CEN26LA163

The flight instructor reported that while in flight, he heard a loud noise and the noise inside the cabin increased. He turned around and realized that the aft (cargo) door had opened. The airplane landed without further incident. He noted that the Cessna 206 baggage door has a safety switch on the forward baggage door latch that prevents use of flaps when the door latch is not engaged and that the flaps were operational during the flight. He noted that the baggage door had been opened at least 2 times during the preflight inspection of the airplane. The pilot receiving instruction stated that during flight he heard a loud bang and a rush of air. He turned and saw that the rear half of the cargo door had opened in flight. They returned to the airport where an uneventful no-flap landing was made. He said that both cargo door handles were in the latched position before the flight. The operator of the airplane provided a video showing that it is possible to move the aft cargo door latch handle into the latched position without the door mounted lower latch hook properly engaging the fuselage mounted latch plate. Additionally, there were scrape marks on the latch plate and door sill that were consistent with the lower latch having not been properly engaged. According to the “Pilot’s Operating Handbook and FAA Approved Flight Manual” for the airplane, the flap interrupt switch that the flight instructor noted is installed in the upper sill of the forward cargo door opening and does not detect if the latch hooks have engaged the latch plates. The preflight checklist for the airplane included the following: “Cargo Doors - CHECK (visually verify upper and lower cargo door latches are securely engaged) (right side only)” The airplane received substantial damage to the aft fuselage when the rear cargo door opened and impacted the fuselage side.