Safety Publications/Articles

Rod Machado

Scanning PFDs

One of the questions raised by instrument instructors training students in airplanes with PFDs (primary flight displays such as Garmin's G1000) is how to scan the flight instruments. After all, the airspeed, altimeter, and vertical speed indicator are read on vertical tape scales, while the entire screen display acts as the artificial horizon.

The answer is, you scan the same way you do with any other arrangement of flight instruments in terms of what data is acquired in what order. Nothing has changed in regard to cross-checking the instruments and controlling the airplane. Interpreting the instruments may take some getting used to (a tape display, for instance), but the type of information presented hasn't changed.

For instance, when making a major attitude change, you select the attitude on the attitude indicator, modify power with the throttle, and then offer an initial dose of trim. The sequence of data acquisition is the same; only the data dance done by your eyeballs differs.

The next step would be radial scanning the primary flight instruments for the particular condition of flight. The attitude indicator is where the radial scan begins. From there you move outward, looking at the primary instruments, then you return to the AI, making pitch or bank corrections as necessary. You may have to look in a different place for the primary instruments, but you're looking for the same information. Go where you need to in order to find it.

After making any necessary attitude or power adjustments, you apply final trim and monitor the flight instruments.

What's changed? Maybe the location and shape of the instrument you're scanning, but not the information it provides or the order in which you seek that information. The scan methodology is the same.

By Rod Machado

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