Amateur-built VANS RV-6 N16DD and Amateur-built RV-8 N189DK accident near Conroe, Texas

Probable cause

The failure of the pilot of the RV-6 airplane to maintain clearance from the RV-8 airplane while practicing formation flight.

NTSB analysis

The RV-6 collided with the RV-8 from below while maneuvering during day visual meteorological conditions. The RV-6 descended uncontrolled to ground impact, and the pilot of the RV-8 made a forced landing in a field. The two airplanes were part of group of seven airplanes practicing formation flight maneuvers for an upcoming airshow. According to the pilot of the RV-8, the RV-6 and another airplane were instructed to move into trail positions behind the RV-8. He saw the two airplanes drift back and out of view. About 5 seconds later, the pilot of the RV-8 heard a loud bang and immediately his airplane's engine stopped operating. He did not see the RV-6. The pilot of the other airplane that was moving into the trail position with the RV-6 said that the RV-6 was supposed to be the last airplane in this formation, but instead it moved directly behind the RV-8. The pilot thought that maybe the RV-6 pilot forgot which slot he was supposed to take, so he let the RV-6 have the position and moved behind the RV-6. Shortly after, he observed the RV-6 drift beneath and then climb up and collide with the RV-8. The collision was not violent. He then saw the two airplanes separate, and the RV-6 slowly nosed over into a 60-degree nose-down descent toward the ground. He reported that the pilot of the RV-6 "didn't seem in control of his airplane" before the collision and might have been incapacitated. However, he did not observe anything unusual with the pilot of the RV-6 that would have indicated a possible medical condition before or during the flight. Autopsy and toxicological testing of the RV-6 pilot revealed no evidence of impairment or incapacitation. Although incapacitation or impairment of the RV-6 pilot could explain why he failed to maintain clearance from the RV-8, there is insufficient evidence to determine whether this occurred.

Text from the NTSB. Open the NTSB docket for CEN11LA573 for the full record.