Engine Failure Leads to Emergency Landing in Experimental P1 LSA

Casualties unknown • UNIÃO, PI, BR

An engine failure during a private flight forced an experimental aircraft to perform an emergency landing on a dirt road, resulting in substantial damage to the aircraft.

What happened

On June 28, 2023, a P1 LSA experimental aircraft, registration PU-DAY, was performing a private flight from Teresina, Piauí, to Chapadinha, Maranhão. Approximately ten minutes into the flight, the aircraft experienced a sudden engine failure. The pilot initiated an emergency landing procedure on a dirt road near Povoado Alvo de Graça, União, Piauí.

During the landing roll, the aircraft veered to the left and collided with a sugarcane plantation. While the aircraft sustained substantial damage, both the pilot and the passenger escaped the incident without injuries.

The investigation

CENIPA investigators examined the engine and the flight parameters. The investigation revealed that a retaining ring for the piston pin in cylinder number one had displaced from its seat. This displacement caused internal component breakage and a subsequent fracture of the engine block, leading to lubricant leakage and a loss of power.

Regarding flight planning, the investigation found that the aircraft was operating outside of its established weight and balance limits. The pilot had planned the flight based on a maximum takeoff weight (MTOW) of 750 kg, whereas the official documentation and the aircraft's operating manual established a limit of 600 kg. The actual takeoff weight was calculated at 671 kg.

Furthermore, the investigation noted discrepancies in engine power usage. The pilot's checklist indicated a cruise power setting of 5,000 RPM, whereas the manufacturer's manual recommended a maximum of 75% power for cruise flight. Additionally, the loss of the aircraft's logbook following the accident prevented investigators from verifying the total hours flown since the last overhaul or confirming if all maintenance inspections were up to date.

Findings

  • Improper pilot judgment and control inputs during the emergency landing contributed to the aircraft veering off the road.
  • The aircraft was operating beyond its certified weight and balance limits due to incorrect MTOW planning.
  • An internal mechanical failure in the engine (displaced retaining ring) caused the loss of power.
  • The use of high power settings during cruise flight was inconsistent with the manufacturer's recommended operating procedures.

Probable cause

The engine failure was caused by the displacement of a piston pin retaining ring, which led to engine block fracture; the severity of the outcome was exacerbated by improper pilot judgment and flight planning errors regarding weight and balance limits.

Frequently asked questions

What happened in the 2023-06-28 aircraft accident near UNIÃO, PI, BR?

An engine failure during a private flight forced an experimental aircraft to perform an emergency landing on a dirt road, resulting in substantial damage to the aircraft.

What aircraft was involved and where did it happen?

The accident on 2023-06-28 involved a aircraft, registration PUDAY, at UNIÃO, PI, BR.

What was the probable cause of the accident?

The engine failure was caused by the displacement of a piston pin retaining ring, which led to engine block fracture; the severity of the outcome was exacerbated by improper pilot judgment and flight planning errors regarding weight and balance limits.

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