The photo above is from an article on a French-language website. It says that the object was found two weeks ago by a French tourist, who gave it to a boat captain, who only gave it to the authorities on Tuesday, May 24. The piece is 80 cm by 40 cm and was discovered on a small island called L’ile aux Bernaches, which lies within the main reef surrounding Mauritius. It is now in the possession of the National Coast Guard, who will pass along photos to the Malaysians and, if they deem it likely to be a part of the missing plane, will send experts to collect it. (According to a second story here.)
The photograph above is the only one that seems to be available so far, and is quite low-res, but it seems to lack any visible barnacles, but has quite a lot of the roughness that barnacles leave behind after they’ve detached, as seen in the Mossel Bay piece. Perhaps worth noting that so far, pieces found on islands (Réunion, Rodrigues) have had substantial goose barnacle populations living on them, while pieces found on the African mainland have been bare. This piece breaks that trend.
Also worth noting, I think, is that all of the objects discovered so far were found by tourists, with the exception of the flaperon, which was found during a beach cleaning of the kind that only happens an tourist destinations. Drift models predict that a lot of the debris should have come ashore on the east coast of Madagascar, but this is not a place that tourists generally frequent. There are also large stretches of the southern African coast that probably see little tourism. All of which is to say that a concerted effort to sweep remote beaches should turn up a lot of MH370 debris.
I haven’t seen any speculation yet as to which part of the plane this latest piece might have come from–any ideas?
UPDATE 5/25/16: In a surprising coincidence, another piece of potential debris has also turned up on Mauritius. According to Ion News, the object was found by a Coast Guard foot patrol along a beach at Gris-Gris, the southernmost point on the island. It was found resting about six meters from the water.
UPDATE 5/26/16: In another surprising turn of events, Australia’s Minister for Infrastructure and Transport, Darren Chesterhas issued a media release in which he “confirmed reports that three new pieces of debris—two in Mauritius and one in Mozambique—have been found and are of interest in connection to the disappearance of Malaysian Airlines flight MH370.”
The release goes on:
“The Malaysian Government is yet to take custody of the items, however as with previous items, Malaysian officials are arranging collection and it is expected the items will be brought to Australia for examination,” Mr Chester said. “These items of debris are of interest and will be examined by experts.”
This means of announcing findings related to MH370 marks a departure for the Australian government, which in the past has provided updates from the ATSB (Australia Transport Safety Board) itself. The items are picture below, courtesy of Kathy Mosesian at VeritasMH370:
Meanwhile, a reader has provided an image analysis of the second Mauritius fragment in order to provide a sense of scale:
He observes: “Some rough scaling puts it at around 14 by 26 inches. Those boulders in the other photo look like pebbles; makes it look the size of one cent piece. Note the increasing curvature left to right; ups the bet on a chunk of flap!”
UPDATE 5/27/16: Another piece turned up yesterday, making it four altogether since Wednesday. I think this qualifies as a “debris storm.” At the rate stuff is turning up, there should be a lot more to come. There hasn’t even been an organized search yet!
The BBC reports:
Luca Kuhn von Burgsdorff contacted the BBC on Thursday to say he found the fragment on the Macaneta peninsula.
The authorities have been notified. The piece must be examined by the official investigation team in Australia.
Experts say it is consistent with where previous pieces of debris from the missing plane have been found.
Mr von Burgsdorff took two photographs of the item on 22 May, and sent them to the BBC after reading a story on Thursday about other debris finds in the region.
He said the pieces were “reasonably light, did not have metal on the outside, and looked extremely similar to photos posted on the internet of other pieces of debris from aeroplanes”.
@Gysbreght – Thanks for your correction regarding LRC being limited by M084 but was my understanding of the AP correct? i.e., at a set Altitude and a speed such as MRC, LRC, ECON or Holding as weight is lost, eventually the air speed is reduced by the AP to decrease lift? For a long duration piloted flight, the pilot will perform a step-cruise in order to maintain speed and economy? For a ghost flight, the AP will not increase altitude, correct?
@Lauren H: That all seems right to me with the understanding that speed is reduced to reduce lift to maintain a constant pitch, as @Gysbreght explained.
Ge Rijn,
I know it sounds horrible; I also spent some time to learn pilot’s and designer’s language. You can find comprehensive lists of the abbreviations in the Boeing Flight Crew Operating Manual (FCOM), and Factual Information (FI) report. Just search by keywords. Also a good online resource is smartcockpit.com.
Specifically to your last question:
“Can this possibly explain the question Erik Nelson asked about this gradualy decreasing speeds from 7.14S till 30.30S?”
In my understanding you are referring to Erik’s question:
“Is there any reason why airspeed would decrease, perhaps to decrease lift as fuel weight decreases ?”
Yes, but not for the reason Erik mentioned. If the aircraft was ascending in SPD mode Mach, or if it was descending in SPD mode IAS, its true airspeed would be decreasing. But here it comes to the accurate estimates, because the relationship between TAS, IAS and Mach are altitude-dependent, which in turn depends on a selected pitch mode.
The second part of Erik’s contemplations is indeed wrong. As total weight decreases, AoA also decreases, not airspeed. Pitch mode remains the same. Indeed, if the aircraft is under the AP control.
Lauren H,
The lift is reduced by reducing AoA, not by the means of reducing TAS. This has additional benefit of reducing head drag, and thus fuel consumption. Do not confuse with pitch mode. There is some optimal TAS, which minimizes head drag.
If AFDS SPD mode is IAS and aircraft is ascending, the pitch mode automatically changes to SPD mode Mach at 0.84 Mach and stays constant after that. If aircraft is still ascending, it will slow down. A pilot may re-enter other desired value, up to 0.87M.
@Lauren H: “… was my understanding of the AP correct? i.e., at a set Altitude and a speed such as MRC, LRC, ECON or Holding as weight is lost, eventually the air speed is reduced by the AP to decrease lift? For a long duration piloted flight, the pilot will perform a step-cruise in order to maintain speed and economy? For a ghost flight, the AP will not increase altitude, correct?”
MRC, LRC, ECON or Holding speeds are not constant but depend on weight. The AP will maintain those speeds in VNAV mode, i.e. when the AP pitch mode and the AT are controlled by the FMC and the particular speed schedule is selected. Yes, in that mode the AP will continually change the speed as the weight of the airplane reduces. In the normal cruise mode the AP will not increase altitude, but the AP can command altitude changes in some conditions such as VNAV with altitude constraints at waypoints, or pitch modes other than VNAV, such as LVLCHG, V/S or FPA.
Lauren H,
Re: “For a ghost flight, the AP will not increase altitude, correct?”
No, incorrect. It depends on FMS and/or AFDS settings. The altitude may increase, it may decrease, as well as it may stay constant.
Gysbreght,
If I recall correctly LVLCHG is called FLCH by Boeing.
Lauren H,
Also note that optimal TAS depends on what is actually being optimized: range, fuel, etc., subject to various constrains.
@Lauren H:
LVLCHG is called FLCH by Boeing. Apologies for any confusion.
@Ge Rijn. The closing panel. Your diagrams convey a different design to that in the AMM. They illustrate a common design across models.
I do not think there is a 50cm panel overhang since I can distinguish a lateral frame immediately in front of the flaperon in the top diagram and I can make out a like piece of framing on the other two also, although faint. What therefore is shown is a series of three panel bays each divided into two, total six.
Rob alluded to your opinion that the recovered piece was 50 cm wide. If you meant that that was actual rather than undamaged width, the undamaged width might exceed that of the three bays bordering the flaperon in your diagrams. If you meant undamaged, they look to be wider than that to me. Naturally based on the design in your diagrams the recovered part could not be from the three bays behind because the seal would abut the flaperon.
The AMM design has the lateral frame in your diagrams that divides the three bays adjacent to the flaperon from the rear three, more away from the flaperon, around about 80 cm or more. Furthermore it extends across just the inner bay only, the longest. It is this 80 by about 80 bay, plus a small amount of overhang of the seal, which I have my eye on, the other bays which abut the flaperon being too long.
If you meant the 50 cm to be the width as recovered, the undamaged width would of course be greater. I doubled the width from the seal edge to the centre of the hump to get an idea, supposing symmetry.
I might add that if it did come from the 80 by 80 inner bay and the panel is all one piece (as you observe) with four (in my opinion) “humps” then the evidence of the straight edge uppermost in the photo where there were fasteners suggest that that would have been attached to the inner longitudinal frame seen in the analysis exhibit 2. In turn that would mean that this closing panel came from the aircraft right side.
One other point for Rob while I think of it. I have read that the closing door does not open a gap between the flaperon and wing until the flaperon is well down. You will notice the overhang of the nose of the flaperon which keeps this gap tight during initial movement. Thus there would be no gap if the flaps were not well down, in turn requiring a powered ditching for there to be a decent gap in my opinion.
There may be more points which I will get to in a five or six hours.
trying to clarify some concepts:
——————————–
Flight Path Angle (angle from horizon to velocity vector) plus Angle of Attack (angle from velocity vector to tail-to-nose chord-axis of the aircraft) = Pitch Angle (angle from horizon to longitudinal axis of the aircraft)
FPA + AoA = PA
http://sportysnetwork.com/airfacts/wp-content/blogs.dir/13/files/2015/04/aoa5.jpg
A B-777 probably stalls above an AoA ~= 20deg or so. That would plausibly be the maximum-lift holding-pattern AoA. The Lift Coefficient at 20 degrees might be 1.5-2.0, whereas at zero AoA it might only be 0.5.
So, in particular, specifically, ’tis most likely quite feasible, to double the Lift Coefficient (LC) factor, by adjusting AoA from 0-10deg or so, all without greatly increasing drag. Or, more specifically for our purposes, one could halve the LC, by reducing AoA, as fuel is used up. The mass of MH370 only decreased by 22%, so decreasing AoA could surely be one means to compensate. I guess engine thrust would decrease slightly, due to slight decrease in drag.
Also in addition to boot, according to the “LRC tables” of the Continental B-777 Flight Manual (Sec.5, Pg.5), as the mass of MH370 decreased from (to the nearest table row) 500K lbs to 380K lbs, the optimal M0.84 LRC altitude increases from FL350 to FL430. Naively, such implies that LRC requires positive altitude changes, mimicking the Flight Level Changes human pilots would input, in steps, over the course of a cruise.
In any event, please note, that the Inmarsat JoN article’s best-fit “ghost-flight path” occurs at 800kph, whereas they model the LRC from KLIA to IGARI up at 867kph. FL350 is already near the Tropopause temperature inversion boundary between Troposphere & Stratosphere, so deceleration all the way down to 800kph doesn’t seem to be consistent, with a high-and-fast LRC / ECON / MRC flight mode.
If a lower-and-slower ghost-flight occurred, then perhaps it occurred, on some other (e.g. THRUST HOLD) speed mode ?
Oleksandr is stating, that negative AoA adjustments, not negative speed changes, are utilized to reduce lift as fuel is consumed. His TN-CTS-Rev1.0 article also shows a marked climb over the course of the southern trajectory.
Speed decreases, AoA decreases, ALT increases, all decrease lift. An a/c could hypothetically utilize any combination of those means to compensate for fuel usage.
Evidently, various flight modes utilize various combos of those adjustments.
If the aircraft followed an eastward-veering, constant magnetic-heading track, out over the SIO, towards somewhere near (30S,100E)…
Then the TAS must have decreased from ~450kts to <400kts…
As indicated by Dr. Duncan Steel's constant-speed paths, i.e. paths of 450-460kts are very straight southwards, whereas only slower 300-350 kts paths curve eastwards.
So if the aircraft really actually followed a constant Magnetic heading, as some say is the default mode after a "Route Discontinuity", then the plane gradually veered eastwards due to magnetic anomaly, and so its TAS must have decreased, from ballpark 800kph, to 0 for negative AoA LRC @ CI=180… And we know MH370 flew out of KLIA @ CI=52, whereat speed is -2.5% < LRC…
So MH370 flew at 867kph @ CI=52 = -4.5% < VMO = M0.87. That would imply VMO = 906kph…
And that, conversely, 800kph M0.768 ~= M0.77
Even 829kph M0.796 ~= M0.80
MRC = ECON @ CI=0 is 852kph = M0.82…
SO
—
VMO = M0.87 (CI = 450+)
LRC = M0.84 (CI = 180)
MRC = M0.82 (CI = 0)
out of KLIA = M0.83 (CI = 52)
ghost-flight = M0.77 to M0.80 (CI = ???)
according to the Inmarsat JoN article. So, their best-fit ghost-flight-path appears to require TAS << MRC-ECON-LRC-VMO speed modes. Yet what else is there ?
Maybe one more quick point… evidently, the drag induced by deployed landing gear is enormous, perhaps it is possible, even easy, to exclude any-and-all flaps and/or gear scenarios ??
Sorry for some important typos…
========
So if the aircraft really actually followed a constant Magnetic heading, as some say is the default mode after a “Route Discontinuity”, then the plane gradually veered eastwards due to magnetic anomaly, and so its TAS must have decreased, from ballpark 800kph, to <700kph…"
========
"for negative AoA LRC @ CI=180… And we know MH370 flew out of KLIA @ CI=52, whereat speed is -2.5% 0 for some negative AoAs, then is it possible that some landing & descent scenario, could render the a/c into a configuration, with negative AoA and negative FPA (yet remain airborne) ? Say -1 deg or so ??
Something is garbling all of my posts…
QUESTION:
If LC > 0 for AoA < 0, then is it possible that some landing & descent scenario, could render the a/c into a configuration, with negative AoA and negative FPA (yet remain airborne) ? Say -1 deg or so ??
@David said;
“…I think the right flaperon would operate likewise as an aileron,
it and the left retracting on hydraulic power failure.”
Were’nt you the David that was posting in the comments section here?
http://www.theaustralian.com.au/news/inquirer/flight-mh370-is-a-mystery-beyond-the-deep/news-story/9b32c96f47cab77cda56f2b5eecf28dd
because it covered most of the points regarding flaperon operation.
e.g.;
“Andrew Feb 20, 2016
…The following is a quote from a B777 technical training manual:
‘The flaperon PCU is in the bypass mode when there is an electrical or hydraulic failure with the PCU or its ACE. The ACE then de-energizes the bypass solenoid. If both PCUs on a flaperon are in the bypass mode, the flaperon can move freely. In flight, the aerodynamic lift then causes the flaperon to move 10 degrees up from the faired position.
If the RAT is supplying hydraulic and electrical power, then…”(the)
“…outboard PCU on the right flaperon remains powered and the inboard PCU is unpowered. The flaperon does not have any hydraulic damping to prevent flutter if both PCUs are unpowered.'”
_
So if you mean by ‘retracting’, that the flaperon moves to 10
degrees up from the faired position, that would be in accordance with the above. Note, of course, that 10 degree position is what
you would see during level flight – airflow over the wing during a
dive or spiraling flight would cause the flaperon to flutter
violently from that 10 degree position.
@Oleksandr
Thanks for explaining.
At least I now ~understand what ‘AoA’ means.
A set negative AoA at ~7.14S was what I had in mind with that suggestion to Erik Nelson. Resulting in a gradual descent and a gradual decrease in speed.
But as far as I understand the comments this conclusion is not valid.
@David @buyerninety
The B777 cutaway only shows three compartments inside that box. Outside of the end spar of that box it shows the part of that panel also divided in three parts.
Each of them I estimate ~80cm x ~50cm (like the found piece).
It’s this part of that panel that overhangs the flaperon’s leading edge and seals it for optimum airflow during operation.
The flaperon does not extract or retract it only rotates around a fixed pivot point as far as I can see.
@buyerninety
‘if the RAT is supplying hydraulic and electrical power then.. the outboard PCU on the flaperon remains powered and inboard PCU is unpowered. The flaperon does not have any hydraulic damping to prevent flutter if both PCUs are unpowered’.
Actualy this says also under RAT always one of the PCUs is powered providing at least hydraulical damping.
Preventing flutter also in a dive or spiraling flight imo.
I misunderstood something here?
@Rob @David
In exhibit 3 you can actualy see the end part of that flange shown in exhibit 2 (600% zoom).
It confirms the flange is attached to that panel with fasteners on the inside of that flange to the ~50cm edge of this panel.
Regarding the found panel piece this tells me the flange was ripped off this edge.
The small rod is a fixed adjustable one. I think it serves the purpose of adjusting the seal on the trailing edge to the flaperons outer surface for leaving no gap preventing disturbance of airflow.
A secondary purpose could be to to fix that trailing edge preventing it from fluttering.
Wrt: “If LC > 0 for AoA < 0, then is it possible that some landing & descent scenario, "
Where in the flight does this show? Is there any reasonable landing locations nearby ? Mh370 could hack landed to get more fuel if the scenario I am considering has any hints of such evidence.
@Erik Nelson @others
Now I cann’t leave it..
It seems with a set small negative AoA a descent scenario with gradual decreasing speed is possible afterall?
Could it been set for the purpose of ending up at a certain altitude somewhere?
@Ge Rijn
Re the closing panel:
Yes, I think you’re right about the flange. What we have called a flange (for want of a better term) is actually the inboard edge of a rectangular mounting frame which the closing panels are fixed.
In exhibit 2, when highly enlarged, you can just make out the top of a closing panel behind the flange (frame member)
Your explanation for the adjustable strut that’s fixed to the frame, sounds very plausible.
Next week, I am going to trawl the net and search for more pictures of this area. Hopefully, there will be some.
@Erik Nelson and @Ge Rijn: Why do you worry about AoA at all? Both the automatic flight control system and the human pilot control airspeed and altitude without even knowing the angle of attack.
@Ge Rijn
Correction, I should have said when you enlarge Exhibit 2, you can just make out the underside (not the top) of a closing panel behind the flange. It is dimly lit, and out of focus, but you can just male it out.
@MH & Ge Rijn
First off, I made a mathematically slight, but effectually important, error in my MS Excel model… Whilst upgrading the same, from a spherical-earth approximation, to WS84 ellipsoid, I noticed I hadn’t been converting Excel time in days to seconds (*86400).
The net effect, is that all of my meticulously & tediously calculated estimated BTOs, all along the military radar track, changed, since morphing my mathematical earth from sphere –> ellipsoid moved the aircraft locations, and multiplying with the correct units the satellite velocities in km/s * s simultaneously moved the satellite locations.
So all the estimated military track BTOs shifted, along with the near-NILAM sat data points, and they all actually aligned, almost perfectly, onto a linear best-fit trend line, with R2 = 1, and a slope of about -80,000 microseconds / day.
So, the summary synopsis bottom-line result upshot of all the new numbers…
is I find no mathematical evidence, for any deceleration or slowing or even major heading change of the a/c, from military radar track past MEKAR to NILAM and on up until 18:28.
And I continue to still observe, that the high-and-fast cruise speed of 867kph, at ANOKO, on a heading of 200deg, at 18:40, fits the BFO value of 88Hz exactly.
It’s 96nm from NILAM straight to ANOKO, that’s 175km, covered in slightly a tad over 12min @ 867kph. So, MH370 would have reached ANOKO about 18:38, and turned 90deg from 290 to 200 by 18:39-18:40 comfortably prior to the 1st sat-phone-call. In fact, a speed that high is almost required, to make it to an FMT location near IGOGU or ANOKO… i.e. a late FMT, almost immediately prior to the first sat-fon-call, requires a high-and-fast speed, to reach from MEKAR & NILAM at 18:21-26 all the way to the FMT before the call.
So, if there was a deceleration down to 800kph, per Inmarsat’s best-fit flight-path, such a deceleration would have occurred AFTER the first call @ ANOKO…
which WOULD be contemporaneous with the highly-disputed “cabin disintegrating” transmission at 18:43…
So, my revised model is telling me, no deceleration from the approx. ballpark of M0.83 = 867kph, prior to the FMT… Any deceleration occurred after the FMT, on some trajectory resembling 200deg heading from ANOKO to BEDAX…
And possibly somehow triggered a “cabin disintegrating” scenario, which, IF true, then most obviously suggests an “exceeding the Never-Exceed-Speed” scenario, where the aircraft descended without decelerating sufficiently, and flew headlong into a veritable wall of high-density air at lower altitudes, and the resulting “dynamic” “ram” pressure started ripping things off of the fuselage.
IDK if that would imply an amateur pilot at the helm ? Or desperate ones ??
Revised Excel model is telling me high-and-fast all the way through to FMT, no major speed changes when there were no major heading changes… but, perhaps a major heading change (the FMT) implies a major speed change (deceleration) ??
Inmarsat’s best-fit flight-path starts south on 180-deg @ 800kph… That would jive well with ANOKO-BEDAX-ISBIX trajectory circling WITT Banda Aceh airport airspace.
That would naturally imply a descent attempt, which obviously did not succeed, but which could have left the a/c with a slight negative AoA and FPA, say roughly -1deg… Then the plane would slowly gradually descend & slow… It would probably descend UNDER the high-velocity westerly winds aloft in the 20s and 30s southern latitudes, and so could more easily maintain the …BEDAX-ISBIX –> Route Discontinuity 180deg MAG heading… which eventually crosses the 7th arc near 30S,100E.
Quick calculation…
ghost-flight = 5.5hours
5.5hr x 800kph = 4400km
ultimate change in altitude = 11km
descending ~10km over the course of 4000km is a FPA = -0.15 deg…
That sounds alot like the minimum 0.1 deg FPA… would such a flight path resemble a controlled-glide-ditching ?? The plane gradually “landed” itself at sea, touching down lightly near 30S,100E ???
@Rob
Yes I looked for that too but couldn’t see it but your eyes must be better then mine so no suprise 😉
But to me it’s obvious now that part of the panel is behind this flange.
I don’t see a rectangular mounting frame and I doubt it’s there. I don’t think so but we’ll see.
I think there is only a similar flange with rod on the opposite side of this panel.
Goodluck with finding more photos!
With your eyesight I’m sure you come up with something 🙂
@buyerninety. Yes I remember asking Andrew questions and now am more familiar with hydraulic failure modes and consequences. One thing Andrew could not answer was whether with the left flaperon retracting (to minus 10 deg as you say)on main hydraulic failure and RAT deployment, the right stabiliser would retract also even though it had one PCU still operative by the RAT powered (limited) hydraulics and had been been deployed earlier with flaps. If not I asked would the aircraft become unmanageable. His answer was he did not know but he thought if it did not retract the aircraft would remain manageable. I imagine what he had in mind is that the flaperon has a limited moment arm in roll compared to an outer flap or aileron, or outer spoilers.
My supposition that it would be commanded by ACE to retract has no more grounding than that there is feedback of the positions of high lift devices for the purpose of precluding lift asymmetry, this would remain operative after AC loss and that it would indeed operate. Besides, I do not see the designers or certificators being happy if such an operation were not designed in.
But if not, as speed slows during an approach for a RAT landing and the RAT losses its grunt, with high lift devices biting more and more, roll and other control being limited anyway, this would not help with pilot workload. Andrew made clear as an experienced 777 pilot that a RAT landing would not be something he would look forward to and that his opinion was that really the prospects of complete fuel exhaustion was so remote that it was not really designed for these days or required to be.
The alternative to an asymmetric landing if the right flaperon did not retract would be to raise flaps and do a flapless Gimli Glider landing but so far as I know there is no guidance to do this in flight manuals, nor for that matter to get flaps down in the circumstances. I suspect that residual fuel available to the APU has been either unknown hitherto or at least has not been planned for.
As to violent (ie divergent) high frequency flutter, which can quickly lead to fatigue, I do not think the left flaperon would, within the flight envelope for two reasons, even though free to rotate. The first is my faith that the aircraft would not be designed or released such that during RAT flight, bits fell off and particularly those that could twist on up into the tail. Second, while Boeing acknowledges that some flutter can occur during take off, with PCUs in bypass, that occurs with flaps down and clearly is not hazardous. The PCUs become operative at 100 knots. Beneath that speed the angle of incidence on the flaps differs from that at the 10 or 11 degrees trailing edge up faired position in flight. For example there could be flow separation and buffeting at low speed whereas in flight in the faired position the Training Manual notes that there will be “aerodynamic lift” holding it up. Boeing acknowledges also that during ground runs there can be flutter, presumably from buffeting by the entrained engine exhaust wake. However even with that and a high speed wake the consequences apparently are benign – otherwise redesign would have been needed.
The second reason I offer is like earlier, the aircraft would not be designed or cleared to operate with any lifting or flight control subject to flutter within the envelope, flutter being a well known and ‘No,No” phenomenon subject to various design solutions, wind tunnel and flight testing.
As to the right flaperon and flutter, the same applies except that it has the added flutter constraint of the RAT keeping one PCU operative and constraining the whole from movement. I for one would be surprised to find that the right flaperon came off due to flutter fatigue unless the aircraft got to such a speed that it was vulnerable to flutter generally. The Silk Air 737 was assessed as having suffered elevator flutter but that was after a considerable dive under power and with manual assistance. I would expect the right flaperon if not both would have been assessed (including wind tunnel testing) as going well beyond flight envelope requirements in flutter resistance.
Yes there is a photo at the top of this page where a flight control trailing edge has separated but looking at the photo of the hole in it on this site:
https://twitter.com/ashren/status/737971778488664065
and bearing in mind Ken Goodwin’s earlier comment I would say this hole had happened before or at separation and the ejection of a high speed dense item. In other words the separation was from shock which caused the high speed debris. If it had been fatigue due to flutter, how to explain the hole?
I did write to Boeing about the flutter propensity of flaperons some time back, naively I suppose, but you never-never know if you never-never go.
No response.
My apologies to all for the fullsome(!) posts recently which I will now attempt to curtail, but I have found that truncated comments on some issues can be unsatisfactory at times.
Andrew was particularly helpful and informative Buyerninety, as was “Mick”. Did you participate in those comments, about the Bailey thesis?
@Erik Nelson
Thank you.
You actualy describe, in a professional way, what I had in mind.
Only with the big differance that I was thinking of the possibility of a pilot who set this -0.1 degree AoA/FPA on purpose after the FMT with in the end the same result as you suggest.
Ge Rijn and Erik,
AoA can be negative only if an aircraft flies upside down, or if it is in a “plunging” mode. You need to differentiate AoA, nose pitch, and pitch modes.
@Ge Rijn. “The flaperon does not extract or retract it only rotates around a fixed pivot point as far as I can see.”
The flaperon hinge point is well below it. Consequently as it rotates it moves for and aft.
“The small rod is a fixed adjustable one. I think it serves the purpose of adjusting the seal on the trailing edge to the flaperons outer surface for leaving no gap preventing disturbance of airflow.
A secondary purpose could be to to fix that trailing edge preventing it from fluttering.” Yes. The other longitudinal frame supports of this panel have braces between them and the wing spar bottom. it is unclear whether they are adjustable. I expect one could get at them with the cove door off.
As to the design of the structure supporting the structure and bay sizes you are relying on your interpretation of the diagrams you have found. Leaving aside that interpretation your diagrams are contradicted by the Boeing Aircraft Maintenance Manual. I will not go into all that again except to say that the Manual diagram is dated September 2004. Of course it could lack currency but so I think could yours.
@Oleksandr
I’ll leave that to the professionals to differentiate if you don’t mind 😉
@David
Yes in that sence you are right about extracting or retracting of the flaperon but as a consequence of rotating around a fixed pivot point. Not like the extracting or retracting of f.i. inboard flaps I meant.
And you are right about the diagram being the only one of a B777-200 I could find and to go by.
If you could supply a more accurate diagram with this area it would be most welcome.
To comment on that other piece you talk about in a previous post; ‘the flight control trailing edge’. I was the first to suggest here that this hole might be caused by a small massive object shooting through it with high speed (page 2 may 26 4:36AM).
Assuming the angle of entry on the trailing edge of this object was a horizontal one (maybe a part of a disintegrating engine?) it would suggest this flight control surface was in a lowered position.
I just mention this as a possible option to keep in mind.
Thanks for being so clear and detailed in your last comments.
@David: ” Leaving aside that interpretation your diagrams are contradicted by the Boeing Aircraft Maintenance Manual.”
It would help the discussion if you could post a link to that AMM material. The structural elements shown in the cutaway drawing make a lot of sense IMO, structurally speaking.
@Ge Rijn
@David
Looking again at photo Exhibit 3, yes I agree with you now; there must be 3 panels up there. The third, nearest to the camera is almost hidden by the foreshortening effect. 3 times 80cm = 240cm = width of the flaperon, as you pointed out earlier!
I am blessed with an eye for detail, which can sometimes be at the expense of the bigger picture.
@David
Just to explain something else. It may look a bit childisch to mentioned that hole in that trailing edge as being the first one here that mentioned it.
But this was the second time you brought forward an observation as done by yourself that was done by me a week or so earlier (the estimating of the panel by the foorprint at ~80cm as the other one).
Offcourse people can make extactly the same observations and conclusions seperately later but I felt I had to mention it.
Anyway ‘synchronicity’ seems to be a phenomenon accuring more often relating to this blog.. 🙂
quick calculation:
TAS ~ IAS * sqrt(rho_sealevel / rho_altitude)
rho_altitude ~ rho_sealevel * exp(-altitude / 30K’)
440 kts ~ 330 kts * (4/3)
altitude ~ 17K’
explanation:
————
Inmarsat says 800kph = 440kts TAS for the ghost-flight
Maximum operating velocity for B-777 = 330kts IAS
330kts IAS = 440kts TAS @ 17K’
If there really was some sort of scenario, where MH370 descended too low, too quickly, such that air resistance started ripping things off of the fuselage…
and if it then wound up at 440kts TAS…
then it would have had to have descended below 17K’ before 440kts TAS became dangerously close to its VMO (Vel max op) and VNE (vel never exceed)…
Assuming some margin of safety factor above VMO –> VNE, the altitude would have had to have been about 15K’…
Co-incidentally, lower altitudes of 15K’-20K’ are qualitatively consistent with the slower-and-lower flight paths towards ~30S,100E in the ATSB’s most recent updates.
The China Times “cabin disintegrating” article implies that alleged unspecified sensitive military detection equipment had been listening to faint transmissions from the aircraft for some protracted period, and that the “cabin disintegrating” broadcast was the ultimate & most important of that series of broadcasts.
An improper descent towards the dangerous leading edge of the B-777 flight envelope (on the xy = IAS Altitude graphical plane) and structural failures of the fuselage at around 440kts TAS = 330kts IAS @ 15K’ or so… could account for the claimed faintness of the transmissions, as radio antennae protrude the most and would plausibly be the first parts to incur damage.
Erik,
Normally flight envelope protection (FEP) would not allow for overspeed. In addition, your latest suggestion conflicts with the last SDU reboot: disintegration would lead to instant silence.
@Rob
Together we nail it or together we fail it.. 😉
@Erik – In May 2015 Gysbreght posted a graph that showed Range (how far it flew) and Endurance (how long it flew) versus Altitude at LRC (no wind & std ISA).
If you agree that MH370 burned 35,600kg fuel from 18:22 to 00:17, these graphs show the altitude would have been either FL410 or FL290 for this endurance. These altitudes would give ranges of 2900 & 2590 nm respectively. Allowing for some PDA, these values would change slightly.
These graphs highlight the relationship of speed and altitude with range and endurance. As you calculate your flight scenarios, you need to be aware of these relationships.
For example, using the values from Gysbreght’s graphs, you cannot say it flew at FL350 because that altitude yields an endurance of 6.04h, which pushes fuel burnout to after 00:24.
@Lauren H: Just to add to your post: the airplane could have flown more slowly than LRC speed after 18:22. If it always flew at optimum altitude, maximum endurance would have been 18:22 plus 6h48m.
All of the FM’s I find state that, after a “Route Discontinuity”, the LNAV defaults into “Heading Hold”.
I understand that HDG HOLD is affected by wind vectors. With my crude model, I do find that TRUE HDG HOLD, bantered about by winds estimated from the plot in FI, on an initial heading of 181 south from BEDAX-ISBIX, best fits the satellite data, with RMS BFO error <4Hz.
MAG TRACK HOLD also works very well. But neither other combo does, RMS errors 8-15Hz. A MAG TRACK HOLD, invented despite the literature clearly stating "HDG HOLD", ambiguous only in TRUE vs. MAG, also requires a decreasing airspeed, to account for the "hook" eastwards, increasingly perpendicular to the ping-rings. If the aircraft ascended as it lightened, into higher colder air, at constant Mach, then its TAS would indeed decrease… especially as the air cooled towards Antarctica. However, why would the TAS be M0.77 << MRC/ECON/LRC ?? Increased drag from a fractured fuselage could account for that… you could model that with an increased PDA… An increased PDA would shrink the fuel-range-ring inwards… And only 7th-ring crossings near 30S,100E have any fuel-mileage to spare.
Obviously, the plane did not disintegrate entirely in the air, but perhaps leading surfaces, like cockpit windows and radio antennas, suffered mechanical failure ??
6.90,96.20
7.14,94.41
0.30,93.77
-6.30,93.44
-13.80,93.52
-20.90,94.29
-24.30,94.33
-31.30,95.93
-32.10,96.27
http://www.darrinward.com/lat-long/?id=2002698
@Rob @David
Some second thoughts.
Estimating the leading edge of the flaperon being ~20cm thickness, the original widht of the panel will come closer to ~70cm.
The estimate can be made by using exhibit 2.
An explanation of the flange not being attached to the found piece could be the found piece is what’s left of the middle section compartment of this one panel of three compartments.
@Ge Rijn
Don’t worry about the flange (support frame) missing from the panel.
The frame stayed with the wing, in my considered opinion.
Just think of it; the frame is a very strong metal construction, possibly titanium.
The powerful surge of water up through the space between the rear of the wing, the rear spar, and the leading edge of the flaperon, literally tore the panel from its mountings.
The flaperon was drooped at the time, witness the damage to its trailing edge. The flaperon was in effect damming the flow of water, forcing it up through the gap under pressure.
Wh have the flap fairings, and flap trailing edge, all pointing clearly to flaps down. When the flaps go down, the flaperon is drooped, too.
@Gysbreght – I have always thought that your graphs were a valuable tool in helping to predict the impact point. Have you created these for ECON 52, MRC and VMO? If so, do any of these speeds yield an interesting impact point at an endurance of 5.92 hr? (I believe you can adjust for overall headwind by subtracting about 30 nm from the range.) I cannot produce these graphs as I would have to use average fuel burn rates as I have forgotten the appropriate calculus long ago.
@Lauren H: “Have you created these for ECON 52, MRC and VMO?”
No, the graph you are referring to is based on the FCOM, which only provides fuel flow for LRC and Holding speeds.
The range at MRC is 1% greater than at LRC, and ECON 52 is between MRC and LRC. The range at holding speeds is about 89% of that at LRC for same weight and altitude.
@Rob
You are jumping to conclusions faster than I’ll do. I agree if all confirmed it’s generaly pointing to a kind of ditching event. But most pieces are damaged quite bad.
Also this panel. Only the force of water cann’t explain the damage done imo.
Maybe a shearing off the engine knocked the panel part out.
To me the panel is still not 100% nailed.
Waiting for further confirming photos/information! 😉
@Ge Rijn
I very much admire your cautious approach in these matters 🙂
@David,
Could you please explain how the mechanism for the left flaperon retracting on main hydraulic failure and RAT deployment? How did the hydraulics fail?
Also what do you mean by the right stabiliser would retract?
OZ
@OZ. The scenario I had in mind was main hydraulics failing as both engines stopped at fuel exhaustion. This would revert all PCUs on the flaperons to bypass, their PCUs being compressed as the flaperons rose (retracted) under aerodynamic lift. On the RAT deploying it would power the right flaperon outer PCU as an aileron via its outer PCU, the left remaining in the 10 deg up position.
Had the flaps been deployed at engine failure I am surmising that any deployment asymmetry between the flaperons would be corrected after sensing of that as the left retracted, the right retracting to 2 deg trailing edge down and thence acting as an aileron, in other words as with flaps up.
If it does not retract it can still operate as an aileron in a down (drooped) position. I have encountered no authoritative statement on this particular retraction question.
Maybe my terminology is a problem. The manuals say the flaperons “move” up and do not use the word ‘retract’ except for flaps. Likewise, as above a down position they refer to as “droop”, the extent of that depending on flap position, primary vs secondary modes, aircraft speed during take off and speed brake lever movement back on the ground.
@David,
The engines would continue to windmill after fuel exhaustion therefore the hydraulic pumps still provide output; albeit reduced. The left flaperon outboard PCU would still be powered.
OZ
quick claim — an FMT at ANOKO is somewhat more consistent with the trend-line best-fitting the estimated BTOs all along the military radar track + cluster at 18:25-28…
than is IGOGU, which is 8nm ~ 1min farther from NILAM, yet also 80us farther from the satellite, such that an FMT @ IGOGU would require a higher BTO at a later turn time, and so the point would be above and to the right of the trend-line…
Qualitatively, the track out of Penang is “up-and-over”, up to Pulau Perak, over to MEKAR, up to NILAM… over to ANOKO is a slightly better extrapolative fit to the data…
than more “up” to IGOGU…
and also explains the Inmarsat best-fit heading of 200-deg around 18:40…
Not saying IGOGU is inconsistent with the data, however simple linear trends “point towards” ANOKO more naturally
Ge Rijn. “Estimating the leading edge of the flaperon being ~20cm thickness, the original width of the panel will come closer to ~70cm.The estimate can be made by using exhibit 2.” If what you have in mind is the length of the exhibit 2 “beam” to which the adjustable link is attached at its top, being around 70 cm, I reckon it to be well over a metre.
I seek no credit and do not understand you there. I mentioned Ken Goodwin’s view I think that an object had punched a hole and to that extent gave him “credit”. Yes, you mentioned it earlier as you say. I do not see discovery of the hole or the supposition that it was caused by an object that went through as being other than an observation. My intention was to point out another, that imo the trailing edge did not depart in fatigue: it had to await the projectile. I seek no credit (nor blame I hope!) for the outcome of that observation, which is hardly startling.
On the 80cms I made clear that this was my estimate. Yours ( I overlooked it seems) was 80 by 50, mine 80 by 80 more or less. Not the same. I gather (from Rob) we both used the footprint as a datum – not much else around. I can tell you that I spent some time on that and hence my very qualified estimate. The 80 along the seal is dead easy if you are looking for a site for that object behind the flaperon, which I was doing; a third of the flaperon’s length. That did require research to show that there were three bays, not two. Even then I needed to qualify that by the supposition that all bays were of equal width.
You have now lifted your estimate above 50!
I hope the item found matches the space available, that’s all I have been looking at. Right now I am uncertain still. I am troubled by lack of evidence of fasteners near the seal along that edge. The Boeing diagram depicts a frame there.
Can you help with an explanation of that? I imagine you will respond that that is evidence there is no frame there, which will be hard to argue with. Hope I haven’t stolen your thunder.
More seriously you have lifted my awareness of the sensitivities to acknowledgement of contributions which lead to a “find” and ensuring that credit goes to where it is due.
@David: Thank you for posting the AMM page that shows the mounting of the flaperon PCUs.
I dont’t see a conflict with the cutaway drawing that Ge Rijn has posted. The AMM drawing omits part of the upper skin structure because that would have hidden the PCU’s. The spanwise beam shown is on the lower skin. There could well be a similar beam supporting the upper skin that is not shown in the drawing.