Rudder Jam During Spin Training Leads to Fatal Crash in Quebec

Casualties unknown • Lac Saint-François, Quebec, CA

A Cessna 152 crashed into Lac Saint-François during a training flight after the rudder became irreversibly jammed, resulting in one fatality and one serious injury.

What happened

During a local training flight from Montréal/Les Cèdres Aerodrome, Quebec, a flight instructor and a student pilot were performing spin exercises. While the student was executing a left spin at approximately 3,600 feet above sea level, the aircraft entered a stabilized descent that could not be recovered. Despite the instructor taking control and applying full right rudder, full power, and full flaps, the aircraft continued its rotation and descent.

The Cessna 152 eventually struck the surface of Lac Saint-François. The student pilot sustained serious injuries and was able to evacuate the sinking aircraft through a rear window, where he was later rescued by a fisherman. The flight instructor, however, was unable to evacuate and died in the accident.

The investigation

Investigators examined the wreckage and found the aircraft had struck the water at a relatively low forward velocity. Crucially, the rudder was found locked in a full left deflection of 34 degrees, significantly exceeding the maximum allowable deflection of 2ability 23 degrees. Technical analysis revealed that the rudder stop plate had moved behind its stop bolt, creating a jam.

Further investigation into the aircraft's maintenance history showed that the aircraft was released for flight with a missing rudder bar return spring. This omission was not recorded in the journey or technical logbooks. Testing on similar aircraft confirmed that the combination of the missing spring, incorrect rudder rigging, and the specific design of the rudder horn stop plate created a condition where full rudder input during a spin could cause an irreversible jam. Because of the way the control cables pulled on the rudder horn, attempting to apply right rudder actually increased the jamming effect.

Findings

  • The aircraft entered a left spin with the rudder locked in a full left deflection.
  • The rudder jammed in a way that could not be overcome by the crew due to the direction of the cable pull.
  • The aircraft was not airworthy because it was released for flight with a missing rudder bar return spring.
  • Maintenance records were improperly maintained, as the missing spring and recent rudder work were not documented in the required journey or technical logbooks.
  • The design and condition of the rudder horn stop plate allowed for over-travel and subsequent jamming during spin entries.

Probable cause

The rudder became irreversibly jammed in a full left deflection during a practice spin, a condition made possible by a missing rudder bar return spring and the specific design of the rudder horn stop plate.

Frequently asked questions

What happened in the 1998-07-18 Cessna 152 C-GZLZ accident near Lac Saint-François, Quebec, CA?

A Cessna 152 crashed into Lac Saint-François during a training flight after the rudder became irreversibly jammed, resulting in one fatality and one serious injury.

What aircraft was involved and where did it happen?

The accident on 1998-07-18 involved a Cessna 152 C-GZLZ, operated by Laurentide Aviation, at Lac Saint-François, Quebec, CA.

What was the probable cause of the accident?

The rudder became irreversibly jammed in a full left deflection during a practice spin, a condition made possible by a missing rudder bar return spring and the specific design of the rudder horn stop plate.

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