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Purpose of instrument panel bonding straps

Aviation Mechanic Airframe (AMA) practice question 19 of 20 on Aircraft Instrument Systems. ACS element AM.II.H.K22 · 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 is the purpose of the bonding straps installed on a shock-mounted instrument panel?

  1. ATo ensure continuity to the airframe.
  2. BTo damp low-frequency panel vibration.
  3. CTo limit panel movement in a landing.
Show the answer and explanation

Correct answer: A. To ensure continuity to the airframe.

  • A — correct Bonding straps are used to ensure electrical continuity from the instrument panel to the airframe across the shock mounts.
  • B — incorrect The shock mounts themselves absorb low-frequency, high-amplitude shocks; that is not the function of the bonding straps.
  • C — incorrect A shock-mounted panel is meant to be free to move in all directions with sufficient clearance, so restraining its travel is not the purpose.

BACKGROUND

Instrument panels are usually made from sheet aluminum alloy and painted a dark, nonglare color, sometimes with subpanels for access to the backs of instruments. They are normally shock-mounted to absorb low-frequency, high-amplitude shocks, with the mounts absorbing most vertical and horizontal vibration while allowing the instruments to work under minor vibration. Because the resilient mounts interrupt the metal-to-metal path between panel and structure, bonding straps are installed to ensure electrical continuity from the panel to the airframe. The type and number of shock mounts depends on the weight of the unit. A shock-mounted panel should be free to move in all directions and have sufficient clearance to avoid striking supporting structure, and when clearance is inadequate the mounts should be inspected for looseness, cracks, or deterioration.

STUDY TIP

Remember that any resilient mount breaks an electrical path, so expect a bonding strap wherever an isolated component must remain electrically tied to structure.

KEY POINTS

  • Shock mounts isolate the panel from vibration but interrupt electrical continuity.
  • Bonding straps restore continuity from the panel to the airframe.
  • A shock-mounted panel must move freely and clear supporting structure.

SOURCES

  • sources/ama-airframe/ch10.txt "Instrument Panels"
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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.