Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

Malaysian Airlines MH370 contact lost

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

Malaysian Airlines MH370 contact lost

Old 15th Mar 2014, 09:47
  #3781 (permalink)  
 
Join Date: Mar 2014
Location: Northern California, U.S.
Posts: 24
Likes: 0
Received 0 Likes on 0 Posts
ADS-B Hard to Jam

Like cell phones, ADS can be disrupted by jamming in interactive mode.

On the other hand, in one-way broadcast mode, ADS-B only transmits without waiting to receive any signals.

To jam the transmitted ADS-B signal, a jammer would need to generate and radiate a conflicting signal at the same or greater effective power as seen from a land-based receiver. This is difficult to do without a specialized antenna mounted outside the metal fuselage.

It is not entirely clear at present whether ADS-B transmissions from MH370 were actually disabled, or whether they were merely not received due to range issues. FR24 appeared to say that they lost the signal as the aircraft disappeared below the horizon.
Communicator is offline  
Old 15th Mar 2014, 09:54
  #3782 (permalink)  
 
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 80
Posts: 1,330
Likes: 0
Received 0 Likes on 0 Posts
@rh200,
Could the logs just be time tagged when the ping was recieved.
You are absolutely right. That timing will produce a position line (in this case a curved one) and the originating signal will be somewhere along that line.

IMHO that is the clear reason why the authorities are talking about either to the NW or the SW. If the reason to go SW was a "terminal" one, then a very deep spot in the Indian Ocean would be a likely outcome. The reason to go NW, would probably be politically based. Take your pick.
mm43 is offline  
Old 15th Mar 2014, 09:56
  #3783 (permalink)  
 
Join Date: Aug 2003
Location: At work
Posts: 292
Likes: 0
Received 0 Likes on 0 Posts
It would be interesting to find out if there was an abnormally large discretionary uplift above the flight plan fuel. That might point to a deliberate attempt to extend the range.
belowMDA is offline  
Old 15th Mar 2014, 09:58
  #3784 (permalink)  
 
Join Date: Mar 2014
Location: Perth
Age: 61
Posts: 65
Likes: 0
Received 0 Likes on 0 Posts
A detailed post of mine about how to use INMARSAT satellite coverage to narrow down the location of signals has not appeared yet after I posted it.

However, a brief extra point is that, even with just one ACARS satellite communicating with you (which is the case over most of the Indian Ocean and subcontinent), you can determine distance (from signal to satellite) quite accurately from ping times (as there are usually several time-stamped messages going each way).
ana1936 is offline  
Old 15th Mar 2014, 10:00
  #3785 (permalink)  
 
Join Date: Apr 1999
Location: In front of a computer
Posts: 2,330
Likes: 0
Received 48 Likes on 19 Posts
Amazing fact !!

The police have only just started searching the aircrew's houses some 8 days - read that again - 8 days after the event.

We discussed this course of action on about page 2 - why are they just starting to check the "obvious"??
ETOPS is offline  
Old 15th Mar 2014, 10:01
  #3786 (permalink)  
Props are for boats!
 
Join Date: Oct 2000
Location: An Asian Hub
Age: 56
Posts: 994
Likes: 0
Received 0 Likes on 0 Posts
They need now to do a live test with B777 fly it on the same track with all radar and facilitates watching and recording and see if the can replicate what the THINK they have already!! I'm sure if they do this they will eliminate or confirm their assumptions to date. Otherwise the search windows are too large and there are not enough assets worldwide to cover such a large search zone.
Sheep Guts is offline  
Old 15th Mar 2014, 10:02
  #3787 (permalink)  
 
Join Date: Mar 2014
Location: Houston
Posts: 9
Likes: 0
Received 0 Likes on 0 Posts
anybody wondering what took them so long to let us know the possible new tracks the aircraft may have taken, Inmarsat data, etc?
I'm probably biased by being in the telecom engineering industry, but calculating the signal strength boundaries to create a 2-dimensional range would take a good bit of effort. Not to mention, if I'm at Inmarsat, my model is going to change based on every piece of new information that comes in regarding the possible actions undertaken during the flight.

Imagine you're holding your cellphone, and some guy looking at two towers worth of signal strength data is asked to find you. In a 2-d world it wouldn't be that difficult. I could pretty easily nail you down to two points. But now, get in an elevator, and I'm going to have a hell of a time mapping your movement.

In this scenario, going only off received signal strength data between two satellites, I have to figure out a boundary for a high and low signal that I want to say you crashed in. Now I look at all of the other data but some critical pieces are missing. I don't know how fast you were moving between two points when the satcom pinged, I don't know your changes in altitude, and on top of that, I don't know what interference or noise could've been introduced into the system at any given time by your environment or your actions on the plane.

I'll guarantee you one thing though - every hour spent by an RF engineer to limit that range saves somewhere on the order of half a day's worth of ocean to cover.

This is an incredibly complex system with limited knowledge of all of the variables.

To describe the difficulty, it would be like me asking you to find out which cows your hamburger came from after visiting a random McDonalds. You could probably limit it down to a few slaughter houses, but you'd never be able to pinpoint the cows.
TelcoAg is offline  
Old 15th Mar 2014, 10:02
  #3788 (permalink)  
 
Join Date: Oct 1999
Posts: 134
Likes: 0
Received 0 Likes on 0 Posts
Communicator

Don't know how to paste your post here.

If that's the case (Satellite com/data system still "pinging" satellite after ACARS/CPDLC/ADS-C turned off) then the authorities would know how long the 777 system was active for. Is this the case?
Jet Man is offline  
Old 15th Mar 2014, 10:03
  #3789 (permalink)  
 
Join Date: Sep 2001
Location: Connecticut, USA
Age: 64
Posts: 251
Likes: 0
Received 0 Likes on 0 Posts
If the climb to F450 and then the erratic descent to ~F230 is true, it looks awfully like someone was at the controls who was finding that the real thing wasn't quite the same as Flight Sim. and it took him a while to get his head around handling it.
Everything I've seen suggests that F450 would at best have been nearly impossible - and the rapid descent WOULD have been impossible. That said, if there was a climb to anything approaching that altitude, I suspect it was done to eliminate opposition from the cabin. From what has been posted, the drop down oxygen masks are useless at that altitude.
jugofpropwash is offline  
Old 15th Mar 2014, 10:05
  #3790 (permalink)  
 
Join Date: May 2012
Location: Australia
Posts: 131
Likes: 0
Received 0 Likes on 0 Posts
The Two Possible Flight Corridors...



Source: NewsBreaker ‏@NewsBreaker 1h
MAP: Shows 2 possible corridors that Malayasian Prime Minister mentioned for flight #MH370 pic.twitter.com/rv3q3FFA4e - @KHOLMESlive
StormyKnight is offline  
Old 15th Mar 2014, 10:06
  #3791 (permalink)  
 
Join Date: Sep 2009
Location: Internet
Age: 47
Posts: 43
Likes: 0
Received 0 Likes on 0 Posts
I think it is safe to say the IAF has sufficient coverage to pick up a T7

IAF scrambles Su-30MKI after spotting UFO near Amritsar border
Just for a weather balloon they scrambled Sukhois.. may be they are more vigilant on their western borders..
Neogen is offline  
Old 15th Mar 2014, 10:06
  #3792 (permalink)  
 
Join Date: Feb 2008
Location: UK
Age: 66
Posts: 757
Received 19 Likes on 14 Posts
latest Press conf

Malaysian PM says seems the US NTSB, FAA and our own UK AAIB are working on the data too and concur
rog747 is online now  
Old 15th Mar 2014, 10:07
  #3793 (permalink)  
 
Join Date: May 2012
Location: Australia
Posts: 131
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Jet Man
Communicator

Don't know how to paste your post here.

If that's the case (Satellite com/data system still "pinging" satellite after ACARS/CPDLC/ADS-C turned off) then the authorities would know how long the 777 system was active for. Is this the case?
Last Satellite communication was seen at 8:11am Malaysian time (GMT+8)
StormyKnight is offline  
Old 15th Mar 2014, 10:14
  #3794 (permalink)  
 
Join Date: Jun 2011
Location: Australia
Posts: 14
Received 0 Likes on 0 Posts
Captain PB #3932.

That actually sounds possible. How would you explain the cut of the ACARS info though?
Centre of Pressure is offline  
Old 15th Mar 2014, 10:14
  #3795 (permalink)  
 
Join Date: Feb 2008
Location: UK
Age: 66
Posts: 757
Received 19 Likes on 14 Posts
but the sea is 4000m deep where they are now searching
rog747 is online now  
Old 15th Mar 2014, 10:28
  #3796 (permalink)  
 
Join Date: May 2012
Location: Australia
Posts: 131
Likes: 0
Received 0 Likes on 0 Posts


Last location reported to be somewhere on the red lines...(the 40 degree lines)

This looks more logical, but the lines appear to be angulation related stopping at 0...

The angle appears to be the angle from the ground to the satellite, so 0 the satellite would be at the horizon.

So these 40 degree arcs is what the PM was referring to? & of course they are not a track, it is just that the last received signal was on these arcs somewhere.

Would the 40 degrees be determined by received signal strength as suggested?
StormyKnight is offline  
Old 15th Mar 2014, 10:30
  #3797 (permalink)  
 
Join Date: Feb 2001
Location: Pub
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
As a Professional Pilots forum, these fanciful posts are embarassing. Heists, gold bullion, conspiracies. If you haven't anything sensible to post may I request you desist or join a different forum for fictional creative writing. 200 pages of posts, mostly drivel. Thanks to those few who have the expertise to elaborate on the facts.
Oceanic is offline  
Old 15th Mar 2014, 10:32
  #3798 (permalink)  
 
Join Date: Jun 2009
Location: sydney
Posts: 3
Likes: 0
Received 0 Likes on 0 Posts
All BS to date.

Come on people - I haven't seen anything posted in this discussion that remotely resembles anything professional, from pilots or rumour. It's all guessing and what-ifs. Why not hold off until you really have something? What is MAS senior staff really thinking and doing? What are the Malaysian armed forces holding (if anything?). What detail is available from other sensors (US etc) throughout the area? Somebody out there knows some of that detail....but I haven't seen it from anyone to date in this thread.
OrvilleW is offline  
Old 15th Mar 2014, 10:32
  #3799 (permalink)  
 
Join Date: Mar 2014
Location: Perth
Age: 61
Posts: 65
Likes: 0
Received 0 Likes on 0 Posts
The INMARSAT which must have been involved in the last hours of pinging communication must have been IOR which is geostationary above the equator at 64 degrees east. (This is the only INMARSAT which deals with ACARS comms which has coverage over the longitudes that the plane was in then).

As I have said before, there would be no triangulation, just (accurate) distance information gleaned from the time to negotiate a single ping (a few short messages backwards and forwards).

The announced northern corridor (N Thailand to Kaz/Tkm) tells us that the distance measured from the final (8:11am) pings was about 4550 km as measured on the earth's surface (to a spot below the satellite). That is how far those two ends of the corridor are from the spot.

So the possible 8:11am locations lie on a circle of that radius around that spot.

I will post a map shortly.

Interestingly, also on that circle, within the northern corridor is Hotan.
ana1936 is offline  
Old 15th Mar 2014, 10:35
  #3800 (permalink)  
 
Join Date: Jul 2008
Location: Bali, Indonesia
Posts: 264
Likes: 0
Received 0 Likes on 0 Posts
I have operated SIN LHR for the last few years routing over KL, Port Blair then over Calcutta. The new info about this flight being flown over this similar route makes we wonder if it "tailgated" such a flight heading towards India.
SQ068 was discussed earlier as such a possibility but nobody was ever able to confirm its routing on the evening in question. This is clearly not an amateur operation and that might be quite likely. Coupled with the US General stating that the flight's destination was Pakistan would also compute. Beyond Pakistan, they would start running into some very sophisticated US Military kit, both on the ground and in the air so Kazakhstan seems less likely?

That asssumes the NW track, which would logically be more likely in the case of piracy. IMHO, that is less likely than the SW track, more likely in the event of a suicide mission by a party or parties unknown and for unknown reasons. The US has already deployed assets to the IO and, I'm sure Submarines will already be lurking thereabouts also.
philipat is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.