06 — Temperature and altitude: construct the procedure

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

Learning objective: Separate conditioning, stabilization, exposure and functional evidence in Section 4.

Translate the matrix into stages

A temperature procedure needs a chronological sequence and an acceptance matrix. Label unpowered survival, short-time operation and normal operation separately. For each stage specify chamber setpoint, tolerance from the adopted method, power state, required stabilization basis, timing origin, minimum duration, functions and measurements. Time spent approaching a setpoint does not automatically count as stabilized exposure.

In DO-160G the low/high operating tests include at least two hours of operation after equipment temperature stabilization; ground-survival conditions include at least three hours after stabilization. Applicable short-time operation is at least 30 minutes with its prescribed preceding conditioning. Use §§4.5.1–4.5.4 and the full profile to place these intervals correctly. Do not assemble a new sequence merely by joining the three durations.

Instrument the actual boundary

Chamber air, enclosure, LCD glass, backlight heat spreader and processor can have different temperatures. Choose thermocouple points that support the required stabilization and the allocated component limits. Do not let sensors or instrumentation wires alter a seal, cooling path or EMI arrangement without assessing their influence. Preserve raw temperature histories along with summarized dwell times.

Representative heat and cooling

Use installed mounting conduction, airflow and specified cooling interfaces. Establish modes that challenge the thermal design: maximum backlight, high graphics load, heater startup and combinations permitted by the design. A thermostatic heater may dominate a cold startup; a dim mode can still stress processing electronics. Loss-of-cooling subtests apply where required by the selected category and architecture; they are not assumed for every passively cooled display.

Worked discrepancy

The chamber reaches +70 °C at 09:00. The defined equipment stabilization condition is reached at 09:40. The log stops normal high-temperature operation at 11:00. Only 80 minutes follow stabilization, so this record does not demonstrate a two-hour post-stabilization requirement. Investigate the actual method, then extend or repeat as dispositioned. Do not relabel chamber arrival as equipment stabilization.

Procedure output

Prepare a stage table with columns for source paragraph, target, power, stabilization, start trigger, duration, measured functions and stop conditions. At altitude, include absolute pressure and pressure history. Section 4.6.1 requires at least two hours after stabilization, or the duty cycle if longer, under its specified conditions. Check combined temperature/altitude requirements explicitly rather than assuming an ambient-altitude test represents the hottest installation.