Accident Details
On 12 February 2002 at 0600 Z, an HS-125-400B aircraft registered as ZS-JBA was involved in a ground incident at Lanseria Airport (FALA). The aircraft, operating a commercial flight, was parked on the international departures apron, ready for a flight to Blantyre, Malawi. There were four people on board (2 crew and 2 passengers). No injuries or fatalities were reported.
Sequence of Events
According to the investigation report, the pilot assumed that the engineer had pressurised the hydraulic accumulator and therefore did not inspect it personally. When the passengers arrived, the pilot entered the aircraft and began internal pre-start checks. The co-pilot removed the chocks after boarding the passengers, closed the door, and then started to brief the passengers. At that moment, the pilot noticed that the aircraft was rolling forward. Attempts to stop the aircraft were unsuccessful. The aircraft rolled forward, narrowly missed a hangar and a parked Bell Long-ranger helicopter next to the hangar, crossed the taxiway, and finally stopped after entering a ditch between the taxiway and the runway.
Hydraulic System Inspection
Subsequent testing found that the operation of the hydraulic system was satisfactory. The hand pump was used to pressurise the system, after which the brakes could be applied successfully. This indicated that the lack of hydraulic pressure at the time of the incident was due to the system not being pressurised during the pre-flight inspection.
Probable Cause
The probable cause, as stated in the report, was that "the hydraulic system was not pressurised during the pre-flight inspection of the aircraft. The chocks were therefore removed without adequate hydraulic system pressure available."