Cessna TU 206F Landing Accident at Mashuin

Flight Details and Accident Sequence On February 6, 2010, a Cessna TU 206F was conducting its first flight on the Sucúa-Mashuin route under Visual Flight Rules. The aircraft carried 660 pounds of fuel and 865 pounds of cargo. At 15:20 UTC, the pilot reported to the Taisha Control Tower that he was five miles from Mashuin and at 2,000 feet above the terrain, canceling his flight plan. While over Mashuin, the pilot circled the runway to check conditions and landed on runway 10. The first contact with the runway was made by the right main gear, 55 meters from the threshold. Six meters later, the left main gear touched down. After rolling three meters, the left main gear wheel assembly detached. The aircraft traveled a total of 175.1 meters before turning left and stopping within the runway strip. The Taisha Control Tower did not realize the aircraft had been involved in an accident until the following afternoon, when the pilot notified them through local residents of Cosurúa. ## Personnel and Aircraft Information The pilot in command was a 49-year-old Ecuadorian national holding a Commercial Pilot License and a valid Second Class Medical Certificate. He had a total of 8,302:20 flight hours, including 1,030:00 hours in the PA-32-300. The aircraft had a valid airworthiness certificate, and its maintenance was performed according to manufacturer specifications. The aircraft's logbooks showed no issues related to the landing gear or main wheel axles. The last 500-hour progressive inspection found no abnormalities. The investigation board's weight and balance calculations confirmed that the aircraft did not exceed the manufacturer's limits for the operation and runway. ## Meteorological and Navigation Conditions The weather conditions at the time of the accident were good and did not contribute to the occurrence. The company argued that the flight was scheduled with knowledge of the weather conditions in Mashuin, but the investigation board determined that the flight departed Sucúa without knowing the destination's weather conditions. The flight was conducted under Visual Flight Rules, and the runway was not equipped with radio navigation aids. ## Communications and Aerodrome Information Communications between the aircraft and the control towers at Macas and Taisha were reported to be without any issues. However, the pilot stated that he canceled his flight plan three times without receiving an acknowledgment. The Taisha Control Tower controller did not receive the cancellation message and assumed the aircraft had landed safely. The Mashuin runway, according to the Ecuadorian Civil Aviation Directorate's runway manual, has dimensions of 500 x 25 meters, a dirt surface, an elevation of 800 feet, a 1% slope, and an orientation of 090°-270°. The investigation board found that the runway designators did not match reality and should have been 010°-280°. At the end of runway 10, there is a 170-meter extension that is not suitable for aeronautical operations due to unevenness and trenches. ## Wreckage and Impact Analysis There was no impact. The aircraft suffered the detachment of the left main gear wheel three meters after contact with the runway. The wheel was found on the right side of the runway, 108 meters from the beginning of runway 10. The aircraft continued its path, veering to the left. After traveling a total of 175.1 meters, it turned left on its vertical axis, producing forces that detached the right main gear due to the rupture of the anchor bolts to the wing. The aircraft stopped 230.10 meters from runway 10, with its nose oriented at 040° magnetic. No evidence of fire was found on the aircraft. ## Survival and Emergency Response The pilot abandoned the aircraft on his own. The pilot's belt, harness, and seat withstood the forces produced during the accident. Despite the accident occurring at 15:20 UTC, the Taisha Control Tower controller did not initiate the emergency notification chain. The Macas Control Tower reported that the Río Amazonas Approach Control had informed the Search and Rescue Coordination Office, which decided to wait for news before initiating search and rescue activities. ## Investigations and Analysis The left main landing gear was installed on the aircraft on March 31, 2009, with zero service hours. An analysis of the aircraft's logbooks for the last six months did not show any reports of hard landings that could have affected the strength of this axle. It was found that the aircraft's logbooks were not properly recording the work performed, as the daily pre-flight inspection was noted three times on February 1, 2010. The company presented the Flight Location Record, which did not have a signature of responsibility and showed the check points made by the pilot and the landing time at Mashuin runway, even though the pilot did not report his intentions and estimates to the company. The investigation board's weight and balance calculations confirmed that the aircraft landed with a weight below the maximum mass established by the manufacturer, so weight was not a contributing factor. The first contact of the aircraft with the runway was with the right main gear. After rolling three meters, it made contact with the left main gear. The mark produced by the left main gear during landing was not deep, indicating that the landing was normal (not hard). The investigation found that the left main gear wheel axle had a break at the point of connection with the gear leg, which allowed the wheel to detach. The investigation of the Sucúa runway, where the operating company is based, showed that its surface has many potholes and loose material (stones of regular size), but no large stones were found against which the gear could have hit during the start of this flight, causing an overload of the gear. During the investigation board's transfer to Mashuin runway in a C-206 aircraft, the pilot canceled the runway when he was at 2,000 feet of altitude, and the message was received by the Taisha Control Tower. The weather conditions during this flight were completely visual. The presence of potholes and stones of regular size in the Sucúa runway, from which the aircraft operates, and in the runways to/from which this aircraft usually operates, allowed the investigation board to establish that the physical conditions of them affected the resistance of the gear.