The day my Parrot Bebop 2 quadcopter crashed began like any other day. It ended, for the drone, at 9:02 a.m., 4:32 into its second flight of the day.
TWO MISSING SCREWS CAUSED THE CRASH
At about 8:58 a.m. Friday April 1, 2016 I was flying my Bebop drone just north of Arizona's Interstate 10 off Gold Nugget Road. The weather was clear. The drone was at 31 metres AGL; it had just finished a 360 degree pan of the area. Visibility was 20 miles. Four minutes into the flight a loud pop sound interrupted the whirring of the Bebop's four electric motors. An examination of video from the drone's camera revealed that 4:29 into the flight a wobble appeared that its image stabilization system was unable to correct. The wobble lasted three seconds before the motor failed. The craft immediately began an uncontrolled descent to the desert floor some 30 metres below.
A thorough search of the area was begun. Owing to the nature of the brush in the area, cholla for the most part, special care was taken as the searcher lacked safety gear (gloves and goggles). The drone landed in the branches of a small fallen and dessicated tree. It is believed this cushioned its impact, sparing major damage to the airframe. The Bebop's battery was found on the ground a few centimeters away. It is believed the battery remained attached to the airframe during its fall, separating at the moment of impact. The battery sustained a puncture with cracks and tears emanating from a point on its starboard side several centimeters aft of where it attaches to the cowling.
About 30 minutes after the crash the partial remains of the propellor, one vane, from motor number two were found approximately nine meters from where the Bebop came to rest. As of the time of this writing the location of the two remaining propellor vanes remain unknown.
After a tear down of motor number two it was determined that two of the three screws mounting the motor housing to the airframe's aft-port pylon had not been attached. It is believed vibration during the three hours of total flight time caused microcracks in the propellor that resulted in its catastrophic failure.
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