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Units of the METAR altimeter setting

Remote Pilot (Part 107) practice question 6 of 18 on Weather / Sources. ACS element UA.III.A.K1 · difficulty: recall. Want to answer it in a timed quiz? Use the Remote Pilot (Part 107) practice mode.

Question bank updated 2026-09-22

QUESTIONA METAR contains the group A2970. In what units and value is this altimeter setting reported?

  1. AHectopascals, 2970
  2. BMillibars of pressure, 297.0
  3. CInches of mercury, 29.70
Show the answer and explanation

Correct answer: C. Inches of mercury, 29.70

  • A — incorrect The METAR altimeter setting in the study guide is expressed in inches of mercury, not hectopascals.
  • B — incorrect The four digits represent 29.70 inches of mercury; they are not a millibar value.
  • C — correct The altimeter setting is reported as a four-digit group preceded by A and is expressed in inches of mercury, so A2970 is 29.70 inches of mercury.

BACKGROUND

The altimeter setting in a METAR is reported as inches of mercury ("Hg) in a four-digit number group and is always preceded by the letter A. The group A2970 therefore represents a barometric pressure of 29.70 inches of mercury. Rising or falling pressure may also be noted in the remarks section as PRESRR (pressure rising rapidly) or PRESFR (pressure falling rapidly). The altimeter setting follows the temperature and dew point group in the report sequence.

STUDY TIP

Read the four digits as two whole inches and two hundredths: A2970 is 29.70. The leading A is the cue that you are looking at the altimeter setting.

KEY POINTS

  • The altimeter setting is always preceded by the letter A.
  • It is a four-digit group in inches of mercury: A2970 = 29.70 "Hg.
  • PRESRR and PRESFR in the remarks indicate rapidly rising or falling pressure.

SOURCES

  • remote_pilot_study_guide.txt, Chapter 3a "Aviation Routine Weather Report (METAR)", item 10 Altimeter setting
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SkyDrill is not affiliated with the FAA. This is an original practice item based on 14 CFR part 107, 14 CFR part 89, and the FAA Remote Pilot – Small UAS Study Guide (FAA-G-8082-22). Regulations and handbooks are revised; confirm details against the current edition.