Propeller Overspeed Leads to Forced Landing of Beech F33A near Witbank

Casualties unknown • 5nm SE of Kromdraai near the Witbank mines, ZA

A private Beech F33A experienced a propeller overspeed condition during flight, forcing the pilot to perform an emergency landing in an open field.

What happened

On June 29, 2001, a BEECH F33A, registered ZS-INH, departed from Grand Central Aerodrome on a private flight destined for Nelspruit Aerodrome. During the flight, while positioned near the Witbank area, the aircraft encountered a sudden propeller overspeed condition.

As the pilot determined that Witbank Aerodrome was outside of the aircraft's gliding range, an emergency landing was initiated in an open field near the Witbank coal mines. During the touchdown, the aircraft rolled through a ditch. This impact caused the nose gear to detach from the airframe, led to the collapse of the left-hand main landing gear, and resulted in the propeller striking the ground. The pilot escaped the incident without injury, though the aircraft sustained substantial damage.

The investigation

SACAA AIID investigators examined the mechanical state of the engine and the flight path. The investigation noted that the aircraft was operating under fine weather conditions at the time of the incident. Records indicated that the aircraft's last major periodic inspection (MPI) had been completed at 3488.53 airframe hours, meaning the accident occurred 65.53 hours after that inspection and 65.53 hours following an engine overhaul.

Probable cause

A fracture in the camshaft at the number 3 bearing oil transfer point caused the constant speed unit's bevel gear to fail, leading to a propeller overspeed and subsequent forced landing.

Frequently asked questions

What happened in the 2001-06-29 Beech F33A accident near 5nm SE of Kromdraai near the Witbank mines, ZA?

A private Beech F33A experienced a propeller overspeed condition during flight, forcing the pilot to perform an emergency landing in an open field.

What aircraft was involved and where did it happen?

The accident on 2001-06-29 involved a Beech F33A, registration ZS-INH, at 5nm SE of Kromdraai near the Witbank mines, ZA.

What was the probable cause of the accident?

A fracture in the camshaft at the number 3 bearing oil transfer point caused the constant speed unit's bevel gear to fail, leading to a propeller overspeed and subsequent forced landing.

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