This January 2008 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Cessna 172, Cessna 150. Location: Corona, Calif. Injuries: Five Fatal. Aircraft damage: Destroyed.
What reportedly happened: A Cessna 172 and a Cessna 150 were maneuvering 1.4 miles southwest of the uncontrolled airport during day visual meteorological conditions. The 150 lifted off from runway 25 and entered the downwind leg of the pattern. Radar data shows that during this time, a Cessna 172N was on a 45° traffic pattern entry path to the downwind leg of the runway. The airplanes were on converging courses for about 13 seconds, the collided. The four occupants in the airplanes and one person on the ground were killed.
Calculations based on radar data show that the Cessna 150 turned onto the crosswind leg prior to reaching 700 feet above ground level, which is contrary to the FAA’s recommended procedures. A visibility study determined that while on the crosswind leg and during the turn onto the downwind leg, the Cessna 150 pilot had a 14-second window of opportunity to observe the approaching Cessna 172, which was traveling at 106 knots. The field of view of the Cessna 150 as it was turning to the downwind leg was limited in the area from which the Cessna 172 was converging by the door post structures. As the Cessna 172 was approaching the airport, the Cessna 150, which was traveling at 74 knots, would have been in his view at the 10:30 to 11 o’clock position and low in the windscreen. A witness reported that neither airplane appeared to alter its course during the final seconds of flight. No airport facilities or any of the pilots flying in the vicinity reported hearing any communication from either airplane.
Probable cause: The failure of both pilots to see and avoid the other airplane.
For more information: NTSB.gov