Illustration By Charles Floyd
Scan pattern example
When maintaining level flight, the altimeter (1, above) 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.
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 “round-dial” 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.
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