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Meaning of a green instrument range marking

Aviation Mechanic Airframe (AMA) practice question 5 of 20 on Aircraft Instrument Systems. ACS element AM.II.H.K11 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Airframe (AMA) practice mode.

Question bank updated 2026-09-22

QUESTIONWhat does the color green indicate when used as a range marking on an instrument dial face?

  1. AA caution range needing monitoring.
  2. BThe normal operating range.
  3. CA maximum or minimum limit.
Show the answer and explanation

Correct answer: B. The normal operating range.

  • A — incorrect Yellow is the color used to indicate caution, not green.
  • B — correct Green is the color used on instrument dial faces to show the normal operating range of the system or component.
  • C — incorrect Red marks maximum and minimum ranges, beyond which operation is dangerous and should be avoided.

BACKGROUND

Many instruments carry colored markings on the dial face so a crewmember can tell at a glance whether a system is operating in a safe range. These markings are applied by the original equipment manufacturer in accordance with the aircraft specifications in the Type Certificate Data Sheet, and the same data can appear in the maintenance and flight manuals. The colors used are red, yellow, green, blue, and white, applied as arcs or radial lines. Red indicates maximum and minimum ranges where operation is dangerous, green indicates the normal operating range, and yellow indicates caution. Blue and white are used on airspeed indicators to define specific conditions. When a technician applies markings to an approved replacement instrument, a white slippage mark is extended from the cover glass to the case so any rotation of the glass becomes obvious.

STUDY TIP

Learn the five marking colors as a set, and remember that the white slippage mark is a check on the glass, not an operating range.

KEY POINTS

  • Red marks maximum and minimum ranges, green marks normal operation, yellow marks caution.
  • Blue and white define specific conditions on airspeed indicators.
  • A white slippage mark spanning the glass and case reveals rotation of the cover glass.

SOURCES

  • sources/ama-airframe/ch10.txt "Instrument Range Markings"
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MORE ON AIRCRAFT INSTRUMENT SYSTEMS

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-31B Aviation Maintenance Technician Handbook – Airframe, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.