Ocean Shield's "PINGS" Revisited.
Kirill Prostyakov (https://twitter.com/kprostyakov) has released some very interesting information on the Famous TPL-25 ping detections obtained by Ocean Shield.
He thinks the discounted ping detection by HMS Echo on 2-Apr-2014 was in fact exactly on top of the 5-Apr-2014 detections by ADV Ocean Shield.
The quick takeaway is that he thinks that the pings were real, and that the CVR and FDR are 35 kilometres apart, on an azimuth axis of 167 degrees true.
The direct implication of which is, that the aircraft may have (probably) broke up in flight, at high altitude. Moreover, the apparent tensile failure of control surface elements, (I presume he means Item 8 - the flap track fairing rear aerodynamic cone cover) and the actual presence of cabin debris indicates breakup at altitude, because he thinks that if the aircraft collided with the water intact, all debris would get compressed.
His data and computer code is here:
https://github.com/kprostyakov/beacon_location
6.7Mb File (ZIP)
https://codeload.github.com/kprostyakov/...zip/master
There is some interesting "reasoning" in his presentation here:
https://github.com/kprostyakov/beacon_lo...slides.odp
2.36Mb File
https://raw.githubusercontent.com/kprost...slides.odp
His twitter posts of 2nd May 2017 are summarised as follows:
The CVR had a better battery than the FDR, and he thinks that the TPL survey was done below refraction cone (layer ?), thus he seems to think that the actual "detections" were made when the TPL-25 was pulled up (through the layer ?) during Ocean Shield's turns at the ends of the straight towing runs.
Locations on map.
Image Map-CVR-FDR.jpg
The FDR and CVR separated by 35km at sea bottom at approx 167 deg azimuth (N->S). Mid-air breakup.
The code uses real bathymetry and does ray tracing to get transmission loss for all points on the bottm outside UAV survey limits. Red = can hear.
FDR transmission map - the source is likely to be in NW corner not covered by UAV due to being at a depth greater than 5,000 metres.
Image FDR-1.jpg
CVR transmission map - at reported 27kHz (lower parasite mode around battery depletion time)
Image CVR-1.jpg
~31 kHz in first video - possibly pinger #2 at 1.02sec repetiton rate.
More distant, as only lower frequency parasite band left.
05-Apr-2014 ADV Ocean Shield DID detect 37.5kHz signal.
33.3 peak is LSB, USB @ 41.6kHz. Why modulation though ?
