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AhaBulb: Stuff Everyone Should Know · ahabulb.com/pilot-vacuum-failure-gyros

When vacuum pressure drops below normal, which instruments may become unreliable?

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  1. The attitude and heading indicators
  2. The airspeed indicator and altimeter
  3. The magnetic compass and clock

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References

  1. Pilot's Handbook of Aeronautical Knowledge FAA-H-8083-25C, Chapter 8 www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/phak/10_phak_ch8.pdf Checked 2026-10-09.

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