After French authorities retrieved the MH370 flaperon from Réunion Island, they flew it to the Toulouse facility of the DGA, or Direction générale de l’Armement, France’s weapons development and procurement agency. Here the marine life growing on it was examined and identifed as Lepas anatifera striata, creatures which have evolved to live below the waterline on pieces of debris floating in the open ocean.
Subsequently, flotation tests were conducted at the DGA’s Hydrodynamic Engineering test center in Toulouse. The results are referenced in a document that I have obtained which was prepared for judicial authorities by Météo France, the government meteorological agency, which had been asked to conduct a reverse-drift analysis in an attempt to determine where the flaperon most likely entered the water. This report was not officially released to the public, as it is part of a criminal terrorism case. It is available in French here.
Pierre Daniel, the author of the Météo France study, notes that the degree to which a floating object sticks up into the air is crucial for modeling how it will drift because the more it protrudes, the more it will be affected by winds:
This translates as:
The buoyancy of the piece such as it was discovered is rather important. The studies by the DGA Hydrodynamic Engineering show that under the action of a constant wind, following the initial situation, the piece seems able to drift in two positions: with the trailing edge or the leading edge facing the wind. The drift angle has the value of 18 degrees or 32 degrees toward the left, with the speed of the drift equal to 3.29% or 2.76% of the speed of the wind, respectively.
The presence of barnacles of the genus Lepas on the two sides of the flaperon suggest a different waterline, with the piece being totally submerged. In this case we derive a speed equaly to zero percent of the wind. The object floats solely with the surface current.
This suggests a remarkable state of affairs.
Inspection of the flaperon by Poupin revealed that the entire surface was covered in Lepas, so the piece must have floated totally submerged—“entre deux eaux,” as Le Monde journalist Florence de Changy reported at the time. Yet when DGA hydrodynamicists put the flaperon in the water, it floated quite high in the water, enough so that when they blasted it with air it sailed along at a considerable fraction of the wind speed.
As point of reference, Australia’s CSIRO calculates that that the drifter buoys that it uses to gather ocean-current data pick up a 1.5% contribution from the wind. Here is a picture of one such drifter, kindly supplied to me by Brock McEwen. You can see that more than half of the spherical buoy is out of the water.
It is physically impossible for Lepas to survive when perched up high in the air. Yet the buoyancy tests were unequivocal. So Daniel pressed on, conducting his analysis along two parallel tracks, one which assumed that the piece floated high, and the other in which it floated submerged. For good measure, he also considered scenarios in which the flaperon floated submerged until it arrived in the vicinity of Réunion, and then floated high in the water for the last two days. (Note that he doesn’t present any mechanism by which a thing could occur; I can’t imagine one.)
After running hundreds of thousands of simulated drift trials under varying assumptions, Daniel concluded that if the piece floated as its Lepas population suggests, that is to say submerged, then it couldn’t have started anywhere near the current seabed search area. (See chart above.) Its most likely point of origin would have been close to the equator, near Indonesia. His findings in this regard closely mirror those of Brock McEwen and the GEOMAR researchers which I discussed in my previous post.
Daniel found that when simulated flaperons were asssumed to have been pushed by the wind, their location on March 8, 2014 lay generally along a lone that stretched from the southwest corner of Australia to a point south of Cape Horn in Africa (see below). This intersects with the 7th arc. However, as Brock has pointed out, such a scenario should also result in aircraft debris being washed ashore on the beaches of Western Australia, and none has been found. And, again, the presence of Lepas all over the flaperon indicates that such a wind contribution could not have been possible.
Pierre Daniel’s reverse-drift analysis for Météo France, therefore, presents us with yet another block in the growing stack of evidence against the validity of the current ATSB search area in the southern Indian Ocean.
The most important takeaway from this report for me, however, is the stunning discrepancy between how the flaperon floated in the DGA test tank and the “entre deux eaux” neutral buoyancy suggested by its population of Lepas. No doubt some will suggest that the flaperon may have contained leaky cells that slowly filled as it floated across the ocean, then drained after it became beached. However, I find it hard to believe that an organization as sophisticated as the DGA would have overlooked this eventuality when conducting their wind tests. Rather, I read Daniel’s report as evidence that the French authorities have been unable to make sense its own findings. I suspect that this is the reason that they continue to suppress them up to this day.
Here is a fundamental question. When the flight control system of a B777 is operating in normal law, and the autopilot is off, is the roll mode attitude stabilized? The pitch mode is, where the input is the column position. However, the wheel position controls the roll rate, not the bank angle. So at neutral position of the wheel, is the roll mode stabilized, i.e., is the bank angle held constant via closed-loop feedback?
Most believe that the plane would eventually enter into a steep bank as the roll mode is not stabilized. I am searching for a precise description of the algorithm.
Here is a useful (although elementary) description of the flight controls for a B777:
https://www.linkedin.com/pulse/analysis-boeing-777-fly-by-wire-system-jaime-beneyto-g%C3%B3mez-de-barreda
@Ed
At the fourth time of trying but failing to reply, I’ll make this brief (no links)… to sum up, the MH370 black box doesn’t float. There is debate going on surrounding deployable (i.e. floatable) black boxes, some stating they should be mandatory. But at the moment, deployable ones are used mostly by the military.
@Jia_Zijian_chn, @Susie
Good spot from Jia Zijian! On Twitter they are serving up a variety of possibilities – WWII plane, Russian or UN helicopter, Somali Airforce plane… or even a crash far away from Somalia.
But what is odd, a Twitter user (@Malick1975) has claimed MAS officials will be arriving in Somalia today to investigate??? Huh!?
@VictorI:
“However, the wheel position controls the roll rate, not the bank angle. So at neutral position of the wheel, is the roll mode stabilized, i.e., is the bank angle held constant via closed-loop feedback?”
The neutral position of the wheel commands zero roll rate. Yes, the Flight Control System will activate ailerons, spoilers and rudder to maintain a constant bank angle with the wheel released. In normal mode it will also control pitch attitude through the elevators to maintain a constant airspeed as required for proper turn coordination, and there will be overbank protection.
The steep bank
Commanding zero roll rate is not the same as maintaining a constant bank angle. A disturbance on the plane will create a roll rate, and the control system will return the roll rate to zero by moving control surfaces. However, by the time the roll rate is returned to zero, the bank angle is no longer zero. So a constant force disturbance would create a change in bank angle from zero if roll rate is commanded and not bank angle
@VictorI:
My understanding is that active control of zero roll rate is the same as maintaining a constant bank angle, even with disturbances in light to moderate turbulence.
In the pitch axis that covers also changes of thrustsetting and configuration – read the description you linked to.
@Gysbreght: The reference make a clear distinction between control of the pitch and roll axes. If we take the words literally, a neutral position of the wheel would not maintain zero bank angle for the reasons I mentioned. I am looking for a more technical description to be sure the literal interpretation is correct, not impressions that people have because those impressions vary widely. A state variable of a system (bank angle) cannot be controlled to a particular setpoint (zero) by controlling its derivative (roll rate) because a disturbance will create an offset (non-zero bank angle) as I have described.
@Erik Nelson
Hi Erik, Good to hear from you. I knew a short break and some sea air would do wonders for the multiple scenario syndrome 🙂
Re. Kerguelen Island: a straight track in that direction would not cross the BTO arcs at the required times, imho.
My guess is that soon after the turn at IGOGU (estimated time 18:37) while the a/c was tracking toward waypoint ISBIX, the pilot set up a manual, along-track waypoint in the FMC, calculated to be beyond the fuel range of the aircraft. The aircraft would then proceed along the same geodesic until fuel exhaustion.
If the pilot set the cruising speed at a constant Mach 0.81 at 35,000ft, he would cross the 7th arc at S37.62, E89.08, having crossed all the other arcs in the right place, at the right time.
This crossing point is close to the DSTG’s Bayesian hotspot, centered on S38.0, E88.4.
A few months ago, lot of media coverage was given to Simon Hardy’s “reverse engineered” solution. This envisaged a constant track or loxodrome of 188deg azimuth, starting near ANOKO, and flown at a constant groundspeed of Mach 0.84 (I know, but don’t shoot the messenger) His path crosses the 7th arc at about S39, E86.5. An aircraft flying this path would cross the 4th, 5th, 6th arcs in the right place at the right time, but the 2nd and 3rd arc crossings would have been way out.
you have realise though that this is a computer simulation,how well do we really know the oceans currents, do we trust our ocean current knowledge or do we trust our technological knowledge of satellite pings?
Gysbreght,
Re “In the ATT position of that switch the affected ADIRU (1, 2 or 3) only provides attitude and heading information, but does not provide navigation data such as groundspeed, windspeed, track, and latitude/longitude. The switch does not select an autopilot mode.”
If all ADIRUs do not provide navigation data you listed above, how can autopilot maintain selected HDG, TRK or LNAV mode?
Re :”I doubt that A320, A330 autopilots even have an ATT mode comparable to that on the B777.”
Do you have more information to compare ATT modes of A320, B757, B767 against B777? My impression from reading semi-accurate forums was that B757, B767 and 320 have similar functionality of ATT mode. I did not find anything on B777.
Gysbreght,
Re “My understanding is that active control of zero roll rate is the same as maintaining a constant bank angle, even with disturbances in light to moderate turbulence.”
No, no understanding is wrong.
I meant your undestanding is wrong. Active control of zero roll rate is not the same as maintaining a constant bank angle. This depends on the feedback system, which has to sense non-zero roll rate to apply correction. When correction is applied, bank angle is not the same as it was before.
@ Victor I: Your interpretation is consistent with the ATSB’s assessment that after double flame-out with the FCS in secondary mode a turn at low bank angle would ‘eventually’ develop.
What is the basis for the myth of steep bank angle?
@oleksandr:
“My impression from reading semi-accurate forums was that B757, B767 and 320 have similar functionality of ATT mode.”
Your impression could be correct. For those airplanes the ADIRU panel rotary selector ATT position controls ADIRU output so that it supplies attitude and heading information only.
Maybe something else to consider on buoyancy and barnacles with the flaperon.
If the plane (and the flaperon with it) came down around 30S or further south it would have come down in colder water of around 17C at that time.
It was March and the southern ‘winter’ was coming. The flaperon would have floated than first to the north maybe for months in this colder water while the warmth retreated till november 2014 when the ‘summer’ started to heat the water again and push south again.
Asuming (logicaly) the flaperon started with great buoyancy and partly sticking above the surface picking up (mostly southern) wind, this leg to the north could have been traveled faster without the or lesser possibility of barnacle growth.
Arriving in warmer water say, on the line around Exmouth N.W. Australia in October/November 2014 and allready filled with water, it could have started its journey to the west almost completely submerged and starting to grow barnacles all around and from that point on slowed down substantialy only moving on the surface current to arrive in july 2015 the way it was found on Reunion.
МСРП-12-96!
This type of spherical flight recorder is displayed in Russian version of wiki page for “Flight Recorder” (as i excepted!)
Correction. The warm water starts to come back in august to september. So that leaves more time for barnacles to grow. But the principel stays the same.
And for ‘impossible’ about having to come out of the water in between to drain its internal water and after that put it back in the ocean again; its possible when someone picked it up out of the ocean, got drained and planted it later back in.
This would support Jeff’s previous hypothesis..
@Jeff Wise.
By the way, you did not show the pictures in the report that show the mixed results with barnacles and angles. They show other pictures.
Could you provide coloured versions or a link to it?
@Gysbreght @Oleksandr @VictorI.
Me being a nerd on AP or manual possibilities wonders how this discussion on ATT or not, can be of big importance to the question on how a AP or other mode could lead to a position on circa 29S 98E.
Is it too complicated to just answer that question?
Ge Rijn,
“Is it too complicated to just answer that question?”
Not complicated at all. I still believe that a technical failure could be responsible for the disappearance. Triple-redundant ADIRU with quad-redundant computer is a primary source of the navigation data. FMC relies on ADIRU and GPS data. If ADIRU fails (there quite a number of known cases when it failed), the secondary source of data is SAARU. However, the latter cannot provide data to maintain TRK or HDG HOLD, or LNAV modes, but sufficient for ATT HOLD mode. In this mode an aircraft’s trajectory depends on the Coriolis force and cross-wind drag. That is it.
Cheryl,
Regrading jettison. Citation from:
http://ads-b.ca/777/B777-Electrical.pdf
——–
If both IDGs and the APU generator are inoperative, a backup generator powers
essential airplane equipment. To reduce electrical loading on the backup
generator, the following systems are inoperative:
• TCAS
• SATCOM
• Right HF radio
[HF Datalink installed]
• Right HF radio and associated datalink
• Center tank override/jettison pumps (center tank fuel is unusable and
cannot be jettisoned)
[777-200LR]
• Center tank override/jettison pumps (center tank and auxiliary fuel is
unusable and cannot be jettisoned)
• Position and other exterior lights (except nose gear landing lights)
• All non-essential cabin equipment (galleys, entertainment systems, etc.)
• Passenger cabin lighting (except night, galley and cross-aisle lights)
• Cabin temperature control (remains operative, but in degraded mode)
——-
I have not found anything yet on the bus, which feeds jettison pumps.
@oleksandr:
Yesterday at 4:22 PM you wrote (quoting from FCOM 11.20.4) that HDG HOLD/SEL is available when standby magnetic compass heading is entered on the POS INIT page.
meanwhile:
“As a responsible nuclear weapons state, our Republic will not use a nuclear weapon unless its sovereignty is encroached upon by any aggressive hostile forces with nukes,” KCNA quoted Kim as saying.
“And it will faithfully fulfill its obligation for non-proliferation and strive for the global denuclearization.”
“The WPK and the DPRK government will improve and normalize the relations with those countries which respect the sovereignty of the DPRK and are friendly towards it, though they had been hostile toward it in the past,” Kim was quoted as saying.
http://www.reuters.com/article/us-northkokrea-congress-idUSKCN0XY0QB
no words to the Alberta fire hell; God bless ’em all
http://s32.postimg.org/st4p4v39h/FMT_to_POVUS.png
According to Excel, the two best-fit trend-lines, fitting BTO values, both calculated for Penang to MEKAR, and raw for the southern leg, intersect at {18:36:18, 12075}.
At that time, the BTO to waypoint IGOGU was only 11999.
So, I very tentatively conclude, that the a/c did not reach IGOGU, but FMT’d prior to reaching that waypoint. Also, given last-known airspeed, the a/c may not have had sufficient time to reach IGOGU by ~18:36, either. That strengthens the suggestion, that the a/c did not actually get to IGOGU.
Given the elevation angle of 52-degrees, the ~75 microsec difference from IGOGU (<12000) to FMT (12075) corresponds to ~16nm. I.e. I suggest that the a/c only traversed 88nm of the 104nm from NILAM to IGOGU. Plotting this proposed position on a waypoints chart, I observe that this hypothesized FMT would have occurred precisely due north of waypoint POVUS.
So I offer that the a/c may have FMT'd towards waypoint POVUS, over perhaps 120 seconds, from 18:35-37.
Does anyone think the plane was carrying a nuclear weapon, with passengers on board, would we put this past them? Was this plane sent way out to sea to detonate? Sonic boom?
Remember my arguement for ‘neutral boyancy’ and my little video demo, when you ssid objects either “sink or they float”…theybcsnt do both?
This suggests a remarkable state of affairs.
Inspection of the flaperon by Poupin revealed that the entire surface was covered in Lepas, so the piece must have floated totally submerged—“entre deux eaux,” as Le Monde journalist Florence de Changy reported at the time. Yet when DGA hydrodynamicists put the flaperon in the water, it floated quite high in the water, enough so that when they blasted it with air it sailed along at a considerable fraction of the wind speed.
@Oleksandr. Training Manual 28-31-00 p158
“The left fuel jettison pump receives 115v ac power from the left main bus.” Presumably the right receives it from the right.
Gysbreght,
Re: “Yesterday at 4:22 PM you wrote (quoting from FCOM 11.20.4) that HDG HOLD/SEL is available when standby magnetic compass heading is entered on the POS INIT page.”
So what is your question?
If you mean my previous response to Ge Rijn, then what I meant is that a B777 cannot operate in TRK HOLD or LNAV modes after ADIRU fails, while a manual input of heading is required for HDG HOLD again. In which mode a B777 will operate during this transitional period? An additional question: why would a pilot opt for HDG HOLD instead of ATT HOLS if ADIRU fails? Any advantage?
If you mean the keyword “magnetic”, then I think it is entered only once to initialize operative IRUs (it is very unlikely all IRUs of ADIRU become inoperative simultaneously). Complete realignment does not appear to be possible in the air as ADIRU senses aircraft’s movement. An interesting question is whether it equally well senses both NS and WE components of the motion.
David,
Wow, that is very important piece of information. Thanks.
Just a speculative thought:
In the unlikely event of comlete depowering, SATCOM becomes inoperative. If ACARS was switched to SATCOM channel, it would stop transmitting. It could possibly take some time for the crew to realize this fact and switch ACARS to VHF channel. But when they switched to VHF, they were not in a coverage zone (I recall Don or someone else mentioned that ACARS VHF coverage is very poor in Asia). When SDU came back by 18:25 the crew was busy and forgot to switch ACARS back to SATCOM channel, and indeed there is no VHF coverage over the Indian Ocean.
Does this explanation why ACARS remained silent after SDU reboot make sense?
Now you’re twisting your words dear chap, but never mind.
@Oleksandr
MH370 should have been within VHF coverage until at least 18:25.
http://bronze-qa2.mygdc.com/attachment/DatalinkCoverageMap.jpg
Also, normal setting is “auto” rather than either SATCOM or VHF.
@all
On May 6, 2016 at 7:05PM
@Rand said to DennisW.
“The work of the IG is data driven – period. They are more focused on the location science. Perhaps it is a good thing that they are thus so preoccupied, leaving speculation as to various scenarios to other good people found here……”
I appreciated his wording, it was such a clarifying statement, a necessary reminder of what they do and the importance of it.
Today being Mother’s Day I was given the luxury of a few hours to do exactly as I wanted. If one is an MH370 junkie “free time” often means a prodigious amount of reading, sifting through the trash of information trying to find something of value. My experience with social media prior to this was nil and not something I
find comfortable or enjoy, unfortunately it is the “nature of the beast”.
On May 8, I posted a comment, questioning a response from ALSM to someone on Twitter which read:
“Your suggestion that Isat data is fraudulent is offensive, hurtful to NOK…..”
It appeared to me as cliche and without merit. I responded, questioning the accuracy and did not give it another thought.
Then today, I ran across 2 posts on Reddit from GuardedDon. The two posts were as follows:
(1) – This comment referenced the JW article
“The report was produced by France Meteo, France’s meteorological agency. It includes a reference to a DGA hydrological study of the flaperon’s buoyancy and orientation.
The report is dated Feb 2016 and has no ‘protective marking’ to indicate that its distribution should be restricted in any way. To claim that information has been hidden for a considerable period of time, or that the information is secret, or that the conclusions (if any) are baffling is pure journalistic license. It’s this bias in the Wise presentation that I am most uncomfortable”
Guarded Don
The only pertaining reference in Jeff’s piece infers nothing of information being “hidden” or “secret”. This is what Jeff wrote;
“Subsequently, flotation tests were conducted at the DGA’s Hydrodynamic Engineering test center in Toulouse. The results are referenced in a document that I have obtained which was prepared for judicial authorities by Météo France, the government meteorological agency, which had been asked to conduct a reverse-drift analysis in an attempt to determine where the flaperon most likely entered the water. This report was not officially released to the public, as it is part of a criminal terrorism case. It is available in French here.”
(2) His response to Brock McEwen;
“Slumming around here in online chat groups”
“And somehow the secret ‘dens’ of Facebook and the comments stream at jeffwise.net are in someway more erudite? How condescending”
Below is the corresponding link;
https://m.reddit.com/r/MH370/comments/4hj6p0/jw_has_a_copy_of_french_judiciary_report/
For those of you without “erudite” grammar, see definition below;
er·u·dite
ˈer(y)əˌdīt/
adjective
having or showing great knowledge or learning.
synonyms: learned, scholarly, educated, knowledgeable, well read, well informed, intellectual
It is discouraging to find this disrespectful rhetoric from the “data driven – period” IG, it should be beneath all of us.
Should read “On April 8”
@Susie, Thanks for pointing this out. This strikes me as strange behavior. Is there really any question as to whether the Météo report was in the public record or not? If Don feels otherwise than he should obtain and release the other reports generated by the French judicial investigation. And as to his claim that it’s not baffling–well, again, if it’s gin-clear to him then he should enlighten the rest of us, because I sure don’t see how an object can at the same time be floating submerged and sticking substantially out.
I have enormous respect for the technical skill of all the IG’s members but to say that they are purely data-driven is at this point delusional. I don’t think we should tar everyone with the same brush, but I’ve come to wonder whether Don, Mike and Richard were ever really interested in solving the mystery or only were ever interested in promoting the official ATSB narrative, however untenable. Scientists change their minds as the facts before them evolve; lawyers, mystics and propogandists stay on track and come up with a new set of justifications.
Jeff – It’s getting nasty as you would expect as this thing winds down. Confirms that there are ego’s and jealousies and I always knew that. I’ve felt for ages that elements of the IG had become more interested in sustaining a credit sharing pact than anything else. From a bit of retirement glory to nothing after two years of hard graft. Not all are going to take it well, but that again confirms where the motivations have ended up heading. Not content with sucking up all of the 200 million thrown at it, they now belittle themselves.
@Susie Crowe, @Jeff
I do follow the topics on Reddit but only because there is sometimes interesting new information or links there. However, there are a lot of nasty comments and put-downs which I try and ignore; its been like that for a long time. Also, a couple of Jeff’s recent articles have been linked to on the MH370 France facebook page. Lots of comments there, some nasty; a few commenters provide interesting thoughts but I haven’t found any new information there. Lately, another good blog, Plane Talking – Crikey, hasn’t been updated for quite a while; pity.
Thanks Jeff for this particularly good article. Assuming DGA did comprehensive buoyancy testing (I wouldn’t expect otherwise and they have had plenty of time) then the flaperon appears to have been tethered and then planted; if so all the technical discussion about flight modes, trajectories and such like will be irrelevant. I mean no disrespect to those who have earnestly endeavoured to find this plane using the ISAT and radar data.
@Susie Crowe
Happy Mother’s Day.
As far as data-driven is concerned, there is no such thing relative to MH370. It is simply a matter of where your speculation comfort zone lies. I am not speaking about data validity here, but rather how the data is used and what assumptions are layered on top of that use.
If one believes the ISAT data and debris finds are valid, which I do, you can make some strong statements about where the plane did not terminate.
If one cannot model the BFOs to an autopilot mode that ends in an area not yet searched, the BFOs basically go out the window.
They may still be accurate, but it no longer matters because no model can estimate every move by a pilot over 6 hours if it’s flown manually. They may also still be accurate but not accurate enough to focus a search that still hasn’t found a single beer can.
So without making an attack on the IG personally, despite clashing with them at times, the real story is that the BFO model is irrelevant and with it, the IG’s models. No BFO model can now guide the search unless another major assumption is abandoned.
The only thing that we currently have is the same thing we started with – ping rings. Might be time to reconsider those too – maybe the only thing we really know is that the plane exhausted its fuel and is missing a flaperon.
@JS
I feel pretty confident about the BFO data telling us the plane flew South after the FMT. I agree that extracting more detail than that requires flight dynamic assumptions to be made. I think just about any 7th arc position South of Java can be made to work – limited by fuel range and debris finds. That still leaves a lot area.
Flaperon flotation, its consequences and interpretation are issues. Another, about which there is no information at all is its mode of separation from the wing. Was it after fatigue, meaning flutter and high speed? Surely fracture examination would establish this in no time. If overstress, are the circumstances unfathomable?
@JS
I agree it would be difficult to fly the plane for 6 hours manually.
If Shah continued as he started, using waypoints and letting the plane do the flying he would only have needed to cross three waypoints while flying between the ping rings from 19:40 on.
He would have flown straight paths and would not have had to vary the speed to do this.
The final ditching would have been well North.
It was based on the calculations done by Duncan back in the early days and it fitted all the ping rings like a glove.
And now this just in..Unknown object found in Somalia.
http://www.malaysia-chronicle.com/index.php?option=com_k2&view=item&id=614866:mh370-conspiracy-theories-rise-again-unknown-flight-recorder-found-on-somalia&Itemid=2#.VzAXO74f7m4
Backup Power from the engines’ secondary generators does NOT supply either L/R Main electrical buses. However, L/R Transfer buses + Standby bus are powered:
L AC Transfer bus:
——————
forward boost pump L, Radio ALT L, Radio ALT C, GPS L, ILS L, ADF L, Weather Radar L, XPDR L (Shed if both AC MAIN buses unpowered), HF L (Shed if both AC MAIN buses unpowered), CVR, some cockpit lighting, MasterBright Control for cockpit panel (Normal), Overhead panel dimmer switch, Integrated Panel Dimmer switch (Normal)
Standby bus:
————
GPS R, VOR L, ILS C, MasterBright Control for cockpit panel (Backup), Integrated Panel Dimmer switch (Backup), L Engine IGN 1 (backup for left main AC) and fire detection, L Engine IGN 2 (backup for right main AC) and fire detection, R Engine IGN 1 (backup for left main AC) and fire detection, R Engine IGN 2 (backup for right main AC) and fire detection
R AC Transfer bus (?):
———————-
forward boost pump R, Radio ALT R, GPS R, ILS R, ADF R, Weather Radar R, XPDR R (Shed if both AC MAIN buses unpowered), HF R (Shed if both AC MAIN buses unpowered), VOR R
SO, if prior to SatCom reboot at 2:25am, the aircraft received NO power from either main engine IDG or the APU, then…
No Radar Altimeters, No GPS, no ILS or ADF or VOR, no Weather Radar, no XPRDs & no HF radios & no SatCom (shed), no VHF radios (main buses inop)…
Because that is consistent with the dark-quiet profile of the flight until 2:25am reboot, perhaps the plane was reduced to (at most) Backup Power until that time. All three APs would still have been op. L/R GEN CTRL switches would have been set to OFF (but not disengaged), with one or both pushed to ON about 2:25am.
Moreover, with SatCom, HF & VHF radios ought to have become op as well (unless all had been individually isolated). If radios were op, and if MH370 was in radio coverage, and if ACARS reboots to utilize radio, and if no ACARS messages were received, then ACARS remained inop.
Re-engaging one or both main engine IDGs could have been aimed, to try to activate HF and/or VHF radios, cf. “aviate navigate communicate”. Non-use of radios or SatCom implies amateur inexpert acting pilots ??
@David
It is interesting that the pieces of 9M-MRO recovered from the ocean are
mainly pieces that would be expected to tear away if the aircraft exceeded
its safe speed e.g. in a dive (even a prolonged shallow angle dive).
The flaperon(s) may well have been one of the first pieces to separate. If
you observe videos of 777 flaperons upon takeoff, they are allowed to
‘flutter’ for a short time. The given reason is that they are partly
situated in the maximal jet-thrust during take-off, and by allowing them to
move in response to the impinging jet-thrust, the likelihood of damage to
the flaperon (and its positioning actuators) is less than if they were locked
in a specific position. During this short time, the flaperon is in what is
called ‘hydraulic bypass’.
The Reunion flaperon is missing its triangular metal hinge attaching parts,
so I assume it fluttered so much as hydraulic pressure lessened (due to
unfuelled engines & APU) that it ripped from the wing & and free fell to the
ocean.
As to the missing (a bit less than approximately 40%) rear of the flaperon
that appears to have been broken off – that could have occurred whilst it
was flutting on the aircraft, or after it had detached and the flaperon
tumbled through the air at high velocity.
A few surface parts of the flaperon appear ‘twisted’, as would occur if
the flaperon fluttered then detached, and the flaperon itself appears to
lack any major ‘crush’ lines/damage, which you would expect to see if it
remained on the aircraft and all the (remaining) wing had crushed/compacted
when the wing hard impacted the ocean surface in a dive.
(I note, however, that others on this forum consider the flaperon most
likely was torn off by water action whilst the aircraft ditched into the ocean.)
FI states that the 3x VHF radios all derive power from the DC electrical system, which derives power from primary power (IDGs & APU), secondary power (backup generators), standby power (RAT), main battery. Depowering all three VHF radios would be as difficult as deactivating all three APs and all FBW controls. However, VHF communications may be routed through other systems, whose failure would then silence the signals, even with power supplied to the VHF transceiver hardware.
Ref my post May 9, 2016 at 1:51 AM;
I modify my previous post – where readers see the term “jet-thrust”,
please consider as substituted there instead, the term ‘jet-wash’,
which is closer to the idea I was trying convey (jet-wash meaning
may contain components of both or either the thrust from the
jet engine and/or the close turbulence accompanying near the thrust.)
@Erik Nelson,
Depowering all VHF radios is as difficult as pulling three circuit breakers.
OZ
Nederland,
Thanks for this coverage map. I suspected something like this. One interesting observation is that there is the edge of the VHF ground coverage at FL300 somewhere near IGARI (need to overlap waypoints on top to say more accurately).
Re: “Also, normal setting is “auto” rather than either SATCOM or VHF.”
I think Don or someone else earlier pointed out that ACARS was set to SATCOM channel on this flight. Please correct me if I am wrong.
So what does ACARS do if it is switched from SATCOM mode to VHF mode, but finds no coverage? Will it continue attempts to transmit? If yes, what is the period/delay before next attempt to connect the network?
Gysbreght,
Yes, words (and thoughts) sometimes twisted. Notably after midnights.
Erik Nelson said;
“However, VHF communications may be routed through other systems, whose failure would then silence the signals, even with power supplied to the VHF transceiver hardware.”
Yes, I see what you are suggesting – so the transceiver hardware could send
‘internal to the hardware’ generated messages (such as Log On after a power
outage) whilst communication from the flight deck may not be possible due to
damage to the wiring leading up to the flight deck.
I note that it will probably be suggested that the crew could have attempted
communication using the terminal situated down in the EE Bay, however if they
were involved in fighting a fi-, er, involved in a ‘major distracting event’,
then they are hardly likely to be tapping keys down in the EE Bay terminal
whilst the ‘major distracting event’ is raging above them in the flight deck (or raging in the EE Bay, a possibility due to a fault in the “generator bus
relays and when they fail the result is usually electric arcing and”…
according to Simon Gunson).