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”.
697 thoughts on “New Potential MH370 Debris Found on Mauritius — UPDATED x3”
David, Thanks for tracking down the framework diagram. It shows a lot of useful detail. The panels in question have obviously been omitted for clarity.
@Ge Rijn, there cannot be a frame member along the seal edge, because that would obstruct the airflow passing through the gap and over the top of the flaperon when its in the drooped position. That is why there are no fasteners along the edge with the seal.
That is very interesting what you say about ANOKO being a slightly better fit of the BTO data than IGOGU.
Originally, I thought it was IGOGU that defined the position of the FMT, because the speeds for the various legs on the journey south were uniform, as you would expect for a cruise on autopilot. If I used ANOKO, the leg between The FMT and the 2nd arc (19:41 arc) was significantly slower than the remainder of the flight.
Then I saw the famous radar chart displayed at the Lido Hotel, Beijing, and noticed that if the track was projected westwards, it went straight to ANOKO, passing just to the north of MEKAR, which made me think the a/c was not following N571 after all.
I subsequently re-estimated the position of the 2nd arc crossing point, aided by the DSTG’s Bayesian analysis result for the statistically most likely crossing point, and found that IGOGU produced a much better fit, particular iro the timing of FMT mid turn point – for ANOKO It’s 18:36, while for IGOGU, it’s 18:37.
Either way, it doesn’t make much difference to the position of the 7th arc crossing, for my estimated great circle flight path.
I suggest we leave it as just another case of ‘synchronicity’.
So back on topic as far as I’m concerned. Thanks for that diagrams. It shows a somewhat different structure than the diagram I posted. Yours make it more clear to me especialy the PCU drawing with surroundings.
First the panel we look at in exhibit 2 must indeed be ~1 meter in lenght with maybe two compartments of ~50cm behind eachother.
On this side the panel is not supported by a frame but only by that hinge and rod.
But the other two parts of the panel are supported by a frame dividing the panel there in two parts of ~50 x 80cm of the complete panel sticking out of this frame the rest covering a box-like construction.
In the PCU drawing you can see the spant of that second panel compartment and in the overall drawing you can see the other spant and a kind of end spar on the two outer parts of the panel forming a box construction here that’s not present on the most left part of the panel (visible in exhibit 2).
My diagram shows a box-like frame under all three panel parts. This is imo obviously not the case in your diagrams and in exhibit 2.
So I guess we end up with a mix of both suggestions: one ~100cm x 80cm outer part of the panel without a frame construction at the front and the left side (only that flange and rod there to support it) and two panel parts with a frame construction consisting of two spants in the middle and maybe one end spant at the outer right edge plus a kind of end spar supporting the front of this two parts of the panel leaving two compartments of ~50 x 80cm sticking out of that end spar-like construction that partly cover the leading edge of the flaperon.
But I have to say also your overall diagram (not the PCU drawing) is still rather unclear and without sufficient enough detail.
Hopefully even clearer diagrams and/or photos show up. (Rob, still searching?) 😉
@Gysbreght. You have your ‘h’ back this time.
….”The AMM drawing omits part of the upper skin structure because that would have hidden the PCU’s.” The beam traversing all three bays in Ge Rijn’s drawings looks to be well to the rear of that in the inner bay of the Boeing. Makes quite a difference in the available sizes. I think the bays in Ge Rijn’s drawings adjacent to the flaperon might be too narrow longitudinally. As I see it, only the inner bay was too long in the Boeing drawing for one panel in which case the beam needn’t extend further. I note there appears to be double fastening on the beam there, suggesting the “square” panel adjacent to the flaperon might be separate. Access?
…”The spanwise beam shown is on the lower skin.” I agree.
….”There could well be a similar beam supporting the upper skin that is not shown in the drawing.” Appropriate caution but I think the lack of fasteners spells the end of that.
@David @Rob @Gysbreght
Want to add both somewhat different diagrams may show Boeing used somewhat different constructions over time.
Maybe my diagram showing an older version and Davids a newer one or visa versa (together with exhibit 2)
Yes, that’s very perceptive, even with my crude MS Excel model, moving the FMT south from IGOGU “scrunches” and “telescopes” the subsequent crossing points, such that it is very difficult to fit anything resembling a constant-speed trajectory, I’m sure Inmarsat thought themselves justified in selecting IGOGU, even though the military radar track “points” more towards ANOKU.
Once again, the longitudes of BEDAX-ISBIX are almost identical to that of the equatorial swath of the first ghost-flight ping-arc… that jumps out at me as significant…
But shifting FMT to ANOKU = 1/3deg latitude S seems to throw most of the rest of the ghost-flight-path-segments out of alignment…
implies manual maneuverings ??
quick comment… a ~180S TRUE TRACK HOLD route, almost due south straight from ISBIX, and which mainly amounts to shifting the Inmarsat best-fit route S-wards -0.365deg, actually fits the data very well, especially for judicious choice of estimated BTO @ 2nd phone call…
A 180S TRUE TRACK HOLD from BEDAX is almost identical, but I find that a 181-182S from BEDAX-ISBIX shifting to 180S fits the data the best… that’s the best this crude model can calculate, but with a higher estimated airspeed of quasi-constant 850kph, maybe winds aloft doesn’t shift the route that much, perhaps this could be consistent, with either a TRACK HOLD or HDG HOLD, but ‘twould have to be TRUE not MAG.
One more quick observation, on the FI winds aloft chart, there is a “anomaly” near 20S,95E off the top of my head, where the winds point due S, instead of to the E as on either side… these BEDAX-ISBIX-180ish routes fly straight through that region, so IDK if that has some relevant meaningful importance or not
quick comment —
I tried the Inmarsat coordinates, subtracted -0.365deg (difference between IGOGU-ANOKU) and rounded off the numbers…
And with a couple quick minor tweaks, the “artificial satellite-stars align”, and I get a path with almost constant heading ~180ish and almost constant speed ~460kts, and RMS BFO error <<7Hz…
I've never actually seen such a fit from my crude Excel model before, it's like everything fell into place…
ANOKO-BEDAX-ISBIX-181 TRUE HDG HOLD with some slight deviations consistent with winds seems to fit the data like a pilot's glove…
You wind up near 35S = Inmarsat's best-fit path shifted S 0.365deg or so
I'm not using super-computers or heavy computational firepower like Mathematica or Matlab or SciLab or such, but my model is conspicuously particularly fond of ANOKO-BEDAX-ISBIX-181S to ~35S…
low BFO error, almost constant HDG & speed…
Don't know how the ATSB has overlooked the crash-site all this time… maybe it's somewhere just to the south of the search area, did a better job of gliding than people give the AP credit for ??
@Erik Nelson: “Don’t know how the ATSB has overlooked the crash-site all this time… ”
Ornstein-Uhlenbeck, the emperors new clothes?
Very interesting, but there must be many other possible paths south that fit the BTO data about as equally well. This was the ATSB’s dilemma, namely that the BFO values when interpreted as aircraft horizontal velocity, are so ambiguous, that in reality all they do is tell you the aircraft went south!
This problem forced the ATSB to resort to modelling autopilot modes matched against the range of cruising speeds you might expect, and taking into account that apparent fuel exhaustion seems to tie up with what you could expect from an FMC cruise mode. Hope I’m not waffling, my unwritten motto seems to be “why use 20 words, when a couple of hundred will do!”
I cannot see the need to invoke manoeuvring after the FMT to make the path fit the BTO and BFO data as precisely as possible.
I prefer the other approach, namely find a path that appears the most plausible, taking everything into consideration, and then seeing if the path can be reconciled with the ISAT data.
I know others might not agree, but I still think that’s the best approach.
@Rob @David @Gysbreght
After studying Davids diagrams again there seems to be no closing end spar before the trailing edge of that panel frame construction afterall.
It seems to be an all open construction with two spants dividing the construction in three parts with two diagonal struds fixed to the end spar of the main wing box supporting the top panel. Only the inboard PCU seems to be attached to a seperate spar construction with the outboard PCU attached straight on the end spar of the main wing box.
There is a beam shown at the end of the lower panel construction where those two spants close with the top beams of those spants showing a clear overhang.
I assume it’s on this ‘overhang’ that the last ~50cm part of the panel is attached with its three seperate compartments as visible in exhibit 3 (well..at least two of them).
But it still remains all difficult..
At least I found a youtube video where you can clearly see that black seal at the end of that top panel. Not of much help maybe but nice to see that flaperon in action:
“I prefer the other approach, namely find a path that appears the most plausible, taking everything into consideration, and then seeing if the path can be reconciled with the ISAT data.”
How about revisiting the idea of Ile St-Paul?
Can it fit the BTO and BFO data?
If the idea of a pilot-flown, planned glide at sunrise, somewhere where boats and people can wait, where the leeward, smoother waters approach is possible due to the island’s configuration, where its possible (almost impossible?) to skim into the caldera…and anyway, be able to retrieve sunken cargo in the shallow-ish slope of the island?
Didn’t the Ukrainians have cold water scuba gear?
Theoretically, isn’t it possible that the cargo bay was accessed and what was valued was prepped for the ditching?
Crazy? Maybe. Just throwing it out there…..
And I’ll throw in another video 😉
One with good close ups from the debated flaperon area in flight (at the end):
Thanks, but regrettably, I never was very good at ball games. Hope you don’t mind if I let that one pass? 🙂
Here is a report that has been long in preparation on Coriolis forces. It turned out to be a more interesting problem than anyone anticipated. If anyone wants to churn through the math, any errors noted would be appreciated.
As usual, I keep an index of all my reports, and this one is at the top.
“I prefer the other approach, namely find a path that appears the most plausible, taking everything into consideration, and then seeing if the path can be reconciled with the ISAT data. I know others might not agree, but I still think that’s the best approach”
Rob you ask can a path be reconciled with the ISAT data. In addition, can we at the same time produce such a convincing fit that it realistically confirms the ISAT data as accurate?
Take a motive outlined in detail within days of MH370 disappearing.
Take ISAT data that is calculated and plotted as ping rings on a globe by Duncan Steel within weeks of the plane disappearing.
Take a professional pilot flying straight paths at a constant speed using waypoints to fly the plane.
Take a flightpath based on the motive as outlined that crosses all the ping rings from 19:40 to 00:11 within a tolerance of ±1 nm.
This should be a convincing argument that the ISAT data is accurate while reconciling with the path.
It should also be a plausible path to a ditching between Christmas Island and the coast of Java.
Although the authorities were aware of this motive and flightpath over 2 years ago, other than the Chinese vessel that spent a short time searching in this area very little other interest has been shown.
Groundhog day again!
Perhaps the Chinese vessel, if there was a Chinese vessel, I will take it on trust there was Chinese vessel, was doing something totally unconnected with MH370?
I have nothing against conspiracy theories if they have a legitimate role in for example, filling a psychological need, just as long as they don’t acquire a veneer of respectability, purely by default. If something cannot be refuted, doesn’t mean it ought to be taken seriously.
Sorry if my reply sounds provocative and irresponsible, but that’s how I respond to the rediculous. There is as saying; the truth only hurts when you don’t tell it. Trite, but true. and I was accused earlier on of spreading false information!
I rest my case. Over and out.
@sk999: That is a nice summary paper. I have one small comment. What you call the force due to the “ram pressure” would be more typically called the transverse drag, given by the drag coefficient Cd times 0.5 rho v^2 (neglecting compressibility effects). For a long cylinder, Cd is about 0.82. Therefore, if you are referencing the projected area, I think the drag force is about 41% what you estimate.
I think the uncertainty in our knowledge of the wind field should produce path errors larger than the Coriolis for the HDG HLD roll mode.
Thanks for reading – I’m still making updates. I will check out “transverse drag”. Drag coefficient does depend on Reynolds number (which I have not calculated, but doubt the dependence is significant in the regime of interest.) A bigger effect must be the impact of the wings – gak!
Very much agree that wind field errors are more important.
@sk999: Yes, the drag coefficient is definitely a function of the Reynolds number. But you have to be careful about how you define the Reynolds number because the flow regime will be determined primarily by the Reynolds number of the longitudinal flow over the fuselage. (You can’t have turbulent flow for the axial flow and laminar flow for the cross-flow, for instance). It’s really not an easy problem to do accurately.
Issues were raised with flutter and fatigue analysis.
There is extensive testing on the flutter and fatigue of each design. The individual components are analyzed in detail. Each flight surface from the wing, stabilizer, to all the control surfaces individually and in combination are analysis through basic analysis, Finite Element Modeling, structural testing, fatigue testing, material testing, functional testing, model testing in the wind tunnel and flight testing. Flight dynamics are tested for each part and its interaction with all other parts. The CG (Center of Gravity), CL (Center of lift), the rotational center of each part, the torsional strength, and the harmonic frequency of the parts can be reviewed. New materials like composites can allow improvements in designs that are more efficient and less fatigue and flutter susceptible.
These tests and analysis is done over the complete flight envelop of the design with reasonable margins of safety.
A design that is within operating parameters and maintained to design tolerance should not fail. However; it does happen. Parts fall off airplanes. Airplanes crash. To support the fleet; flight procedures, operating procedures, maintenance procedures, software and hardware; is continually updated and improved. Airworthiness directives, etc ; are regularly issued that correct issues with the design or with the manufacture or the maintenance of the design or the operating procedures. The history of each part of the airplane is kept and reviewed for issues.
Nothing seems to be perfect and stuff happens.
Not trying to defend the 777. Just stating my experience.
Some important points but you left one out; CFR Part 25.
Boeing and other manufacturers have to comply with regulations; they have to demonstrate that the aircraft is designed to preclude the aero elastic instabilities of flutter, divergence, and control reversal.
In eq (15) you missed drag coefficient.
In HDG HOLD mode ADIRU provides accurate heading to user systems, so that the AP adjusts control surfaces as needed to balance whatever forces including Coriolis.
I’m sorry to say, but your paper suffers from the same fundamental aerodynamic misunderstanding as Oleksandr’s CTS paper.
Unless an airplane is forced into sideslipping by thrust asymmetry or crossed control inputs, an airplane always turns so that it is aligned with the relative wind velocity. Any sideslip (transverse wind ‘blowing agaist the side of the aircraft’) is immediately corrected by either the inherent directional stability produced by the vertical tail acting as a a wind vane, or by control systems such as a yaw damper.
@VictorI: What is the reference area for your Cd and what is the orientation of the cylinder to the airflow direction?
FYI. Be careful what you make public.
I was issued a copyright notice from Boeing after linking manual extracts…
“I’m sorry to say, but your paper suffers from the same fundamental aerodynamic misunderstanding as Oleksandr’s CTS paper.”
That means you misunderstood my CTS paper. You are always confusing static and dynamic situation, as well as B777 mode controls with aerodynamic principles. Here is a simple example: an arrow or bullet. Are they affected by Coriolis and side wind? Another example: Airbus EY440, the trajectory of which was clearly affected by cross wind. I agree with regard to mode controls and feedback systems of B777, where my knowledge is very limited. But with regard to the aerodynamic, I can only refer again to the textbook I cited.
Perhaps this will help. You said:
“an airplane always turns so that it is aligned with the relative wind velocity.”
Exactly. But this process takes some time, during which it is not aligned. And this is a core of my CTS model: the plane turns to get aligned.
Boeing is a weird company these days. It was spoilt by its previous top management. An MBA from Procter&Gamble is a joke. I believe if you place a proper reference, you have nothing to afraid. Otherwise you may ask for help from Blaine Gibson.
When you pauze this video:
at 0:43 and take a snapshot of the screen (right mouse click in the screen), save it and zoom in on the picture, you can see the trailing edge of that panel is divided in three compartments of each ~80cm widht.
The dividing shades and also some angles of the flattened piramide-like structure of those compartments are visible including the black seal on the outer trailing edge.
When the flaperon goes down, the cove door goes up to close the open frame structure between the top and underside panel behind the flaperon. Therefor it must be necesaary also the back of those three compartments have a sloped angle just like you see in the found piece to allow full movement and closing of this open space. With this all the dimensions of the found piece would ~fit one of those three compartments of the trailing edge of this large panel being ~80 x ~50cm each.
I’m almost 100% confident know the found piece is from that panel from that place.
If confirmed implications could be rather huge imo.
It would highly suggest the flaperon did not broke off due to flutter but was seperated during a relatively slow speed impact with the water surface or by shearing off an engine during this relitively slow speed impact.
Considering 8 out of 9 till now found pieces are from flight control surfaces, an engine cowling fragment and a flap fairing fragment (maybe two of them) and considering the amount and kind of damage done to them (especialy the flaperon) a more or less controlled ditching becomes becomes inevitable imo.
I am not confusing anything. After spending a lifetime professionally as well as privately with those things I know what I’m talking about. You have obviously never held the controls of an airplane in flight.
“Another example: Airbus EY440, the trajectory of which was clearly affected by cross wind.” You are still confusing sideslip and crab amgles.
“But with regard to the aerodynamic, I can only refer again to the textbook I cited. ”
I don’t know the textbook you cited, but I suspect the textbook is correct but you are misunderstanding what it says.
You both should find an agreement about what you are intending to talk about relative to the end point or waypoint you or the aircraft is intending to navigate.
Let’s say you are intending to fly from point A = present position to point B= waypoint. Plotted on a map the true course is 180°. Let’s assume, the variation is zero, therefore mag course would be the same as true course.
At take off your aircraft is already subjected to the rotational speed of the earth, and the atmosphere you are going to fly ( except you are sitting in an SR71) will have the same rotational speed as the earth below.
Local deviations in the atmosphere from the rotational speeds are winds and jet streams.
If you fly under the above conditions from A to B, you simply fly mag heading 180 under no wind conditions. With wind present you correct for wind in order to track 180° and you will arrive at your destination.
With wind and variation true track of 180° will get you to your intended destination. With a mag compass and a map the correction for variation and wind to get the desired true track was brainwork, today the modern gadgets do that for you.
There was no need to worry about Coriolis force and earth rotation in the old days and no need to do it now as long as flying in the atmosphere of mother earth. Although I honor the mathematical skill in proving the minimalistic influence, the effect on flying is only academic.
But thanks for the distraction from debris forensics.
@OZ. “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.”
Which raises some questions. With the drag of hydraulic pumping on the windmilling engines and that of AC generators also, what would be the effect on the speed of the rotor powering this? What of the airspeed dropping as it would during a RAT landing/ ditching? I would expect that the power to be gained from windmilling engines (and RAT too) to be to the square of airspeed if not cube.
Is that why the RAT is provided, sized to provide the final fallback of keeping hydraulics supply to minimum flight controls for landing?
At some point I would expect the engine driven hydraulic pressure will drop and the pressure sensors will signal failure to PFCs/ACEs, which then will command PCUs to bypass, enter damping mode etc and the left flaperon to retract. I am not at all sure that the right flaperon would retract then to maintain lift symmetry as I speculated earlier – I have found mention in manuals of asymmetry balancing of flaps and spoilers but not flaperons.
The RAT is designed to deploy, amongst other causes, when both engines drop beneath idle, which should be well above self-sustaining speed (I assume that to be synonymous with windmill start speed). That suggests that beneath idle speed, which would be above the 250 knots IAS for windmill starting, the hydraulic supply from one engine would be insufficient for aircraft control, though I have found no statement to that effect.
Still, were the aircraft in a shallow dive and indicated airspeed sufficient to keep windmilling hydraulic power up, the RAT should not deploy, engine windmill powered AC centre pumps and engine hydraulics keeping the controls going without that. Depending again on airspeed, flaps and slats could be deployed at least partially for landing, hydraulically or electrically.
Indeed were there been no break in AC power the autopilot would not disconnect…..
However most likely this scenario is unrealistic since to my knowledge in simulations the RAT has deployed and the autopilot has disconnected.
Final thought. My memory has it that the Gimli Glider with RAT deployed was running short on hydraulic power on landing, engines windmilling.
To summarize some of the observations on the the debris found till now:
-a fairly undamaged flaperon with a missing trailing edge
-three other pieces which are likely to be other trailing edges of flight control surfaces.
-one (or two) parts of a flap fairing
-one fragment of an engine cowling
-one fragment of a H.stabilizer panel
-one piece of a cabin closet
All pieces are relatively large around ~80cm lenght except the flaperon which is even fairly complete.
All pieces are not shattered, torn, wrinkled and fragmentated as they would be after a high speegd impact except maybe the engine cowling piece. But an engine (cowling) would take the brunt of forces head on during a ditching event which could explain that kind of shattering imo.
All pieces except maybe the cabin closet piece are pieces likely to get damaged and seperated during a ditching event.
This one although requires an open R1 door or a broken/shattered fuselage to get out of the cabin which remains an open question.
Imo an open door seems more likely for with a broken/shattered fuselage there would have been a lot more (different kind of) debris found by now.
The missing of the trailing edge of the flaperon and the hole through the trailing edge piece of the other flight control surface suggest imo those flight control surfaces were in the ‘downward’ position when hitting the water.
The trailing edge panel piece also suggest the flaperon was in the downward position allowing water to force through the gap between the flaperon and that panel to shear off that trailing panel piece.
I realize it’s much to early to draw any definite conclusions out of this all but I think it would justify a more serious consideration of a more or less controlled ditching scenario with all it’s possible implications for possible flight paths and crash/search areas.
@RetiredF4: I was discussing the wind ‘blowing agaist the side of the aircraft’ which, for practical purposes, is non-existent in symmetrical cruise flight.
i have no problem with the Coriolis effect which, by the way, is not a force but a translation between two frames of reference.
Re: “I am not confusing anything. After spending a lifetime professionally as well as privately with those things I know what I’m talking about.”
Apparently you still confuse slip angle, slip, force, moment and other relevant things, as confirmed by your post 6:19 AM and inability to comment on simple examples I asked for.
Re: “You have obviously never held the controls of an airplane in flight.”
That is true. I never pretended I did. But what is to do with “fundamental aerodynamic misunderstanding”? As I said in the previous post you probably confuse fundamental aerodynamic with flight controls.
Re: “You are still confusing sideslip and crab amgles.”
Certainly I don’t. And I even don’t know why you think so. Crabbed landing and EY440 are examples of the cross-wind effect, the existence of which you refuse to admit.
Re: “I suspect the textbook is correct but you are misunderstanding what it says.”
I recall you refused to read the textbook as you did not want to waste your time, didn’t you? If not, please show where my understanding is wrong.
Re: “I was discussing the wind ‘blowing agaist the side of the aircraft’ which, for practical purposes, is non-existent in symmetrical cruise flight.”
You confuse real flight with ideal simulators. Symmetrical flights do not exist in the reality. Varying wind, slightly different engine thrusts… all this result in asymmetric flight.
Take your example. Let’s make it a bit more complex, say WE 10 knots wind at 5 km altitude and SN 20 knots wind at 10 km altitude, gradually changing. Imagine an aircraft climbing from 5 to 10 km altitude. What does happen if the aircraft is in HDG HOLD and LNAV modes?
“But what is to do with “fundamental aerodynamic misunderstanding”?”
I wrote that you never held the controls of an airplane, because if you had you would understand the difference between sideslip and crab angle. So far you have only demonstrated that you don’t.
“Crabbed landing and EY440 are examples of the cross-wind effect, the existence of which you refuse to admit.”
In crabbed landing and EY440 the cross-wind results in a crab angle, which is the difference between heading and track for zero sideslip. With zero sideslip the airflow is aerodynamically symmetrical and there is no sideforce. In the case of EY440 the airplane probably flew perfectly coördinated turns at constant bankangle and zero sideslip, describing a perfectly circular path relative to the moving airmass, which results in a distorted track relative to earth due to crabbing. An airplane can fly a complete circle in this way, and after turning through 360 degrees it will encounter the wake it left behind where it started the turn, while that point and indeed its entire trajectory relative to earth has moved downwind with the wind speed. When we were discussing EY440 you even gave a correct mathematical formulation of that trajectory, but that doesn’t address the aerodynamics. Perhaps some day you will understand, if you are able to step over your arrogance.
“I recall you refused to read the textbook”.
I don’t have your texbook, don’t need it, and do not intend to buy it for your benefit, just to point out any errors it may contain. As I said, the book may well be right, in which case your understanding is wrong. If your book says anything that conflicts with my understanding you just have to spell it out for me.
“You confuse real flight with ideal simulators.”
I never mentioned simulators in this context. The asymmetries you mention are not what we are discussing here, and are usually small enough to be ignored for practical purposes.
@Ge Rijn, I disagree, I believe that the relatively small size of the fragments indicates a high-speed impact. The cabin closet piece by itself would seem to rule out a ditching scenario.
@jeffwise: “The cabin closet piece by itself would seem to rule out a ditching scenario.”
Perhaps you should look again at the video of an Ethiopian B767 ditching. That could have been perfect if the wings had been as level as in the Hudson ditching. The airspeed and pitch attitude were as good as they could be, and the vertical speed was close to zero. Unfortunately the left wing tip digged in, causing the airplane to yaw to a large sideslip angle, so that the fuselage hit the water moving sideways, which caused the break-up of the fuselage.
I’m not familiar with different Autopilot modes, so spare me some slack.
The point though is, that an aircraft heading ( true or magnetic) does not necessarily point to the direction where the aircraft will end up.
Simplest example is a crosswind landing. To stay on the extended centerline and land on the runway the track has to be the same as the runway heading, although the aircraft heading might be way off.
– Heading is the direction the nose of the aircraft is pointed to
– track is the direction the velocity vector of the aircraft is pointed to
If MH370 was flown in a mode with no pilot or autopilot commanded wind correction, then even with a constant heading the resulting track ( project it to the earth for better understanding) will be bent according to the strength and time of such an influence.
In the stone age of flying, when only the TLAR method was used for applying wind correction, a resulting curved path to the destination was not unusual, as the drift from the intended track was used to apply the amount if wind correction.
“Unfortunately the left wing tip digged in, causing the airplane to yaw to a large sideslip angle, so that the fuselage hit the water moving sideways, which caused the break-up of the fuselage.”
Imho with low wings and underslung engines that seems to be the normal expected outcome for a water landing, and especially one in the open sea. Add in the proposed power out with limited systems available and the chance for a successfull ditching goes to zero. All the time when I’m shown those yellow things under the seat prior a flight I remind myself, that they are usefull for calming people though.
We are arguing with Gysbreght whether cross wind may have impact on a trajectory or not. My understanding is that it is flight-mode dependent. Crabbed landing is the simplest example when heading, orientation and air flow direction vectors are not parallel. I insist that similar but transient “crabbing state” may exist in the air, when an aircraft needs to adjust its heading in varying wind conditions.
@Gysbreght, I would draw a distinction between a ditching scenario, in which the plane winds up in the water more or less intact, and an unsuccessful ditching scenario, which is a low-speed crash. If we all agree that the plane crashed, the question becomes whether it was a low-speed or a high-speed crash. I would suggest that the size of the debris suggests a high-speed crash. In the case of AF447, which I would also categorize as a low-speed crash, numerous large pieces were found floating around, such as the tail fin and service carts. I would expect that larger pieces would be more likely to survive long periods of drifting across the ocean and would be found sooner.
@jeffwise: ” I would draw a distinction between a ditching scenario, in which the plane winds up in the water more or less intact, and an unsuccessful ditching scenario, which is a low-speed crash. If we all agree that the plane crashed, … ”
Agreed so far.
“… the question becomes whether it was a low-speed or a high-speed crash”
I would think that there are more important distinctions than that. Most important is the flight path angle which, together with the airspeed or groundspeed, defines the vertical speed at impact. Also important is the attitude of the airplane in pitch, roll and yaw.
Closing comments here now, thank you all for your contributions. Please add your thoughts to the most recent post.
@Ken Goodwin, With regards to the South Australia debris fragment, is it possible for a single aircraft to have “no step” written on it in different places in different fonts?
Comments are closed.