Evaluation of a Low-Cost Visual Approach Slope Indicator (VASI) as a Pilot Training Aid

The purpose of this project was to determine the effectiveness of a simple low-cost Visual Approach Slope Indicator (VASI) in developing and reenforcing proper aircraft control technique during approach and landing under actual pilot I training conditions. A simplified two-box, single-lamp system was evaluated at two pilot training schools which summarized the results of training given to comparable groups of student pilots instructed with and without the use of the abbreviated VASI.

Results showed that the simplified VASI made flight instruction easier enabling the students to quickly grasp the fundamentals of final approach glide path control. VASI-trained students made better, safer approaches earlier in their training than the regular students trained without it and had no trouble subsequently landing without benefit of the system during daylight or nighttime approaches.

The system provided reliable visual guidance and good sensitivity for glide path control within its design capability of 1 to 1.5 miles. Maximum benefit of the system appeared to be derived during night approaches where judgement of altitude is difficult.

FAA-DS-70-4

Authors: Warren G. Crook