Introduction O Jan. 14, 1992, an F-14A aircraft experienced an unsafe landing gear indication prior to recovery at a Naval air station. The air crew requested a chase aircraft to conduct a visual inspection of their landing gear in accordance with standard operating procedures. A T-34C aircraft with instructor and student pilot joined on the F-14 to inspect the landing gear. Shortly after the F-14 crew was notified that their gear looked good, the T-34 collided with the substantially larger aircraft. The T-34 and air crew were lost and the F-14 received minor damage and returned to the airfield. A study of Navy and Air Force midair collisions involving formation flying over the past 10 years has shown that pilot error is the predominant common denominator. Task saturation, preoccupation with cockpit duties, and failure to judge closure rates and to take sufficient, timely, and appropriate action to avoid a collision are major factors in mishap findings.' Mutual aerodynamic interference of aircraft in close proximity is rarely discussed in mishap findings or in flight training, yet may be a significant causal factor. Interference of airflow over lifting surfaces, because of the pressure field of another aircraft and to the changes in local flow direction, can alter the aerodynamic characteristics of the trailing aircraft. Unexpected changes in lift and pitching moments may occur that affect closure rate and task saturation of the unaware or uninformed pilot. A numerical study of the aerodynamic interference between dissimilar aircraft in close proximity was conducted. The example aircraft involved a T-34 flying beneath an F-14 in an approach configuration. A short training video and report were produced for the Naval Air Systems Command to indicate the causal mechanisms of the aerodynamic interference and the trim changes to be expected by the pilot in such a situation with the aim of improving aviation safety education. This Note briefly describes the results of the study. For more complete information see Ref. 5.