[LINK] stream weather/GPS/flight data

Scott Howard scott at doc.net.au
Sun Jun 7 08:18:12 EST 2009

On Sat, Jun 6, 2009 at 2:14 PM, <stephen at melbpc.org.au> wrote:

> With officials warning they may never find the black boxes from Air
> France Flight 477, some experts are calling for a feature that would:
> automatically stream flight data to land-based computers, making on-board
> recorders redundant.

They could even call it something funky like "Aircraft Communications
Addressing and Reporting System", or even ACARS for short!

The Airbus A330-200 is fitted with ACARS, and during whatever incident
caused the crash (now confirmed - bodies have been found) it did sent back a
total of 24 messages to Air France, describing multiple failures through out
the on-board systems, and finally a cabin vertical speed alert. ACARS
coverage is available globally via a combination of VHF and HF frequencies
as well as via Satellite.

Each of these ACARS alerts included GPS coordinates, which were used in the
search, with the first debree and bodies from the crash being found 70kms
from the corrdinates included in the last alert.

ACARS certainly isn't as complete as the Flight Data Recorder (FDR) and
doesn't provide any voice like the Cockpit Voice recorder (CVR), and thus is
no replaecment for the two "Black Boxes" - but it is a good compromise for
commercial airlines that fly thousands of miles away from the nearest
worthwhile land-mass. (The Air France A330 involved was "ETOPS 180" rated,
which means that it is allowed be up to 3 hours away from the nearest
airport at any time. Some other 2-engine jets and most 4-engine jets can go
even further).

> One former NTSB official says such transmissions are "totally possible
> today" and, already in use at some helicopter fleets.

Helecopters generally don't make trans-atlantic, trans-pacific, or
trans-polar crossing.  I'm not sure how something being visable in "some
helicopter fleets" makes it "totally possible" for commercial airliners.
(I'm not saying it's not possible - especially given that ACARS already
implements some of what is being described - just that the logic is
flawed).  Helecopters also do not fly at altitudes which can make
communication with satellites difficult, which is especially an issue with
polar crossings.

Besides helping air traffic controllers keep better watch over aircraft,
> satellite-based systems also can beam real-time weather maps directly
> into airplane cockpits -- a feature that might have saved the Air France
> plane.

Presuming that the crash was even caused by weather, which is look less
likely as time goes on. Of course, the A330, like all other modern jets, is
equipted with a relatively advanced weather radar in it's nose cone. Whilst
this isn't as sophisitcated as land/satellite-based systems, it's not like
the crew would not have been aware of the general conditions around them.
Ground-base weather radar can also be sent to the crew via ACARS.

"The point is if we have GPS to monitor airplanes, could it save lives?"
> asks aviation consultant Michael Boyd. "The answer is clearly yes."

Clearly not in this case.  The A330 involved had GPS.  It did report it
position back to Air France at the time of the crash, and would have
continued to do so for as long as it was able to.


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