The aircraft Captain had received a Garuda Route Clearance Unit presentation on the Perth route prior to departure from Bali and he had made one previous flight into Perth as the First Officer on a DC-10 in May 1988. After an evidently uneventful flight the aircraft was making an approach to Runway 03 at Perth. The cloud base at the time was approximately 800 feet above sea level. Air Traffic Control had used radar vectoring to position the aircraft for the approach and the crew was then instructed to make a pilot intercept of the appropriate radial from the Perth VOR. The aircraft did not accurately follow the required radial and the aircraft diverged up to about one kilometre either side of the published final approach path. The First Officer who was visually monitoring the approach was unable to sight the runway lighting and an overshoot was commenced when the aircraft was about three kilometres from the runway threshold. At about the same time as the Captain commenced his overshoot procedure the Perth Tower controller who had monitored the aircraft's approach from the time it had descended below the cloud base decided that the aircraft was not in a position to make a normal landing. He therefore instructed the aircraft to overshoot. The subsequent approach and landing were without incident. The investigation revealed that the details of the approach published by the Jeppesen Company in the USA contained an error of 5 degrees in the direction of the VOR radial required for the final approach path for the particular runway. These approach details were contained in company documentation available to the crew. Whether this error had any relevance to the incident circumstances was not established. It was noted that there are areas of significant lighting in the vicinity of Perth Airport which could hamper visual acquisition of the runway lighting under conditions of poor visibility. A precision approach aid such as ILS is not available for Runway 03 and runway approach lighting is not installed.
