Not sure it can be considered as an issue but: When you put a helicopter over the sea with elevation 0.2 for example and with flying mode: the helicopter touch the sea a little instant and fly. But after that the pilot will drown himself in the air.
EDIT CSR Kryssar:
Pilot is not actualy drowing (seems that pilot won't die); the game only starts the drowing graphical postprocess. When player land the chopper on dry land everything changes back to normal.