What happened
On November 27, 2011, a Cessna 177B, registration PT-ION, departed from the Aeroclube de Santa Catarina in São José, Brazil, for a scenic flight over Florianópolis. The aircraft was carrying a pilot and three passengers. Approximately 50 minutes into the flight, the pilot experienced intense vibrations throughout the airframe. In response to the instability, the pilot executed an emergency landing at Florianópolis International Airport (SBFL).
Following the landing, a post-flight inspection revealed that one propeller blade had fractured approximately 15 cm from its tip. Despite the structural failure of the propeller component, there were no injuries to the four occupants, and the aircraft sustained only minor damage.
The investigation
CENIPA investigators examined the engine at a maintenance facility in São José and found no abnormalities that would have accelerated fatigue. The damaged propeller blade was sent to the Department of Aerospace Science and Technology (DCTA) for forensic analysis. The laboratory results confirmed that the blade failure was caused by fatigue originating from a nick in the metal.
Maintenance records indicated that the propeller's last overhaul was performed on July 16, 2007. However, the records showed that this overhaul was conducted 225 flight hours after the 2,000-hour Time Between Overhaul (TBO) limit had been reached. While a 100-hour inspection had been completed approximately two months prior to the accident, there was no record of a nick being detected on the blade during that inspection. Investigators also noted a previous incident involving propeller damage to this same aircraft in 1992, though they could not confirm if the propeller involved in the current occurrence was the same one from that earlier event.