Cessna 172S N108VK and Amateur-built F1 N540LK accident near San Marcos, Texas

Probable cause

The F1 pilot’s failure to see and avoid the lower altitude Cessna while on final approach for landing. Contributing to the accident were the restrictions to pilot visibility inherent to low- and high-wing airplanes, and both pilots’ failure to recognize the conflict that developed between their airplanes.

NTSB analysis

A low-wing Team Rockets F1 airplane and a high-wing Cessna 172 airplane were involved in a mid-air collision on final approach for landing. The airplanes entered the downwind leg of the traffic pattern within one minute of each other, with the F1 in front of the Cessna. There were four other airplanes in the traffic pattern or communicating on the airport’s common traffic frequency at that time. Shortly after entering the traffic pattern, the F1 pilot announced and performed a right 360° turn to increase spacing with the preceding airplane. The instructor onboard the trailing Cessna could not see the F1 and asked if the F1 had completed the turn. The F1 pilot responded that he was about to turn base, but he saw a Cessna below him and that he would extend downwind before turning to final.

The instructor onboard the Cessna began a turn to base and reported that they saw the F1. About 45 seconds later, the F1 pilot reported that he was on final approach over a highway about 2 miles from the runway, which indicates he did not extend his downwind sufficiently to attain sufficient separation. The Cessna crossed the highway about the same time and also reported a 2-mile final. About 45 seconds later, the F1 pilot reported a 1 mile final. The instructor onboard the Cessna then reported a .8-mile final. Shortly after the last radio calls from the two airplanes, the F1 impacted the Cessna on the Cessna’s top left side. Both airplanes impacted the ground short of the runway. The Cessna flipped over and the F1 came to rest against a fence and caught fire. The Cessna sustained substantial damage and the F1 was destroyed.

The F1 pilot recalled an airplane making position calls on final, which he assumed was behind him. He said that he had a clear view of the runway while on final and he did not see any traffic between him and the runway. It is likely that the low-wing configuration of the F1 prevented the F1 pilot from seeing the Cessna below him. Likewise, the occupants of the high-wing Cessna were restricted from seeing the F1 above them.

Although the F1 pilot stated that he would extend his downwind leg, he did not extend it enough to gain safe separation from the Cessna, which resulted in the F1 and the Cessna arriving at nearly the same geographical point on 2- mile final at the same time. The standard position reports issued by both pilots were sufficient for the pilots to have had awareness of each other’s position on final; however, neither comprehended the conflict between their airplanes, possibly due to the high volume of radio calls from other aircraft in the traffic pattern and both pilots’ increased attention on preparing for landing.

A low-wing amateur-built F1 airplane and a high-wing Cessna 172 airplane were involved in a mid-air collision on final approach for landing. The airplanes entered the downwind leg of the traffic pattern within one minute of each other, with the F1 in front of the Cessna. There were four other airplanes in the traffic pattern or communicating on the airport’s common traffic frequency at that time. Shortly after entering the traffic pattern, the F1 pilot announced and performed a right 360° turn to increase spacing with the preceding airplane. The instructor onboard the trailing Cessna could not see the F1 and asked if the F1 had completed the turn. The F1 pilot responded that he was about to turn base, but he saw a Cessna below him and that he would extend downwind before turning to final.

The instructor onboard the Cessna began a turn to base and reported that they saw the F1. About 45 seconds later, the F1 pilot reported that he was on final approach over a highway about 2 miles from the runway, which indicates he did not extend his downwind sufficiently to attain sufficient separation. The Cessna crossed the highway about the same time and also reported a 2-mile final. About 45 seconds later, the F1 pilot reported a 1 mile final. The instructor onboard the Cessna then reported a .8-mile final. Shortly after the last radio calls from the two airplanes, the F1 impacted the Cessna on the Cessna’s top left side. Both airplanes impacted the ground short of the runway. The Cessna flipped over and the F1 came to rest against a fence and caught fire. The Cessna sustained substantial damage and the F1 was destroyed.

The F1 pilot recalled an airplane making position calls on final, which he assumed was behind him. He said that he had a clear view of the runway while on final and he did not see any traffic between him and the runway. It is likely that the low-wing configuration of the F1 prevented the F1 pilot from seeing the Cessna below him. Likewise, the occupants of the high-wing Cessna were restricted from seeing the F1 above them.

Although the F1 pilot stated that he would extend his downwind leg, he did not extend it enough to gain safe separation from the Cessna, which resulted in the F1 and the Cessna arriving at nearly the same geographical point on 2- mile final at the same time. The standard position reports issued by both pilots were sufficient for the pilots to have had awareness of each other’s position on final; however, neither comprehended the conflict between their airplanes, possibly due to the high volume of radio calls from other aircraft in the traffic pattern and both pilots’ increased attention on preparing for landing.

Text from the NTSB. Open the NTSB docket for CEN20LA419 for the full record.