CF6-50 max n1 125% before the engine had to be pulled and 119.5% before maintenance action was necessary (approx 4300 and 4070 rpm!). Auto throttle servo is a linear actuator attached to the throttle clutch pack commanded by the autothrottle computor, the servo drives all 4 T/L together, so if one T/L was displaced relative to the other 3 they would still move together but from the different null points.
That 10 disc failure was due to poor manufacturing process I think.
The difference in N1 could be due to a tired engine or MEC (main engine control)
[This message has been edited by gas path (edited 06 January 2001).]