Unverified Fuel Filter Warning Leads to Unauthorized Flight Path Changes in Robinson R44

Casualties unknown • FIR Lisboa, PT

A pilot operating a Robinson R44 requested direct routing due to reported low fuel levels, though no technical malfunctions were ever confirmed.

What happened

On June 27, 2007, a Robinson R44 helicopter, registration CS-HFU, was performing a general aviation flight from Moura to Odivelas via the "Túnel Leste" route. While approaching Viana do Alentejo, the pilot observed a flashing fuel filter warning light. To address the potential issue, the pilot decided to return to Moura to await technical assistance.

After landing in Moura, the warning light ceased to illuminate. Believing the issue had resolved, the pilot resumed the flight toward Odivelas. Near Alcácer do Sal, the pilot contacted FIS to request a direct route to Odivelas, citing low fuel levels. Upon being transferred to LIS APP, the pilot repeated the request and justification, which was authorized. As the aircraft passed near Lisbon Airport, the fuel filter warning light illuminated once again; however, the pilot continued to Odivelas and landed.

Three minutes after landing in Odivelas, a relief pilot took command. Because the warning light had turned off again and the fuel level appeared sufficient, the aircraft departed Odivelas for Cascais (LPCS) at 1,200 feet.

The investigation

The GPIAAF examined the pilot's communications and the aircraft's maintenance records. The investigation focused on the pilot's decision-making regarding the reported technical failure and the lack of documentation following the intermittent warning light.

Findings

  • The pilot reported being faced with a technical failure and performing multiple landings and take-offs to clarify the issue, which resulted in low fuel.
  • Given the reported fuel scarcity, it was noted that the pilot's decision to fly to Odivelias rather than directly to Cascais was illogical.
  • No technical anomaly or malfunction was confirmed in the aircraft's systems during or after the event.
  • There were no entries in the Flight Log or Technical Maintenance Log regarding the intermittent warning light or any subsequent troubleshooting.
  • No records were presented to support that any search for the cause or repairs had been conducted.
  • The investigation noted that the pilot's actions appeared to use emergency privileges for personal convenience rather than a genuine emergency.

Probable cause

The pilot requested direct routing and flight path changes by citing a fuel-related emergency that could not be verified, and failed to document or investigate an intermittent fuel filter warning light.

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Frequently asked questions

What happened in the 2007-06-27 Robinson R44 accident near FIR Lisboa, PT?

A pilot operating a Robinson R44 requested direct routing due to reported low fuel levels, though no technical malfunctions were ever confirmed.

What aircraft was involved and where did it happen?

The accident on 2007-06-27 involved a Robinson R44, registration CS-HFU, at FIR Lisboa, PT.

What was the probable cause of the accident?

The pilot requested direct routing and flight path changes by citing a fuel-related emergency that could not be verified, and failed to document or investigate an intermittent fuel filter warning light.

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