Canopy failure leads to fatal ultralight accident in Germany

Casualties unknown • Kedingshagen, DE

An improperly secured cockpit canopy opened during flight, causing an unrecoverable descent and the deaths of both occupants in an Evektor Eurostar EV97.

What happened

On May 20, 2011, an instructional flight involving a flight instructor and a student pilot ended in a fatal accident near Kedingshagen, Germany. The flight departed from Stralsund airfield on runway 23 in an Evektor Eurostar EV97 ultralight aircraft. After completing a standard circuit and a go-around, the aircraft was on final approach for a landing.

During the flight, the aircraft's cockpit canopy unexpectedly opened. Witnesses observed the aircraft transition from level flight into a steep, nearly vertical descent. The aircraft struck the ground with the engine running, resulting in the destruction of the aircraft and the deaths of two persons.

The investigation

The BFU investigation focused on the mechanical state of the aircraft and the cockpit canopy mechanism. Investigators found that the canopy frame was located 1.5 meters away from the main wreckage, indicating it had separated from the fuselage during the impact. Physical evidence on the canopy latch, including wear marks and deformation on the locking hook, suggested the latch had not been properly secured.

Further examination of the aircraft revealed that the takeoff weight was outside of permissible limits. The investigation also reviewed manufacturer flight tests, which had previously noted that an open canopy could cause vibrations and aerodynamic disturbances to the tail surfaces. Additionally, reports from other pilots indicated a history of difficulties in verifying the canopy was locked, as the latch is positioned behind the pilot's seat and is difficult to inspect visually from the cockpit.

Findings

  • The primary cause of the accident was the unintentional opening of the cockpit canopy during flight due to an improperly secured latch.
  • The open canopy created turbulent airflow over the horizontal and vertical stabilizers, significantly impairing the aircraft's controllability.
  • The crew, consisting of an instructor and a student with relatively low flight experience, was overwhelmed by the sudden emergency and the low altitude.
  • The physical effort required to close the canopy in flight (estimated at 10-20 kg) likely distracted the pilot or hindered manual flight controls.
  • The aircraft was operating above its maximum takeoff weight.

Probable cause

The accident was caused by the accidental opening of the cockpit canopy during flight, which induced aerodynamic instability and loss of control that the inexperienced crew could not recover from at such a low altitude.

Frequently asked questions

What happened in the 2011-05-20 Evektor Aerotechnik a.s./ Eurostar EV97 accident near Kedingshagen, DE?

An improperly secured cockpit canopy opened during flight, causing an unrecoverable descent and the deaths of both occupants in an Evektor Eurostar EV97.

What aircraft was involved and where did it happen?

The accident on 2011-05-20 involved a Evektor Aerotechnik a.s./ Eurostar EV97, at Kedingshagen, DE.

What was the probable cause of the accident?

The accident was caused by the accidental opening of the cockpit canopy during flight, which induced aerodynamic instability and loss of control that the inexperienced crew could not recover from at such a low altitude.

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