DO-160 Section 23 is one of the environmental qualification tests defined in RTCA DO-160.

What DO-160 Section 23 Covers, and Why It Exists

Section 23 covers the physical effects of a direct lightning strike: high-voltage strike-attachment testing, including initial-leader and swept-channel attachment, and high-current physical-damage testing, including arc-entry effects, plus additional requirements for externally mounted fuel-related equipment and methods for detecting ignition sources.

The Real Damage Mechanisms

Lightning strike protection engineering documents real physical failure modes this section prevents: streamers puncturing fiberglass-honeycomb radome walls, carbon-fiber composite skins shattering or delaminating under a direct strike, and an arc carrying as little as one ampere being enough to ignite fuel vapor. Radomes can face strikes carrying on the order of 200,000 amps in the most severe zone classification, which is the energy this section’s testing has to credibly represent.

The Galley-System Angle Most People Miss

The galley insert itself, mounted inside the pressurized cabin, isn’t a realistic direct-strike attachment point, and on its own would be a non-applicable determination. But the galley and lavatory water and waste system extends outside the fuselage: drain masts that carry water overboard are externally mounted, and they’re electrically heated to prevent freezing. That makes them external, powered hardware sitting in a potential strike zone, part of the same water system a galley program is responsible for, even though they aren’t the oven or boiler. It’s a good reminder that “internal equipment” and “the whole system the equipment belongs to” aren’t always the same scope.

How to Mitigate or Document This

• For the galley insert itself, document the direct-effects non-applicability determination clearly
• For any externally mounted, electrically heated galley or lavatory system hardware, such as drain masts, evaluate direct-effects requirements separately rather than assuming the cabin-internal exemption covers it

Further reading: NTSB accident report archive.

How Eminent Helps: Direct lightning effects are usually non-applicable for the galley insert itself, but the externally mounted, heated drain masts in the water system are a different story. Scoping where the system extends outside the fuselage is exactly the kind of boundary we help define. See how we support galley insert programs.