With the last correction at 29.92 and a subsequent new setting of 29.80 received before landing, before you reset, what is the true altitude relative to indicated altitude?

• A. 120 feet higher
• B. 120 feet lower
• C. The same
• D. Cannot determine

Answer: (B)

The altimeter’s reading depends on the pressure setting. If you’re using a higher pressure setting than the actual ambient pressure, the instrument will indicate a higher altitude than you actually are. Here, the last setting used was 29.92 inHg, but the actual local pressure is 29.80 inHg. That 0.12 inHg difference means the altimeter is reading about 120 feet higher than your true altitude (roughly 1000 ft per inHg near sea level, so 0.12 × 1000 ≈ 120 ft). Since you haven’t reset to the lower local pressure yet, the true altitude is about 120 feet lower than the indicated altitude.