Engine failure leads to forced landing of Cessna Skyhawk near Warrington

Casualties unknown • Near Warrington, Cheshire, GB

A Reims Cessna F172P Skyhawk experienced a sudden loss of engine power during cruise flight, resulting in a forced landing in a field in Cheshire.

What happened

On 27 September 2014, a Reims Cessna F172P Skyhawk, registration G-BITM, was performing a flight near Warrington, Cheshire, when the aircraft experienced a sudden and significant reduction in engine power during the cruise phase. Upon the loss of power, the pilot identified a suitable field for an emergency landing. However, during the approach, the aircraft struck trees at the edge of the field and subsequently stalled, dropping into the intended landing area.

The investigation

Investigators examined the aircraft's engine through a detailed engineering inspection. This process revealed that the rocker cover for the number 3 cylinder had been punctured from the inside out by the inlet valve rocker arm. The lack of external impact marks on the cover indicated that this damage had occurred prior to the accident sequence.

Further disassembly of the engine core showed that the inlet valve in the number 3 cylinder had fallen into the cylinder. During the removal of the induction system, investigators discovered a fragment of a broken valve head lodged within the induction tube leading to the number 1 cylinder, which was partially obstructing the airflow. The inspection of the number 3 cylinder also revealed extensive damage to the piston top and the inlet valve itself.

Findings

  • The primary cause of the engine power loss was the fracture of the upper valve spring retainer in the number 3 cylinder.
  • This fracture allowed the inlet valve to drop into the cylinder, where it struck the piston.
  • The impact caused the valve head to break into three large fragments; one remained on the stem, one lodged in the valve seat, and one was forced into the induction tube for the number 1 cylinder.
  • Small fragments of the valve were also found to have likely entered the number 2 cylinder, causing damage to its piston before being expelled through the exhaust.
  • The combination of the compromised number 3 cylinder, the partial blockage of the number 1 induction system, and the damage to the number 2 piston resulted in insufficient power to maintain sustained flight.

Probable cause

The engine failure was caused by the mechanical failure of the number 3 cylinder's upper valve spring retainer, which led to the valve dropping into the cylinder and causing widespread internal engine damage and power loss.

Frequently asked questions

What happened in the 2014-09-27 Reims Cessna F172P Skyhawk accident near Near Warrington, Cheshire, GB?

A Reims Cessna F172P Skyhawk experienced a sudden loss of engine power during cruise flight, resulting in a forced landing in a field in Cheshire.

What aircraft was involved and where did it happen?

The accident on 2014-09-27 involved a Reims Cessna F172P Skyhawk, registration G-BITM, at Near Warrington, Cheshire, GB.

What was the probable cause of the accident?

The engine failure was caused by the mechanical failure of the number 3 cylinder's upper valve spring retainer, which led to the valve dropping into the cylinder and causing widespread internal engine damage and power loss.

Loading the flight search…