Engine Failure Leads to Forced Landing of Beechcraft A36 in Brazil

Casualties unknown • TERESINA, PI, BR

A Beechcraft A36 experienced an in-flight engine failure during its landing circuit in Teresina, resulting in a forced landing in a protected environmental park.

What happened

On June 11, 2023, a Beechcraft A3/36, registration PT-DLO, was performing a private flight from Redenção to Teresina, Brazil. While the aircraft was executing a right-hand turn to align with the runway at Senador Petrônio Portella Aerodrome (SBTE), the engine suffered an in-flight failure. Realizing the aircraft could not reach the runway, the pilot performed a 90-degree turn to the right, executing a forced landing within a native vegetation area of an environmental park.

The impact resulted in substantial damage to the aircraft, including ruptures in the fuel system lines, damage to the right-hand wing root, and damage to the vertical stabilizer, fuselage, and electrical system. The pilot and the passenger sustained no injuries.

The investigation

CENIPA investigators examined the engine and its accessories, specifically focusing on the fuel system components. The investigation revealed that the mechanical fuel pump and the fuel controller exhibited leakage during functional tests. Physical inspections identified wear on the fuel pump seal shaft and deformations on the internal O-ring of the fuel controller shaft.

Technical analysis of the maintenance records showed that while the aircraft's airframe and engine logs were up to date, the engine accessories had exceeded the manufacturer's recommended overhaul interval. According to Continental Motors Aircraft Engine’s Service Information Letter 98-9C, components such as the mechanical fuel pump and fuel controller should be overhauled every 1,700 hours or 12 years, whichever occurs first. At the time of the accident, the engine accessories had been since overhauled for over 184 months, significantly exceeding the 144-month (12-year) recommendation.

Findings

  • The engine failure was caused by malfunctions in the fuel system components, specifically the mechanical pump and fuel controller.
  • The engine accessories had exceeded the manufacturer's recommended time between overhaul (TBO) based on the 12-year calendar limit.
  • The absence of a trend-monitoring program prevented the adequate assessment of the engine accessories' condition, which could have identified the deteriorating seals and prevented the failure.
  • The pilot was properly qualified and held valid medical and flight credentials for the operation.

Probable cause

The engine failure was driven by the degradation of fuel system components (mechanical pump and fuel controller) that had exceeded their recommended service life, a condition that went undetected due to the lack of an engine trend-monitoring program.

Frequently asked questions

What happened in the 2023-06-11 aircraft accident near TERESINA, PI, BR?

A Beechcraft A36 experienced an in-flight engine failure during its landing circuit in Teresina, resulting in a forced landing in a protected environmental park.

What aircraft was involved and where did it happen?

The accident on 2023-06-11 involved a aircraft, registration PTDLO, at TERESINA, PI, BR.

What was the probable cause of the accident?

The engine failure was driven by the degradation of fuel system components (mechanical pump and fuel controller) that had exceeded their recommended service life, a condition that went undetected due to the lack of an engine trend-monitoring program.

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