DUASxx20 - Always expect the unexpected

Initial Report

The flight was part of an educational challenge taking place on an approved and managed site. The aircraft was scrutineered by experienced aircraft professionals, as well as pre-flight checked and the failsafe and all controls checked. The remote pilot checked the controls and took off with the UAS, which was a VTOL-type aircraft.

The aircraft took off well, hovered nicely and responded to all controls. At this point the remote pilot took the aircraft higher (100ft) and transitioned to airplane mode, which again was successful, and the remote pilot began a circuit in plane-mode. At the right end of the circuit the UAS became unresponsive, and the remote pilot put it back into multirotor mode to hover, which it did, however control was still unresponsive.

At this point the remote pilot activated the manual failsafe, which did not work, so went to the electronic failsafe and turned off the controller, which also did not work. The UAS was then tracked visually as far as it could be seen until power failed and it glided to the ground in a distant field but could not be found.

The reporter subsequently noted that one of the learnings was anticipating the reaction of the crowd, when the pilot shouted “flyaway and loss of control” and started the emergency response sequence. Somewhat unexpectedly, those on site looked up and started to follow the aircraft, rather than remain clear. This was dealt with by an onsite debrief the next day.

CHIRP Comment

Perhaps the HF point most worthy of noting with this occurrence is the reaction of the spectators. Whenever you are flying it is important to consider what the reaction of the public might be when triggering an Emergency Response Plan (ERP). The crowd may well react in an unexpected manner that may have an impact on what you choose to do as part of the ERP. In this instance, the crowd regarded the flyaway as something to watch and participate in, rather than stay away from; they may have regarded it as helpful to follow the aircraft for the purpose of assisting in its recovery or it is possible there was a competitive element motivating the need to watch someone else’s aircraft suffer from a flyaway!

Unfortunately, the aircraft wasn’t recovered so diagnosing the reason for the flyaway, (which we emphasise happened after it had been scrutinesed, had its failsafes checked and had its geofencing checked), has not been possible. It would undoubtedly have been very useful, if it had been found.  It’s worth remembering sometimes that no matter how many checks and re-checks you perform, there’s always scope for something unexpected to go wrong that you hadn’t considered so never be complacent that you’ve got all the bases covered!