Cessna 170B N3558C and Amateur-built SAVANNAH N991TP accident near Yerington, Nevada

Probable cause

The failure of the Savannah pilot to maintain awareness of the position of the Cessna while attempting a join up maneuver. Contributing to the accident was the impaired decision-making of the Savannah's pilot due to the combined effects of licit and illicit medications. Also contributing to the accident was the failure of the Cessna pilot to maintain awareness of the position of the Savannah as it was departing.

NTSB analysis

A Cessna 170B and a Pettit Savannah collided in midair shortly after both took off from the same airstrip. The airplanes were the second and third airplanes in a group of three airplanes whose pilots planned to depart from a fly-in at the airstrip, form up together in the traffic pattern, and then depart the area. The first airplane took off and turned left 180 degrees onto the downwind leg of the traffic pattern, and it was followed by the Cessna. Subsequently, the Savannah took off on a heading about 45 degrees to the left of the airstrip's heading and entered a climbing left turn. Witnesses reported that when the airplanes collided, the Cessna was flying level on a westerly heading on the downwind leg, and the Savannah was on about a north heading in a climbing left turn. The witnesses observed the airplanes collide at nearly a perpendicular angle.

Postaccident examination of the airplanes' wreckage revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation of either airplane. A collision angle calculated from paint transfer and scratches on the Savannah's right wing indicated that the airplanes collided at an angle of about 90 degrees, consistent with the witness reports.

The evidence indicated that the Savannah pilot attempted a join-up maneuver without maintaining adequate awareness of the Cessna's position. Before the collision occurred, the Savannah was in a climbing left turn and likely could not see the Cessna. The Savannah's pilot should have executed a clearing procedure during climb out to verify the position of the Cessna before attempting the join up. Also, had the Cessna's pilot executed a clearing procedure while on downwind, he might have been able to observe the Savannah as it was departing.

The Savannah pilot's toxicology testing identified diphenhydramine, tramadol, mefloquine, and trazodone in the muscle and liver. Additionally, tetrahydrocannabinol (THC) and its inactive metabolite tetrahydrocannabinol carboxylic acid were detected in the lung, liver, and brain. The investigation was unable to determine why the pilot was using mefloquine or if he had any adverse effects from the medication. The combined effects of diphenhydramine, tramadol, trazodone, and THC, all of which cause sedation, likely impaired the Savannah pilot's decision-making.

A Cessna 170B and an amateur-built Savannah collided in midair shortly after both took off from the same airstrip. The airplanes were the second and third airplanes in a group of three airplanes whose pilots planned to depart from a fly-in at the airstrip, form up together in the traffic pattern, and then depart the area. The first airplane took off and turned left 180 degrees onto the downwind leg of the traffic pattern, and it was followed by the Cessna. Subsequently, the Savannah took off on a heading about 45 degrees to the left of the airstrip's heading and entered a climbing left turn. Witnesses reported that when the airplanes collided, the Cessna was flying level on a westerly heading on the downwind leg, and the Savannah was on about a north heading in a climbing left turn. The witnesses observed the airplanes collide at nearly a perpendicular angle.

Postaccident examination of the airplanes' wreckage revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation of either airplane. A collision angle calculated from paint transfer and scratches on the Savannah's right wing indicated that the airplanes collided at an angle of about 90 degrees, consistent with the witness reports.

The evidence indicated that the Savannah pilot attempted a join-up maneuver without maintaining adequate awareness of the Cessna's position. Before the collision occurred, the Savannah was in a climbing left turn and likely could not see the Cessna. The Savannah's pilot should have executed a clearing procedure during climb out to verify the position of the Cessna before attempting the join up. Also, had the Cessna's pilot executed a clearing procedure while on downwind, he might have been able to observe the Savannah as it was departing.

The Savannah pilot's toxicology testing identified diphenhydramine, tramadol, mefloquine, and trazodone in the muscle and liver. Additionally, tetrahydrocannabinol (THC) and its inactive metabolite tetrahydrocannabinol carboxylic acid were detected in the lung, liver, and brain. The investigation was unable to determine why the pilot was using mefloquine or if he had any adverse effects from the medication. The combined effects of diphenhydramine, tramadol, trazodone, and THC, all of which cause sedation, likely impaired the Savannah pilot's decision-making.

Text from the NTSB. Open the NTSB docket for WPR15FA010 for the full record.