# Incident 20210721016089I: Amazon Logistics Inc MK27, Pendleton, OR, July 21, 2021

- Type: FAA incident report (Accident/Incident Data System), as reported
- Date: July 21, 2021, 08:30 local time
- Place: Pendleton, OR
- Airport: Eastern Oregon Regional At Pendlet
- Damage: Substantial damage
- Phase of flight: Other, Specify
- Operating rules: General operating rules (Part 91)
- Location: 45.6951° N, 118.8434° W: Placed by OpenAirDocs at EASTERN OREGON RGNL AT PENDLETON (PDT), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=45.6951&lon=-118.8434&mi=10
- Aircraft: N139PA, a cancelled registration (https://openairdocs.org/deregistered/N139PA-2022-07-23) (OpenAirDocs)
- Registry model: Amazon Logistics MK27 (registry code 061011S, https://openairdocs.org/model/amazon-logistics-mk27) (OpenAirDocs)
- Registry engine: Amateur-built UNKNOWN ENG (registry code 99999, https://openairdocs.org/engine/amateur-built-unknown-eng) (OpenAirDocs)
- Reported make and model: AMAZON LOGISTICS INC MK27
- Reported engine: AMA/EXPR UNKNOWN ENG
- People aboard: 1
- Fatal injuries: 0
- Other injuries: 0
- Pilot certificates: Commercial pilot, flight instructor
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/20210721016089I

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

UNMANNED AIRCRAFT (UA) ^PRIVACY DATA OMITTED^ WAS LAUNCHED AT APPROXIMATELY 8:30 FOR AN EXPERIMENTAL R&D FLIGHT.  THE UA PERFORMED A VERTICAL TAKEOFF USING ALL SIX MOTORS AND PROPS, TRANSITIONED TO FORWARD FLIGHT FOR A SHORT DISTANCE AND HAD TRANSITIONED BACK TO VERTICAL FLIGHT FOR THE DESCENT AND PACKAGE DELIVERY PORTION OF THE MISSION WHEN IT DEPARTED FROM CONTROLLED FLIGHT WITH A RAPID ROLL TO THE RIGHT.  A GROUND SAFETY OBSERVER INITIATED FLIGHT TERMINATION SYSTEM WHICH COMMANDED THE UA TO DISCONNECT ALL POWER TO ALL SIX OF THE MOTORS.  THE UA FELL APPROXIMATELY 120 FEET AND IMPACTED THE GROUND IN AN UPSIDE DOWN POSITION WHICH MINIMIZED IMPACT FORCES TO THE 18 POUND LIPO BATTERY.  THE BATTERY CASE WAS BROKEN ON FORWARD BOTTOM EDGE BUT DID NOT HAVE ANY RESULTING THERMAL RUNAWAY.

NO PRE-FLIGHT ANOMOLIES WERE DETECTED.

POST-INCIDENT INVESTIGATION REVEALED THAT THE #2 PROPELLER DISBONDED FROM THE PROPELLER HUB CAUSING A LOSS OF TORQUE AND POWER.  THE FLIGHT CONTROL COMPUTER INCREASED MOTOR RPM TO COMPENSATE FOR THE LOST TORQUE AND THE MOTOR SHAFT "WALLOWED OUT" THE PROPELLER MOUNTING HOLE AT THE HUB.

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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