# NTSB FTW93LA233: Aero Falcon Intl. Knight Falcon, N502AF, Mineral Wells, TX, August 6, 1993 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: August 6, 1993, 17:40 local (22:40 UTC) - Place: Mineral Wells, TX - Coordinates: 32.819622, -98.070152 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.8196&lon=-98.0702&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report August 1, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 18811 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW93LA233 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18811/pdf - Page: https://openairdocs.org/ntsb/FTW93LA233 ## Probable cause FAILURE OF THE AUTOPILOT WHICH RESULTED IN AN IMPROPER FLIGHT CONTROL CONDITION. A FACTOR WAS THE PILOT'S INABILITY TO REGAIN CONTROL. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, takeoff - initial climb - autopilot/flight director,servo - failure,partial (cause) - Loss of control - in flight, takeoff - initial climb - remedial action - not possible, pilot in command (contributing factor) - In flight collision with terrain/water, descent - uncontrolled ## Analysis THE EXPERIMENTAL PROTOTYPE, PILOT OPTIONAL, AIRPLANE WAS DEPARTING ON A TEST/ORIENTATION FLIGHT AFTER THE FIRST FLIGHT OF THE DAY HAD BEEN DELAYED DUE TO AUTOPILOT MALFUNCTIONS AND INTERRUPTED DUE TO ELECTRICAL MALFUNCTIONS. AFTER MAINTENANCE WAS PERFORMED, THE FLIGHT TOOK OFF INTO A RIGHT CROSS WIND OF BETWEEN 5 AND 20 KNOTS. THE PILOT SAID THAT AT ABOUT 50 FEET AGL, THE AIRPLANE ENTERED AN UNCOMMANDED RIGHT YAW AND ROLL THAT HE WAS UNABLE TO CORRECT. HE SAID THAT THE YAW AND ROLL INCREASED IN SEVERITY UNTIL THE AIRPLANE IMPACTED THE GROUND AFTER THREE 360 DEGREE TURNS. THE PILOT REPORTED THAT THE FLIGHT CONTROL MALFUNCTION WAS A RESULT OF A RUDDER HARD OVER, SIMILAR TO THE ONE THAT HAD BEEN EXPERIENCED DURING THE GROUND CHECKS PRIOR TO THE FIRST FLIGHT. ## Factual narrative On August 6, 1993, at approximately 1740 central daylight time, an Aero Falcon International, Inc., Knight Falcon, N502AF, was substantially damaged when it impacted the ground near Mineral Wells, Texas, following a loss of control. The loss of control occurred during the initial climb immediately after liftoff. The experimental prototype, pilot optional, airplane was being flown by a commercial pilot with an ATP rated pilot aboard as a passenger on the test/orientation flight. Visual meteorological conditions prevailed. The pilot received minor injuries while the pilot rated passenger was not injured. The pilot stated that the initial flight of the day had been delayed due to an autopilot malfunction during run up and interrupted after about 30 minutes of flight due to an electrical malfunction. Maintenance was performed and the airplane was prepared for a second flight. The pilot further stated that the engine run up and systems checks were normal prior to his beginning the second takeoff. He said the airplane responded normally during the takeoff roll and liftoff, but that it immediately assumed a right yaw and roll attitude as it passed through about 50 feet AGL. His efforts to correct were not successful and the yaw and roll rate increased and the airplane began to descend. The pilot said it impacted the ground in a nose down, right wing down attitude after three 360 degree turns. The pilot also stated that at the same time the uncommanded roll manifested itself, the cockpit communications system ceased functioning. The passenger's statement confirmed the pilot's observations. The pilot, who was also a design engineer on the project, said it was his opinion that the airplane experienced an autopilot commanded rudder hard over, similar to one experienced earlier in the day. According to the FAA coordinator and the pilot's statement, the takeoff was made with a right cross wind of between 5 and 20 knots. ## Aircraft - Registration: [N502AF](https://openairdocs.org/deregistered/N502AF-2013-11-04), registration cancelled 2013-11-04, S/N 600501 (OpenAirDocs) - Reported make and model: AERO FALCON INTL., INC. KNIGHT FALCON (KNIGHT FAL) - Registry model: [Aero Falcon Intl KNIGHT FALCON](https://openairdocs.org/model/aero-falcon-intl-knight-falcon) (registry code 05623NQ) (OpenAirDocs) - Registry engine: [Bombardier ROTAX (ALL)](https://openairdocs.org/engine/bombardier-rotax-all) (registry code 09050, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 600501 - Airframe hours: 6 - Engines: ROTAX 503 52 horsepower reciprocating - Damage: Substantial damage - Flight: Part 91 - Registered owner: Aero Falcon Intl., Inc. - Airworthiness certificate: Special, Experimental (Special) - Departed: MWL - Airport: MWL, Mineral Wells Municipal, runway 31, 4,325 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--w/ waivers/lim; seat: front; flight hours: 1,590 total, 100 in this make and model, 1,245 as pilot in command, 25 in the last 90 days, 10 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 45° at 5 knots, gusting 20 - Visibility: 15 statute miles - Lowest ceiling: none - Temperature: 84 °F ## 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 19930806030739A](https://openairdocs.org/incident/19930806030739A), Aug 6, 1993: Amd FALCON, Mineral Wells, TX, Substantial damage. Loss of control on initial climb. Uncommanded right yaw and roll to ground impact. Auto pilot rudder induced yaw. 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.