Instrumentation

Not quite. The correct answer is B.

Correct answer: B

• A. This reverses the direction of the error. A subscale set too high relative to actual pressure makes the altimeter read too high, not too low.
• B. Correct: 20 hPa x 30 ft gives 600 ft, and a stale, too-high setting mimics flying from high pressure into low pressure without updating, which over-reads and hides a lower true altitude.
• C. An altimeter only knows what its subscale tells it. It cannot sense that the setting is stale, which is exactly why the setting has to be updated by the crew.
• D. This skips the 30 ft per hPa conversion entirely and just relabels the pressure difference as a height difference.

Not quite. The correct answer is C.

Correct answer: C

• A. A flux valve is built to respond to the horizontal component of the earth's field, the same component a direct-reading compass uses, not the vertical one.
• B. Remote mounting helps with deviation, but it does nothing about acceleration and turning errors, which come from pendulosity, not nearby magnetic material.
• C. Correct: the gyro provides short-term stability, so the flux valve's momentary disturbances during acceleration or turning are damped out rather than shown directly.
• D. The flux valve's sensing element is still subject to the same dip and pendulosity effects as a direct-reading compass; the improvement comes from the gyro stabilisation downstream, not immunity at the sensor.