What happened
On December 23, 2009, a Cessna 170A, registration PT-AGV, was conducting an aerial advertising flight (banner towing) along the coast of São Paulo, Brazil. The aircraft departed from Itanhaém for a mission spanning several coastal cities, including Santos and Guarujá.
At approximately 13:20 UTC, the pilot experienced a sudden-onset mechanical issue described as a "small jerk" in the control column, after which the left flight controls ceased to function. In an attempt to maintain control, the pilot moved the yoke to the right, but the aircraft failed to respond. The pilot subsequently reduced power and, as the aircraft neable approached the water, deployed the flaps fully and released the advertising banner. The aircraft struck the water at a shallow angle, causing the landing gear to impact first. The momentum of the engine impact caused the aircraft to capsize and sink approximately 130 meters from the shoreline. The pilot survived the impact without injury.
The investigation
CENIPA's investigation focused on the mechanical failure of the control system and the organizational safety culture of the operator. Investigators examined the aircraft's maintenance history and found that while the aircraft had undergone recent inspections, the maintenance program lacked specific, detailed procedures for inspecting sensitive components. The investigation also reviewed the pilot's training, noting that while the pilot was properly licensed, this was his first flight performing banner towing operations. Furthermore, the investigation looked into the company's training program, which was found to be insufficient in covering emergency procedures for water landings and aircraft evacuation.
Findings
- The primary cause of the accident was the disconnection of a pin at the universal joint connecting the left control column to the control linkage.
- The maintenance program was deficient, lacking rigorous visual or technical inspection methods (such as magnaflux) to identify fatigue or disconnection in critical flight control connections.
- The pilot's decision-making was compromised by a lack of experience in this specific type of operation and an inadequate check of the remaining control effectiveness.
- The operator's training program was inadequate, failing to include technical evaluations of aircraft systems or specific training for water ditching and emergency evacuation.
- There was a lack of standardized operational regulations regarding flight profiles, safety equipment, and pilot requirements for aerial advertising services.