17 — Installed display verification and human viewing conditions
DO-160 Display Qualification | A-P02 — Draft / Not Released
Learning objective: Close installation assumptions without repeating the full environmental suite on the aircraft.
Photo: Joao Carlos Medau · Airbus A-350 XWB F-WWYB cockpit view · CC BY 2.0. Original image, displayed at reduced size.
What remains to verify after installation
Installation work confirms that the assumptions behind qualification remain true. It is not normally a repeat of the whole chamber test suite on the aircraft.
For the display, the installation evidence should address:
- Mounting and retention. Verify brackets, fasteners, support stiffness, clearances and the load path. Assess changes from the laboratory fixture.
- Cooling and environment. Establish local temperatures, ventilation, heat from neighboring equipment, solar loading where relevant, and loss-of-cooling behavior. A cool cabin does not guarantee a cool display cavity.
- Power and wiring. Confirm voltage at the display, voltage drop, protection, returns, bonding, shields, connector terminations and harness routing against the qualified configuration and installation instructions.
- Electromagnetic compatibility. Conduct the required aircraft compatibility checks while observing display performance and unintended interference. The scope here remains the display and its installation, not qualification of neighboring equipment.
- Viewability and controls. Evaluate the actual eye positions, viewing angles, reflections, day/night dimming, control reach and any specified eyewear or NVIS compatibility.
- Display behavior. Verify startup, power transfers, display-to-display reversion where fitted, input-loss indications and recovery with the installed configuration. Use ground and flight evaluations where required by the compliance plan.
HIRF and lightning need a documented relationship between the installed exposure and equipment capability. Depending on the system and accepted compliance method, substantiation can combine equipment tests, installation data, analysis, similarity and aircraft-level testing. FAA’s current guidance includes AC 20-158B for HIRF and AC 20-136C for lightning protection. These do not make every aircraft-level test mandatory for every display. FAA AC 20-158B, FAA AC 20-136C.
Example installation verification record
| Assumption in equipment evidence | Installed check | Evidence |
|---|---|---|
| Cooling inlet remains unobstructed | Inspect clearances and substantiate operating temperatures | Identified installation drawing, survey and thermal results |
| Specified shield terminations and bonds | Inspect production routing and termination; measure where required | Harness configuration, bond records and approved limits |
| Required viewing envelope | Evaluate real eye positions, reflections and day/night settings | Geometry, lighting conditions, observations and measured performance |
| Power-transfer behavior is supported | Exercise allocated transfers with the installed configuration | Time-aligned power and display-event record |
Viewing is a system property
Reflections from windows and cockpit surfaces, viewing angle, sunglasses, display recess depth and adjacent lighting can change readability. A high room-temperature on-axis contrast number cannot establish installed readability in sunlight or at night. Include applicable dynamic behavior, dimming range, color coding and controls in the intended use.
Exercise
The installed bezel partially covers a vent, although the electronic unit is unchanged. Worked response: reopen the cooling assumption, assess thermal and functional consequences, and resolve the installation or qualification evidence. Configuration control includes the mounting environment, not only the supplier's electronics part number.
Use FAA AC 25-11B within its transport-airplane electronic-flight-display scope. Other aircraft or display roles need their applicable requirements and guidance. Ground and flight evaluations follow the accepted compliance plan; this course does not prescribe a universal flight-test program.
Installed checks for airplanes and helicopters
Plan representative aircraft operating conditions instead of repeating the laboratory suite onboard. The following are proposed planning items; the aircraft compliance plan determines what must be demonstrated.
- Mechanical and crew use: compare actual mounts, brackets, isolators and panel stiffness with the qualification assumptions. For helicopters, include the relevant rotor-speed and operating-condition range when evaluating image readability, touch targeting and physical controls. For propeller aircraft, consider the applicable engine/propeller operating range; jet installations have their own structural and abnormal-condition assumptions.
- Electromagnetic interactions: define the applicable transmitter states, receiver checks, electrical loads and power transfers. Observe both disturbance of the display and interference from the display into relevant installed functions. Use the actual shielding, returns and mount-bond arrangement.
- Exposure and mission: identify pressurization, doors-open operation where intended, dust/water exposure, solar loading, night operations and specified NVIS/eyewear/glove conditions. These depend on the installation and mission, not on a blanket airplane/helicopter rule.
- Evidence closure: list any unverified difference and its disposition. Ground or flight testing, analysis, similarity or additional equipment tests follow the accepted method; none is automatically replaced by the equipment report.
AC 25-11B addresses transport-airplane electronic flight displays. Use the applicable Part 27/29 rotorcraft requirements and guidance for a helicopter program rather than treating that airplane circular as a universal rotorcraft approval basis. FAA AC 20-158B and FAA AC 20-136C cover their stated airplane and rotorcraft compliance contexts.
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