Turbulence caused the Aquila drone to suffer a “structural failure” during its inaugural flight
The National Transportation Safety Board (NTSB) in the US has carried out an investigation into the crash-landing of Facebook’s Aquila drone and revealed the full details of the incident.
Back in June, Facebook launched Aquila – its autonomous, solar-powered aircraft which has a wingspan bigger than a Boeing 737 – for its inaugural flight over the Arizona desert.
After a 90-minute flight during which there were “no anomalies noted,” the drone came back down to Earth with a significant bump which the NTSB has determined was down to “an increasing amount of turbulence.”
Brace for impact
According to the report, the crew noted that the wind speed increased over the “intended test limit of 7 knots” during the landing phase. A strong gust of wind took the drone above its projected flight path, causing the autopilot to respond by lowering the nose, resulting in the increase in speed which led to the “structural failure” of the aircraft.
The report reads: “At 0737, the crew commanded a landing to the designated landing site. During the final approach, the aircraft encountered an increasing amount of turbulence and wind speeds of up to 10 knots at the surface and 12 to 18 knots, as measured by the aircraft at flight altitude. The operators post-flight telemetry analysis showed that the aircraft experienced significant deviations in pitch, roll, and airspeed, consistent with turbulence during the final approach.
“At 0743, while on final approach at 20 feet above the ground, the right outboard wing experienced a structural failure with a downward deflection. Four seconds later, the aircraft impacted the ground at a groundspeed of 25 knots in an approximately wings-level attitude. The aircraft sustained substantial damage as a result of the impact and wing failure. As a result of the aircrafts design (skid landing gear, low-slung engines and propellers), the operator expected some damage during normal landings.”
Weighing in at 400kg and having taken 14 months to build, Aquila is able to stay airborne for 90 days at a time and will be used to provide internet access to parts of the world without existing infrastructure.
It is the next step in Facebook’s somewhat controversial Internet.org initiative to connect the entire world to the internet, an area that Google is also looking into with its Project Loon programme which recently started trials in Sri Lanka.
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