# NTSB FTW94LA189: Beech 35, N3956N, Mckinney, TX, May 29, 1994 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 28, 1994, 19:05 local (May 29, 1994, 00:05 UTC) - Place: Mckinney, TX - Coordinates: 33.169986, -96.700881 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.1700&lon=-96.7009&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report December 7, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 19080 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW94LA189 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/19080/pdf - Page: https://openairdocs.org/ntsb/FTW94LA189 ## Probable cause THE AILERONS BEING LOCKED BY A FOREIGN OBJECT. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - vfr pattern - final approach - flt control syst,yoke/control stick - foreign object (cause) - flt control syst,aileron control - locked (cause) - aircraft control - not possible, pilot in command - In flight collision with terrain/water, descent - emergency - terrain condition - crop ## Analysis WHILE ON FINAL APPROACH AT APPROXIMATELY 300 FEET AGL, THE AILERONS BECAME LOCKED AND THE PILOT WAS UNABLE TO RETURN THE AIRPLANE TO THE LEVEL FLIGHT ATTITUDE. THE AIRPLANE, CONFIGURED WITH THE LANDING GEAR AND FLAPS RETRACTED, ENTERED A LEFT SPIRAL, COMPLETING TWO 360 DEGREE TURNS PRIOR TO IMPACTING IN A WHEAT FIELD. INVESTIGATION REVEALED THAT A BRASS ALLOY FOREIGN OBJECT ENTERED THE INTERIOR OF THE CONTROL WHEEL THROUGH AN OPEN INSPECTION WINDOW IN THE BACK SIDE OF THE SINGLE THROWOVER TYPE CONTROL YOKE. THE FOREIGN OBJECT, WHICH WAS NOT RECOVERED, BECAME TRAPPED BETWEEN THE SPROCKET AND THE CHAIN, LOCKING THE AILERONS. ## Factual narrative On May 28, 1994, at 1905 central daylight time, a Beech 35, N3956N, was substantially damaged during descent near McKinney, Texas. The private pilot and his two passengers were not injured. Visual meteorological conditions prevailed for the personal flight. The pilot stated that the airplane was at approximately 300 feet AGL on final approach at the Aero-Country Airport, when the ailerons became locked. The pilot was not able to return the airplane to the level flight attitude. The pilot reported that the airplane entered a left 60 degree spiral, completing two 360 degree turns, until he was able to drag the left wing into a wheat field approximately a quarter of a mile west of the airport. At the time of ground impact, the airplane was configured with the landing gear and flaps retracted. The 1948 vintage airplane was equipped with a single throwover type control yoke, being operated from the left side. Examination of the control wheel, control wheel cast, chain and sprockets, revealed that a brass alloy foreign object, which was not recovered, became trapped between the sprocket and the chain, blocking the ailerons. The control wheel arm assembly has an open inspection window on its back side. ## Aircraft - Registration: [N3956N](https://openairdocs.org/deregistered/N3956N-2012-06-21), registration cancelled 2012-06-21, S/N D-1216, built 1947 (OpenAirDocs) - Reported make and model: BEECH 35 - Registry model: [Beech 35](https://openairdocs.org/model/beech-35) (registry code 1151502) (OpenAirDocs) - Registry engine: [Continental E185 series](https://openairdocs.org/engine/continental-e185-series) (registry code 17014, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: D-1216 - Airframe hours: 3850 - Engines: CONTINENTAL E-185-8 205 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Duval, Randall L. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 30, 1993, 250 hours before ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 25; private; airplane ratings: single-engine land; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 1,350 total, 340 in this make and model, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 14 knots - Visibility: 8 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 70 °F - Altimeter: 29.00 inHg - Observed at: DAL, 24 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 19940528012809A](https://openairdocs.org/incident/19940528012809A), May 28, 1994: Beech 35BEECH, Mckinney, TX, Substantial damage. Aileron controls locked on final. Spiraled to impact near airport. Brass alloy foreign object jammed chain sprocket ## Other investigations on N3956N (2) 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. - [NTSB FTW75DRJ36](https://openairdocs.org/ntsb/FTW75DRJ36), Jun 10, 1975: Beech 35 (N3956N), Leesville, LA, substantial damage - [NTSB CHI73FEV15](https://openairdocs.org/ntsb/CHI73FEV15), Nov 5, 1972: Beech 35 (N3956N), Quincy, IL, substantial damage 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.