System Power Generation

FAR 23.2525 — System Power Generation

FAR 23.2525 sets design rules for power generation, storage, and distribution—ensuring backup power for safe flight and landing if the primary source fails.

In Plain English

FAR 23.2525 is a design and certification standard for small airplanes covering how the power generation, storage, and distribution systems must be built and installed. While you won't be tested on building these systems, understanding the rule helps you appreciate why your aircraft has redundant electrical sources and why certain loads are prioritized after a failure.

The regulation requires the power system to:

Supply the power required for all connected loads during every intended operating condition.
Tolerate a single failure — no single failure or malfunction of a power supply, distribution system, or utilization system can prevent power from reaching the essential loads needed for continued safe flight and landing.
Have enough reserve capacity if the primary source fails to power essential loads — including non-continuous essential loads — long enough to complete the flight safely.

Operationally, this is why your airplane likely has a battery backup, standby alternator, or bus-tie design, and why the POH lists load-shedding procedures after an electrical failure.

Regulation Text

14 CFR § 23.2525

§ 23.2525 System power generation, storage, and distribution. The power generation, storage, and distribution for any system must be designed and installed to— (a) Supply the power required for operation of connected loads during all intended operating conditions; (b) Ensure no single failure or malfunction of any one power supply, distribution system, or other utilization system will prevent the system from supplying the essential loads required for continued safe flight and landing; and (c) Have enough capacity, if the primary source fails, to supply essential loads, including non-continuous essential loads for the time needed to complete the function required for continued safe flight and landing.

Oral Exam Questions a DPE Might Ask

Q1What does FAR 23.2525 require of an airplane's electrical power system?

Per FAR 23.2525, the power generation, storage, and distribution system must supply all connected loads during normal operations and continue to supply essential loads needed for safe flight and landing even after a single failure.

Q2If the primary power source fails, what does the regulation require regarding backup capacity?

FAR 23.2525(c) requires that, if the primary source fails, the system must have enough capacity to supply essential loads — including non-continuous essential loads — for the time needed to complete safe flight and landing.

Q3Why does the airplane have redundant electrical sources like a backup battery or standby alternator?

FAR 23.2525(b) prohibits any single failure of a power supply or distribution system from cutting power to essential loads, so manufacturers install redundant sources to meet that single-failure protection requirement.

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Related Sections in Part 23

§ 23.1457

Cockpit Voice Recorders

§ 23.1459

Flight Data Recorders