Cessna 172S N2459K and Piper PA-28-181 N327PA accident near Anthem, Arizona

Probable cause

The failure of the pilots in both aircraft to maintain adequate visual lookout in a known training area where multiple aircraft frequently operated, which resulted in a midair collision.

NTSB analysis

A Cessna 172 and a Piper PA-28 collided in midair; both airplanes were operating as instructional flights. Radar data showed the airplanes operating about 1 mile apart. The Cessna was operating to the west of the Piper at 2,500 ft mean sea level (msl) and 106 knots ground speed. The Piper was operating to the east of the Cessna at 2,600 ft msl and 92 knots. The Cessna was on a northerly heading and made a right turn to a southerly heading. The Piper was also on a northerly heading and made a left turn to a southwesterly heading. Both airplanes executed the turns simultaneously. Shortly after each airplane completed its turn, the track of both airplanes intersected.

Calculations determined that the two airplanes collided at a 72-degree angle with a 116-knot closure rate. Propeller slashes on the Cessna's left wing indicated that the Piper was slightly above the Cessna at the moment of collision. During the collision sequence, the right side of the Piper's nose contacted the Cessna's rudder and continued forward into its left wing, which allowed the propeller to slash the trailing edge. The wreckages of both airplanes were found in the immediate vicinity of the radar-depicted track intersection. It is likely that the pilots had an opportunity to see each other during the turns. However, as the flights converged and rolled out of their simultaneous turns, structure from both airplanes would have blocked the pilots' visibility and prevented them from seeing the other airplane and avoiding the collision.

The area where the accident occurred is commonly used by local flight schools to practice ground reference maneuvers, which are normally performed at 1,000 ft above ground level (about 2,700 ft msl); therefore, the pilots should have been aware that other aircraft were operating in the area and should have been monitoring the environment. Further, the training area had an associated radio frequency to coordinate training activities between aircraft, and the pilots of both airplanes were making position reports and other radio transmissions on the established frequency and should have been listening for other traffic.

Text from the NTSB. Open the NTSB docket for WPR13FA254 for the full record.