A takeoff site has a field elevation of 1,000 feet. Using the altimeter setting conversion table on the Density Altitude Chart (Figure 8), what is the pressure altitude if the current altimeter setting is 30.1" Hg?

Why: Figure 8's altimeter setting conversion table lists a conversion factor of −165 for an altimeter setting of 30.1" Hg. Pressure altitude is found by adding the field elevation and the conversion factor: 1,000 ft + (−165 ft) = 835 ft.

• Adds the conversion factor with the wrong sign — treating the negative factor at 30.1" Hg as a positive correction, which would be correct only for altimeter settings below 29.92" Hg.
• Ignores the conversion factor entirely and assumes pressure altitude always equals field elevation, which is only true when the altimeter setting reads exactly 29.92" Hg.