I added the following to the base.cfg to fix the unknown keys in controls. it probably should be added to the en locale file but this worked for me.
[controls]
heli-down=Land the heli and shutdown engines.
heli-up=Start engines and prepare heli for flight.
heli-zaa-height-increase=Inrease Heli flying height.
heli-zab-height-decrease=Decrease Heli flying height.
heli-zba-toogle-floodlight=Toggle Heli floodlights on/off.
