Aviation Accident Summaries

Aviation Accident Summary CHI99LA261

PLYMOUTH, MN, USA

Aircraft #1

N93JL

Hodre-Buull-Kolb MARK III

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 Information

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.

Probable Cause and Findings

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.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports