Cessna 150F N8072F and Cessna 150F N8642S accident near Alexandria, Louisiana

Probable cause

Failure of the wingman to maintain proper separation from the lead airplane during formation maneuvers. Contributing to the accident was lead's abrupt right bank and both pilots' lack of formation training.

NTSB analysis

Two airplanes departed as a formation to perform a low pass followed by a full-stop landing at the destination airport. Both pilots had flown formation together, but neither were formally trained. After performing the low pass, the formation began a climb to enter the downwind pattern to land. The wingman was positioned slightly aft and below lead and to the right, spaced approximately 100 feet. The lead radioed his intention to start a right turn. The wingman was not comfortable with his position in relation to lead so he radioed that lead should not turn "too hard" to the right. Following the radio call the lead airplane was observed to enter a 45-degree right-bank turn. The wingman initiated a climb and rolled to the right in an attempt to obtain spacing away from the lead; the airplanes then collided. A photo from a photographer depicted the post-collision sequence. The lead's airplane was damaged to the extent that controlled flight would not have been possible, with a missing vertical fin and a structurally damaged right wing. The wingman's airplane engine stopped following impact of the wingman's propeller with the wing spar of the lead's airplane. Both airplanes impacted a heavily wooded area. An examination of both airplanes and engines did not reveal any preimpact anomalies. A Federal Aviation Administration (FAA) Advisory Circular AC 90-48B, Pilot's Role in Collision Avoidance, cautions general aviation pilots of several key points of flying in formation to include "avoid attempting formation flight without having obtained instruction and attained the skill necessary for conducting such operations." Toxicology findings performed on the lead pilot were consistent with recent use of two different prescription muscle relaxants. The investigation could not determine whether sedation from the use of those medications or distraction from the condition for which he was taking them may have impaired the pilot’s decision-making on the day of the accident.

Text from the NTSB. Open the NTSB docket for CEN10FA011 for the full record.