Malaysian Airlines MH370 contact lost
unencrypted radio transmissions are in the public domain
"Although it is not illegal to sell, buy or own a scanning or other receiver in the UK, it must only be used to listen to transmissions meant for GENERAL RECEPTION. The services that you can listen to include Amateur and Citizens' Band transmissions, licensed broadcast radio and weather and navigation broadcasts. It is an offence to listen to any other radio services unless you are authorised by a designated person to do so."
Full text here:
RA 169 - Receive-Only Radio Scanners etc
In practice, of course, I've never heard of someone being prosecuted for listening to, or recording, ATC.
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Someone said earlier that the messages are sent in well-defined timeslots, so you wouldn't necessarily have to look at the round-trip delay, but the difference between the time the message was received from the aircraft and the 'ideal' start of the timeslot if the aircraft was directly below the satellite. That's assuming it's fairly well synchronized to the satellite, which you could determine by looking at previous flights that sent position reports.
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Imersat Track
Thanks Dave
Hate to say your right and cleared my misunderstanding.
If they released the other pings and the last four are possible strait line. I'm sure someone by maths could work a possible track out.
Hate to say your right and cleared my misunderstanding.
If they released the other pings and the last four are possible strait line. I'm sure someone by maths could work a possible track out.
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The imersat track is shown as an Arc if transposed onto a globe does it become a direct great circle track as normally flown?
A Great Circle track is a 'segment' originating roughly from the centre of the earth.
These arcs are segments exactly centred at the satellite sending and receiving the 'pings'.
Don't worry, you are not the only one who is having difficulty understanding what these arcs are and why they are not going to add much to the search for either a track flown or the final destination.
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Max Nightstop said,
it is a Government owned and Run airline, the Government is effectively the CEO.
Trying to figure out the timeline of recent CEOs, I have run into a handful of confusing "appointments" press releases since 2010. Specifically, it looks as though Anand Selvaratnam and Ahmad Jauhari Yahya may have kind of been switched back and forth a couple times as CEO & Managing Director since April 2011, but who knows for sure. Before that, I am able to figure out
August 2009 - April 2011 - Tengku Datuk Azmil Zahruddin
Archives | The Star Online.
2005 - August 2009 - Idris Jala, current Senator and CEO of the Performance Management and Delivery Unit (Pemandu)
Idris Jala - Wikipedia, the free encyclopedia
A quick search reveals lithium batteries have UN code 3090 or 3481 in the dangerous goods manual, so they are categorized and the CEO is lying.
Trying to figure out the timeline of recent CEOs, I have run into a handful of confusing "appointments" press releases since 2010. Specifically, it looks as though Anand Selvaratnam and Ahmad Jauhari Yahya may have kind of been switched back and forth a couple times as CEO & Managing Director since April 2011, but who knows for sure. Before that, I am able to figure out
August 2009 - April 2011 - Tengku Datuk Azmil Zahruddin
Archives | The Star Online.
2005 - August 2009 - Idris Jala, current Senator and CEO of the Performance Management and Delivery Unit (Pemandu)
Idris Jala - Wikipedia, the free encyclopedia
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In-flight re-fuelling
I haven't seen anyone post the other gem from today's press conference when a reporter asked if the SAR aircraft were being air refuelled, where that was technically possible, and had they asked the USA to provide tankers to do the honours. The reply was "no we haven't but I will now, now that you've asked!"
An Australian poster here made the point very clearly, days ago on PPRune, that the RAAF assets could air refuel so they weren't limited to just 2 hours on station in the Southern Indian Ocean. Sad then that they haven't done it.
An Australian poster here made the point very clearly, days ago on PPRune, that the RAAF assets could air refuel so they weren't limited to just 2 hours on station in the Southern Indian Ocean. Sad then that they haven't done it.
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The Ping, The Satellite and The Ship
I am not quite sure if this discussion is about how sat pinging is/was used for a/c positioning (a lot of inputs, harder and harder to follow).
However, pretty clear explained here:
Help from above: Satellite signals can confirm a plane's identity - CNN.com
The probable track was obtained (backwards) starting from the last estimated position, using the know position of the (stationary) sat, the ground reference and the computed angle between the emitter (plane) and receiver (sat) when last ping has been sent - that is, not by time delay means (as GPS works). Which is straightforward...
They also said that's new territory:
regards,
However, pretty clear explained here:
Help from above: Satellite signals can confirm a plane's identity - CNN.com
The purpose of the hourly "handshakes" is to allow the satellite to know the approximate location of the aircraft so that it can efficiently relay any messages. For this, the satellite needs to know the angle of the aircraft from the satellite. An aircraft directly under the satellite would be at a 90 degree angle to the satellite; an aircraft at the poles would be at 0 degrees. (Inmarsat Official via CNN)
The probable track was obtained (backwards) starting from the last estimated position, using the know position of the (stationary) sat, the ground reference and the computed angle between the emitter (plane) and receiver (sat) when last ping has been sent - that is, not by time delay means (as GPS works). Which is straightforward...
They also said that's new territory:
"We're trying to get up to speed on what that means and how to interpret it," one U.S. official told reporters. "It's sort of a new technology for us."
GMM, if I recall correctly, the poster stated that the RAAF Orions were unable to do AAR, however the US Navy Poseidon is capable of it. Of course others have already mentioned the other factors which come into play such as crewing levels and duty times...
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SLFplatine said
The problems come in it getting there - or more specifically, back over the peninsula in the manor it did without a crew. Also the issue of ACARS having completely failed to alert anyone to said catastrophic event taking place. (although it appearntly, per Malaysian Press Conferences at least, let them know of WP changes (at least 2) in the last report at 1:07)
Possibility of incapacitated crew after exiting the Straights(/radar) area; very high. Up to that point though; unbelievably low. (and that seems to pretty much be the Official stance of the Investigation team, so...)
That there is a 50% possibility the flight ended at the southern most reaches of the Indian Ocean could indicate an attempt to return to KL which an incapacitated flight crew was unable to execute beyond setting HDG
Possibility of incapacitated crew after exiting the Straights(/radar) area; very high. Up to that point though; unbelievably low. (and that seems to pretty much be the Official stance of the Investigation team, so...)
To answer Pontius several pages back
It would depend on the system fitted, if chemical generators than only the masks in the units where one mask was pulled would flow. Therefore any units above unoccupied seats which were not activated would be available to the crew. I know on the 777 I trained on each unit lasts approximately 22mins. We know there were c50 empty seats on this flight...
However if it is a gaseous (bottled) systems as per 747, which one poster has suggested it was, duration would vary depending on altitude, number of masks in use and how many bottles are fitted to the system. Theoretically if only a couple of CC were quick enough they could long outlast the flight deck oxygen which is only designed for 2-4 people to use for as long as it takes to make an emergency descent. Of course if the pax are on it, it wouldn't last as long with 250+ using it...
However I don't know whether the drop downs work on a common system, ie one group are exhausted even is some drop downs have not been used. If that is the case then those crew on drop downs will be no better off than the pax.
However if it is a gaseous (bottled) systems as per 747, which one poster has suggested it was, duration would vary depending on altitude, number of masks in use and how many bottles are fitted to the system. Theoretically if only a couple of CC were quick enough they could long outlast the flight deck oxygen which is only designed for 2-4 people to use for as long as it takes to make an emergency descent. Of course if the pax are on it, it wouldn't last as long with 250+ using it...
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Radar
Have I missed it somewhere? How do they Know :
A. The radar tracks WERE 370 without IFF
B. The origin of the "waypoints"
Does MAS subscribe to ADS-C?
Please do not de-bunk unless you KNOW and can give the evidence!
A. The radar tracks WERE 370 without IFF
B. The origin of the "waypoints"
Does MAS subscribe to ADS-C?
Please do not de-bunk unless you KNOW and can give the evidence!
I don't own this space under my name. I should have leased it while I still could
By definition these lines do not provide positions from which to drive a strait (sic) line. The lines will be a measurable distance apart. Let us assume they are at one hour intervals and are 200 miles apart; this gives a velocity vector of 200 mile/hr towards the statellite sub-point. You can then use a ruler marked off with the max ground speed, say 450 kts, and use this to fit the 450 mile marks to the arc. If you subtend this from the last know position it will give to a track at a given angle to the North with a similar mirror image to the South.
If you now mark the rule with either the minimum speed you can get another track which will be closer to the direct line to the satellite ground position.
You now have two sectors, one to the north and one to the south. The line joining the two points at the end of the sector arcs will give a possible line of position. These lines can then be plotted further on if it is assumed that the aircraft flew one for a time after the last ping. Only if you assume the correct groundspeed would you have a discrete pair of tracks.
The closer together the ping arcs the greater the track angle would be to the north and south.
The logic only holds good if the aircraft made no course changes between pings and flew at a constant ground speed.
Last edited by Pontius Navigator; 21st Mar 2014 at 19:31.
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Deriving the course from the Inmarsat pings
Given a number of recent posts on the methods of interpreting the INMARSAT ‘ping’ data, here is my understanding of how this will have been done by the NTSB.
Each ping specifies a distance from the INMARSAT F1 sub-satellite point at 64degrees East on the equator. On the Earth’s surface this is a circle (but not a great circle). A model track can be specified from the last reported position of the aeroplane off the West coast of Malaysia to any point on the circle described by the last ping. The length of that track specifies the speed of the aeroplane (since the times are known) and hence where it would be when the intermediate (every hour) pings were exchanged. The distances of these ping positions from the sub-satellite point can be compared to the actual data (held by NTSB but not us). The point on the final ping circle (the arcs) can be moved until the model track matches the data. If there is no good match, change parameters like the final turning point, smooth changes in speed along the track etc. to get a good match to the data (there is a limit to how many things can be changed before the model can fit any data). Unless the aeroplane was performing extreme and random manoeuvres during its flight (in which case it would have crashed earlier) a course and speed of quite high accuracy can be obtained, I think.
The fuel exhaustion point is a different calculation and more uncertain IMHO.
A longer and even more boring post is at #5911 of this thread.
Each ping specifies a distance from the INMARSAT F1 sub-satellite point at 64degrees East on the equator. On the Earth’s surface this is a circle (but not a great circle). A model track can be specified from the last reported position of the aeroplane off the West coast of Malaysia to any point on the circle described by the last ping. The length of that track specifies the speed of the aeroplane (since the times are known) and hence where it would be when the intermediate (every hour) pings were exchanged. The distances of these ping positions from the sub-satellite point can be compared to the actual data (held by NTSB but not us). The point on the final ping circle (the arcs) can be moved until the model track matches the data. If there is no good match, change parameters like the final turning point, smooth changes in speed along the track etc. to get a good match to the data (there is a limit to how many things can be changed before the model can fit any data). Unless the aeroplane was performing extreme and random manoeuvres during its flight (in which case it would have crashed earlier) a course and speed of quite high accuracy can be obtained, I think.
The fuel exhaustion point is a different calculation and more uncertain IMHO.
A longer and even more boring post is at #5911 of this thread.
I don't own this space under my name. I should have leased it while I still could
I will start by stating that I don't KNOW and no one except the relevant military air defence operations centre will be able to tell you how they KNOW.
What I can say is how they should have known.
The air defence centre is responsible for compiling a recognised air picture in its AOR. A civilian aircraft entering the AOR will be wearing a civil squawk which will display adjacent to the primary radar return on the military radars. Now assuming the squawk decode and its position in the airway structure correlate with a known civil flight it will be allocated a Friendly track number - this is an AD assignment and not exchanged with the civil ATC (unless they are co-located).
If the aircraft then 'strangles its parrot' (
) this will not affect the allocated track number. As the aircraft leaves the airway structure it will continue to 'wear' the same track number.
Should this aircraft then depart the relevant AOA it can be handed off to the adjacent Air Defence Centre, in this case that would be Thai if a bilateral agreement existed but we have not heard of such bilateral liaison.
The air defence centre is responsible for compiling a recognised air picture in its AOR. A civilian aircraft entering the AOR will be wearing a civil squawk which will display adjacent to the primary radar return on the military radars. Now assuming the squawk decode and its position in the airway structure correlate with a known civil flight it will be allocated a Friendly track number - this is an AD assignment and not exchanged with the civil ATC (unless they are co-located).
If the aircraft then 'strangles its parrot' (
) this will not affect the allocated track number. As the aircraft leaves the airway structure it will continue to 'wear' the same track number.Should this aircraft then depart the relevant AOA it can be handed off to the adjacent Air Defence Centre, in this case that would be Thai if a bilateral agreement existed but we have not heard of such bilateral liaison.
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QUESTION RE PINGS:
Are the packets time stamped to enough accuracy for ranging or is INMARSAT timing the round trip or ?????
The error rate is around 186 miles (distance to satellite) per millisecond if I remember my math. You are deriving a sphere around the satellite and then plotting it against the surface of the planet which is another sphere.
Are the packets time stamped to enough accuracy for ranging or is INMARSAT timing the round trip or ?????
The error rate is around 186 miles (distance to satellite) per millisecond if I remember my math. You are deriving a sphere around the satellite and then plotting it against the surface of the planet which is another sphere.
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Who did Boeing send there to make such unqualified remarks? An accountant? A lawver? A salesman?
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However if it is a gaseous (bottled) systems as per 747, which one poster has suggested it was,
The BA B777 have a gaseous system, customer option.
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This hypothesis fits most of the bill. Even the cracks were found near the antennas. The only thing is the low flying reports from Maldives, if reliable. But the plane would have pinged and flown on until given an new waypoint and if the FMC had been damages or was getting bad input it could have gone haywire and given waypoints that had recently been used that were in its memory.
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jmmilner
It should be noted that the words also perfectly fit the official position of the investigation (of which Boeing is a part of), and therefore could have very likely been said near exactly as Chambliss described them
The words are from a U.S. Senator, Saxby Chambliss, who was a lawyer before he entered politics 20 years ago. He threw out Boeing's name when he couldn't provide any direct support for his prior statement. This is standard behavior for US politicians.
The only reliable LKP available to the public is the last SSR position.
Note that it's a few degrees above the equator.
Moving West from the LKP would reduce the distance to IOR -- as would a course of 180 True until crossing the Equator, whereupon the distance would steadily increase.
The first ping arc after LKP coupled with a/c g/s might be useful to determine whether MH370 turned North or South. The second ping arc may also be helpful in determining the relative probability of which way the a/c turned.
That said, there remains the possibility the a/c assumed a closed course. In that case, we might see a steady oscillation in ping arc distances or a constant one depending on cycle times. For example if the a/c was tracking a wide circle n times an hour, the ping distance could remain constant.
Note that it's a few degrees above the equator.
Moving West from the LKP would reduce the distance to IOR -- as would a course of 180 True until crossing the Equator, whereupon the distance would steadily increase.
The first ping arc after LKP coupled with a/c g/s might be useful to determine whether MH370 turned North or South. The second ping arc may also be helpful in determining the relative probability of which way the a/c turned.
That said, there remains the possibility the a/c assumed a closed course. In that case, we might see a steady oscillation in ping arc distances or a constant one depending on cycle times. For example if the a/c was tracking a wide circle n times an hour, the ping distance could remain constant.