BY ORDER OF THE SECRETARY OF THE AIR FORCE AIR FORCE ...

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AFMAN 11-217V1 3 JANUARY 2005
Chapter 3
BASIC INSTRUMENT FLYING-HELICOPTER
3.1. Instrument Categories. This chapter contains helicopter unique instrument procedures
that are not covered elsewhere in this manual. In addition, you should be very familiar with
the navigation instruments (chapter 5), electronic aids to navigation (chapter 6), and
navigation procedures (chapter 7) that apply to all aircraft. Instrument flights should be
planned and conducted according to chapters 8 through 11 and 13 through 20 (as applicable)
of this manual. Helicopter performance is achieved by controlling the aircraft attitude and
power. This attitude is the relationship of the longitudinal and lateral axes to the Earth's
horizon (Figure 3.1). An aircraft is flown in instrument flight by controlling the attitude and
power as necessary to produce the desired performance. This is known as the "control and
performance concept" of attitude instrument flying and can be applied to any basic
instrument maneuver.
3.2. Instrument Types. The three general categories of instruments are:
3.2.1. Control Instruments. These instruments display attitude and power indications and
are calibrated to permit attitude and power adjustments in definite amounts. In this
discussion, the term power is used to replace the more technically correct term thrust to
drag relationship. Power is controlled by reference to the power indicators. These vary
with different helicopters but typically measure torque in either pounds or percentage of
maximum rated torque.
3.2.2. Performance Instruments. These instruments indicate the aircraft's actual
performance. Performance is determined by reference to the altimeter, airspeed, vertical
velocity indicator, heading indicator, and turn and slip indicator.
3.2.3. Navigation Instruments. These instruments indicate the position of the aircraft in
relation to a selected navigation facility, fix, or relative position. This group of
instruments includes various types of course indicators, range indicators, glide slope
indicators, bearing pointers, and Flight Management Systems (FMS)/Global Positioning
Systems (GPS) displays.
Figure 3.1. Attitude Instrument Flying.