Originally Posted by ChristiaanJ
… but why does it jump to +5000ft/min shortly after the disconnect, and then drop abruptly back to approx. zero?
- The part
after the AP disconnect has some logic :
Whenever FD reengage, they do it basic mode, which is HGD – V/S.
The selected V/S commanded by the FD will be the current V/S at the time of the FD reengagement.
There is almost good correlation between both FD and V/S SEL V/S traces, but not entirely.
- The part
before the AP disconnect raises questions :
- Why the SEL V/S is cycling from zero to -5000FT/MIN ? That’s not commanded by the crew.
- When did start that regular cycling ?
- The V/S trace in red is partially masked by the green line, but seems to indicate an oscillation getting stronger, up to the AP disconnect.
- It could indicate that the AP was trying to follow that cycling SEL V/S ?
- What does indicate the AP/FD VERTICAL MODE trace for that very period ?
- What does indicate the AP/FD VERTICAL MODE trace for the all event ?
- Where is the AP/FD VERTICAL MODE trace ?