None of the articles you cited contradict what I have previously said. In this message,
I will extract quotes from YOUR cited articles which back up my previous comments.
ACARS is the Aircraft Communications Addressing & Reporting System.
It utilizes both VHF and SATCOM (e.g.
What I have previously mentioned about Rolls Royce getting it's information through
ACARS was reiterated in your cited article ... but please note of the difference of the
bolded words "and" in your statement, as opposed to the bolded word "or" in the article ...
http://www.newscientist.com/article...ne-sent-out-engine-data-before-vanishing.html
These reports are sent via VHF radio
OR satellite at take-off,
during the climb, at some point while cruising, and on landing.
When a plane is close to base, it can transmit via VHF
to ground stations, which can then be uploaded to Boeing, Rolls Royce, etc. on the internet.
When a plane is too far from base for line-of-sight VHF communication, it can use SATCOM to transmit directly.
This distance is typically 200 miles from Air Traffic Control Tower.
During the functioning time of MH370's transponder, AT NO TIME was the plane further
than this distance. Actually 200 miles is about where the plane should have transferred
to Vietnam ATC (where it would have continued to use it's transponder to send data).
During 12:40 to 1:22am MYT, when MH370 was on it's scheduled flight path.
It was not necessary for MH370 to switch to SATCOM during this time.
SATCOM will only be used WHEN the transponder is further than 200 miles from
ANY air traffic control tower (typically over an ocean like the Atlantic).
Please see the image at the end of this message ... it shows a map depicting the
200 mile radius of the local Malaysian ATCs. The top circle is Vietnam ATC radius
& the circle below it (which slightly overlaps) is the Kuala-Lumpur ATC radius,
In fact, I don't think MH370 would have ever switched to SATCOM on their
scheduled flight path to Beijing. I think for all of the trip, it probably would
have been within 200 miles of an ATC ... but as the 8 March 2014 flight did not
enter China, I did not feel the need to check that country's radar maps.
two engine-health messages WERE sent to Rolls-Royce in Great Britain
... shortly before MH-370 disappeared from transponder radar.
Malaysia Airlines MUST have been subscribed to SOME service.
I assume that these messages to Rolls-Royce were not free? If they were free,
I am interested in transferring my cell phone service to those guys.
As I have previously mentioned these 2 data transmissions were sent through ACARS,
which the article you cited confirmed ...
http://www.newscientist.com/article...ne-sent-out-engine-data-before-vanishing.html
To aid maintenance, most airlines use the the Aircraft Communications Addressing and Reporting System (ACARS)
... These reports are sent via VHF radio or satellite at
take-off,
during the climb,
at some point while cruising,
and on landing.
One theory is that someone in the cockpit disabled
VHF, SATCOM & the radar transponder. Easy-peasy, right? Wrong.
As I mentioned SATCOM was NOT being used during this part of the flight.
VHF (Very High Frequency) is a radio frequency band across which data is transmitted.
It is the transponder which sends the data.
If you turn off the transponder, then NO data will be sent across VHF.
There darn well better be, because no engine health messages were sent to
Rolls-Royce in Great Britain from MH-370 after the transponder quit working.
Very odd, don't you think?
NO I DO NOT think it is odd at all ! As I have stated in 3 previous messages
here (with a reference provided), it is totally what I expect !
Since the engine health reports are sent through ACARS, once the MH370 transponder
ceased functioning, no more reports were transmitted. Totally as I would expect
... all of which WAS confirmed in the article you cited.
If SATCOM was shut down, how did the plane continue to be able to handshake with a satellite every hour?
In principle, SATCOM is either completely disabled or completely enabled.
& do not forget, some talking heads disagree whether it is even possible to
shut down VHF & SATCOM from the cockpit.
If the transponder is not functioning, then the plane will not communicate through VHF.
However even if the SATCOM channels are disabled in the cockpit area,
an onboard computer in the satellite antenna on top of the plane will STILL
respond to an hourly satelllite query ... which is what happened with MH370.
Here is a quote from your cited reference in the SATCOM-PING section ...
http://theaviationist.com/2014/03/16/satcom-acars-explained/
The question is why the hijacker(s) did not prevent the plane from responding to pings:
most probably, being a networking detail,
not even pilots know that their system/antenna respond
"I am here" even if the SATCOM is not being used by any onboard systems (i.e. ACARS).
Now I will address the last portion of your post, where you provide the timing
of the Inmarsat pings. Let us pretend that the terrorist masterminds figured
out how to turn off SATCOM on MH-370, but failed to recognize that it was not
really turned off & still working perfectly for Inmarsat handshakes
First of all, can you please share ANY sources that say SATCOM was shut down ?
I certainly have not seen anyone, except you, propose that theory.
In fact, for me, the later handshakes prove that SATCOM was not shut down.
Second, we don't have to pretend, because as the quotes above have shown,
that is exactly what happened ! NO MATTER what someone did in the cockpit area,
the satellite antenna would STILL respond to a satellite query!
Regarding any interpretation of where the pings originated from
- these plane-to-satellite handshakes DO NOT yield latitude-longitude coordinates.
These pings have nothing to do with GPS. The error range (limited by complete guesses
as to the hourly velocity of MH-370, doppler frequency effects, etc.) is huge.
I have previusly said
many times that the Inmarsat data gave NO location data
& that the location of MH370 is the ONLY part of the Inmarsat data that is theory.
And I have further repeatedly said that the location is debatable because of that.
Since we may have years, or maybe even decades to wait for a solution in the southern Indian Ocean
We have no disagreement that it will be hard to find MH370
Satellite handshakes were never intended to be used in plane location,
however these "ping rings" ARE an operating principle of satellite technology
- the only new part is HOW they are applying them IN THIS CASE. Furthermore,
this technology WAS identified when Air France went down. Since then, Inmarsat has had it
in mind as a tool for helping to locate missing aircraft & as a result, they have been
keeping records of these "ping rings". Here is an extract from a previous ATSB report ...
The satellites normal function is essentially communication and it was never initially
intended to have the capability to track an aircraft. Following the Air France 447 accident,
Inmarsat engineers began recording the BTO in order to provide another
potential means of geo-locating aircraft in the event of a similar accident.
Further discussion about this can be found at this Duncan Steel webpage ...
http://www.duncansteel.com/archives/791