# NTSB DCA21LA094: Bell APT70, N314AQ, Fort Benning, GA, March 1, 2021 - Type: NTSB accident investigation - Classification: Accident · Class 4 · Limited · Final report - Date: March 1, 2021, 17:00 local (22:00 UTC) - Place: Fort Benning, GA - Coordinates: 32.35339, -84.952859 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.3534&lon=-84.9529&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Major Investigations Division - NTSB case key (mKey): 102742 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA21LA094 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102742/pdf - Page: https://openairdocs.org/ntsb/DCA21LA094 ## Probable cause failure of an electronic speed controller that resulted in a descent and impact with trees. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Flight control system](https://openairdocs.org/ntsb-findings/01022700): Aircraft › Aircraft systems · Failure; cases with it: [Bell Helicopter Textron APT70, 1 case](https://openairdocs.org/ntsb-findings/01022700/cases.md?model=061014W), [All aircraft, 65 cases](https://openairdocs.org/ntsb-findings/01022700/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333) (defining event); cases with it: [Bell Helicopter Textron APT70, 1 case](https://openairdocs.org/ntsb-events/333/sequence.md?model=061014W), [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md) ## Analysis According to the operator/manufacturer, the flight was a demonstration for a component of the U.S. Army in a remote area on the grounds of Fort Benning, Georgia. The APT-70 is an unmanned aircraft with vertical take-off and landing (VTOL) capability. Takeoff and landing is conducted in a “tail-sitter” configuration and lifts off with four quad-rotor propellors providing powered lift. The aircraft transitions to forward flight using the propellors for thrust, and a bi-wing configuration for lift. During the flight, the Electronic Speed Controller (ESC) on the number 1 motor faulted, resulting in a loss of thrust from that motor. The aircraft flight controller automatically reduced thrust on the opposite motor to maintain stable attitude control, which caused an overall reduction in thrust and led to a descent and to impact with trees. The aircraft was substantially damaged and there were no injuries. The aircraft is capable of entering a hover and controlled descent in the event of a failed motor; however, this maneuver requires crew action. The impact with the trees occurred about 5 seconds after the failure, before the pilot could take action. The operator/manufacturer identified an ambiguous paragraph in their safety checklist regarding the appropriate response to ESC failure. The examination of flight data and the ESC by the operator/manufacturer identified a cracked ceramic capacitor in the ESC circuitry. ## Aircraft - Registration: [N314AQ](https://openairdocs.org/deregistered/N314AQ-2021-07-10), registration cancelled 2021-07-10, S/N 006, built 2020 (OpenAirDocs) - Reported make and model: BELL APT70 - Registry model: [Bell Helicopter Textron APT70](https://openairdocs.org/model/bell-helicopter-textron-apt70) (registry code 061014W) (OpenAirDocs) - Registry engine: [Hacker Q150 series](https://openairdocs.org/engine/hacker-q150-series) (registry code 36441, electric) (OpenAirDocs) - Category: Powered-lift, unmanned - Serial number: 6 - Year built: 2020 - Engines: Hacker electric; Hacker electric; Hacker electric; Hacker electric - Damage: Substantial damage - Flight: Public use - Operator: Bell Helicopter Textron - Registered owner: Bell Helicopter Textron - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Unknown, September 22, 2020 - Destination: Same as departure - Equipment: Data recorder ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; injuries: none; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: unknown; last flight review October 13, 2020; seat: none; flight hours: 0 total, 0 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 333° at 5 knots - Visibility: 6 statute miles - Lowest ceiling: 7,000 ft overcast - Temperature: 64 °F - Observed at: KCSG, 2 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20210301003059A](https://openairdocs.org/incident/20210301003059A), Mar 1, 2021: Bell Helicopter Textron Inc APT70, Fort Benning, GA, Destroyed. Under VFR conditions, a large unmanned aircraft system (337LBS). Crashed while conducting a flight demonstration onboard Fort Benning, GA in restricted… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.