An unmanned airship was on a test flight in Keysborough, Victoria when its remote-pilot lost control before the aircraft flew into the controlled airspace of Moorabbin Airport.
The incident occurred on 28 October 2012, when a team comprising a pilot, observer and software engineer were conducting a test flight of the airship. The aircraft, weighing less than 8 kg, consisted of a 10 m long balloon with a gondola suspended below and was remotely controlled by the pilot using a portable radio-controlled transmitter. The crew planned to fly the airship below 200 ft and within 200 m of their location to ensure it remained clear of the Moorabbin Class D control area.
Shortly after take-off, the crew noticed that the airship’s nose was tilting up due to its rearward centre of gravity. The pilot corrected the tilt but a minute later, when the aircraft was at about 130 ft off the ground, he realised that he could not turn it to the left, although it still could turn right.
The pilot attempted unsuccessfully to contact the Moorabbin control tower by radio to advise them of the situation.
The pilot tried to land the airship, but the rearward centre of gravity resulted in it climbing. The airship’s elevator (or height) controls were also not responding. As it climbed through 200 ft above the ground, the pilot realised he had lost total control of the airship, He reduced the engine power, but the airship continued to climb and fly in a north-westerly direction toward the Moorabbin Airport.
The pilot attempted unsuccessfully to contact the Moorabbin control tower by radio to advise them of the situation. He and the software engineer then got in a car with the portable radio-controlled transmitter to follow the airship by road. The observer remained at Keysborough and contacted the Moorabbin control tower and emergency services via telephone.
The air traffic controllers at Moorabbin spotted the airship around 4 km to the south-east at about 1,000 ft above the ground. This was also confirmed by the pilot of an aircraft flying in the Moorabbin circuit.
Thirty minutes later, the airship landed on the roof of a commercial building, sustaining minor damage.
Data provided to the ATSB by the airship operator indicated that the airship reached a height of 1,930 ft and, at its closest, was 5 km from Moorabbin Airport.
The airship operators have advised the ATSB that they will take a number of measures to prevent similar incidents. This includes developing a pre-flight checklist and change management process to consider risks when changes are made to hardware or processes. They will also be locating a suitable site for flight testing away from populated areas.
There are regulations that set out the requirements for the operation of unmanned aircraft (including airships); however, the size of the airship’s balloon meant that it did not have to be registered, and it was not subject to airworthiness and flight crew qualification requirements.
The Civil Aviation Safety Authority is currently working to provide more comprehensive guidance on the regulatory requirements and approval processes for the commercial operation of unmanned aircraft systems in Australia. The guidance will consider the long-term integration of unmanned aircraft systems into normal aviation operations in all classes of airspace.
More details of the safety actions and the civil aviation regulations can be found in the investigation report Airspace incursion involving unmanned airship, Airship 11, 2.7 NM east of Moorabbin Airport, Victoria, on 28 October 2012