AnFI (really!)
It is patently obvious that, with such a high unuseable fuel quantity, the cockpit situation faced by this pilot may well have left him with an excessively confusing and unexpectedly complex set of actions. Maybe unpredictable issues of timing wrt Governor response rates and pilot action. Everything points to that.
"Confusing and unexpectedly complex set of actions!"
LOW FUEL 1 and/or2
Check fuel contents
If pos contents, check XFER pumps on
Check cb's in
If remains on, switch off bleed air
Land within 10 mins
(That Land being an immediate action!)