Structural failure leads to forced landing of Sycamore gyrocopter in Limpopo

Casualties unknown • Private farm 14 nm northwest of Mokopane, ZA

A Sycamore MK1 gyrocopter sustained substantial damage after a structural failure in the main mast assembly forced the pilot to perform an emergency landing on a dirt road.

What happened

On 17 October 2013, a Sycamore MK1 gyrocopter, registration ZU-EUI, was conducting a private flight departing from Mokopane Aerodrome in Limpopo province. While the aircraft was climbing at approximately 300 feet per minute, the pilot and passenger heard a sudden, loud noise originating from behind the cabin. Immediately following this sound, the aircraft experienced a significant nose-down pitch of about 30 degrees.

Facing a sudden loss of control authority, the pilot identified a narrow dirt road through the mountainous terrain and attempted a forced landing. Despite using significant physical effort to pull back on the control stick, the aircraft touched down heavily in a nose-down attitude. While the aircraft remained upright and no injuries were sustained, the impact caused substantial damage to the airframe, including the nose and right main wheel assemblies.

The investigation

An investigation by the SACAA AIID examined the wreckage and the mechanical state of the aircraft. Investigators discovered that the main mast had bent backwards and slightly to the right. This structural shift caused the engine cradle and propeller to shift, resulting in the propeller blades striking the oil cooler.

Upon removing the mast fairing, investigators found that the main rotor head attachment brackets were deformed. Metallurgical analysis revealed that these brackets were manufactured from an inferior quality material compared to standard reference units. Furthermore, the investigation noted that these critical components lacked part or serial numbers, making their maintenance history untraceable.

Findings

  • The primary cause of the accident was an unsuccessful forced landing following the deformation of the main rotor attachment brackets and the subsequent bending of the mast assembly.
  • The deformation of the attachment brackets likely occurred over an extended period due to the use of substandard materials.
  • The installation of a cosmetic mast fairing obstructed the pilot's ability to visually inspect the critical attachment brackets during pre-flight checks.
  • The lack of part numbers or serial numbers on the brackets prevented the establishment of a traceable maintenance history for the components.

Probable cause

The accident was caused by a structural failure of the main rotor attachment brackets and the bending of the mast assembly, which severely restricted flight control and necessitated a forced landing.

Frequently asked questions

What happened in the 2013-10-17 Sycamore MK1 accident near Private farm 14 nm northwest of Mokopane, ZA?

A Sycamore MK1 gyrocopter sustained substantial damage after a structural failure in the main mast assembly forced the pilot to perform an emergency landing on a dirt road.

What aircraft was involved and where did it happen?

The accident on 2013-10-17 involved a Sycamore MK1, registration ZU-EUI, at Private farm 14 nm northwest of Mokopane, ZA.

What was the probable cause of the accident?

The accident was caused by a structural failure of the main rotor attachment brackets and the bending of the mast assembly, which severely restricted flight control and necessitated a forced landing.

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