# NTSB CHI99LA261: Hodre-Buull-Kolb Mark III, N93JL, Plymouth, MN, July 21, 1999 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: July 21, 1999, 13:34 local (18:34 UTC) - Place: Plymouth, MN - Coordinates: 45.009407, -93.41957 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.0094&lon=-93.4196&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report January 18, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 46903 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI99LA261 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/46903/pdf - Page: https://openairdocs.org/ntsb/CHI99LA261 ## Probable cause The failure of the airplane's rudder control pulley due to corrosion and inadequate maintenance inspection of the airplane by the owner/pilot mechanic of the airplane. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, climb - flt control syst,rudder control - failure,total (cause) - maintenance,inspection - inadequate, owner/pilot mechanic (cause) - Loss of control - in flight, climb - remedial action - attempted, pilot in command - In flight collision with terrain/water, descent - uncontrolled - terrain condition - water ## Analysis The pilot reported the experimental amphibian airplane climbed to about 200 feet above the lake when it lost all rudder control. A witness said the airplane was '...tilting...' its wings and then impacted the water nose first. The pilot said that after the airplane lost its rudder control he tried to turn it away from a beach populated with swimmers and sunbathers. The on-scene investigation revealed the airplane impacted the water outside the swimming area. The investigation revealed that the airplane's right rudder control cable phenolic pulley had split in half. The pulley is located under a shroud below the right rudder pedal. Its shaft was corroded and the pulley would not rotate on it. The slackened rudder cable prevented the rudder from functioning. ## Factual narrative On July 21, 1999, at 1334 central daylight time (cdt), a Horde-Buull-Kolb Mark III, N93JL, piloted by a commercial pilot, was destroyed when it collided with the surface of a lake following an inflight loss of control. Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under the provisions of 14 CFR Part 91, and was not operating on a flight plan. The pilot was seriously injured. The flight departed from Medicine Lake, located near Plymouth, Minnesota, at 1330 cdt. The pilot said the airplane took off and climbed to "...about 200 feet..." above the lake's surface when it lost rudder control. He said he "Tried to turn 180 degrees to get away from the beach..." that was populated with swimmers and sunbathers. The pilot's drawing on National Transportation Safety Board Form 6120.1/2 showed the airplane made an approximate 180-degree turn away from the beach. The airplane impacted the water "...outside the swimming area..." according to the pilot. According to the Plymouth, Minnesota, Police Department report, the pilot "...stated that he had taken off from his lake place at his residence, got airborne and then made a circle and was going to land back on the lake. He stated that after he had made the turn he had lost most of his rudder control." After the loss of rudder control the pilot said his main concern was to clear the beach area. A witness said he saw "...the plane was making loops and ...[was] out of control." This witness said the airplane "...hit nose first..." in the water. Other witnesses described the airplane flying overhead with its wings "...tilting..." and the airplane impacting the water at "...a sideways angle..." or "...on its side... ." The on-scene investigation revealed that the right rudder control cable phenolic pulley, located under a shroud under the rudder pedals, had split in half. The pulley was frozen in place by corrosion on its shaft. The cable did not move the pulley. ## Aircraft - Registration: N93JL (not matched to a registry record) - Reported make and model: Hodre-Buull-Kolb MARK III - Category: Airplane, amateur-built - Engines: Rotax 912 81 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Registered owner: Bruce W. Fletcher - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, January 31, 1999, 50 hours before ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 67; commercial; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 3,500 total, 50 in this make and model, 3,500 as pilot in command, 50 in the last 90 days, 25 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Lowest ceiling: none ## 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 19990721009899A](https://openairdocs.org/incident/19990721009899A), Jul 21, 1999: Amtr MARKIII, Plymouth, MN, Substantial damage. Accident reported by sheriff. Damage reported as substantial. Other circumstances are unknown. (.19) on July 21, 1999, at 1334 central daylight time, a kolb… 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.