What happened
On September 12, 2002, a Cessna U206G, registration OB-1226, was performing a scheduled flight from Atalaya to Pucallpa under RAP Part 135 regulations. Approximately six minutes after departing from Atalaya, the pilot contacted the Atalaya Tower to declare an unspecified emergency, stating that the aircraft was heading toward the river. Contact was lost approximately one minute after this transmission.
Following the loss of communication, search efforts were initiated. An aircraft (OB-1722) overflew the area but could not locate the downed plane. However, the activation of the Emergency Locator Transmitter (ELT) provided coordinates that allowed a Helisur helicopter to locate the wreckage at 20:54 UTC. The aircraft was found approximately 15 kilometers from the right bank of the Ucayary River. The impact was of such high energy and a steep nose-down angle that the aircraft was destroyed, and all six fatalities (one pilot and five passengers) were confirmed at the scene.
The investigation
The CIAA investigation focused on the wreckage and technical records of the aircraft. Investigators examined the Teledyne Continental IO-520-F engine and found a 6 cm diameter hole in the upper engine block near cylinder number 2. This damage was determined to have occurred prior to the impact. Physical evidence from the propeller suggested there was little to no rotation at the moment of impact, indicating the engine was likely not functioning during the final descent.
Additionally, investigators noted that the aircraft's weight and balance documentation and recent fuel load records could not be verified because the original documents were lost among the wreckage. While the aircraft was within its maximum takeoff weight limits according to type certificate, the lack of available records prevented a definitive calculation of the actual takeoff weight.
Findings
- The primary cause of the accident was an internal failure of the Teledyne Continental IO-520-F engine during flight, which resulted in a loss of power.
- The loss of engine power led to a loss of airspeed, causing the aircraft to enter a stall and subsequently lose control.
- The pilot's decision to depart shortly after a storm had passed through the area, rather than waiting for more stable weather, acted as a contributing factor.
- Pressure from passengers to depart Atalaya quickly to catch a connecting flight in Pucallpha likely contributed to a rushed pre-flight preparation.
- The possibility of an overweight condition could not be ruled out due to missing weight and balance documentation.