Uav operator reported losing control of the aircraft following an undetermined significant failure t...

Narrative:

I am part of a research team. For this research project; we use [uav] aircraft to measure atmospheric conditions. For our flights; the [uav] climbs vertically from the takeoff point to 2;500 feet AGL. It then descends back to the takeoff point to land. As pilot in command for these flights; my responsibility is the same as PIC of a manned aircraft. I ensure that the aircraft is operated according to procedures; I ensure that safety is considered at all times; I watch the aircraft and scan the area for other air traffic. I have full authority under 14 crash fire rescue equipment 91.3 to end the flight or take any other action I see fit at any time. I do not; however; manipulate the controls. A separate [uav] operator does so under my supervision and under my authority. The incident in question occurred during descent from the 8th flight of the day. The previous 7 had gone perfectly; without incident. On this flight; during descent; the rotors and motors sounded different than they usually do during this phase of flight. Believing this to be nearby air traffic; I quickly scanned the area. Seeing no traffic; I returned my line of sight to the [uav]; which was descending more quickly than normal. Suddenly; a large cloud of smoke emanated from the [uav]. All personnel on the ground moved away from the [uav]; which fell to the ground and landed in a patch of grass.

Original NASA ASRS Text

Title: UAV Operator reported losing control of the aircraft following an undetermined significant failure that resulted in the UAV crashing to the ground.

Narrative: I am part of a research team. For this research project; we use [UAV] aircraft to measure atmospheric conditions. For our flights; the [UAV] climbs vertically from the takeoff point to 2;500 feet AGL. It then descends back to the takeoff point to land. As Pilot in Command for these flights; my responsibility is the same as PIC of a manned aircraft. I ensure that the aircraft is operated according to procedures; I ensure that safety is considered at all times; I watch the aircraft and scan the area for other air traffic. I have full authority under 14 CFR 91.3 to end the flight or take any other action I see fit at any time. I do not; however; manipulate the controls. A separate [UAV] operator does so under my supervision and under my authority. The incident in question occurred during descent from the 8th flight of the day. The previous 7 had gone perfectly; without incident. On this flight; during descent; the rotors and motors sounded different than they usually do during this phase of flight. Believing this to be nearby air traffic; I quickly scanned the area. Seeing no traffic; I returned my line of sight to the [UAV]; which was descending more quickly than normal. Suddenly; a large cloud of smoke emanated from the [UAV]. All personnel on the ground moved away from the [UAV]; which fell to the ground and landed in a patch of grass.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1495784
Time
Date	201711
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	UAV - Unpiloted Aerial Vehicle
Operating Under FAR Part	Other 107
Flight Phase	Descent
Person 1
Function	Single Pilot Pilot Flying Other / Unknown
Qualification	Flight Crew Commercial
Experience	Flight Crew Total 25
Events
Anomaly	Aircraft Equipment Problem Critical Conflict Airborne Conflict Deviation - Procedural Published Material / Policy Ground Event / Encounter Ground Strike - Aircraft Inflight Event / Encounter Loss Of Aircraft Control

Uav operator reported losing control of the aircraft following an undetermined significant failure that resulted in the uav crashing to the ground.