LSO

Landing Signal Officer. These are officers who stand near the fantail and monitor the approach of incoming aircraft. They are in direct communications with the aircraft, can not only issue flight path correction information, but can verbally instruct the pilot to go around or by clicking a switch in their hand, can illuminate a go around signal on the visual landing aid (ball).

LSOs on the port side of the flight deck just forward of the fantail.

Red lights flash on either side of the ball to wave off the pilot (instruct him to go around).