THE remains of a Royal Hongkong Auxiliary Air Force (RHKAAF) plane that crashed in Tolo Harbour last December will be used to help train engineers, it was revealed yesterday as the organisation made plans to celebrate its final day before disbandment. A RHKAAF helicopter lifted the fuselage of the twin-engined Norman Islander on to the roof of the Hongkong Aircraft Engineering Company's (HAECO) headquarters at Kai Tak. The 20-year-old fixed-wing aircraft was due to be withdrawn from service today, the day before the RHKAAF is consigned to the history books and becomes the Government Flying Service. But the plane was written off after a training flight went wrong on December 15 last year when it crashed into the sea near Tolo Harbour. The plane was later salvaged and moved to Kai Tak. A HAECO spokesman said: ''The Auxiliary Air Force had no further need of the plane, but we can put it to good use as a training cabin for our engineering trainees. ''The plane will never be airworthy again, but it will be a tangible reminder of the auxiliary air force.'' Eight RHKAAF aircraft will mark the last day of the force with a fly past over Victoria Harbour today.