Robinson R44 crashes near Boppard due to loss of directional control

Casualties unknown • nahe Boppard, DE

A Robinson R44 helicopter experienced an uncontrolled yaw during takeoff from a landing site near Boppard, resulting in a hard landing and significant aircraft damage.

What happened

On July 29, 2012, a chartered Robinson R44 Raven I helicopter was performing a return flight from a landing site at Jakobsberg to Egelsbach. The flight included the pilot and three passengers. Shortly after lifting off from the landing site near Boppard at approximately 18:43 local time, the aircraft began rotating to the right around its vertical axis.

The pilot attempted to counteract this rotation by applying full left pedal input. After the helicopter had completed approximately three rotations at an altitude of about 7 meters, the pilot reduced collective pitch to force the aircraft toward the ground. This resulted in a hard landing, which caused the right skid to break and the helicopter to tip onto its side. All four occupants were able to exit the heavily damaged aircraft without further injury, though the pilot sustained minor injuries.

The investigation

The BFU examined the wreckage and the flight parameters. The investigation found that the aircraft's center of gravity was outside the permitted range at the time of the accident. The total takeoff mass was approximately 1,086 kg, near the maximum allowable takeoff weight of 1,089 kg.

Physical examination of the tail rotor control system revealed a separated control rod. The investigation determined that this was a ductile fracture occurring at the end of the threaded section of the rod head. No defects were found in the main rotor controls, and the tail rotor drive remained intact and functional.

Findings

  • The aircraft was operating at a weight near its maximum allowable limit.
  • The center of gravity was outside the permitted range.
  • The pilot's attempt to correct the yaw occurred after the rotation had already developed.
  • In helicopters with counter-clockwise rotating main rotors, high power demands during takeoff require precise pedal input to manage torque. A lack of sufficient forward airspeed or an improper climb profile out of ground effect can lead to an uncontrolled yaw.
  • A significant reduction in main rotor RPM can lead to an exponential loss of tail rotor thrust, further contributing to directional instability.

Probable cause

The accident was caused by an uncontrolled yaw during takeoff, likely exacerbated by the aircraft operating with an out-of-limits center of gravity and near maximum takeoff weight, which complicated the pilot's ability to maintain directional control during the transition out of ground effect.

Frequently asked questions

What happened in the 2012-07-29 Robinson Helicopter Company R44 Raven I accident near nahe Boppard, DE?

A Robinson R44 helicopter experienced an uncontrolled yaw during takeoff from a landing site near Boppard, resulting in a hard landing and significant aircraft damage.

What aircraft was involved and where did it happen?

The accident on 2012-07-29 involved a Robinson Helicopter Company R44 Raven I, at nahe Boppard, DE.

What was the probable cause of the accident?

The accident was caused by an uncontrolled yaw during takeoff, likely exacerbated by the aircraft operating with an out-of-limits center of gravity and near maximum takeoff weight, which complicated the pilot's ability to maintain directional control during the transition out of ground effect.

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