Malaysian Airlines MH370 contact lost
Join Date: Jan 2008
Location: UK
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
"Can't comment on that but he definitely said that the aircraft could have been sinking at the moment the ping was interrupted and that if could have been floating prior to that."
Fair enough - wouldn't be the first mixed message to be communicated in this sad affair.
Fair enough - wouldn't be the first mixed message to be communicated in this sad affair.
Join Date: Jan 2008
Location: Australia - South of where I'd like to be !
Age: 59
Posts: 4,261
Likes: 0
Received 0 Likes
on
0 Posts
One Track
Understand it will be a hive of activity and round the clock work but
using a helo at night to search for non human items ?
Would have thought launch would be a dawn.
Understand it will be a hive of activity and round the clock work but
using a helo at night to search for non human items ?
Would have thought launch would be a dawn.
Join Date: Apr 2000
Location: Canberra, ACT, Australia
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Partial ping at 8.19
There have been a few comments on the partial ping at 8.19 (including latest one that it may be been when aircraft sank). Most seem to suggest that the ping could have been caused by power being cycled off and on to satellite system on the plane causing it to restart and sending ping to satellite. I am not an expert on these large aircraft but from what others have said this could be caused by the first engine shutting down due to fuel exhaustion which then caused power interruption as systems switched over to power supply from the other engine.
The question would then be why only a partial ping? Obviously one possibility is that power was then lost again but could another reason be unusual attitude of the plane? I don't now about 777 but on smaller/older aircraft loss of an engine will cause autopilot to disconnect and if pilot doesn't stop it pretty quickly the asymmetrical thrust will cause plane to rapidly bank towards dead engine and potentially enter a spiral dive, etc.
Just wondering whether anyone with more experience on these aircraft can comment on whether autopilot will remain connected when first engine fails and if not whether there would be anything (other than a conscious pilot of course!) that would stop the aircraft rapidly losing control (which could explain the partial ping if the satellite antenna was no longer pointing skywards??).
The question would then be why only a partial ping? Obviously one possibility is that power was then lost again but could another reason be unusual attitude of the plane? I don't now about 777 but on smaller/older aircraft loss of an engine will cause autopilot to disconnect and if pilot doesn't stop it pretty quickly the asymmetrical thrust will cause plane to rapidly bank towards dead engine and potentially enter a spiral dive, etc.
Just wondering whether anyone with more experience on these aircraft can comment on whether autopilot will remain connected when first engine fails and if not whether there would be anything (other than a conscious pilot of course!) that would stop the aircraft rapidly losing control (which could explain the partial ping if the satellite antenna was no longer pointing skywards??).
Join Date: Aug 2008
Location: With the fairies!
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
The helicopter has to be prepared for flight having just been transported across Australia.
It then needs to fly out and embark in HMAS Success from where it will operate. It can certainly do that at night but with limited SAR capability and no life saving reason why take such a risk on such a long transit by night?
Far better to launch at dawn with the top cover of other SAR fitted fixed wing aircraft around.
It then needs to fly out and embark in HMAS Success from where it will operate. It can certainly do that at night but with limited SAR capability and no life saving reason why take such a risk on such a long transit by night?
Far better to launch at dawn with the top cover of other SAR fitted fixed wing aircraft around.
Usual disclaimers apply!
Join Date: Nov 1999
Location: EGGW
Posts: 843
Likes: 0
Received 0 Likes
on
0 Posts
Just wondering whether anyone with more experience on these aircraft can comment on whether autopilot will remain connected when first engine fails and if not whether there would be anything (other than a conscious pilot of course!) that would stop the aircraft rapidly losing control (which could explain the partial ping if the satellite antenna was no longer pointing skywards??).
The electrical system has a 'no break' power transfer so the A/P should stay engaged. The TAC will correct for the asymmetry with a bit of rudder input.
The electrical system has a 'no break' power transfer so the A/P should stay engaged. The TAC will correct for the asymmetry with a bit of rudder input.
Join Date: Jan 2008
Location: Australia - South of where I'd like to be !
Age: 59
Posts: 4,261
Likes: 0
Received 0 Likes
on
0 Posts
Looks like one of the Chinese warships has been sent to look for the objects.
From AMSA
"AMSA has tasked Chinese Maritime Administration patrol ship Haixun 01 which is in the search area and will be in a position to relocate the objects on Saturday."
From AMSA
"AMSA has tasked Chinese Maritime Administration patrol ship Haixun 01 which is in the search area and will be in a position to relocate the objects on Saturday."
Join Date: Sep 2008
Location: about there
Posts: 78
Likes: 0
Received 0 Likes
on
0 Posts
OCEAN SHIELD
Ocean Shield disappeared for while on marine traffic but I see it is a few hours out of Albany at this time. Google marine traffic. It is a fuscia coloured hull.
Join Date: Aug 2008
Location: With the fairies!
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Why just to the point of no return? If you think about it a little more, what will be it's 'point of no return' once it operates from a ship? That said it could well 'hop' from one deck to another as stages however there are difficulties with cross operating with other nations' ships.
Having spent a couple of thousand hours operating from ships with 'non-diversion' flying you work with 'Mother' being your destination!
Having spent a couple of thousand hours operating from ships with 'non-diversion' flying you work with 'Mother' being your destination!
Join Date: Jun 2009
Location: Paris
Posts: 691
Likes: 0
Received 0 Likes
on
0 Posts
AMSA media release
Official news about today search here:
http://www.amsa.gov.au/media/documen...a_Update25.pdf
http://www.amsa.gov.au/media/documen...a_Update25.pdf
Join Date: Nov 2006
Location: Berks
Posts: 125
Likes: 0
Received 0 Likes
on
0 Posts
Why just to the point of no return? If you think about it a little more, what will be it's 'point of no return' once it operates from a ship? That said it could well 'hop' from one deck to another as stages however there are difficulties with cross operating with other nations' ships.
Having spent a couple of thousand hours operating from ships with 'non-diversion' flying you work with 'Mother' being your destination!
Having spent a couple of thousand hours operating from ships with 'non-diversion' flying you work with 'Mother' being your destination!
Join Date: Nov 2000
Location: Deepest Kernow
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
ADV Ocean Shield
Updates on Ocean Shield position from Marinetraffic.com
OCEAN SHIELD - Offshore supply ship: current position and details | IMO 9628374, MMSI 503728000, Callsign VHEH | Registered in Australia - AIS Marine Traffic
OCEAN SHIELD - Offshore supply ship: current position and details | IMO 9628374, MMSI 503728000, Callsign VHEH | Registered in Australia - AIS Marine Traffic
Join Date: Jul 2009
Location: Atlanta, GA USA
Age: 60
Posts: 183
Likes: 0
Received 0 Likes
on
0 Posts
I think the final "partial" ping was partial because of a bad signal between the satellite and the aircraft, because the aircraft may not have been straight and level at that point, thus putting it's antenna in a non-optimum position, rather than the ping being cut off in mid signal due to the plane sinking in the ocean.
I don't own this space under my name. I should have leased it while I still could
Coagie, all things are possible. It would need an AOB over 50 degrees (I guess) for airframe blanking followed by a recovery so the antennae could see the satellite.
Join Date: Mar 2014
Location: Texas
Age: 51
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
I've never been clear on the "partial ping"...was it the satellite system pinging the aircraft or was it a message initiated by the aircraft's satcom? I've been assuming the later, but...that would mean that "ping" is not an accurate term. Or at the least, the final ping is quite different from the other pings. Yet, I continue to see it referred to as a "ping".
Join Date: Jan 2006
Location: US
Posts: 2,205
Likes: 0
Received 0 Likes
on
0 Posts
AAKEE- 3500, and perhaps 4000 nm, would be a reasonable estimate.
Optimum performance would start at approx FL 380 and increase as the aircraft weight was reduced with fuel burn off.
Range at very low altitude would be around 60-70% of it's high altitude range but the endurance at low altitude would be very similar (90-95%?).
Optimum performance would start at approx FL 380 and increase as the aircraft weight was reduced with fuel burn off.
Range at very low altitude would be around 60-70% of it's high altitude range but the endurance at low altitude would be very similar (90-95%?).
Join Date: Mar 2014
Location: Below glidepath
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
Partial ping
From what I can infer from the comm protocol, the partial ping was initiated by the aircraft. I won't speculate on why. The satellite did not know to initiate the ping.
IMHO:
The partial ping can be analyzed for doppler and that might give some indication of position. However, since only one satellite is involved, this would produce a curve of possible positions, with an associated uncertainty, not a point.
Unless there was a complete handshake with the satellite (ie. aircraft sends ping to satellite, satellite replies, aircraft replies) timing data would not be generated, so one can not calculate a corresponding curve for aircraft position due to timing.
I have not analyzed the time and doppler information (don't have the proper tools in place and would take to long to generate - would rather work on my boat), but from experience on other systems, these might create somewhat orthogonal or independent curves which at their intersection would produce a position. Just speculating.
IMHO:
The partial ping can be analyzed for doppler and that might give some indication of position. However, since only one satellite is involved, this would produce a curve of possible positions, with an associated uncertainty, not a point.
Unless there was a complete handshake with the satellite (ie. aircraft sends ping to satellite, satellite replies, aircraft replies) timing data would not be generated, so one can not calculate a corresponding curve for aircraft position due to timing.
I have not analyzed the time and doppler information (don't have the proper tools in place and would take to long to generate - would rather work on my boat), but from experience on other systems, these might create somewhat orthogonal or independent curves which at their intersection would produce a position. Just speculating.
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,350
Likes: 0
Received 0 Likes
on
0 Posts
The aircraft systems logon to the satellite(s) by calling them first then they are polled at intervals to check that their receiver is still ready and the low level link is still good. If the aircraft system thinks it has lost the signal - say due to a power down then back up - it might try to restart the lost link. As this last ping was from the aircraft and out of time, it is possibly another log on attempt from the aircraft system that was interrupted.
Join Date: Nov 2013
Location: California
Posts: 154
Likes: 0
Received 0 Likes
on
0 Posts
3. Changing the assumed speed would cause problems for the Doppler model that INMARSAT used. This is very sensitive to the aircraft speed which has to be removed to reveal the spacecraft Doppler signal used to decide it was on the Southern route.
If (if) the interim ping arcs are being used and are still constraining the choice of route and hence search area, I would guess that the constant magnetic heading option is now being used, which allows a shorter required range.
If (if) the interim ping arcs are being used and are still constraining the choice of route and hence search area, I would guess that the constant magnetic heading option is now being used, which allows a shorter required range.
Doppler shifts are measurements of "radial speed": speed with which the aircraft is getting closer to or further away from the satellite.
If you have a bunch of speed values and you assume that the trajectory is reasonably smooth (no zigzagging), you can calculate the change in radial distance (ie arc) by summation of speed*time.
In other words, if the aircraft is moving in a smooth manner, Doppler shifts and arcs are not independent sources of information. You can fit a number of trajectories to the Doppler shift curve, but, as long as they fit, all points always end up on the same arcs. The unknown is the transverse speed and the transverse distance traveled: how far along each arc your points end up.
So, if we take the previous search point and recalculate the trajectory using lower speeds, all points move northeast and the point of last transmission moves northeast quite a bit, while staying on the ~40 degree arc.
If you look at my spreadsheet a couple of pages ago, I had possible Southern routes worked out for 400 knots and 450 knots, and the results were as expected: going from 450 to 400 moved the endpoint 4 degrees north and 5.5 degrees east.