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Chapter 5 - Flight Instruments: Clocks, Tops & Toys 5-39

when the vertical speed value exceeds 100 feet per
VERTICAL SPEED INDICATION ON THE PFD
minute. The Avidyne display creates a traditional swing-
ing vertical speed needle to provide the vertical speed
reading, along with a digital readout at the bottom (or
top) of the vertical speed scale.
These display differences reflect, in part, the fact that
we are still working to understand how pilots can most
easily comprehend various graphical presentations of
information. Should PFDs just try and look like digital
versions of traditional instruments, or unleashed from
the mechanics of dials and pointers, are there better ways
to show various things? Everyone has an opinion (some
people have several, one for each of their personalities),
but so far not a lot of scientific data exist.
Attitude Indication On a PFD
Primary flight displays (Figures 77A and B) present a
larger sky-ground horizon picture than traditional atti-
tude indicators, making it much easier to identify the air-
Fig. 76 plane’s attitude even if you’re sitting in the back seat
(which I hope you aren’t doing when you’re the pilot in
Vertical speed information is provided by a vertically command). The pilot’s attitude, fortunately, is not dis-
moving pointer on the Garmin G1000 display (left) or a played.
rotating needle on the Avidyne display (right).
On many PFDs, if the pitch exceeds 50 degrees above
the horizon or 30 degrees below the horizon, you’ll see
Digital Vertical Speed Indicators the appearance of large red chevrons on the display
PFDs display vertical speed in similar but slightly dif- (Figure 77C). This doesn’t mean you’re over a service sta-
ferent ways, as shown on the Garmin G1000 display tion, either. It is a not-too-subtle suggestion that it’s
(Figure 76, position A and the Avidyne display (Figure probably time to apply your unusual-attitude recovery
76, position B). The G1000 PFD displays vertical speed techniques. Other than size, there really isn’t much dif-
with a vertically moving speed pointer. A numerical verti- ference between the attitude picture shown on a tradi-
cal speed value can also be read inside the moving needle tional instrument and the picture painted by a PFD.
PRIMARY FLIGHT DISPLAY - ATTITUDE INDICATIONS

Fig. 77

Attitude information on a PFD is a big deal, a really big deal, in that the background (so to speak) of the entire display fronts as the
attitude indicator. The horizon line on two different PFDs in position A and B. When the attitude exceeds 50 degrees pitch above the
horizon or 30 degrees below, large red chevrons appear (on Garmin’s G1000 display, position C) pointing the direction toward a more
normal flight attitude. Some PFDs use white chevrons to provide the same information.