DO-160 Section 6 is one of the environmental qualification tests in RTCA DO-160, and most environmental sections in DO-160 ask whether equipment survives a condition. Section 6 asks whether moisture absorbed into the equipment changes how it behaves, electrically, mechanically, or chemically, after repeated exposure.
What DO-160 Section 6 Covers, and Why It Exists
Section 6 defines three categories by environmental control: Category A, Standard Humidity Environment, for environmentally controlled compartments; Category B, Severe Humidity Environment, for zones without environmental control; and Category C, External Humidity Environment, for equipment in direct contact with outside air. The test is a cycling profile, not a single soak. For Category A, the equipment is stabilized at 38°C and 85% relative humidity, raised over two hours to 50°C and 95% RH, held six hours minimum, then brought back down over 16 hours while staying above 85% RH, two cycles, 48 hours total. Category C peaks at 55°C and runs six cycles, 144 hours total. At the end of exposure the standard calls for draining condensed moisture rather than wiping it, which affects what the post-exposure functional check actually proves.
The Typical Failure Pattern
This is a well-documented field-reliability problem across aviation, not just a chamber concern. Reliability literature on airborne electronics has long attributed a meaningful share of total field failures to humidity, moisture, and the corrosion they drive, and maintenance histories going back decades describe recurring, confusing intermittent faults eventually traced to moisture at connectors rather than a hard component defect. The mechanism is consistent: moisture at a contact raises resistance or opens a leakage path, and the symptom looks random until someone connects it to humidity.
Why Galley Equipment Faces a Different Version of This
Most equipment in this section deals with humidity as something the environment does to it. Galley equipment is unusual because much of it generates its own humidity, ovens producing steam, water boilers, coffee and espresso equipment. The chamber test verifies resistance to an environment the equipment is also actively contributing to in service, which means the real-world exposure is often steadier and more aggressive than the category alone implies. Connectors, contacts, and any hygroscopic potting or insulating material are where this concentrates.
How to Mitigate This
- Match the category to the installation zone’s actual environmental control status, not an assumption about cabin comfort
- Give particular attention to connector and contact protection, since that’s where humidity failures concentrate over time
- For equipment that generates its own moisture, weight your real-world margin lower than the chamber result alone suggests, and design conformal coating and sealing accordingly
Further reading: NTSB accident report archive.
How Eminent Helps: If you’re qualifying equipment that produces its own steam and condensation, the chamber category is only half the story, the connector, sealing, and coating choices that determine real-world reliability are the other half. That’s the design review we do. See how we support galley insert programs.
