# NTSB FTW96LA305: Stol UC-1, N9507U, Princeton, TX, July 16, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 16, 1996, 07:20 local (12:20 UTC) - Place: Princeton, TX - Coordinates: 33.180267, -96.500694 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.1803&lon=-96.5007&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report November 25, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 19910 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW96LA305 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/19910/pdf - Page: https://openairdocs.org/ntsb/FTW96LA305 ## Probable cause improper adjustment of the left propeller governor which resulted in uncommanded feathering of the left propeller. Factors were: the airplane's inadequate engine out performance and the lack of suitable terrain for the forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - nonmechanical, cruise - 1 engine - propeller system/accessories,governor (cause) - maintenance,adjustment - improper, other maintenance personnel (cause) - Forced landing, emergency descent/landing - aircraft performance,engine out capability - inadequate (contributing factor) - On ground/water encounter with terrain/water, landing - roll - terrain condition - none suitable (contributing factor) - terrain condition - ditch ## Analysis While in cruise flight, the left engine propeller 'went into feather, causing the engine to stall.' The pilot's attempts to unfeather the propeller and restart the engine were unsuccessful. The airplane's single engine performance was inadequate to maintain altitude. A forced landing was made to an open field, and during the landing roll the airplane impacted a ditch. Bench testing of the left engine propeller governor revealed that the feather stop was set at 2,000 rpm instead of the specified 1,690 rpm. ## Factual narrative On July 16, 1996, at 0720 central daylight time, a Stol UC-1, N9507U, registered to and operated by a private owner under Title 14 CFR Part 91, was substantially damaged during a forced landing near Princeton, Texas. The airline transport rated pilot and his pilot rated passenger were not injured. Visual meteorological conditions prevailed for the cross-country flight and a flight plan was not filed. The flight originated from Gladewater, Texas, at 0610, and the intended destination was Childress, Texas. According to the pilot, the airplane was in cruise flight at 4,500 feet MSL when the left engine propeller "went into feather, causing the engine to stall." The pilot's attempts "to unfeather the propeller and restart the engine" were unsuccessful. The pilot reported that "the aircraft's single engine performance was inadequate to maintain altitude." A forced landing was made to an open field with the landing gear up. During the landing roll, the airplane impacted a drainage ditch, resulting in substantial damage to the right lift strut and the fuselage. The accident flight was the continuation of a trip which started on July 13, 1996, in Hollywood, Florida, with a planned final destination of Lake Havasu City, Arizona. The pilot had purchased the airplane in Florida and was flying it to his home in Arizona. According to the pilot, "through-out the entire flight (7-13 to 7-16)," he "had difficulty keeping the props in synch." He further stated that "the longest period of time they would remain synchronized was approximately one minute." Both the pilot and the passenger held mechanic certificates with airframe and powerplant ratings. The left engine propeller governor was removed and bench tested under the supervision of an FAA inspector. The manufacturer's specifications called for the feather stop on the governor to be set at 1,690 rpm. Testing revealed that the stop was set at 2,000 rpm. ## Aircraft - Registration: [N9507U](https://openairdocs.org/deregistered/N9507U-2014-05-01), registration cancelled 2014-05-01, S/N 017, built 1975 (OpenAirDocs) - Reported make and model: STOL UC-1 - Registry model: [Stol UC-1](https://openairdocs.org/model/stol-uc-1) (registry code 8640202) (OpenAirDocs) - Registry engine: [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series) (registry code 41515, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 017 - Airframe hours: 5063 - Engines: Lycoming IO-360-B1D 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Joseph La Placa - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 5, 1996, 10 hours before - Departed: 07F, GLADEWATER, TX - Destination: CDS, CHILDRESS, TX ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 67; flight instructor, airline transport; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 20,000 total, 10 in this make and model, 18,000 as pilot in command, 150 in the last 90 days, 50 in the last 30 days, 8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Temperature: 90 °F, dew point 75 °F - Altimeter: 30.00 inHg ## 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 19960716046149A](https://openairdocs.org/incident/19960716046149A), Jul 16, 1996: Stolac UC1, Princeton, TX, No damage. (-23) At cruise altitude of 4500 ft, with engines set at 2300 RPM and 23 inches of manifold pressure, left engine propeller went to feather position without… 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.