Originally Posted by
Reveal1
speed trim fail maybe? ..due maybe a seizure engine? just guessing , in this case N1 drops instantanly < than 5% with N2> than 50%
in this case you lose the vertical mode (v/s, Vnav, Lvl Chg) as spd lim shown on PFD.
There were no engine related issues mentioned in the incident report (NASA's ASRS ACN: 948442) just the partial failure of the MCP subsequent to windshield arcing.