10 — Salt spray, fungus, sand and dust

DO-160 Display Qualification | A-P02 — Draft / Not Released

Learning objective: Connect material and enclosure evidence to Sections 12–14.

Exposure must reach the relevant parts

Salt spray can affect connector contacts, coating edges, fasteners, grounding joints and conductive optical treatments. A display can still show an image while a bonding joint has deteriorated. Specify the relevant electrical, mechanical and optical checks in addition to appearance. Salt exposure is particularly relevant to maritime or exposed service; the intended installation drives applicability.

DO-160G Section 14 uses a solution of 5 ±1% sodium chloride by mass, at 35 °C, with pH 6.5–7.2 and a collection rate of 1–3 mL per 80 cm² per hour. Category S alternates 24 hours of fog and 24 hours of drying, then repeats: 48 hours of fog in a 96-hour sequence before subsequent checks, subject to the adopted procedure. Category T uses a different sequence including two 48-hour fog periods and drying stages. Do not copy a Category S total duration into a Category T purchase specification.

Fungus resistance

Assess susceptible materials including adhesives, coatings and other organic materials. Where the selected category permits material-based substantiation, retain the identification and rationale for the actual materials used. A supplier's generic material family statement may not identify additives, finish or adhesive changes. Otherwise follow the applicable exposure and evaluation procedure.

Sand and dust

Consider optical abrasion, ingress, clogged cooling paths, moving controls and electrical connections. Define openings, seals, operational states and orientation as required by the selected category. A fan operating during service but disabled during a test can change both ingestion and cooling; the procedure and representation must justify the state used.

Exercise: corrosion with continued operation

After exposure the image works, but a chassis bonding joint is visibly corroded and has changed resistance. Can the unit pass solely because the image is present? Worked response: assess the agreed bonding, corrosion, physical and functional criteria. Image presence is insufficient evidence of electrical protection or long-term integrity. If a requirement was omitted from the plan, record the gap and obtain a technically justified disposition rather than inventing a favorable limit afterward.

Evidence to retain

Photographs before and after exposure, material and finish identity, contact and bonding measurements where required, chamber conditions, collection checks, cleaning/drying history and functional results make the report reviewable. Keep any disassembly effects distinct from exposure damage.

Salt-spray conditions and Category S timing