Some may be asking why so much talk about display systems;
A fault relating to one of the display systems was recorded and further work is being undertaken to establish the meaning and possible causes of the fault.
http://www.aaib.gov.uk/cms_resources...4%20G-SPAO.pdf
The last few pages of this thread have given the scenario that the CAD had failed,
yes this is purely speculation and conjecture.
However, this has highlighted the problems that this would cause, including such things as a total loss of fuel indication and the loss of the majority of cautions being displayed if the circumstances arose, such as the low fuel caution, the prime pumps on caution and the transfer pumps off/dry caution.
As a consequence of a CAD failure, the only indication of the aircrafts fuel state would be the
LOW FUEL 1 &
LOW FUEL 2 warnings on the warning panel and their associated 'Gong' audio warnings.
In the latest report (Special Bulletin S2/2014), there were at least 4 seperate red warnings that appeared in reference to the fuel state and each time they would have also produced a 'Gong' in the i/c system.
It subsequently recorded intermittent LOW FUEL 1 warnings for the left fuel supply tank, (1+) then a permanent LOW FUEL 2 warning for the right fuel supply tank. (1) This was followed by a further temporary LOW FUEL 1 warning, (1) before it became permanent for the remainder of the flight. (1)
my brackets to total up the warnings, 4+
The big technical question that may never be answered is, when were these warnings and gongs presented to the crew?
However, the biggest question for me is;
Given that 4 minutes before the engines ran dry (22:22), ATC was contacted (22:18)
Approximately 4 minutes before that they were on a task to the East of Glasgow (Bargeddie area is 8 miles away)
The drill for
LOW FUEL 1 &
LOW FUEL 2 warnings is to land within 10 minutes.
Why would anyone continue to spend 2 minutes on a task with a
LOW FUEL warning displayed?
Yes there's no getting away from the reports finding that the switches were not in a 'normal flight' configuration, but it appears to me that the system built in to warn of this, for whatever reason, didn't.