What happened
On the afternoon of July 25, 2002, two PZL M18B Dromader aircraft, operated by Aeronorte, departed from Proença-a-Nova to combat a forest fire near Vila de Rei. After performing initial retardant drops, both aircraft landed at Ferreira do Zêzere to replenish their water supplies.
Following the refilling process, the aircraft with registration SP-ZWT was the first to depart for the fire zone. During the flight, the pilot released a water load over the area of S. Martinho, an area where no active fire was present at that specific location. Shortly thereafter, the aircraft's engine experienced an unexpected failure. The pilot attempted an emergency landing in the rugged, heavily forested terrain of Pessegueiro, Vila de Rei. The impact was severe, causing the aircraft to strike a slope and come to rest nose-down. The pilot sustained fatal injuries in the crash.
The investigation
The GPIAAF investigation examined the wreckage and the aircraft's maintenance records. Technical analysis of the engine and propeller indicated that the engine was not operating at the moment of impact. Investigators also noted that the fuel selector valve was found in the "closed" position, a state that could only have been achieved through pilot action.
While the aircraft was found to be in good operational condition with valid maintenance inspections, the investigation could not determine the specific cause of the engine's unexpected shutdown. The investigation also reviewed the pilot's background, noting a high level of flight experience (9,580 hours) and a clean medical and toxicology report, which ruled out impairment by drugs or alcohol.