Loss of Control in BRM Citius Sport Following Engine Power Loss

Casualties unknown • Montargil, PT

A BRM Citius Sport ultralight aircraft experienced a loss of control during takeoff at Foros do Mocho, Portugal, due to a partial loss of engine power.

What happened

On November 10, 2023, at 10:54 UTC, a BRM Citius Sport (registration F-JAYP) was performing a takeoff from Foros do Mocho, Montargil, Portugal. The flight was a private general aviation operation intended to travel from Monte do Lago, Portugal, to Guadalupe, Spain. During the takeoff roll, the aircraft experienced a partial loss of engine power, which subsequently led to a loss of control in flight.

The investigation

The GPIAAF investigation examined the technical condition of the aircraft, the fuel system, and the flight planning process. The investigation focused on the aircraft's construction history, noting that the aircraft was built as a kit. Investigators found that the builder had originally intended to use the aircraft personally but later decided to sell it. Crucially, the aircraft had not yet undergone a formal validation process, which includes systematic functional, ground, and flight testing to ensure the integrity of systems like the fuel supply across all flight attitudes.

Furthermore, the investigation looked into the transfer of ownership. It was determined that the transition of the aircraft to new owners occurred without the necessary technical information being passed along, leaving the new operators unaware of the aircraft's unvalidated status. The investigation also reviewed the pilot's flight planning, which was found to involve deviations and the acceptance of unknown risks.

Findings

  • The aircraft had not completed the necessary post-construction validation and flight testing required to ensure safe operation.
  • The partial loss of engine power was a critical factor in the loss of control.
  • The transfer of ownership occurred without providing the new owners with essential information regarding the aircraft's technical constraints.
  • The flight planning and preparation process demonstrated a lack of technical, operational, and regulatory knowledge, characterized by the acceptance of unknown risks.

Probable cause

The accident was caused by a partial loss of engine power during takeoff, compounded by the fact that the aircraft had not undergone a formal validation and testing phase following its kit construction, and the operators lacked sufficient technical knowledge regarding the aircraft's unverified operational status.

Frequently asked questions

What happened in the 2023-11-10 ULM BRM Citius Sport accident near Montargil, PT?

A BRM Citius Sport ultralight aircraft experienced a loss of control during takeoff at Foros do Mocho, Portugal, due to a partial loss of engine power.

What aircraft was involved and where did it happen?

The accident on 2023-11-10 involved a ULM BRM Citius Sport, registration CS-USI, at Montargil, PT.

What was the probable cause of the accident?

The accident was caused by a partial loss of engine power during takeoff, compounded by the fact that the aircraft had not undergone a formal validation and testing phase following its kit construction, and the operators lacked sufficient technical knowledge regarding the aircraft's unverified operational status.

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