What happened
On March 20, 2022, a Cirrus SR22, registration N745AJ, was conducting a private IFR flight from Roskilde to Itzehoe. During the initial climb phase, the pilot began leaning the engine using the Multi-Function Display. While passing approximately 1,500 feet, the Cylinder Head Temperature (CHT) for cylinder number one exceeded the recommended limit of 380°F. Within moments, the temperature continued to rise, entering the manufacturer's caution area.
As the aircraft climbed further, the engine experienced a rapid degradation. The pilot reported low oil pressure to air traffic control, which quickly escalated to a total loss of oil pressure. During the emergency, the pilot reported an engine fire on board. While attempting to manage the emergency, the pilot declared a Mayday, stating that the engine was failing and that the crew would deploy the Cirrus Aircraft Parachute System (CAPS). The parachute was deployed at approximately 1,000 feet, leading to an uncontrolled ground impact that destroyed the aircraft and resulted in serious injuries to the occupants.
The investigation
The Danish Accident Investigation Board examined the mechanical and operational factors leading to the engine failure. The investigation focused on the temperature fluctuations in the engine, the subsequent loss of oil pressure, and the decision-making process regarding the use of the emergency parachute system. Investigators analyzed engine components, including the piston of cylinder number one, and reviewed cockpit communications and radar data to reconstruct the sequence of events.
Findings
- The primary cause of the engine failure was a temporary high Cylinder Head Temperature (CHT) in cylinder number one, which likely induced engine detonation.
- This detonation triggered a chain of mechanical failures, including severe damage to the piston of cylinder number one, a drop in oil pressure, and eventual engine disintegration.
- The engine failure and subsequent fire were compounded by non-compliance with established emergency procedures.
- High workload and specific type training influenced the pilot's perception, leading to the decision to deploy the CAPS despite having sufficient altitude and favorable weather conditions to attempt a forced landing in an open area.