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Instrument Flying Handbook
Flight Instruments
Flight Support Systems

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Instrument Flying


Table of Contents

Chapter 1. Human Factors
Chapter 2. Aerodynamic Factors
Chapter 3. Flight Instruments
Chapter 4. Section I
Airplane Attitude Instrument
Using Analog Instrumentation
Chapter 4. Section II
Airplane Attitude Instrument
Using an Electronic Flight

Chapter 5. Section I
Airplane Basic
Flight Maneuvers
Using Analog Instrumentation
Chapter 5. Section II
Airplane Basic
Flight Maneuvers
Using an Electronic Flight

Chapter 6. Helicopter
Attitude Instrument Flying

Chapter 7. Navigation Systems
Chapter 8. The National
Airspace System

Chapter 9. The Air Traffic
Control System

Chapter 10. IFR Flight
Chapter 11. Emergency

Air Data Computer (Collins).
Figure 3-37, Air Data Computer (Collins).

In Figure 3-38, the aircraft heading displayed on the rotating
azimuth card under the upper lubber line is North or 360°.
The course-indicating arrowhead shown is set to 020; the
tail indicates the reciprocal, 200°. The course deviation bar
operates with a VOR/Localizer (VOR/LOC) navigation
receiver to indicate left or right deviations from the course
selected with the course-indicating arrow, operating in the
same manner that the angular movement of a conventional
VOR/LOC needle indicates deviation from course.

Horizontal Situation Indicator (HSI).
Figure 3-38. Horizontal Situation Indicator (HSI).

The desired course is selected by rotating the course-
indicating arrow in relation to the azimuth card by means
of the course select knob. This gives the pilot a pictorial
presentation: the fixed aircraft symbol and course deviation
bar display the aircraft relative to the selected course, as
though the pilot were above the aircraft looking down.
The TO/FROM indicator is a triangular pointer. When the
indicator points to the head of the course arrow, it shows
that the course selected, if properly intercepted and flown,
takes the aircraft to the selected facility. When the indicator
points to the tail of the course arrow, it shows that the course
selected, if properly intercepted and flown, takes the aircraft
directly away from the selected facility.

The glide slope deviation pointer indicates the relation of
the aircraft to the glide slope When the pointer is below the
center position, the aircraft is above the glide slope, and an
increased rate of descent is required. In most installations,
the azimuth card is a remote indicating compass driven by
a fluxgate; however, in few installations where a fluxgate is
not installed, or in emergency operation, the heading must
be checked against the magnetic compass occasionally and
reset with the course select knob.

Attitude Direction Indicator (ADI)
Advances in attitude instrumentation combine the gyro
horizon with other instruments such as the HSI, thereby
reducing the number of separate instruments to which the
pilot must devote attention. The attitude direction indicator
(ADI) is an example of such technological advancement.
A flight director incorporates the ADI within its system,
which is further explained below (Flight Director System).
However, an ADI need not have command cues; however,
it is normally equipped with this feature.

Flight Director System (FDS)
A Flight Director System (FDS) combines many instruments
into one display that provides an easily interpreted
understanding of the aircraft's flight path. The computed
solution furnishes the steering commands necessary to obtain
and hold a desired path.

Major components of an FDS include an ADI, also called
a Flight Director Indicator (FDI), an HSI, a mode selector,
and a flight director computer. It should be noted that a
flight director in use does not infer the aircraft is being
manipulated by the autopilot (coupled), but is providing
steering commands that the pilot (or the autopilot, if coupled)

Typical flight directors use one of two display systems for
steerage. The first is a set of command bars, one horizontal
and one vertical. The command bars in this configuration
are maintained in a, centered position (much like a centered
glide slope). The second uses a miniature aircraft aligned to
a command cue.

A flight director displays steerage commands to the pilot on
the ADI. As previously mentioned, the flight director receives
its signals from one of various sources and provides that to the
ADI for steerage commands. The mode controller provides
signals through the ADI to drive the steering bars, e.g., the
pilot flies the aircraft to place the delta symbol in the V of the
steering bars, "Command" indicators tell the pilot in which
direction and how much to change aircraft attitude to achieve
the desired result.