At first glance, the “glass cockpits” found in modern aircraft may look like they come from a different planet than the round “steam gauge” instruments found in older general aviation cockpits.
But upon closer examination you can see that most primary flight displays (PFDs) actually conform closely to the “standard T” layout of round flight instruments found in older cockpits. Look closely at the illustration and you’ll see the similarities in layout.
For those who are not familiar, note that the HSI (horizontal situation indicator) may be found in both round-instrument and “glass” cockpits — it’s simply a combination instrument including both heading indicator and CDI (course deviation indicator) needles.
©2009, 2020 Gregory N. Brown
To learn more about turbine aircraft and how they work, see Greg’s new The Turbine Pilot’s Flight Manual Fourth Edition, coauthored with Mark Holt. Available in print and ebook. (Autographed copies available.)