Re: [time-nuts] Aircraft ping timing
I just red somewhere that the last "ping" was the only one recorded by
Inmarsat system, Pings up to that point were presumed to occur due to
known reporting intervals. So there is no "track".
The Inmarsat data is a red herring. The plane could have ditched into
the water 85 minutes after the "incident:, at location near last radar
contact and floated with Inmarsat operating on service battery for hours.
The ELT's used in this aircraft have been implicated in two fires due to
shorted lithium battery wires. There was an AD/Recall issued. No
reports whatsoever about the ELT being activated, so if it burned......
Good only for 48 hours or so anyway if looking in the wrong place.
Maybe there is a market for Orbcomm asset tracking transmitters mounted
way up in an inaccessible location of the tail with own back up battery
supply.
--
Joe Leikhim
Leikhim and Associates
Communications Consultants
Oviedo, Florida
407-982-0446
On Thu, 20 Mar 2014 14:42:42 -0400
Joe Leikhim jleikhim@leikhim.com wrote:
I just red somewhere that the last "ping" was the only one recorded
by Inmarsat system, Pings up to that point were presumed to occur due
to known reporting intervals. So there is no "track".
The Inmarsat data is a red herring. The plane could have ditched into
the water 85 minutes after the "incident:, at location near last
radar contact and floated with Inmarsat operating on service battery
for hours.
The ELT's used in this aircraft have been implicated in two fires due
to shorted lithium battery wires. There was an AD/Recall issued. No
reports whatsoever about the ELT being activated, so if it
burned...... Good only for 48 hours or so anyway if looking in the
wrong place.
Maybe there is a market for Orbcomm asset tracking transmitters
mounted way up in an inaccessible location of the tail with own back
up battery supply.
Orbcomm is kind of troublesome.
There is a tracking service used mostly by helicopters, which of course
are notorious for falling off the radar due to low altitude. It is
Iridium based.
I've used or have know users various satellite messaging services over
the years. Iridium is good. I was a Globcomm customer, but it was not
reliable. A friend was on Orbcomm and it had issues as well.
On 3/21/14 8:52 PM, nuts wrote:
On Thu, 20 Mar 2014 14:42:42 -0400
Joe Leikhim jleikhim@leikhim.com wrote:
I just red somewhere that the last "ping" was the only one recorded
by Inmarsat system, Pings up to that point were presumed to occur due
to known reporting intervals. So there is no "track".
T
Maybe there is a market for Orbcomm asset tracking transmitters
mounted way up in an inaccessible location of the tail with own back
up battery supply.
Tracking isn't the problem.. Argos does nice tracks of birds, fish, etc,
with 10 gram transmitters, etc.
It would be a trivial matter to have a GPS receiver feed into a inmarsat
transmitter (like the ACARS data) and beacon every minute. But it would
cost money (big money)
It's more that there's no real economic need to do the tracking. All
the stuff they've been flailing around with provides information that
sort of, sometimes, might be able to infer some kind of position, but
was never intended to do that, and certainly not in real time. Most of
this stuff is intended for long term maintenance and monitoring (is the
satellite in the right place.. are the engines due for service).
It's only after the fact (which is an unlikely occurrence..big planes
are lost something like once every 5-10 years) that people get all
excited and want to do things.
Someone has to foot the bill for it, and in the long run there's not a
lot of benefit. Does the airline care how long it takes to find the
wreck or plane? Not really - it's more of a PR problem than anything
else, and it's hard to put a dollar value on that. In fact, once could
cynically say that the airline (and aircraft mfr, and a lot of people
involved) might rather the plane stay missing and never be found. If
it's found, then there's evidence that will be argued about in court,
and used to attempt to assign responsibility. If it's not found, after a
few months, the excitement will die down, the insurance company will pay
off, etc.
It took months to find and recover the black box from the Air France flight