Passengers reported that after takeoff, there had been a high pitched noise and that a gap had appeared around the top edge of the forward cabin door. The pilot, who was wearing headphones, indicated that he did not hear the noise and was unaware of the gap at the top of the door. A female passenger was seated in the front right seat beside the pilot and adjacent to the door. She was partially resting against the door, watching the terrain below. Her lap harness was secured. Shortly after the pilot commenced descent from 7000 feet, there was a loud bang and the door opened. The events which accompanied, and immediately followed the door opening occurred quickly and could not be determined precisely. However, the female passenger claimed that the door opened 30-40 centimetres, that her right hand contacted the upper surface of the wing, and that her head and shoulders were outside the cockpit. Two articles of clothing she was holding were lost overboard. The male passenger seated directly behind the female passenger thought that the door had opened fully and that the passenger fell so that her upper body was partially outside the cockpit. The pilot reported that he thought the door had popped open only 10-15 centimetres. The male passenger said that he reached around the seat to assist the female passenger and that she then leaned away from the door and held on to the back of the pilot's seat. As the aircraft was slowed to 90 knots, he and the pilot attempted to close the door without success. The pilot then decided to land the aircraft at Maroochydore. The male passenger held the door until the aircraft landed. On a rriva l at M aroochy dor e, the pil ot operated t he door loc king mecha nism a num ber of times an d, as i t appeared t o be fu ncti oning nor mal ly, he ele ct ed to continue the flig ht. The ma le pass en ger offe red to take t he fem al e pas se nger's place in the front rig ht seat adja cen t to the doo r bu t the off er wa s declined. Soon aft er de part ing Maro ochy dor e on the shor t flig ht to Brisban e, a gap again appeared around the top of the door accompanied by wind noise. The female passenger held the door closed until the aircraft landed at Brisbane. The maintenance organization which rectified the fault reported that the upper lock was out of rigging such that it was not held over-centre sufficiently to allow for fuselage flexing in flight. The cable was adjusted and the aircraft returned to normal flight status. The effect on the sequence of events, if any, of the female passenger leaning against the door was not determined. The cause of the the female passenger's injuries was not established. This occurrence was not the subject of an on-site investigation.