Originally Posted by
jcjeant
Hi,
Post reread .. and can you reread mine
Suppose IF
You are responsable of a plane (and so .. directly of all people aboard)
Someone came to you with a bad news:
We have lost contact with our plane.
What you will do ? by all means find what happened to the plane ...
Read the comms timelines in the earlier reports, eg.
http://www.bea.aero/docspa/2009/f-cp...90601e1.en.pdf [sections 1.9.1 and 1.15].
If anyone was negligent in the delay in searching for this flight, it was ATC. First a failed handover seems to have got the flight "lost" for some hours, then by around 4.30, other flights asked to try contact (AF459) and AF is alerted to try and contact. At this point this is just a lost-contact.
But ATC seems to think all is fine, because at 5.09:
the ATLANTICO controller requested confirmation that the flight was already in the SAL FIR. The DAKAR controller replied: "yes, no worry".
By 6am., AF is onto SARSAT looking for ELT transmissions (none - normally that would be good...) and talking to all the ATCs, and then ...
At 6 h 35, the MADRID centre told the BREST centre that the flight was at that time in contact with CASABLANCA FIR and would enter the LISBOA FIR within a quarter of an hour. The BREST centre transmitted this information to the Air France Operations Control Centre and to the Cinq Mars La Pile Regional Control Centre.
So ATC told AF all is well (4+hrs after the crash!), and we are talking to your plane.
It then takes a further 1-2hrs (with AF reporting further concerns about lack of contact with base) before the various ATCs seem to agree that actually no one is talking to the plane, and maybe someone ought to raise an alert, but can't decide which zone the event is in and therefore who should raise alert
.
Finally Dakar decides something might be wrong at7.41, 5+hrs after the plane should have contacted them
...At 7 h 41, the DAKAR shift supervisor informed the Dakar Rescue Control Centre that flight AF447 should have passed the TASIL point at 2 h 20 but that it had not had any contact with the plane.
From that point, it looks like SAR starts and I guess ACARS is used to refine LKP from radio comms to direct the search
.
Reminder: ACARS checked ONE HOUR before ETA !! (astonishing fact)
Reminder: shortly before this, AF OCC were told that the plane was in contact with ATC over Morroco
. Why would they therefore be looking at ACARS other than normal review for maintenance (probably shortly before ETA) ?
Reminder2: you (and some other posters) seem to have an idea that ACARS is some kind of aircraft tracking system, crash alert system, crash locator system, or black box subsititute. ACARS is
none of those things. It's basically a messaging system for maintenance so that they know
before they get the the a/c that they need the tools to unblock the aft loo, rather than having to get onto the a/c, download the messages and realise the tools they need are half a mile away on the other side of security.
AFAIK, there is noone (human or automaton) supposed to be watching the ACARS streams looking for nasty fault messages followed by loss of transmission that taken together
might possibly indicate that a plane just fell out of the sky. NOone was "asleep at the switch" as someone else put it.
Could ACARS be used in this way (given hindsight of this event) ?? I'd guess
possibly. But it isn't designed for it, and I think you'd have to be really clever (or lucky) about how you do the analysis (would need to be automated alert system of some sort) to get the false alarm rate acceptably low.