degree bank?
Want the turn diameter of “normal” banks at 494 kts?
5 degree bank = 81nm
10 degree bank = 40nm
15 degree bank = 27nm
20 degree bank = 20nm
25 degree bank = 15nm
Any one of those radii is more believable than a two chandelles making up a box turn pattern. Notice how you don’t go past 1.0 Gs until you’re at 20 degrees. So what on Earth is your point?
Gloria seems to be the only one on this forum who has actually travelled by MH 370 before it became history!
@TBill, @Oleksandr:
Contrails: thanks. Seems likely they would be hard to discern. Without proper instruments/camera.
Turn: I think it would be wishful to assume a turn, any full turn, would pass unnoticed by all passengers and any of the crew. If Gloria’s memories are representative then even less so, naturally. So either there’s an announced actual or feigned excuse for turning back, an announced hijack, hypoxia setting in or quite chaotic back there. Several perhaps being at hand simultaneously.
@ABN397:
I was on the roof of World Trade Center in mid June 2001. Doesn’t that count?
I think the main problem is at what altitude pressure breathing is necessary to stay conscious. Most sources set a limit of around 35.000 ft or higher. That would mean, but again I may be wrong, that portable oxygen bottles (constant flow) would work at those levels (MH370 was flying at around 30.000). This again means that it would take several hours to kill everyone on board. And whoever was in the cockpit quite likely had to throw up in his oxygen mask due to decompression sickness? Would you really want to do that?
Jeff,
With regard to your article “Fascinatingly Mysterious New Flaperon Barnacle Data”.
As usual, there is nothing surprising or mysterious, at least to me.
>A. You wrote: “To find 24 degree water would mean trekking 1000 miles north, above the Tropic of Capricorn”
All the facts point to the crash area in 20 to 30S. Inmarsat data is consistent with this under certain assumptions. It is obvious that the weird combination of the assumptions of a single FMT, TRK/HDG Hold mode, and constant altitude does not work: (1) the aircraft was not found in the corresponding area; (2) such a combination has no logical meaning; (3) it contradicts to all the drift studies. As a matter of fact #2 became clear long time ago. So why are you surprised that (4) barnacles analysis also supports the crash area to the north of the current search area?
>B. “Where the heck could it have gone to find 18-20 degree water? And how did it then get back to the 25 degree waters of Réunion Island, where it finished its growth?”
I took a brief look at NASA’s SST, and they qualitatively confirm what I suspected. The seasonal cooling of the water likely occurred relatively fast compared to the travel of the flaperon towards the equator. Hence the SST was initially dropping. As it was getting close to the equator, the ambient SST rose up again to 25C.
Notably, there were many eddies, and it will take time to quantatively analyse high resolution details. In either case it appears that your new information may help to refine the search area, and my rough prediction is that the ‘hot spot’ will again be around 25S. Can you obtain more detailed information from Patrick De Deckker, in particular how long it stayed in 18-20 deg water, or better a plot showing how the estimated ambient temperature varied with the time?
@Hendrik Beijeman
“It is also mentioned in the FI that SATCOM after the 1720 event never showed the flight number again.
Has any analysis been done under what circumstances the flight number can reset? Isn’t this information stored in non-volatile memory? (i.e. impervious to power cycles)”
I think you can either delete the flight number manually in the FMC or enter/activate a new fight plan without entering a number. Presumably whoever entered a new flight plan wouldn’t bother much about the flight number.
From @Gloria’s link above:
http://code7700.com/rapid_depressurization.html
“Although certificated up to 41,000 ft MSL, system capabilities require very careful attention when using continuous flow oxygen systems above 25,000 ft MSL.”
So, you can use portable oxygen bottles up to 41.000 ft, but you are advised to be careful?
“The pilot masks on most Gulfstream aircraft are certified to a cabin altitude of forty thousand feet and will automatically switch to positive pressurized flow if the cabin altitude exceeds thirty-five thousand feet.”
So, pressure breathing is only necessary/available when flying above 35.000 ft and MH370 was probably flying well below that for most of the time after the diversion?
@Matt Moriarty, @All
Matt, I wondered why I enjoyed flying so much, now I know. It’s the euphoria due to mild hypoxia.
@All
A “chandelle” would have been the manoeuvre of choice at the turnaround, as appears to be borne out by the primary radar trace, If only because a leisurely curve away from the planned point of disappearance would more likely give him away, than a sharp double back.
@Nederland
Thanks for you earlier reply – a lot of speculation.
“I think the main problem is at what altitude pressure breathing is necessary to stay conscious”
The only word I would change is ‘conscious’ – I would make that ‘alive’. People might fall asleep due to low oxygen but they could be easily revived.
Unfortunately, there is no ‘line in the sky’ that applies to everyone – the key issue is at what pressure do the lungs cease to exchange gases and that varies from person to person BUT it is (for 99% of people) in the range of 0.2 atm to 0.25 atm. Atmospheric pressure varies with height around the globe, pressure at 10,000 feet above the equator is not the same as 10,000 above the poles. It is all a bit of estimation and averaging.
I have done quite a lot of scuba diving in my time and the dive tables I started with were developed from research with US Navy divers – they gave divers compressed air and put them at different depths for different periods of time and waited to see what happened. This data was then put into a table that juxtaposed depth against time. Having worked out what was ok for super fit US Navy divers, the depth/line was moved up to provide a good margin of safety for recreational divers. That table was good for more than 99% of people 99% of the time – but there was still a risk, so rules were added (e.g. people do not dive alone etc.) to ensure help was at hand if something went wrong.
The same applies to altitude. One person will have a different result depending on where he/she is on the globe, or whether they are tired, or recovering from an illness etc etc.. So the rules build in a margin of safety.
The range at which pressure breathing equipment becomes necessary is usually somewhere between 34,000 and 40,000 feet.
At 34,000 feet with a sea level temp of 15C pressure is 0.25 atm. At 25C it would be 0.26 atm. At 0C it would be 0.23 atm. All these results show that most (but not all) people would survive and would have little difficulty with a simple continuous flow O2 system.
At 40,000 feet, the results would be: 0.19, 0.20 and 0.17 atm. Very few people could survive without pressurised breathing equipment – but maybe some would.
If you wanted to be 100% sure that everyone dies, you would have to fly higher. We know from the Helios 522 autopsies that many people were alive, although not necessarily conscious, when the plane hit the ground, despite the fact that they had been frozen and without oxygen for almost 2 hours.
@Nederland
Just re-read my last post – I did not mean to suggest that you were speculating but that what you told me showed how much speculation is involved in the depressurisation theory!
I should also have added this link for you, in case you want to play around with alt and temp to calculate atm: http://www.mide.com/pages/air-pressure-at-altitude-calculator
@Hendrik, Thank you for your thoughtful critique, but I think you misunderstand my project in a fundamental way.
You write, for instance, “you make the case (I believe, -again-) that some of the data was manipulated, in this case the BFO. This is a totally unnecessary, and highly unlikely.” First of all, I am not making the case that this happened. What I am doing is raising the question: is its possible? I strongly feel that our mission as researchers must be to elucidate what scenarios are possible, and what are not, so that we can make sense of the information as it comes in. I have asserted, for instance, that a pilot-suicide scenario is a possible explanation for the disappearance of MH370. But is it the only one? If it is not–if there is an alternative, even a less-likely one–then we need to identify what it is.
There is an aspect to MH370 that one does not often encounter in the normal course of things: a recurring surprisingness. Time and again, reasonable assumptions turn out to be incorrect. Just the other day, I emailed a journalist who had written that the path of MH370 up the Malacca Strait had been determined by radar and Inmarsat data. No, I told him, there was no Inmarsat data for that portion of the flight–the SDU had been turned off, then back on again. He was astonished and replied: “But I thought that the system had been designed such that you couldn’t simply turn it off and turn it on again?” I said, that’s exactly right. It shouldn’t have happened. But it did.
One of the reasons that this mystery has proven so tough to crack, I think, is that many continue to make reasonable assumptions. It is precisely where the story departs from reasonable expectations that we find clues. I’ve long argued that the reboot of the SDU is one of the most significant clues to MH370’s fate that we have. Yet to this day the majority of “mainstream” explanations (most recently, Christine Negroni’s book) simply ignore it.
I think you fall into this trap when you assert that it is “unnecessary” to ask whether the BFO data was spoofed. Yes, of course it’s reasonable to assume that it wasn’t. But if you don’t turn over that stone, you may very well miss an essential clue.
@Keffertje, you wrote, “it is hard to conclude that any of the PAX would have the expertise to do so.” Absolutely. Spoofing the BFO data would be such a monumental feat that I think only a state actor could have pulled it off.
You also wrote, “why would someone go through such great lengths to “spoof” the BFO data on this particular flight rather than just disabling the SDU permanently?” One obvious benefit of spoofing the BFO would be to create the impression that the plane was traveling in a direction it actually did not. This would throw investigators off the trail and ensure that they would not discover what happened to the plane.
Worth noting is that investigators have not found the plane.
@PaulC:
Now all we need is to find out that Shah was scuba-diving and had a air-pressure simulator at home. With erased data from the canyon at the bottom of Broken Ridge.
Jokes aside, if anyone of the pilots, crew or main possible hijackers among passengers recently visited a laboratory or clinic to check out his lungs, or started scuba-diving or showed an interest in high mountaineering, we could have a suspect. Maybe there are test you can take privately (or at MAS) to get a picture of what you can handle (as a diver, climber, smoker, pilot, runner). Physical training (going to the gym), diet, or specific lung exercises might perhaps be a factor too. Someone spending much time (living part of year) at high altitude? I am firing a bit blindly.
Will there be a drug that enhances the bloods capacity to absorb oxygen?
If any of the pilots had rehearsed or tried out anything on a previous journey I assume that would have been known (if possible) by now.
…air and water pressure simulator perhaps…
@PaulC
Thanks for those further explanations and I did understand your earlier post in the way you wanted.
I think the fact that MH370 descended to around FL 300 severely weakens the likelihood that it was the pilot’s intention to kill everyone on board. I think the radar return at 17:30, slightly above 35,000 ft, is a glitch, given that all altitude readings are imprecise. And even if not, it would have taken longer than that to depressurise the aircraft if the pilot decided to open the outflow valves (and if he had switched off airconditioning he would have frozen to death anyway). Six minutes later, MH370 was well below 35,000 ft. If MH370 was descending further at 18:40, those on oxygen bottles may well have recovered – even if they fell asleep at some point. They would otherwise have recovered once the plane was repressurised.
As @RetiredF4 has suggested, there is also the risk of altitude decompression, and flying unpressurised at FL300 for a couple of hours or so, more likely than not would have caused serious problems (even for non-smokers).
Bottom line is that if anyone comes up with a plan like that, they would want it to be fool safe rather than offering a 5% rate of success imo.