Chapter 12: Angle of Attack Approaches

CHAPTER TWELVE

ANGLE OF ATTACK APPROACHES

1200. INTRODUCTION

This chapter contains procedures to conduct AOA approaches. The AOA approach is typically

used by carrier based airplanes to perform a precision approach to the carrier. The Air Force

advanced jet trainer (T-38) also utilizes an AOA system to land even though the landing is

conducted on a long runway and not on an aircraft carrier. Similarly, in the T-34C you will be

conducting an AOA approach to an actual runway. The skills learned by conducting AOA

approaches in the T-34C will, however, be used as a building block for advanced jet training.

1201. ANGLE OF ATTACK APPROACHES

Description. The AOA approach is a descending 180 balanced turn to final followed by a

normal landing. During the approach, the optimum AOA is maintained by controlling nose

attitude, and rate of descent is controlled by power adjustment.

General. You are introduced to angle of attack approaches for two primary reasons. One

is to simply broaden your exposure to different aspects of aviation. Additionally, AOA landings

are commonplace in jet and multi-engine aircraft and are virtually mandatory when used with a

visual glideslope indicator during carrier landings. Should you end up flying jets or multi-engine

aircraft, your exposure to AOA approaches in the T-34C should be beneficial.

AOA is displayed both by the AOA gauge, located on the instrument panel, and on the AOA

indexer, located on the glare shield. The gauge provides continuous AOA readout. When the

gear is down, the indexer displays one or two of three illuminated symbols. Depending on which

symbols are illuminated, the indexer tells you if you are flying at optimum, higher than optimum,

or less than optimum AOA. Refer to the T-34C NATOPS Manual for further discussion of the

AOA system.

The AOA system in the T-34C is calibrated in units of AOA, not degrees. An adjustment is

automatically made to the readout based on whether the flaps are up or down. Because of this,

optimum AOA of 20 units remains the same, regardless of configuration.

The question you may ask at this point is, "What is meant by optimum AOA and why is it 20

units?" To help answer this question, consider a situation where you are flying at a constant

AOA on final for a landing. Depending on your configuration (flaps up or down, aircraft weight

and power setting), this constant AOA will result in a certain airspeed on final. Configuration

and weight will also fix stall speed. This is all building up to the fact that for a given AOA, stall

speed is a constant percentage lower than the airspeed associated with that AOA. At optimum

AOA of 20 units, stall speed is approximately 35% lower than this airspeed.

ANGLE OF ATTACK APPROACHES 12-1