Cockpit Display Systems Questions and Answers

Answer: C

Correct answer: False, misleading data is worse

The statement is false. A blank display announces its own failure - the crew sees at once that the information is gone and turns to the standby instruments or the other side's display. A plausible but wrong value announces nothing, and may be flown on until the error becomes apparent some other way.

Certification treats the two accordingly: misleading primary flight information is classified as catastrophic and given a target of \( 10^{-9} \) per flight hour, a more demanding requirement than that for loss of the same information.

Answer: D

Correct answer: It will display obstacles absent from its database

This is the false statement, and it names precisely what synthetic vision cannot do. The system renders only what its database holds, so an obstacle not in the database appears nowhere on the display - and the picture gives no indication that anything is missing.

The other three are true: the image is computed from a terrain and obstacle database, its fidelity depends on the accuracy of the position solution that places the aircraft within that database, and it therefore shows what should be there rather than what is.

Answer: A

Correct answer: No, normal states produce no indication at all

The statement is not correct. Under the dark cockpit principle a normal, correctly configured system produces no indication whatever - the panel is dark, and any light means something requires attention.

Annunciating normal states in green would defeat the purpose: the panel would be lit whenever all was well, and the crew would have to read each legend to confirm the colour was right. The dark convention replaces that reading task with a far faster search for light against darkness.

Answer: B

Correct answer: Increasing the display's brightness

Raising the brightness makes everything on the screen brighter, including the clutter. The number of competing symbols is unchanged, so the time to find a needed value is unchanged - the problem is density, not luminance.

The other three all address density directly: reducing the number of layers drawn at once, using a decluttering function to strip layers on demand, and removing overlays not needed for the current phase of flight. Automatic suppression by flight phase is the most valuable, since it acts without adding to the crew's workload.

Answer: C

Correct answer: False, generators are shared

The statement is false. A single symbol generator commonly drives several screens, so its failure removes all of them at once - typically up to two on a four-screen, two-generator installation.

This is exactly why aircraft carry two or three generators and provide reversion switching: the crew can choose which screens the surviving generator drives, ensuring the primary flight displays are retained and that the content lost is the least critical. The display units therefore outnumber the generators behind them.

Answer: D

Correct answer: Freedom from any possibility of failure

This is not an advantage, because it is not true. Liquid crystal displays fail like any other equipment - backlights dim and fail, pixels stick, drive electronics break down - which is precisely why flight decks carry several displays, multiple symbol generators, reversion switching and independent standby instruments.

The genuine advantages are the other three: a flat panel is far shallower and lighter than a cathode ray tube, it dissipates much less heat and so eases the cooling problem in a crowded panel, and it is more readable in direct sunlight.

Answer: A

Correct answer: No, it shares the same power

Reversion does not remove the need for standby instruments, because it depends on the very equipment that may have failed. It moves content between display units driven by symbol generators fed from the main electrical system - so a failure of both generators, of the display power supply or of the main busses defeats it entirely.

The standby is the answer to exactly those cases, running on its own sensors and its own battery-backed supply. Reversion handles partial failures gracefully; the standby handles the ones reversion cannot reach.

Answer: B

Correct answer: Reversion mode

Reversion is not a navigation display mode. It is a switching function that moves display content from a failed screen onto a working one, and it applies across the display system rather than describing how the navigation picture is drawn.

The genuine modes describe orientation and content: map mode is track-up and centred on the aircraft for flying the route, plan mode is north-up and centred on a waypoint for reviewing it, and approach mode presents the picture needed for an instrument approach.

Answer: C

Correct answer: False, the automation is behaving correctly

The statement is false. In mode confusion the automation is working exactly as designed - the problem lies in the crew's understanding of which mode it is in, so the aircraft does something correct for its actual mode but unexpected for the assumed one.

Because no system has failed, no fault message appears, which is what makes the condition insidious. The design response is to annunciate the active mode prominently at the top of the primary flight display, and to make mode transitions conspicuous rather than silent.

Answer: D

Correct answer: The electrical power the display consumes

Collimation is an optical arrangement - focusing the virtual image at infinity - and it has no bearing on how much power the display draws.

The other three all depend on it. Reading symbols while looking outside requires that the eye not refocus between the two; the transition from instrument to visual flight is seamless only because the eyes never leave the outside scene; and conformal symbology stays registered with the world only because a collimated image is insensitive to small head movements.