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 14th Jul 2014, 14:50
  #11381 (permalink)  
I don't own this space under my name. I should have leased it while I still could
 
Join Date: Dec 2002
Location: Lincolnshire
Age: 76
Posts: 16,606
Ian, I am a tyro there but surely the aircraft narrow or slow connection is not a problem for the satellite companies. It must mean their uplink is slow but not a problem for the satellite.
Pontius Navigator is online now  
Old 14th Jul 2014, 20:18
  #11382 (permalink)  
 
Join Date: Jun 2009
Location: Auckland
Age: 76
Posts: 191
Question for Ian W

[mm flynn] 2 - People have represented that Malaysian Airlines did not use the satcom for ACARS, yet the official preliminary report declares it did,
Did MAS subscribe to a satellite service for acars and was data sent to MAS? Boeing, RR?

Thank you for sharing your knowledge.
Ornis is offline  
Old 14th Jul 2014, 20:47
  #11383 (permalink)  
 
Join Date: Mar 2014
Location: wales
Age: 76
Posts: 316
my understanding was they subscribed to RR but VHF only.

The satcom would be on for the satphone so it would look for a logon, how you stop the RR acars going via sat when you don't pay for it I have no idea, but suspect something like lack of a data key would lead the satellite to ignore it.
oldoberon is offline  
Old 14th Jul 2014, 23:11
  #11384 (permalink)  
 
Join Date: Jun 2014
Location: Montenegro
Age: 37
Posts: 285
anyone comment on this?

(the post from duncansteel.com) :

Byan C.
2014/07/03 at 08:22

I woke up wondering if Duncan thinks I’m some kind of crackpot, so I thought I should send you a clearer explanation. If R represents satellite to plane distance, s, p, r reresents the satellite, plane, and reference satellite respectively. Numbers 1 and 2 represents two points in time and x, y, z are the coordinates. Then,
(x-xs)^2 + (y-ys)^2 + (z-zs)^2 = Rs^2
(x-xr)^2 + (y-yr)^2 + (z-zr)^2 = Rr^2
x^2 + y^2 + z^2 = r^2 where r = earth radius and recognizing that
xs^2 + ys^2 + zs^2 = (r+H)^2 where H is the satellite height above the earth. The same applies to the reference satellite.
Converting BTO data to velocities yield:
V-Vsp-Vps = Vpr
Assuming a constant satellite velocity the Vsp + Vps = Rs2 – Rs1
Similarly, Vpr = Rr2-Rr1 or Rr2 = Rr1 + Vpr
This is where I got into trouble. Since Rr2 depends on Rr1 if I don’t check the methodology using the course defined by the BTO data, I don’t get a good fit to the BTO data at 19:40. After solving, I plug the plane velocities derived from (x2-x1)/(t2-t1) to a program the solves based on the distance traveled between 2 ping rings. This routine calculate the BTO values based on the actual Vsp at time t. Comparisions indicate that my solution using average Vsp values is yielding reasonable results. To calculate values using the actual Vsp value at time t involves solving 10 equations with 10 unknowns. The good news is that the solution would reduce to a quadratic equation. It is interesting that the solution for the equations based on distance traveled yields 2 roots with different latitudes. The solution to the equations based on velocities yields 2 roots with different longitudes. 1 to the west of the satellite and 1 to the east, effectively resulting in 1 solution. As a check, I plugged in Ra and Rs values for the northern and southern paths, it duplicates those paths.

Imagine my shock after I got this debugged (I keep reversing signs in my vector math) and I get a result that indicates the plane took a large circular path to the south heading eventually back to KLIA. I almost fell off my chair. I was not expecting this. I have to admit that I have not been that excited about anything in a long time, hence my need to hurriedly share this with someone.

I’m sharing this at this time because I believe the actual solution will be difficult to achieve. I could sove the 10 equations, but developing reasonable flight paths is beyond my ability.

I indicated that I thought we should keep this private because if there is a 3rd flight path, this will cause hugh controversy and we need to be certain before presenting such a result. Perhaps, my results are just a fluke of the data, but since I achieved these results with absolutely no manipulation of the raw data, I feel like it needs to be pursued further.
AreOut is offline  
Old 15th Jul 2014, 12:03
  #11385 (permalink)  
 
Join Date: Jun 2014
Location: Montenegro
Age: 37
Posts: 285
pardon, forgot to copy his autocorrection

"Byan C.
2014/07/03 at 22:34

I noticed a few typos in my last post. The most significant being that the differences in sat distances should have been divided by (t2-t1). On further reflection and trying a few different scenarios on my constant speed course calculator I’ve deduced the following.
If the radar data does not absolutely preclude a more north-western starting point(this matches the BFO) data better, then you need to proceed south for the next 4 ping rings at about 450 kts. The curious thing is that you can set a slightly north easterly course fo the last ping ring and it does not seem to affect the BTO values. I now think that the more northerly starting point and the interesting fact that you can turn to the northeast on the last ping ring is why my results obtained from not assuming a plane sppeed appears to suggest a route roughly returning to KLIA."

BFO/BTO was also a typo
AreOut is offline  
Old 15th Jul 2014, 15:38
  #11386 (permalink)  
 
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,307
Originally Posted by mm_flynn View Post
I don't believe that understanding is correct. All available information says that the ACARS system used SatCom. I would be really surprised, having made that decision, MAS then decided not to send the engine data via the same link.
.
From way back in the thread.
Malaysian Airways did not subscribe to Rolls Royce or Boeing health monitoring. ACARS was set up to only operate over VHF and the only INMARSAT subscription that the airline had was for satellite phone.

ACARS was set up to make routine reports at 30 minute intervals.

There was no connection of any sort between ACARS and SATCOM this was disabled as the company did not want to pay the subscriptions.
Ian W is offline  
Old 15th Jul 2014, 18:11
  #11387 (permalink)  
 
Join Date: Jun 2014
Location: Montenegro
Age: 37
Posts: 285
yeah he is a bit clumsy in explaining (probably not the lecturer but still good at math) but certainly makes point which has not been disproven yet

I have also mailed ATSB and got the same response, I doubt they even look at that given they probably get tons of crazy conspiracy mails on a daily basis, sorting everything out would take significant amount of time.
AreOut is offline  
Old 15th Jul 2014, 19:15
  #11388 (permalink)  
 
Join Date: Oct 2007
Location: France
Age: 69
Posts: 136
From "MH370 Data Communication Logs.pdf"
Page 36:
17:07 - Last Acknowledged Ground to Air DATA-2 ACARS Message. Link lost at sometime between here and 18:03:41.
7/03/2014 17:07:48.907 IOR-R1200-0-36ED IOR 305 4 R-Channel RX 0x62 - Acknowledge User Data (R-channel)
18:03 - No Response to Ground to Air DATA-2 ACARS Data. Link lost at sometime between 17:07:48 and here.
Page 37:
7/03/2014 18:04:29.413 IOR-P10500-0-3859 IOR 305 10 P-Channel TX 0x61 - Request for Acknowledge (RQA) User Data
18:04 - Last of five requests for Acknowledge to the Air DATA-2 ACARS Data at 18:03
18:05:11 - Data-2 Ground to Air transmission, automatic ACARS retransmission after expiry of 90 sec timer. Terminal is not responding.



IMHO, this indicates that ACARS transited by SATCOM. At least some of them. From the comments, these ACARS are about "AIR DATA-2". From memory, these data contains ??? and fuel remaining at 17:07 (all the contents had not been published).
Shadoko is offline  
Old 15th Jul 2014, 19:45
  #11389 (permalink)  
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,584
All I can see is the ground station REQUESTING the ACARS data. Posts 8869,8872 and 8873 (plus WSJ) state Malaysian did not send.
BOAC is offline  
Old 15th Jul 2014, 20:44
  #11390 (permalink)  
 
Join Date: Oct 2007
Location: France
Age: 69
Posts: 136
From "MH370_Considerations on defining_FactSheet.pdf" (ATSB 26 May):
The final ACARS transmission was at 17:07 UTC and provided location reports from the initial stage of the flight as well as a recording of the aircraft fuel remaining.
And from ""MH370 Data Communication Logs.pdf":
All the transmissions (RX and TX) between 7/03/2014 17:06:49.406 and 7/03/2014 17:07:46.905 (pages 30 to 36).

The fact that channels are assigned and user data acknowledged implies that the communication(s) were established. The SATCOM use and the known ACARS timing published are in same minute. So, my understanding is the data transmitted via SATCOM were, at least part of them, ACARS.
And voice by SATCOM use C channel.
But I can be wrong!
Shadoko is offline  
Old 15th Jul 2014, 21:04
  #11391 (permalink)  
 
Join Date: Oct 2007
Location: France
Age: 69
Posts: 136
About the "circle path": I am afraid it is the result of oversimplification of the sat and the airplane relative trajectories.
Why using a constant speed for the sat? Inmarsat 3F1 data are available.
In my very simple model, I don't use spherical coordinates but Lat, Long and Altitude, because it is easier (for me) to "see" the data. It is not very accurate because "my" Earth is spherical, but just for "see" what can be deduced from the "faint" known data, I think it is enough.
I suspect the circling trajectory obtained by Byan C is from not taking in consideration the fact that all airplanes flying along a "straight" line are, in fact, flying on a circle around the Earth. If the simplification include flying in a (flat) plane, the only way to follow the BFO values is to "curb" the trajectory in the (flat) plane...
Shadoko is offline  
Old 15th Jul 2014, 21:52
  #11392 (permalink)  
 
Join Date: Jun 2014
Location: London
Age: 59
Posts: 72
Yes, I am not at all sure about the "circle path" because it seems to imply such variations of speed and heading. I am also unclear about what failure conditions could cause an aircraft to fly such a path.
Ulric is offline  
Old 15th Jul 2014, 22:02
  #11393 (permalink)  
 
Join Date: Jan 2008
Location: Southampton, UK
Age: 59
Posts: 10
Two lots of ACARS appears in the Inmarsat logs. You'll notice that the first message of each request is different.

The first request is:
17:06:49.406 ... R-Channel RX 0x22 - Access Request (R/T-Channel)
The RX indicates the direction of transmission which means that the aircraft had triggered the sending of ACARS data.

This is followed by a minutes worth of RX and TX messages until the final acknowledge at 17:07:48.907. I interpret this as the period when the ACARS data being sent and accepted. This means that ACARS-over-satellite must have been enabled.

The second request:
18:03:41.405 ... P-Channel TX 0x71 - User Data (ISU) - RLS
In this case the difference is that this is a TX. This means that the request came from the ground. My assumption is that someone (probably ATC) phoned either Boeing or Rolls-Royce to ask if they knew where the aircraft was and this request was triggered by Boeing/RR.

You'll notice that there are no RX messages following the second request so for some reason the aircraft was unable to respond. There are many reasons for a non-reply. It's possible that ACARS was turned off or unpowered. However ACARS-over-satellite needs needs a functioning SDU so it's also possible that this was unpowered.
nick1austin is offline  
Old 15th Jul 2014, 23:16
  #11394 (permalink)  
 
Join Date: Jun 2014
Location: Montenegro
Age: 37
Posts: 285
I'm quite sure there was no failure before 2:22 MYT, after that maybe but it's only speculation based on satcom restart (which doesn't automatically imply failure).

the thing is there are many paths that could fit BFO&BTO values within margin of error, especially since we don't have a clue if any of speed/altitude/heading were constant at all

P.S. http://www.duncansteel.com/ group has made the new statement

this figure is interesting to me

http://www.duncansteel.com/wp-conten...-Figure-1a.jpg

anyone tell me why they assume constant heading from 19:41 onwards for a flight that drastically changed its heading 3 times in first ~2 hours?
AreOut is offline  
Old 16th Jul 2014, 01:33
  #11395 (permalink)  
 
Join Date: Mar 2002
Location: Here & there
Posts: 742
My assumption is that someone (probably ATC) phoned either Boeing or Rolls-Royce to ask if they knew where the aircraft was and this request was triggered by Boeing/RR.
I think ATC would be more likely to contact the airline in the first instance, rather than the aircraft or engine manufacturer. The ground transmission may have been a text message from the airline to the crew asking them to confirm their position.

Last edited by BuzzBox; 16th Jul 2014 at 10:23.
BuzzBox is offline  
Old 16th Jul 2014, 10:14
  #11396 (permalink)  
 
Join Date: Aug 2003
Location: Surrey
Posts: 1,220
Originally Posted by Ian W View Post
From way back in the thread.
Malaysian Airways did not subscribe to Rolls Royce or Boeing health monitoring. ACARS was set up to only operate over VHF and the only INMARSAT subscription that the airline had was for satellite phone.

ACARS was set up to make routine reports at 30 minute intervals.

There was no connection of any sort between ACARS and SATCOM this was disabled as the company did not want to pay the subscriptions.
Ian,

You have said this several times. Yet it (the ACARS over satcom part! not necessarily the RR or Boeing monitoring) is wholly inconsistent with all of the official statements by the Malaysian CAA. Do you have an actual source or is it a repetition of a prior assertion in the thread?
mm_flynn is offline  
Old 16th Jul 2014, 10:37
  #11397 (permalink)  
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,584
mm - if there is 'Acars Data' floating around as you say, where is it and what does it contain?
BOAC is offline  
Old 16th Jul 2014, 12:09
  #11398 (permalink)  
 
Join Date: Aug 2003
Location: Surrey
Posts: 1,220
The Malaysian CAA hasn't released the content of the data stream and I seriously doubt it is relevant. there will have been all of the normal messages and then the 1:07 packet will all most surely be a top of climb report or a routine monitoring report. But the CAA has declared that it was received, they declare it was received via satcom and Inmarsat logs show a set of data packets at exactly the same time.

The ACARS data is irrelevant, I am not in any way suggesting there is data post the 1:20ish loss of comms and transponder. The relevant point is, the earlier statements in the thread that MAS did not use Satcom for their ACARS are clearly not correct. It may well be true that MAS did not subscribe to RR or Boeing monitoring service - but that is irrelevant to the loss of this aircraft.
mm_flynn is offline  
Old 16th Jul 2014, 13:12
  #11399 (permalink)  
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,584
It would still be useful to know what data was being sent from Acars via SAT as there should be no reason why the data should stop at loss of comms - that I can see. Eg if any nav data................?
BOAC is offline  
Old 16th Jul 2014, 16:17
  #11400 (permalink)  
 
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,307
ITU involvement in Aircraft Tracking

ITU to assist in real-time monitoring of flight data

ITU Membership calls for development of standards for aviation cloud

Geneva, 25 June 2014 – ITU has established a new Focus Group on Aviation Applications of Cloud Computing for Flight Data Monitoring. The group will study the requirements for the telecommunication standards to enable an ‘aviation cloud’ for real-time monitoring of flight data, including those for the protection, security and ownership of flight data and the technical mechanisms and policies to govern access to these data.
The formation of the Focus Group comes in response to the call from the Minister of Communications and Multimedia, Malaysia, Mr Ahmad Shabery Cheek in March 2014 urging ITU to develop leading edge standards to facilitate the transmission of flight data in real-time. Subsequently, an “Expert Dialogue on Real-time Monitoring of Flight Data, including the Black Box – the Need for International Standards in the Age of Cloud Computing and Big Data”, held in Kuala Lumpur, 26-27 May 2014 with the participation of airlines, aviation bodies, avionics and ICT companies, service providers, civil aviation authorities, the International Civil Aviation Organization (ICAO) and other international organizations, issued a communiqué outlining a roadmap for the way forward.
Participation in the Focus Group will be open to all interests, including non-members of ITU, and it will work in close collaboration with ICAO, ICT solution providers, aircraft manufacturers, airlines and other standardization expert groups.
ITU Secretary-General Hamadoun I. Touré said that the call from Minister Shabery for an international effort to find solutions to monitor flight data in real time has been given top priority by ITU and its Membership.
“ITU has a long history of developing international telecommunication and ICT standards, policies and regulations and is offering to bring this competence to assist aviation,” said Malcolm Johnson, Director of ITU’s Telecommunication Standardization Bureau. “I applaud our membership for the urgency with which it is addressing this issue by responding so quickly to Malaysia’s call for ITU action.”
The new Focus Group will study advances in cloud computing and data analytics to develop use cases for the application of state-of-the-art data analytics and data mining techniques in real-time. It will develop technical reports to provide the foundation for standards-based aviation clouds. In close collaboration with ICAO, the envisioned reports will address questions surrounding the type of data to be transmitted and the periodicity and reliability of its transmission, as well as the mechanisms to enable data security and privacy and the prevention of data misuse. The reports will be the basis for the development of telecommunications standards providing security and providing interoperable and secure aviation cloud systems.
Note to the editor: ITU-T Focus Groups are formed in response to immediate ICT standardization demands, charged with laying the foundation for subsequent standardization work in membership-driven ITU-T Study Groups. Focus Groups are open to organizations outside ITU’s membership and they are afforded greater flexibility in their chosen deliverables and working methods.
For more information, please contact:
Sanjay Acharya
Chief, Media Relations and Public Information, ITU


See ITU to assist in real-time monitoring of flight data
Ian W is offline  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.