# NTSB ATL00LA095: William J. Knowles KNOWLES-THORP KT-18, N37BK, Opa-Locka, FL, September 30, 2000 - Type: NTSB accident investigation - Classification: Accident · Fatal · Limited investigation · Final report - Date: September 30, 2000, 15:48 local (19:48 UTC) - Place: Opa-Locka, FL - Coordinates: 25.909452, -80.26934 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=25.9095&lon=-80.2693&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 2 fatal - Status: Completed, report April 6, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 50398 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL00LA095 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/50398/pdf - Page: https://openairdocs.org/ntsb/ATL00LA095 ## Probable cause The pilot's failure to maintain flying airspeed during initial climb, resulting in an inadvertent stall/spin. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - in flight, takeoff - initial climb - airspeed - not maintained, pilot in command (cause) - stall/spin - inadvertent, pilot in command (cause) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - grass ## Analysis The experimental airplane was observed by witnesses climbing steeply and banking side to side shortly after lifting off from runway 9L. Upon reaching 200 feet, the airplane spun 360 degrees to the left, then impacted the ground in a nose-down attitude. Witnesses also stated that they did not hear any unusual engine sounds prior to the airplane's impact with the ground. A post-accident examination of the airplane and its related components was performed, and no discrepancies were found. ## Factual narrative On September 30, 2000, at 1548 eastern daylight time, a William J. Knowles Knowles-Thorp KT-18 experimental airplane, N37BK, was destroyed when it collided with the ground during initial climb following takeoff from Opa-Locka Airport in Opa-Locka, Florida. The private pilot-in-command and airline transport pilot-rated passenger were fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight being conducted under Title 14 CFR Part 91. The flight was originating at the time of the accident. According to Federal Aviation Administration (FAA) radio transcripts, the pilot requested a received permission to depart on runway 9L at Opa-Locka Airport. A witness located on the airport stated that he observed the airplane "climbing steeply" in a 15-degree climb immediately after lifting off from runway 9L. Another witness stated that he observed the airplane "banking steeply side to side." According to the first witness, when the airplane reached approximately 200 feet agl (above ground level), it banked left and spun 360 degrees to the left, then impacted the ground in a nose-down attitude. Both witnesses stated that they did not hear any "unusual" engine sounds prior to the airplane's impact with the ground. The airplane came to rest approximately 1,000 feet north of the midfield point of runway 9L just north of a canal that runs parallel to runway 9L/27R. A post-accident examination of the airplane revealed that the propeller assembly was separated from the engine at the propeller flange. One blade exhibited torsional bending and leading edge damage, and the second blade exhibited leading edge scoring and was bent aft. An engine examination was performed and continuity of the crankshaft and accessory drives was established. No pre-impact mechanical deficiencies were found during the engine examination. According to the FAA inspector, "there was no apparent indication of any aircraft structural failure prior to impact." There was no pre or post impact fire. The pilot-in-command held a private pilot certificate, dated February 24, 1995, with airplane single and multiengine land ratings. He possessed a third class airman medical certificate, dated September 18, 2000, with a limitation for wearing corrective lenses for near and distant vision, and a restriction that certificate was "not valid for night flying or by color signal control." According to a friend of the pilot, he had a total of 1,710 hours, 250 of which were in the Knowles-Thorpe KT-18. The passenger held an airline transport pilot's license with a multiengine land rating, and a commercial license with ratings in single engine landing airplanes, instrument helicopters and glider tow. He did not possess a current airman medical certificate. A review of the airplane's maintenance records revealed that a condition inspection was due in August of 2000, and according to the logbook, there was no entry indicating that the inspection was accomplished. Based on full fuel and pilot weight calculations, the airplane was found to be within takeoff cg (center of gravity) limits. According to the airplane's kit manufacturer, the stall speed with flaps in the 'up' position is 68 knots. An autopsy on the pilot-in-command was performed on October 1, 2000, by the Metro-Dade Medical Examiner's Office in Miami, Florida. A toxicological protocol was performed by the FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma. No ethanol was detected on the urine, and no drugs were detected in the liver. Carbon monoxide and cyanide tests were not performed. ## Aircraft - Registration: [N37BK](https://openairdocs.org/deregistered/N37BK-2001-03-30), registration cancelled 2001-03-30, S/N 807 (OpenAirDocs) - Reported make and model: William J. Knowles KNOWLES-THORP KT-18 (KNOWLES-TH) - Registry model: [Knowles William J KNOWLES-THORP KT-18](https://openairdocs.org/model/knowles-william-j-knowles-thorp-kt-18) (registry code 05620YB) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 807 - Airframe hours: 250 - Engines: Lycoming O-320 180 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Registered owner: John C. Tucker Jr. - Airworthiness certificate: Special, Experimental (Special) - Departed: OPF - Airport: OPF, Opa-Locka Airport, runway 9L, 8,002 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 57; private; airplane ratings: single-engine land, multi-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: front; toxicology performed; flight hours: 1,710 total, 250 in this make and model, 75 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 80° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 84 °F, dew point 73 °F - Altimeter: 29.00 inHg - Observed at: OPF ## 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 20000930014569A](https://openairdocs.org/incident/20000930014569A), Sep 30, 2000: Amtr T18, Miami, FL, No damage, 2 fatal. (-23) A/c stalled and entered 1 turn spin after departing off 9L during initial climb at approx. 200' AGL. 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.