Flight Training - March/April 2021 - 26

TECHNIQUE

BY MIKE COLLINS

ILLUSTRATION BY CHARLES FLOYD

GLASS CLASS
FLYING BEHIND AN ELECTRONIC FLIGHT DISPLAY

AN ELECTRONIC FLIGHT DISPLAY SYSTEM, MORE COMMONLY

called a " glass cockpit, " integrates many individual instruments
and a wide variety of data for the pilot, generally displayed on two
screens. Flight instrumentation-heading, altitude, airspeed-is
depicted on the primary flight display (PFD), positioned in front
of the pilot; engine gauges, navigation information, and a moving
map usually will be just to the right on the multifunction display
(MFD). More information is available than in an analog or " rounddial " instrument panel, and much of it is displayed differently.
For example, flight instrumentation will be formatted differently on a PFD, and some information will be displayed in different
locations. The PFD's attitude indicator is larger than a conventional, round-dial artificial horizon. Airspeed and altitude are
presented on vertical tape displays, to the left and right of the attitude indicator. Vertical speed presentation is fairly conventional,
but a segmented triangle near the top of the attitude indicator is
your turn coordinator; rate of turn is indicated by a curved line at
the top of the heading depiction on the lower half of the PFD.
It's not just snazzy screens that make these systems the
trend of the future; electronic flight instruments are less prone

to failure than their analog counterparts. The PFD is driven by
data from a digital attitude and heading reference system and a
solid-state air data computer.
A PFD should not change the way you scan your instruments,
but you'll have to interpret these instruments in new locations and
depictions. Because digital data is much more precise than analog,
it's common to fixate on, and struggle to correct, an altitude deviation of only a few feet-while inadvertently allowing other flight
parameters to make wild swings. It's important to remember that
while you're flying under visual flight rules, the horizon should
still be your primary attitude reference, and you should spend far
more time looking outside the cockpit than at the PFD or MFD.
Airspeed tape

The airspeed indicator is displayed as a vertical
tape. Larger numbers move down from the top
as speed increases. The tape includes the familiar
colors of the flap operating range, normal
range, and caution range. True airspeed
is displayed at the bottom.

Scan pattern example

When maintaining level flight, the altimeter (1, below)
is still your primary instrument for pitch, while the
attitude indicator (2) is a direct indicator and the
vertical speed indicator (3) provides supporting
information. Keep your eyes outside, referencing the
horizon, and scan these instruments periodically.

Trend vectors

Trend vectors are magenta lines that move up
and down both the ASI and the altimeter. They
show the aircraft's projected state 6 seconds
in the future, based on rate of change. By
including trend vectors in their scan, pilots can
more precisely control airspeed and altitude.

Heading indicator

The heading indicator, below the
artificial horizon, resembles the analog
horizontal situation indicator (HSI); like
the HSI, it can incorporate navigation
information.

Turn rate indicator

Tick marks to the left and right of the
lubber line denote half-standard and
standard-rate turns. The aircraft is in
a standard-rate turn when the pointer
reaches the second tick mark.

26 FLIGHT TRAINING MARCH/APRIL 2021

Flight Training - March/April 2021

Table of Contents for the Digital Edition of Flight Training - March/April 2021