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Continuous load limit without load monitoring

Aviation Mechanic Powerplant (AMP) practice question 10 of 13 on Engine Electrical Systems. ACS element AM.III.F.K5 · difficulty: applied. Want to answer it in a timed quiz? Use the Aviation Mechanic Powerplant (AMP) practice mode.

Question bank updated 2026-09-22

QUESTIONA small aircraft has one generator rated at 60 amperes output, with no placards or load monitoring devices installed. Following the handbook guideline for keeping the battery charged in flight, what is the approximate acceptable total continuous connected electrical load?

  1. A48 amperes
  2. B54 amperes, or 90 percent
  3. C60 amperes, the full rating
Show the answer and explanation

Correct answer: A. 48 amperes

  • A — correct Where placards or monitoring devices are not practical, the total continuous connected load may be held to approximately 80 percent of rated generator output capacity, and 80 percent of 60 amperes is 48 amperes.
  • B — incorrect The guideline figure is 80 percent of rated output, not 90 percent, so this leaves too little margin for charging the battery in flight.
  • C — incorrect Loading a generator to its full rated output leaves nothing to charge the battery, which is why the guideline holds the continuous load below the rating.

BACKGROUND

When electrical equipment is added, the total load must stay within the rated limits of the power supply components. Placards are recommended so that crewmembers know which combinations of loads can safely be connected. Where placards or monitoring devices are not practical or desired, and assurance is needed that the battery of a typical small aircraft is charged in flight, the total continuous connected electrical load may be held to approximately 80 percent of the total rated generator output capacity. Short intermittent loads such as a radio transmitter or a landing gear motor are treated separately from that continuous figure. When more than one generator is used in parallel, the total rated output is the combined output of the installed generators.

STUDY TIP

Multiply the nameplate output by 0.8 and treat the remainder as the margin that keeps the battery charging.

KEY POINTS

  • Continuous connected load is held to about 80 percent of rated output.
  • The remaining capacity keeps the battery charged in flight.
  • Short intermittent loads are considered separately.

SOURCES

  • amp-powerplant/ch04.txt "Controlling or Monitoring the Electrical Load"
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MORE ON ENGINE ELECTRICAL SYSTEMS

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-32B Aviation Maintenance Technician Handbook – Powerplant, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.