What happened
On December 14, 2010, a Robinson R-22 helicopter, registration PT-YYG, was conducting an aerial news mission over the city of São Paulo. The flight departed from Campo de Marte at approximately 19:45 UTC with one pilot and one passenger. While maintaining an altitude between 500 and 1,000 feet AGL, the pilot noticed irregular engine performance and decided to abort the mission to return to the departure airfield.
During the return flight, near the Estação da Luz, the engine ceased functioning entirely. The pilot was forced to execute an emergency autorotation, performing a controlled landing on the Avenida Tiradentes, a major thoroughfare in the city. During the descent, the main rotor blades struck tree branches approximately 20 feet above the ground. The aircraft landed in the direction of the oncoming traffic lane, causing the skids to separate and the lower part of the engine to contact the pavement. Despite the impact, the pilot and passenger were unharmed.
The investigation
CENIPA's investigation revealed significant maintenance and organizational irregularities. Investigators found that the aircraft's engine logs and airframe records were outdated, and several flight hours had not been properly recorded in the aircraft logbook. Furthermore, the investigation identified that the engine overhaul performed by a maintenance facility had failed to replace a specific piston pin plug, a task mandated by manufacturer Service Instructions and Service Bulletins.
The investigation also examined the pilot's decision-making process. While the pilot successfully executed the emergency landing, the investigation noted that the pilot's decision to continue the mission after noticing irregular engine performance, combined with an organizational culture that permitted maintenance delays, contributed to the severity of the event.
Findings
- Failure to replace a mandatory component: The primary cause of the engine failure was that the piston pin plug of cylinder number 3 was not replaced during the engine overhaul, as required by mandatory technical publications.
- Maintenance non-compliance: The maintenance workshop failed to follow the requirements of Service Instruction No. 1267C and Service Bulletin No. 240T.
- Human factors: The pilot demonstrated complacency by continuing the mission despite noticing performance issues and was influenced by an organizational culture that encouraged informal, unrecorded maintenance and flight hour logging.
- Organizational deficiencies: The operator's management failed to supervise maintenance activities effectively, and a culture of non-compliance regarding flight hour recording led to the postponement of necessary inspections.
- Aircraft damage: The Robinson R-22 sustained severe damage to the skids and main rotor blades, along with minor damage to the fuselage.