Round Dials To Tapes

IFR Staff

Sunday, August 14, 2022 at 08:11 PM ET

Verified

Key Takeaways:

Pilots transitioning from traditional round-dial instruments to modern digital PFDs often struggle because glass displays lack the "quick glance" intuitive sensing and inherent trend indications found in analog gauges.
Round dials allow pilots to subconsciously assess aircraft state (e.g., "speed spaces") without precise reading, whereas digital tapes demand active reading, which can lead to fixation and difficulty discerning trends.
Studies indicate that while pilots may prefer the look of digital tape altimeters, their performance in tasks like altitude maintenance can be better with traditional round dials due to the challenges in detecting trends on tapes.
To adapt to PFDs, pilots must re-learn scanning techniques, utilize features like trend lines, simplify screen information, and overcome the primacy of their initial round-dial training.

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Recently we heard from a salty aviator having trouble flying his Aspen PFD even though he’s had it for years. Adding to his frustration, he can fly his legacy round-dial instruments accurately. He believes he’s not alone, and he’s right. What’s going on?

Superficially, you wouldn’t expect much difference between round dials and vertical tapes. A digital PFD is appealing because it’s clean and compact. The absence of boundaries between instruments eliminates the need for the eye to skip over at least two instrument edges before reaching the desired instrument. Your scan is easier, shorter, and less tiring.