United States of America

Two wheel-equipped, high-wing airplanes, a Cessna 207 and a Cessna 175, collided midair while in cruise flight in day visual meteorological conditions. Both airplanes were operating under visual flight rules, and neither airplane was in communication with an air traffic control facility. The Cessna 175 pilot stated that he was making position reports during cruise flight about 1,000ft above mean sea level when he established contact with the pilot of another airplane, which was passing in the opposite direction. As he watched that airplane pass well below him, he noticed the shadow of a second airplane converging with the shadow of his airplane from the opposite direction. He looked forward and saw the spinner of the converging airplane in his windscreen and immediately pulled aft on the control yoke; the airplanes subsequently collided. The Cessna 207 descended uncontrolled into the river. Although damaged, the Cessna 175 continued to fly, and the pilot proceeded to an airport and landed safely. An examination of both airplanes revealed impact signatures consistent with the two airplanes colliding nearly head-on. About 4 years before the accident, following a series of midair collisions in the Matanuska Susitna (MatSu) Valley (the area where the accident occurred), the FAA made significant changes to the common traffic advisory frequencies (CTAF) assigned north and west of Anchorage, Alaska. The FAA established geographic CTAF areas based, in part, on flight patterns, traffic flow, private and public airports, and off-airport landing sites. The CTAF for the area where the accident occurred was at a frequency changeover point with westbound Cook Inlet traffic communicating on 122.70 and eastbound traffic on 122.90 Mhz. The pilot of the Cessna 175, which was traveling on an eastbound heading at the time of the accident, reported that he had a primary active radio frequency of 122.90 Mhz, and a nonactive secondary frequency 135.25 Mhz in his transceiver at the time of the collision. The transceivers from the other airplane were not recovered, and it could not be determined whether the pilot of the Cessna 207 was monitoring the CTAF or making position reports.

The airplane manufacturer was conducting spin flight testing for the installation of a cargo pod when the airplane exhibited aberrant behavior and the testing was halted. The chief design engineer (CDE) was consulted, and, to provide a margin of safety for further flights, a forward center of gravity position was authorized for flaps up and flaps takeoff entries to gain more insight into the airplane's behavior on the previous flight. At the final briefing, before the next flight, the flight crew added spins with flaps in the landing configuration (flaps landing) into the test plan without the CDE's consultation or authorization. According to the pilot flying, after two wings-level, power on, flaps landing spins with left rudder and right aileron, a third spin entry was flown in the same configuration except that the entry was from a 30° left-bank turn. The airplane entered a normal spin, and, at one turn, flight controls were inputted for a normal recovery; however, the airplane settled into a fully developed spin. When recovery attempts failed, the decision was made to deploy the anti-spin parachute. After repeated unsuccessful attempts to deploy the anti-spin parachute, and when the airplane's altitude reached about 500 ft above the briefed minimum bailout altitude, both pilots called for and executed a bailout. The airplane impacted the ground and was destroyed. A postaccident examination of the anti-spin parachute system revealed that half of the connector hook had opened, which allowed the activation pin lanyard for the anti-spin parachute to become disengaged. Based on the airplane's previous aberrant behavior and the conservative parameters that the CDE had previously set, it is not likely that the CDE would have authorized abused spin entries without a prior testing buildup to those entries. Thus, the flight crew made an inappropriate decision to introduce flaps landing entry spin testing, and the failure of the anti-spin parachute contributed to the accident.