From
http://www.atsb.gov.au/media/24550/a...503722_001.pdf
The pilot in command reported that he then disconnected the autopilot and lowered the nose of the aircraft. The aircraft autothrottle then commanded an increase in thrust, which the pilot in command countered by manually moving the thrust levers to the idle position. The aircraft nose pitched up again and the aircraft climbed 2,000 ft. The flight crew notified air traffic control (ATC) that they could not maintain altitude and requested a descent and radar assistance for a return to Perth.
The pilot in command reported that he attempted to disconnect the autothrottle by pressing the thrust lever autothrottle disconnect switches and pushing the autothrottle engage switch. The autothrottle arm switches had remained in the ‘ARMED’ position during the occurrence.
With the autothrottle armed it would automatically activate if the autopilot was not engaged and the airspeed was less than a flight management computer calculated value for 1 second, or the thrust was below that required for the mode of flight at the time.
The article (which I found after Clandestino clued me in to the incident - don't hold him responsible for the content) appears substantially correct.
It seems that the crew were unaware that disconnecting autothrottle was insufficient, and even with AP disengaged, the protections would order a thrust increase if the autothrottle system was still set to "ARMED".
Note that I'm not disputing that the T7 system can be disengaged more thoroughly than the Airbus equivalent, but it can be seen - even with that ability - the T7's functions can and do catch crews unaware if there is a problem with the air data.
Lyman, we're talking about FBW here, not autoflight. Can we at least keep the discussion vaguely on track?