What happened
On December 17, 1994, a Cessna 180A, registration PT-AZB, was conducting a parachute jump operation departing from Americana, São Paulo. The aircraft was carrying the pilot and five skydivers, intended to drop jumpers at altitudes of 5,000 and 7,000 feet.
Upon reaching 5,000 feet, the aircraft entered a cloud layer. While performing a left turn to regain visual contact with the drop zone, the occupants experienced heavy positive G-forces, followed by a loud noise and an impact against the right side of the fuselage. The right wing separated from the aircraft at the strut attachment point. The aircraft immediately entered a spin.
During the descent, three skydivers successfully exited the aircraft. The remaining three occupants—the pilot and two passengers—perished when the aircraft struck a paved roadway and power lines, resulting in an explosion. One skydiver who exited the aircraft suffered a leg fracture upon landing.
The investigation
CENIPA's investigation focused on the structural failure of the wing and the operational conditions of the flight. Investigators examined the aircraft's weight and balance, noting that the aircraft was overloaded by approximately 598 pounds and the center of gravity (CG) was at 46.9%, exceeding the maximum aft limit of 45.8%.
The investigation also looked into the aircraft's maintenance history. While the aircraft had undergone a 1,000-hour inspection recently, the maintenance logs could not be located. Evidence suggested a prior incident approximately 15 days earlier, where the aircraft had experienced a violent ground maneuver that caused the right wingtip to strike the ground, with no recorded repairs following the event.
Findings
- Improper flight into IMC: The pilot, who was not instrument-rated and was flying an aircraft not certified for IFR, entered cloud cover, leading to potential spatial disorientation.
- Structural failure: The right wing separated in flight, likely due to the aircraft exceeding structural load limits during the turn, or due to pre-existing structural weakness from a previous ground incident.
- Overweight and out-of-balance: The aircraft was operating significantly above its maximum takeoff weight and with an aft CG limit violation.
- Deficient planning and judgment: The pilot proceeded into instrument meteorological conditions (IMC) without the necessary qualifications or equipment.