What happened
The pilot of Boeing Stearman A75N1, registered as N56270, reported that his VHF radio frequency selector was malfunctioning. This equipment failure required him to manually set the Medford Tower frequency before taxiing, which prevented him from selecting other frequencies. While taxiing, just after passing a Cessna 150, he called the control tower. At this time, he was looking out his right side to ensure clearance from parked aircraft.
A Taylorcraft, N95078, rounded a corner beyond the nose of the Stearman and approached on the left. The Stearman pilot did not see the Taylorcraft until the two aircraft collided. Ground Control had advised N95078 of the oncoming Stearman at 1054:50, and N95078 steered right to provide clearance. The Stearman pilot made his first call to the tower at 1055. Shortly after, the Taylorcraft pilot noted the planes converging and turned to avoid a collision, but the left wings of each struck one another.
The investigation
The investigation focused on the sequence of events leading to the collision. The Stearman pilot's inability to use the radio selector normally contributed to his situational awareness issues. He was distracted by the need to manually adjust frequencies and checking for parked aircraft on his right.
N95078 was substantially damaged in the incident. Both pilots attempted to avoid the collision, but the visual acquisition failed due to the blind spot created by the taxiway corner and the Stearman pilot's divided attention.
Findings
Contributing factors included the malfunctioning VHF radio frequency selector on N56270, which necessitated manual setting of frequencies. The Stearman pilot was looking to the right for clearance from parked aircraft at the time of the incident. The Taylorcraft approached from a blind spot around a corner. Ground Control provided traffic information to N95078, but visual separation was not maintained.
The collision occurred because neither pilot saw the other in time to avoid impact. The Stearman pilot's focus on the radio and right-side clearance compromised his ability to scan for traffic on the left.