Yesterday morning, an old friend sent me a text: “Did you hear the news?”
I always get a pit in my stomach when I hear that. “No,” I emailed back. “What happened?”
What happened, of course, was Germanwings 9525. At the time all that was known was that an Airbus 321 carrying 150 people had crashed into the Alps. Soon enough details began to emerge, but how strange they were: a 24-year-old aircraft, en route from Barcelona to Dusseldorf, had climbed to its crusing altitude of 38,000 feet and then, within a matter of minutes, begun to descend at 3000 to 4000 feet per minute, apparently fairly steadily and while remaining on course, until it crashed eight minutes later into the French Alps. The flight crew issued no distress call.
I’d never heard of anything like it, but as the conversation developed online, some parallels emerged. Foremost was the case of LH1829, which took off from Bilbao last November and began an uncommanded descent of some 4000 feet per minute after the flight management system became confused by frozen angle-of-attack sensors.
In that case the pilots communicated with technicians on the ground and figured out how to solve the problem before a great deal of altitude was lost, but perhaps yesterday’s pilots had tried to tackle the issue by themselves and gotten too absorbed by the challenge to realize how much altitude they were losing, a la Eastern Air Line Flight 401?
Some speculated that a sudden decompression might have caused the tragedy. There have certainly been incidents in which aging, inadequately repaired aircraft have suffered catastrophic failure of their pressure hulls, leading to destruction of the plane, but those don’t generally look like this–the plane either breaks up at altitude or the pilots are able to don oxygen masks and keep flying the plane and communicating, if only for a while.
Another possibility–one hesitates to raise it in today’s climate of fear–is that a hijacker attempted to take control of the cockpit. I don’t think we can rule this out, either.
At this point, frankly, none of these scenarios make a great deal of sense, and I think the overall sentiment among people who spend a lot of time looking at this sort of thing is bafflement. “I’m at a loss,” one veteran 777 pilot emailed me yesterday. I think that about sums it up. Hopefully, the recovered cockpit voice recorder will provide some clarity.
UPDATE 3/26/2015: At a press conference in Marseille today prosecutor Brice Robin revealed that, according to audio recordings recovered from the Cockpit Voice Recorder, co-pilot Andreas Lubitz locked the captain out of the cockpit and initiated the descent that led to the plane’s crash into the Alps. “He took this action, for reasons we still don’t know why,” Robin said. “We can only deduce he destroyed the plane. He voluntarily allowed the plane to lose altitude. I think the victims only realised at the last moment because on the recording you only hear the screams on the last moments.”
Given the latest information, the default scenario going forward will be that Lubitz commandeered the plane in order to commit suicide. However, I think it’s important to resist the tempation to consider the case closed. Indeed, the investigation has only just begun, and hopefully a good deal of information remains to be pieced together (though hope seems to be fading that the Flight Data Recorder will be usable). Though the weight of evidence may seem overwhelming, I still find it strange that a suicidal pilot would prolong his own agony by descending at a relatively modest 3000-4000 fpm instead of just pointing the nose straight down, as the pilots did in the other apparent suicide crashes such as EgyptAir 990 and SilkAir 185.
The case most similar to Germanwings 9525 is probably that of LAM Mozambique Airlines Flight 470, which crashed in 2013 while en route from Mozambique to Angola. The plane had climbed to its cruise altitude of 38,000 feet when it began to descend at a rate of about 6000 feet per minute. Six minutes later, it impacted the ground, killing all aboard. Data from the black boxes revealed that the captain locked the co-pilot out of the cockpit and changed the autopilot settings to initiate a descent.
I haven’t seen any reporting explaining what might have motivated the captain to do this.
Meanwhile, the Guardian is reporting that Lubitz had 630 hours flying time (which is very low) and had been with the company since 2013. “Lubitz was also described by neighbours as being friendly and pursuing his dreams ‘with vigour’. One told the local newspaper, the Rhein Zeitung that he had kept fit through running, ‘How often we saw him jogging past our house.’”
@Matty, I didn’t clearly know that before but there are rules in Germany. If his pilot’s licence is gone, the company has to keep him grounded. They have no choice. Of course a pilot can fight the withdrawal in court, but if he has a history of past mental illness – and Andreas L. had at least in 2009 (that’s one of the known facts of his medical history) it would be very difficult for him.
Well said Matty
“if you were running an airline you would want the right to impose any standard you chose”
Another reason to “Oath” them in. Crews & pilots alike. ATC’s take an oath mostly never to strike. Not looking to start a cult for god’s sack, but to have a family of folks dedicated in these times to deliver pax & crew alive…..Pipe dream? In a time where $$$$$$, luggage and more importantly TIME makes the difference? 911 changed many things it. Our own “Fail Safe” door measures Failed. While in the third month in the last two years we’ve lost 389 souls. 227 (MH370) + 150 (G-wings) And yes…I’ll walk the plank about 370. Suicide. 370 was a slow motion to oblivion. Chances of finding her are slim at best.
@Everyone
20 years from now.
A pilot less AC?
@Chris, would in a pilotless plane the board computer have to take an oath?
Or be programmed according to Arthur C. Clarkes famous three robot laws? 😉
I think more psychological screening or oath – you simply cannot prevent everything. A deluded pilot might even believe he’s fulfilling his oath. And a board computer steering a plane without a pilot’s input in the future might turn into a HAL or the computer of the intelligent bomb from the movie “Dark Star” – hellbent to destroy the plane for some weird internal logic. Or simply because a broken sensor screws up the computing like with the last Lufthansa Airbus incident – when the Captain saved the plane only because the computer could be switched off.
Littlrfoot
“@Chris, would in a pilotless plane the board computer have to take an oath?”
Yes. In the future, they will become drones. Men & Women flying A/C’s from afar oathed & wired, EEG, EKG, Etc. The human experience will never leave the cockpit, BUT only in the way of “Being There”. Oathed & compliant.
@Peter, @Chris
computers are preventing to do lot of bad things with todays planes; although a bit questionable to post such kind of video yet, here it is on A320:
https://www.youtube.com/watch?v=IKBABNL-DDM
Falken
Folks have brought up some good points regarding future A/C’s. They…IMO should be pilot less & droned flown, maybe by 2030?
This is a very serious allegation:
The NY Times claims Andreas Lubitz was treated for VISION PROBLEMS at the Düsseldorf clinic. According to the German newspaper “Die Welt” those problems might’ve been psychosomatic and he was taking a fair amount of medication.
If that is true it is really a bombshell. Andreas Lubitz wouldn’t have had a future as a pilot at all. The illness would’ve grounded him indefinitely and the discovery that he swept vision problems under the rug would’ve resulted in the immediate withdrawal of his pilot licence. And it would’ve been discovered eventually. He really had painted himself into a corner.
And if this is true, he behaved so irresponsibly against everybody who was flying with him and selfcentered in his desire to fly at all costs that the psychological mechanisms behind his seemingly inexplicable deed become a little less mysterious. By ignoring his illness he was jeopardizing knowingly everybody’s life every time he was on the pilot’s seat.
But his doctors will be in hot water, too.
Since the NY Times has been well informed so far and their information is compatible with the news here in Germany, this new info has a certain level of credibility. But they better be right with this story…
It has been discussed here in Germany and in France why the NYT was better and earlier informed than local media. It was suggested that the info sources for the NYT were military and secret service authorities who have been involved since day 1 because a potential terror connection had to be ruled out.
http://www.nytimes.com/2015/03/29/world/europe/pilot-andreas-lubitz-sought-treatment-for-vision-problems-before-germanwings-crash-authorities-say.html
Glaucoma.
Certainly the doctors knew and possibly his family too.
Had preciously been thinking epilepsy, or idiopathic seizures, placing him actually floundering about and accidentally hitting the controls, ending up against the door, preventing anyone’s entry.
OR early onset Alzheimers. But, Alzheimers and seizures would have been known, one can hide those conditions only for so long. Glaucoma in the early stages is more probable.
Hi guys
@jeff
Thank you and all for keeping the thoughtful and creative exchanges going on around 370
I understand how the altitude adjustment was made to crash the flight. Wouldn’t the perpetrator also have had to set coordinates to smash into the precise site where first hand reports indicate he obsessed about ands seems to have begun gliding? Seems he ended his obsession where it began?
A career-threatening illness puts the pilot in a very difficult position – ignore the issue and risk lives, or do the right thing and starve. It’s no better for the airline – risks lives, or either ruin an employee’s life or spend years in court.
At least some of this conflict could be resolved simply by requiring long-term disability insurance on those who are subject to medical dismissal. The risks are fairly easily quantifiable – pilots must retire by 60 (maybe 65 now?) anyway, and wages are pretty predictable. This is an easy problem to insure.
I hear a “laissez-faire” argument coming. While mandating insurance may not be free market, insurance itself is wholly market and statistically driven (or it would never work). Further, even the most capitalist economies mandate unemployment insurance.
Of course, I’d question why anyone with a revocable occupational skill wouldn’t be loaded up with insurance anyway.
@ JS: very fair assessment. Fully agreed.
I am actually not contradicting you. I just wanted to point to Lufthansa’s no-punishment approach: “CARSTEN SPOHR, CEO, LUFTHANSA: “We have at Lufthansa, a reporting system where crew can report without being punished their own problems or they can report about problems of colleagues without any kind of punishment.” (CNN, 26 March 2015, 19:00 ET)
Admitting to his problems would not have automatically ended his career. There would have been a corporate doctor involved and they would have tried to help him while at the same time avoiding any risks for passengers. We don’t know what exactly happened. It might not have been his fault, there is a possibility that he was prescribed pills which had a bad effect on him, who knows.
As far as I know, the target altitude of 100ft is a rumour, not an established fact.
And, unless you are an Airbus pilot, I repeat that “Airbus pilots confirmed, that it does not necessarily take several key strokes, you can just as well push the sidestick forward, then let it go. The plane would keep descending. Theoretically this could happen by accident, when slumping over unconsciously, albeit highly unlikely, since you would probably change the heading as well.”
see:
Just to be clear: I was not addressing the locked cabin door in my previous comment.
I am merely saying that pending evidence-based confirmation that a target altitude of 100ft was selected, there is a (small) chance that a physical problem (heart attack, unconsciousness, etc.) or disorientation (e.g. the vision problems cited by littlefoot) could have led to the sidestick being pushed forward unwittingly.
Although I agree that the sum of all “facts” (as transpired) doesn’t point there.
@Everyone
Jesus, Mary & Joseph, everyone please understand….he killed them all.
@Chris Butler
Ya think?
Going back to the MH370 mystery for a moment – and pretending to still trust the Inmarsat signal data’s authenticity:
Dr. Steel has recently put up a flurry of IG work on MH370 – thanks, Duncan. I’ll put my comments/questions here, in hopes this remains an appropriate channel for communicating with IG members.
Exner/Godfrey/Bennett’s FMT analysis ends at roughly N7°17′ E94°21.3′ at 18:41 UTC.
Yap Fook Fah’s BFO-minimizing path STARTS at S0°16.41′ E93°41.70′ at 19:41 UTC.
Those two points are separated by 60 minutes, but only 453nmi. The only way to connect up these two “BFO-optimized paths” is to have MH370 fly 500KTAS the whole way from IGARI to 00:11 – EXCEPT for the one hour “dead zone” BETWEEN the two analyses, where it must slow down to 450KTAS.
Luckily, Yap’s paper suggests its path could be rotated around the BTO arcs without materially deteriorating the BFO error. If you chose a 19:41 arc entry point just 47nmi south of that paper’s indicated “optimal” point, a constant 500KTAS could be maintained for the entire flight.
But this would move the IG’s best-estimate endpoint west to S38.18, E87.78. If those two papers represent the IG’s best thinking on the path, why wouldn’t they move their published best estimate to this point?
I feel both papers continue to make the critical error of over-weighting the value of MINIMIZING BFO residuals. I haven’t yet seen any logical rebuttal to my criticism of the FMT paper when it was first published: that claiming the 18:40 BFO value “shows” MH370 was in mid-turn is a classic example of “torturing the data until it confesses” to one’s pet theory, and that its lack of statistical validity is easily demonstrated. Two (to me) much more reasonable approaches are to a) attribute the small difference in the 18:40 heading indication to random noise, or b) relax the assumption that the entire heading change MUST have been fully confined to a single, tight turn.
More generally, I feel Dr. Ulich’s August paper remains the gold standard with respect to fitting a flight path to this sparse and noisy data. He assumed a much earlier turn, and ended up on the 7th arc WEST of E84 (where they’ve STILL not even BEGUN to search, over a year later…)
Finally, I take it the IG, by virtue of NOT condemning Yap’s 500KGS “optimal” path, now tacitly accepts that MH370 could have flown its signal data-indicated southern leg at 500KTAS and NOT run out of fuel. Can anyone confirm this for me explicitly?
While we’re at it: an official IG explanation of both…
– the utter lack of surface debris and
– the provable dishonesty* of search leadership
…would also be a good idea, inasmuch as each of these items eviscerates your SIO theory.
* No, it has NOT been mere incompetence – the untruths causing this year-long exercise in chasing rainbows have been far too many, varied, and clever.
I think I have found a smoking gun re MH370, I am still verifying that there is no mistake. Will post soon.
If unrelated to the Germanwings disaster, shouldn’t the MH370 discussion go into the ohter thread ?
Peter – Quickest way to to verify it is put it up here. Can just about guarantee that if there is a hole in it someone here will find it.
The BEA analysis & Brice Robin’s conclusion do not rely wholly on the CVR analysis. The aircraft transponder Mode-S datalink over secondary surveillance communicates flight path intent in addition to immediate location.
Flightradar24 has posted logs from their receiver network showing the flight path intent data: a descent rate & altitude target of 100ft was dialled into the Airbus FCU (Flight Control Unit, what is termed the Mode Control Panel on Boeings).
French air navigation services will have logged this data via their SSR & ADS-B assets. The urgency described for French ATC attempts to contact D-AIPX is understandable with this knowledge.
That data evidences a clear voluntary action on Lubitz’s part: the detail was lost in translation of Brice Robin’s words on Thursday. The CVR replay correlates that the descent was commanded when Lubitz was alone.
:Don
@Spencer
I’m tired…no exhausted with..”he was incapacitated” “There MUST be another reason” 007 BS regarding 370. It’s point blank on this one & people STILL don’t want to believe it. Astounding!!
227 pax & 12 crew on 370…nobody wants to believe it. Another 150 and we have to ACCEPT it. No one wants to believe that Shah did it. No one, in the face of reality wants to believe that this young man with everything going on in his life would to it, but it’s DONE. Proving…. 370 & this flight was doomed at the hand of a suicidal F***ing maniac .
@JS, interesting, that you mention the finacial aspect as well.
Lufthansa trained pilots start their career with hefty debth because they have to pay back the costs of their training. If their career falls apart early – as it could’ve been the case with Andreas L. – they probably still have to pay back. But I’m fairly sure that they have disability insurance.That’s common practice here. The bigger problem might’ve been to find another suitable job, since Andreas L. broke the regulations more than once by continuing to fly despite having been declared unfit by several doctors. That’s not a ringing endorsement to future employers.
We will soon know a bit more about his medical condition because his body has been found. So, some drug and medication tests can be performed.
@Peter Norton,
The reset to 100ft crusing altitude has been verified by the authoritites here. How do you get the idea it hasn’t? That’s actually one of the facts in this case.
@Don, yes, it’s correct to point out that the analysis of the probable string of events doesn’t wholly rely on the audio data. They merely correlate with the data logged by the French ATC.
@littlefoot, where did you see that Lubitz’s body had been found? I searched and wasn’t able to find anything. Thanks!
Jeff
http://www.deccanchronicle.com/150329/world-europe/article/hometown-pastor-says-community-stands-gremanwings-co-pilot-family
“Brice said that none of the bodies recovered so far have been identified, denying German media reports that Lubitz’s body had been found.”
http://www.fci-ophthalmics.com/blog/what-to-expect-after-your-retinal-detachment-surgery/
…Prompt treatment of a retinal detachment is vital to the prevention of permanent vision loss.
…Retinal detachment procedures are highly successful, come with few complications, and are imminent when a detachment occurs to help restore vision before blindness becomes permanent.
http://www.forbes.com/sites/davidkroll/2015/03/29/faa-procedures-for-pilots-with-depression-taking-ssris/3/
Andreas Lubitz and SSRIs
A variety of conspiracy theorists often found online have suggested a role of psychotropic drugs used to treat mental illness and the behavior of mass murderers, dating back to the 1998 Columbine High School killings in Littleton, Colorado. Even CBS News presented a case that considered whether Zoloft (sertraline) was responsible for a 12-year-old South Carolina boy shooting his grandparents to death and setting their home on fire. …
Assuming that Lubitz was taking an SSRI drug, we still have no way to conclude that the drug contributed to what appears to be his intentional act of mass murder and suicide. For one, we don’t yet know if what investigators are calling “depression” was complicated by any symptoms of psychosis that might have compromised or confused Lubitz’s reasoning and perspective on reality. Unless DNA testing could identify human tissue belonging to Lubitz at the crash site, we don’t even know if he was taking the drug or drugs at the time of the crash. …
@Jeff and everybody,
I can’t name a single source right now, but it was all over the German news, that enough of the co-pilot’s body has been recovered to acheive a DNA match, They want to perform tests now in order to find out what was in his system. It might take a while until we get exact data. The announcement was made by the investigating authorities. They didn’t go into any graphic details.
I have to correct myself: According to “The Independent” “Der Spiegel” and “Bild Zeitung” parts of the co-pilot’s body have been most likely recovered, but they still have to perform in debth DNA tests in order to be completely sure.
It’s interesting to observe how things are leaked to the news outlets in this case.
The NY Times and German “Bild Zeitung” seem to be best informed. So far most of their reports have turned out to be accurate. Otherwise those two papers couldn’t be more different.
While “Bild Zeitung” is clearly a tabloid as far as covered themes, events, style of writing (sensational hyperbole) is concerned, in the last decade they’ve had an excellent factual accuracy track record. If you want to know all the grisly facts of an event or the sordid details of a political scandal or messy break up you go to Bild Zeitung. They’re not shy to write about it. Unfortunately they wield their considerable political power not always obelectively,and – while mostly they get their facts straight – the devil can be in the details they chose to ommit.
Have any of the news sources reported cell phone calls from the passengers to their families, as was the case in the September 11th hijackings? Surely, the passengers must have heard the commotion created by the pilot smashing at the cockpit door several minutes before the plane crashed. There would have been enough time to at least get a call started, text message, tweet, etc.
Also, does the fight attendant crew in the passenger compartment have a ground communication radio in this particular aircraft? Is there any news of radio messages from the passenger compartment crew? They would have known almost immediately that something was amiss when the pilot first realized he was locked out of the cockpit.
“… Focus magazine reports that the Germanwings co-pilot who crashed his plane into the French Alps had bought two brand new Audi cars just weeks before he killed himself and and the other 149 people on board the flight, reports Rory Mulholland.
It said Andreas Lubitz ordered the two vehicles – one for himself and one for his girlfriend – from a car dealer in Dusseldorf. One of the two cars had recently been delivered, said Focus. …”
http://www.telegraph.co.uk/news/worldnews/europe/france/11491587/Airbus-A320-crashes-in-French-Alps-with-148-people-on-board-live.html (ongoing updates)
Jeff, I apologize if this is a duplicate post. My first attempt did not appear to succeed.
@Brock,
One minor point is that I did not “assume an early turn.” My only turn assumption was that it occurred after the last radar contact at 18:22:12 and before 19:41. The turn time was one of the variables in my fit of BTO data and a smooth speed profile, with BFO being checked just to make sure it was within 7 Hz. I agree that fitting routes to minimize BFO residuals below the expected statistical variation can only lead to results that are demonstrably incorrect.
My turn time result is consistent with all the BFO data (other than the one point at 18:25:34 which Inmarsat says to disregard) if a climb was occurring during the turn. My fuel analysis indicates it is much more likely that the aircraft reached 40S if it was at FL390 to FL410 near the end of the flight. So, what I am finding is that a single (early) turn and simultaneous climb allows the endurance and range and BFO all to be consistent with data and expectations.
One minor point that needs more scrutiny is the small variation in observed BTOs from 18:25 to 18:28. Most groups (IG and ATSB and me) have not shown that their routes are entirely consistent with all the BTOs here. Perhaps it is just an unlikely statistical variation or perhaps a second turn was made. In my opinion, that is still an unanswered question I plan to address more fully.
Analyses are underway of the available acoustic data. This includes further investigation of the H01 events at 00:52. My preliminary results indicate that the first event came from a different bearing than the second event, confirming the LANL judgment. I get a bearing of 249 +5/-19 degrees, which is consistent with a 40.0S 83.3E impact event at 00:21. I have distributed my draft report to the other parties working on the acoustic data for their critique. The multi-station analyses now include ~18 stations and indicate a 40S location very close to the 7th arc with a single-station error of ~10km RMS using the event timings from Kirill Prostyakov. Work is underway to validate his results. Considerable improvement in localization accuracy could be obtained by recording sounds at these stations from a depth charge exploded at a well-known location near 40S at a precise time. That would allow calibration of the bearing-dependent sound speed and therefore improve the accuracy of the station range calculations.
In the meantime, it is somewhat reassuring to learn that Australia has about 2/3 of this year’s search budget unspent. Hopefully the ATSB will decide to continue searching next season and include 40S in a new priority area.
Hi again-
This is reassuring. I couldn’t figure out how someone who had been declared ‘unfit to fly’ during his initial Lufthansa training in Phoenix had been awarded this special recognition by the FAA. I bet he framed this and had it on his wall.
http://www.newsweek.com/fake-article-claims-faa-praised-germanwings-crash-pilot-andreas-lubitz-316849?piano_d=1
I think you need to check the average BFO error. A non-zero average error may indicate a bias. It should approach zero for a random distribution of errors with sufficient number of samples.
@Gysbreght,
You are correct that the average BFO error for the correct route should be small. I forgot to mention that. For my WITN route the average BFO error is much less than 1 Hz.
@Guarded Don
Thank you for clarifying the data transmission issue I asked about.
A big question remaining in my mind is why the co-pilot used the the auto pilot to put the plane into a controlled descent, rather than simply nose diving it into the ground, or cut the engines and let the plane glide, unpowered into a steeper crash path. Are there experienced pilots who can give a plausible techical reason for the co-pilot’s choice? Or, is the answer simply the obvious: Crazy people do crazy things.
Thanks for that information. Nevertheless, it should be noted that the errors are not random, but increase monotonously from -9.3 Hz at 19:41Z to +6.6 Hz at 00:11Z. Surely that is likely to be significant and should not be ignored?
Gysbreght, Bobby,
If there is a trend in residuals, especially monotonic, I think a path should be discarded… From my experience you can make virtually any point on the 7th arc in the SIO to be the terminal point under some hypothesis (within the fuel range), with the BFO residuals less than 10 Hz. But I observed that residuals often tend to form some trends.
Oleksandr
It would be nice to do a full analysis of the noise component in the BFO data but unfortunately the Investigation has not published enough information to allow that. We have the MH370 BFO data and one graph in the Inmarsat Ashton et al paper plotting some BFO data from the ‘Amsterdam’ flight. Some conclusions on the noise component can be drawn from those data but not enough to be convincing (to sceptics). The Investigation has lots more data from previous flights of 9M-MRO and similar aircraft to fully probe the noise, but that’s not available to us. This problem is not helped by the Ashton et al paper saying:
“While the [BFO] validation demonstrates the general accuracy of the BFO technique, it is important to note that agreement is only achieved with ±7 Hz accuracy during this flight, and to assume better accuracy for the measurements taken on MH370 would be unrealistic.”
which seems on the face of it to be an attempt to discourage any serious use of the BFO data for path modelling, but we know the ATSB data optimisation modellers did precisely that. Was this a sort of product liability statement added by the Inmarsat lawyers? The teaser graph of the Amsterdam flight suggests the noise is much better than ±7 Hz.
Anyway, there are two camps, both inside the investigation and out. The constrained autopilot dynamics method groups give the BFO data low weight, or in the case of the IG discounts BFO points that don’t match (on at least arguable grounds, e.g. a descent at 00:11UT). Clearly, the search has invested a large fraction of its early efforts in the part of the SIO search area that corresponds to these methods, so that group has significant support inside the Investigation. The data error optimisation method case is less clear as very little has been published on the data errors and the Investigation’s analysis methods. Reverse engineering the N/S search area bounds might suggest a BFO random error of ~2.3Hz and a bias error of +/-0.5Hz, if standard probability significance tools have been used, but that’s a bit of a guess, though consistent (the random element) with the published Amsterdam flight data.
The search team’s attention will be moving soon to the inside of the arc in the centre and North areas, so for me this will be the interesting period. I’ve always felt the AP mode paths put the aircraft too far South for the BFO data.
I agree 100%. The idea of an unattended autopilot really doesn’t make much sense. Are we we to believe that someone set up the autopilot and autothrust, turned off the lights and left the airplane, closing the door behind him?
Factual Information figure 1.7A shows the ITCZ (InterTropical Convergence Zone) just south of the equator. Most airplanes crossing the ITCZ have to make a detour to avoid the worst CB’s. AF447 and AWQ8501 crashed while doing just that. And MH370 never deviated a mile from its set course?
Richard Cole,
Thanks for your comment. Besides the absolute error, sometimes there is a problem with trends. For example, BFO residuals might be -1.5, -1, -0.5, 0, 0.5, 1.0, 1.5 Hz. The absolute error of each sample does not exceed 1.5 Hz; the mean error is 0, but there is a linear trend in this sequence.
Just to say that I think the original ATSB data optimization approach corresponds to the “constant thrust settings” flight mode.
As reported several days ago, I now have a Mode-S/ADS-B receiver (only $20 at Amazon) working and have been monitoring air traffic into and out of the local airport. Here are a few observations:
1. All transmissions are on 1090 Mhz. I estimate that I receive 50 messages per second. Most are of the 56 bit variety (1 microsec per bit). So the duty cycle in this channel is of order 3-4%.
2. A Mode-S packet with Downlink Format 20 (DF20) is the message type that provides “vertical intent”; it is this type of message that flightradar24 reported receiving from 4U9525 with an intended altitude of 100 ft. In a random sampling, I found that about 0.1% of all Mode-S packets are of this type. I had to write my own routine to decode the raw packets. As far as I can tell, no aircraft around here actually writes valid data in the message field (or else I am not decoding it properly).
3. Most aircraft do not have ADS-B capability. This means that they do not broadcast their position to other aircraft. (Only the radar operator knows where they are.)
I haven’t bothered much yet with ADS-B broadcasts (Mode-S DF17), which comprise much of the info used by flightradar24. Up next is ACARS.
Oleksandr
There is a rule-of-thumb that a slew in the residuals indicates a poor fit, regardless of other indicators, but I am not aware of an accepted statistical test to the same effect.
I don’t find any effect from speed evolution (up to +/-6kt per hour) on the statistically significant destinations from the BFO data. Similarly, headwind correction on the speed has no effect. I keep a constant true course.
@sk999, That’s very cool! Especially about the “vertical intent” message field. Please do keep us informed about your further experimentation.
Jeff
This seems to be the most informative site that I have come across as of yet and I am hoping that you guys could possibly answer a question of mine that I have not been able to find a response to. Why would Lubitz don an oxygen mask? I keep reading these reports stating that he put on an oxygen mask and I can not deduce why he would. Insight?
@Maya, Great question, I was wondering that myself. As far as I can tell, the only reason they have for thinking he put on the oxygen mask is that his breathing sounded that way. Not to be macabre, but if I was in his shoes I’d be huffing nitrous oxide…
@Maya & Jeff,
I haven’t come across any reports that Andreas L. was wearing and oxygen mask.
There was some speculation that he might because of his audible breathing. But that was explained by the placement of the microphones in the cockpit and some in debth analysing of the sounds in the cockpit.
Is there a trustworthy source that says he wore an oxygen mask?