Earlier today, the Australian Transport Safety Bureau issued a report entitled, “Debris examination — update No. 1: Identification of two items of debris recovered in Mozambique.” The report confirms that the pieces are consistent with a right-hand flap fairing and a right horizontal stabilizer, pointing out that the lettering found on each part matches stencils used by Malaysia airlines. In the case of the piece found by Blaine Alan Gibson, shown above, the report says:
The fastener head markings identified it as being correct for use on the stabiliser panel assembly. The markings also identified the fastener manufacturer. That manufacturer’s fasteners were not used in current production, but did match the fasteners used in assembly of the aircraft next in the production line (405) to 9M-MRO (404).
This wording is ambiguous–does “current production” mean production at the time that 9M-MRO was built, or now? If the fastener wasn’t used when 9M-MRO was built, one wonders what it is doing in this piece. Hopefully the ATSB will clarify what it means. At any rate, the report concludes that both pieces “almost certainly from the Malaysian Airlines Boeing 777 aircraft, registered 9M-MRO.”
Naturally, I was particularly keen to hear what the ATSB would say about the marine life found on these pieces, or lack thereof. The report contains a section entitled “Quarantine and marine ecology” which reads, in its entirety:
On arrival into Australia, both parts were quarantined at the Geoscience Australia facility in Canberra. The parts were unwrapped and examined for the presence of marine ecology and remnants of biological material. Visible marine ecology was present on both parts and these items were removed and preserved. The parts were subsequently cleaned and released from quarantine.
Later, in the “Conclusions” section, the report states: “At the time of writing, ongoing work was being conducted with respect to the marine ecology identification as well as testing of material samples. The results from these tests will be provided to the Malaysian investigation team once complete.”
The key here seems to be to reinforce the idea that the results of the biofouling examination will go to Malaysia, and not released to the public. Which raises the question: why does Australia feel empowered to release a fairly detailed report explaining why they think the pieces came from 9M-MRO, but not to say anything about the marine life on them? Is there a legal distinction between these two kinds of assessment, as pertains to ICAO protocols? Perhaps some legally-minded readers can shed light on the matter.
@Crobbie, very good comment. Thanks.
@StevanG:
~3000 fpm is typical for civilian aircraft during landing approach… ???
@ Jeff: here is a paper where barnacles (Lepas anatifera) were used to estimate the floating time of a corpse:
https://www.academia.edu/15158504/Evaluation_of_the_floating_time_of_a_corpse_found_in_a_marine_environment_using_the_barnacle_Lepas_anatifera_L._Crustacea_Cirripedia_Pedunculata_
(trigger warning: there are some gross pictures in it…)
Note that the authors phrase their conclusions as a minimum time at sea. This is the same thing I’ve been trying to say. Given that barnacles on a piece of debris are however-many months old, all that can be logically concluded is that the object has been at sea for at least that long. One cannot logically conclude that the floating time estimate represents a maximum time at sea.
@Gysbreght
from yahoo
“In order to save fuel, most aircraft try to maximize descent rates in order to gain the beetter fuel efficiency at altitude for a longer period of time. So rather than descending at 1000 feet per minute, we prefer to wait until the last second, chop the throttles to idle, and descend at a faster rate. Depending on the aircraft, it is usually between about 3000 and 3500 fpm.”
although it’s at the start of the descent, not really when you approach the runway
@StevanG: Rubbish. You were talking of landing approach where rod is typically 750 fpm on a 3 deg glidepath. For descent see FCOM, and you’ll see rod at idle typically 1500 fpm.
Yeah I misexpressed myself and JW blog doesn’t have edit option.
I’ve seen lot of examples on flightradar with >3K descent with my own eyes…although yeah “typical” might be an overstatement.
All in all if we have ~5K descent rate at the current search area and ~3K descent rate behind CI, I think the second one is much more probable if you assume piloted flight/controlled ditch.
@jeffwise said:
“As I wrote in an earlier comment on the previous post, the word on the street is that the French were unable to get useful results from their flotation test of the flaperon”
Hmmm … this might be a good opportunity to re-visit Jeff’s original post on how the flaperon floated.
jeffwise.net/2015/08/26/how-did-the-reunion-flaperon-float/
What about looking at quite a radical idea (more to rule it out than in): Could the flaperon have floated at all?
We’ve all assumed it must have, since it appeared on the Reunion beach. But if the discussion is about planting, and that part ‘magically’ turned up on Reunion (and the French seem reluctant to release their report) maybe this is something to consider, if only briefly?
The other items found had a thickness and showed honeycomb cores. In all of the Reunion flaperon photos has anyone seen any sign of a Nomex/honeycomb core along any of the broken edges?
Or does the top / bottom / leading edge appear to be made solely of a (fairly thin) solid (ie. single) composite panel riveted directly to the interior aluminium structure?
If the outer skin was a composite honeycomb structure, there should be an appreciable thickness visible at the inboard/outboard edges – there doesn’t seem to be (?). You’d also expect the honeycomb to be visible in part/at some places along the broken edges, given suitable hi-def photos.
If there isn’t (?) any sealed honeycomb structure to trap air – or there is but it hasn’t sufficient buoyancy – the question would be, of course, how could it float?
It would seem unlikely that there would be any sealed (airtight) aluminium box sections inside the interior structure simply because of the internal pressurisation that would develop at 35k feet (c. 11 psi). The inability to inspect endoscopically for internal corrosion might also be a factor.
Note: The same internal pressurisation problem apparently also applies to Nomex / honeycomb composites (ie. core separation – disbond) – unless vented in some way (eg. by cell wall perforation):
ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011132.pdf
Hexcel state that the thinnest Nomex core is 3.1mm:
hexcel.com/Resources/DataSheets/Honeycomb-Data-Sheets/HRH_10_us.pdf
hexcel.com/resources/honeycomb-data-sheets
So if we imagined a sandwich of composite panel/Nomex/composite panel of (say) 3mm/3.1mm/3mm, that would be 9.1mm total thickness. Looking at the inboard/outboard end photos of the outer skin on the Reunion flaperon, does that seem too thick? Might the outer skin actually be thicker than 9mm? Or would you say the outer skin is thinner than that? The hi-def photo of the policeman loading the flaperon into the Landrover on Jeff’s link (above) gives some scale. There’s also the photos of the ‘new’ (ie. repaired) flaperon to compare, of course. Or is the skin mostly a single solid piece (alu or composite?), with only the trailing edge being a Nomex/carbon fibre composite?
Would some of our math / data people here like to do some quick calcs and see what they get?
For example:
a) If we took (say) a 12″ x 12″ section with 3mm/3.1mm/3mm construction, would the combined density be greater or lesser than seawater (1.093)?
b) If we took what was left of the (guesstimated) entire composite panel (top, bottom, leading edge alone) of the Reunion flaperon at that thickness, would it have enough excess positive buoyancy to support the additional weight of the (guesstimated) alloy internal structure?
c) Or .. what thickness of Nomex would it need to have enough positive buoyancy?
Density of aluminium alloys = c. 2.7 (7055 aviation alloy: 2.86)
http://www.azom.com/article.aspx?ArticleID=8773
Density of carbon fibre composite panels = c. 1.4 (Kevlar) to c. 2.00 (Boron)
performance-composites.com/carbonfibre/mechanicalproperties_2.asp
Density of Nomex = c. 3 lbs / cu ft
At a 500-kt true air speed (TAS), a 3% glide corresponds to a vertical speed of about 2650 fpm. As the plane descends and the TAS falls, this number of course also falls.
ATSB: “the lettering found on each part matches stencils used by Malaysia airlines”
What a big discovery! During all the times quality close-up photos of these debris are on the web, did the ATSB need to wait until now to announce that the font on the debris matches the font used by Malaysia airlines?
@VictorI: 2650 fpm at 500 knots (~50,000 fpm)would be approximately a 5% glide, wouldn’t it? Also, if someone were to glide 125 nm after a flameout at FL35, that would require about a 5% average glide rate.
Also, thanks for the picture showing the Dopplers for the various points on the 7th arc. Those are pretty precise measurements (4 significant figures). What are the error bars for those estimates?
@Warren: As you probably realized, I mistyped. My calculation of the vertical speed represents a standard 3-deg glide as suggested by Gysbreght, not 3%. A 3-deg glide corresponds to a 5.2% vertical-horizontal ratio, so all is in agreement with your numbers.
At 35,000 ft and no temperature offset from ISA, M0.84 corresponds to 484 kt and ISA+10K represents 495 kt. Correspondingly, the vertical speed of 2650 fpm would be closer to 2565 – 2600 fpm. That’s not a big change, but the 500 kt TAS I used previously was a bit high.
As for error bars for the BFO, the JON paper by Ashton et al. says 7 Hz. The DSTG report says 20 Hz due to drift. Each 1 Hz of BFO error corresponds to 57.1 fpm of vertical speed.
http://blogs.crikey.com.au/planetalking/2016/04/20/mh370-search-recovers-its-sharpest-deepest-sonar-scanner/
“The ocean search is now in its final phase, with less than 20K km^2.”
@VictorI:
The point is that 500 knots is not a typical landing approach speed for civil transport aircraft.
A normal Descent at .84/310/250 kIAS with engines at idle from 33000 ft to sealevel takes 23 minutes, an average rate of descent of 1435 foot per minute. At those speeds idle thrust is typically negative, i.e. not much different from dead engines.
P.S. A typical approach speed in a flapless landing would be around 200 kts. With dead engines and gear up the flight path angle would be about 3 degrees.
@Gysbreght
Something else that might have a bearing on the glide subject is the drag from freewheeling engines would be expected to be significantly greater than from engines at idle, when you consider the diameter of the Trent engine fan.
Would this affect the descent rate/gliding distance?
@ROB:
The difference between windmilling drag and idle thrust is insignificant. The ATSB writes in its december 3, 2015 report:
The FCOM gives for the idle descent from FL330 distance 119 NM, time 23 minutes.
P.S. The FCOM descent data include an allowance for a straight-in approach with gear down and landing Flaps 30 at the outer marker. An altitude of 2000 ft at the outer marker would account for the difference of 6 NM.
@Gysbreght
Thank you, that’s useful.
The ATSB determined figure of 125Nn from FL330 would possibly be a theoretical maximum, neglecting wind (I admit this is just my assumption)
There was an estimated headwind of 33Kts at FL350, at the 7th arc, from the Southern Jetstream. The headwind would drop in strength as altitude was lost. In practice, a headwind would reduce the distance that could be achieved.
@ROB:
Yes, zero wind is a reasonable assumption for those descent data. Wind affects the distance over ground but not the rate of descent.
@Gysbreght: I am not sure why you disagree with my vertical speed calculation, which was based on M0.84 and 35,000 ft, i.e., the start of the descent when the descent rate is highest, and a 3-deg glideslope. The descent rate would drop as the altitude dropped and the speed followed the .84/310/250 speed profile (or whatever is speed profile is preferred for a particular carrier/route). I never said the approach speed was 500 kt. The descent rate derived from the BFO is a snapshot at a particular time, so average descent rates are not really helpful.
It just took a 90 dg dive at the end, but no boom.
@VictorI: I don’t think I disagreed with your estimate of descent rate at FL350. According to the FCOM table the airplane descends from 43000 ft to 31000 ft in 4 minutes (give or take 1 minute because the times are rounded to the nearest minute). My response was triggered by the reference to “3000 fpm typical for civil aircraft landing approach” and that is not FL350.
@Gysbreght: Yes, I agree that statement was false.
P.S. The flight path angle changes from 3.2 degrees to 2.4 degrees down when the speed schedule changes from M.84 to 310 kIAS at 31560 ft altitude.
interesting, powerfull and in line
https://www.rt.com/usa/340313-obama-saudi-pages-classified/
(primarily cbsnews, but less ads here on RT)
How is one world government gonna fix everything when we cant be rational, logical and sane? It will be just another empire to fall and the cycle continues: Build, destroy. Until we go extinct.
Thanks god. You leaving us with responsibility of living was too much for such primitive, corrupted, destructive, egomaniacs that we turned ourselves into.
@Trond
You seem to have a pretty simple-minded view of the world. My guess is that you spend a lot of time wondering why no else “gets it”. Funny shit.
@Marc
It seems like a basic call to say two fonts are the same but it can actually be surprisingly difficult.
What was very obvious in the photos was that the font was not the same as the one used by Boeing. What could not be determined 100% is that it is a match with the MAS stencil.
To be sure I would want to be able to lay one on top of the other without the bias that perspective can cause on size, shape,height etc. When using g a photograph. We saw with the Rodriguez piece what perspective can do to our understanding of what we see when relying on photography.
Interestinglynne.pinfold@swft.nhs.uk stencils often have their own ‘fingerprint’ meaning you can tie a stenciled word back to the exact stencil that was used to make it especially if theyou are all stored bunched up in a drawer in the factory. Dents and knocks in the stencil show up in the stenciled words. If the flaperon had been recently painted it may be that they were trying g to see if they could get a specific stencil match.
How was the case of mh370 being in cambodian airspace resolved?
@Crobbie
Thank you for your explanation.
https://mobile.twitter.com/kstaubin/status/719332003397640197
“The only logical way you can spoof both radar&Inmarsat data is to use a decoy a/c.”
https://mobile.twitter.com/MikeChillit/status/722846970491047936
“Could it have realistically taken 7 hours or so to arrive there? I guess if it flew in circles or something?”
“No one knows if it even turned south.”
Fugro Equator and Fugro Discovery vessels closing to 5km distance, both 90km outside 7th arc. Concentration on searching outside the arc?
https://pbs.twimg.com/media/CggQQAcWQAAT0ud.jpg
@Victor, so even with the conservative error bar, if the BFO Doppler is accepted at face value, then the aircraft could not have been going in a normal descent. However, if Mr. Yap’s article is to be believed, the flameout would have occurred a couple of minutes prior to the SDU reboot, when, presumably, the APU would start. In the interim time, it is the case that the pitot heating would fail, would it not? Therefore, since airspeed data would be unreliable, it would be prudent to not push the envelope in a glide and risk a stall. Also, a roughly 10% rate of descent is steep, to be sure, but it’s also not a 90 degree dive. It could be that the BFO recorded an intentional relatively steep rate of descent that was ordered in order to eliminate the risk of a stall.
Question: If the APU was running, would pitot heating be resumed?
For those who are interested, The MAS font is called “Glaser Stencil D”.
It’s available here:
http://www.myfonts.com/fonts/urw/glaser-stencil/d/
@Warren Platts, Pitot heat is only required in icing conditions, that is to say, visible moisture such as the inside of a cloud. I don’t think those conditions prevailed at the presumed altitudes and location in question.
@Ken Goodwin: please bear with me: I’m still ramping up on composite construction (from a starting point of zero). But here goes:
The linked photo of MH17 wreckage (courtesy Jeroen Akkermans) appears to depict Nomex filled with yellow potting compound. Am I right?
https://www.flickr.com/photos/jeroenakkermans/14711470172/in/album-72157645416293108/
If so: the side view of the filled honeycomb cells makes me wonder whether the Maldives debris (the big piece – the one whose honeycomb you had originally believed to be aluminum) might in fact be dark-red Nomex filled with WHITE potting compound (such as was found inside the Nomex honeycomb of debris which we’re now told “almost certainly originated from MH370”.
Any thoughts?
Warren Platts:
“Question: If the APU was running, would pitot heating be resumed?”
Answer: Yes
Reference: FCOM NNC.7.2 DUAL ENG FAIL/STALL
@Trond,
Why are you quoting twitter? What is the point you are trying to make?
@Susie
The first one shows a map of possible a way of spoofing. The other one is source of relevance.
@Jeff
My experience at 35k to 55k has been about -40 to – 50C.
But as usual I have forgotten more than I have remembered.
I Aiways thought it more colder above the Tropics than
the lower Lat.
why is the fastener from alledged MH370 perfectly round and the one from 405 elliptical in the picture?
@Trond
Relevance to what? We’re not discussing the Sunda debris sighting here.
I’m not trying to be confrontational, I’m just having trouble understanding.
@Marc
It’s interesting that they now seem to be focussing on the area downrange of the DSTG’s hotspot.
One ship is doing the bathymetric survey, the other follows up with the towfish.
It’s their best chance of finding the wreckage before the weather turns nasty. The clock is definitely ticking now.
https://www.flickr.com/photos/jeroenakkermans/14699432544/in/album-72157645790319631/
possibly matching material to Madives V2?
Regarding the state of the fastener on the no step piece :
https://www.flickr.com/photos/jeroenakkermans/14515211308/in/album-72157645790319631/
This picture from MH17 is interesting because it shows that the paint doesn’t bond with the fastener very well. It’s been scrapped clean (the one at the base of the “S”). To be fair, it looks like the paint doesn’t bond well with the substrate either in some places.
Around the main damage area, it’s also interesting because we see that in some places the paint over the fastener’s hole is gone (stayed on the fastener, or broke off), while in others the paint remained but the fastener is obviously broken underneath (pulled through).
Back to the piece found in Mozambique, if the fastener we see was the last point of attachment before separation, there would have been some rotation around this point. It could have peeled the paint while the faster would remain attached.
Better example :
https://www.flickr.com/photos/jeroenakkermans/14737382623/in/album-72157645853477595/
It seems there that the fastener was pulled in (but not through) yet the paint flaked off.
And finally :
https://www.flickr.com/photos/jeroenakkermans/14717207062/in/album-72157645853477595/
It’s worth noting that usually the head of the fastener breaks off. This explains the “intact” holes on the Mozambique piece.
@sinux
Another possible explanation is that the fastener that is in the no step piece was a replacement fastener put in place after the latest painting of the aircraft.
This explains 2 anomalies for me. Firstly the relatively pristine state of the fastener and secondly the lack of paint on it.
Aircraft fastener companies do small but steady trade on manufacturing replacement fasteners for use in such cases, producing fasteners in fractionally wider shank dimensions than the original termed +1s or +2s. A +1 is the second fastener to be fitted in a hole, a +2 is the third.
This may also be why THIS fastener still remains whilst others are gone. Being newer it won’t have been subject to wear/fatigue that adjacent fasteners would have been, meaning the joint didn’t fail in the same way.
Crobbie,
if you see a previous post of mine I suggested the same thing however what would be the explanation for the fastener corresponding to those in the adjacent line number aircraft, were it to have been a newer replacement?