Flight Data Recording Questions and Answers

Answer: C

Correct answer: Only three

The first three match sensibly: control column position and pitch attitude both change within a fraction of a second and need several samples per second, while fuel quantity changes over minutes and one sample every few seconds captures it.

The fourth is far too slow. Vertical acceleration is among the fastest-changing parameters recorded - it carries turbulence, hard landings and manoeuvre loads - and is sampled several times a second. Once a minute would miss every event of interest.

Answer: D

Correct answer: Only three

The first three assign the roles correctly. The accident investigation authority reads out a recovered recorder, the operator's safety department runs routine flight data monitoring, and the regulator sets the mandatory parameter lists.

The fourth is wrong on both the actor and the exclusivity. What a recording proves is determined by the investigation, drawing on the manufacturer's expertise among other sources - the manufacturer is a party to an investigation, not its arbiter, and independence from it is a principle of the process.

Answer: A

Correct answer: The quick access recorder

The quick access recorder sits in an ordinary avionics enclosure, which is exactly what makes it quick to access. It exists for routine flight data monitoring, where the data is downloaded after every flight, and armouring it would defeat the purpose.

The other three are all crash protected, with the memory module in a hardened container that must survive impact, crush, penetration, fire and deep immersion in sequence. The combined unit simply holds both recordings in one such module.

Answer: B

Correct answer: A 406 MHz satellite distress signal

Radio does not propagate through sea water - a 406 MHz signal is attenuated within a very short distance of the surface, and nothing from a submerged beacon reaches a satellite.

The other three are all part of an underwater acoustic search: the 37.5 kHz pulse the beacon emits, its characteristic repetition rate which distinguishes it from biological and mechanical noise, and the bearing a hydrophone array takes to the source. Sound is the only signal the medium carries usefully.

Answer: C

Correct answer: Magnetic tape became cheaper

Tape did not drive the growth; it constrained it. Capacity was limited and the transport mechanism was a survivability weakness, so parameter lists stayed short while tape was the medium.

The other three are the genuine drivers. Investigations repeatedly found that the parameter needed had not been recorded, aircraft systems grew more complex and generated more worth recording, and solid-state memory removed the capacity limit entirely - after which the constraint became the data frame layout rather than the storage.

Answer: D

Correct answer: Control surface positions

Control surface positions are parameters, recorded by the flight data recorder from position sensors. A microphone cannot capture them.

The voice recorder captures sound: crew conversation on the boom or mask microphones, radio transmissions, and the cockpit area microphone's record of aural warnings, switch clicks, engine note and airflow. That last channel is often the most informative, since the timing of a warning or the sound of a configuration change fixes events the crew never mentioned.

Answer: A

The other three all test the readout against something independent. Assuming a conversion is correct is precisely the error validation exists to catch, since a wrong factor gives a plausible trace rather than an obvious one.

Answer: B

A two hour voice recorder overwrites anything older than two hours while it keeps running. The 25 hour data recording survives, which is why pulling the voice recorder breaker promptly is a specific post-incident action.

Answer: C

Correct answer: Battery life bounds the acoustic search

The beacon had stopped transmitting by day 30, so from that point the acoustic search could not succeed however well it was conducted, and the site had to be found by mapping the sea bed instead - a far slower method.

Nothing was faulty: the beacon met its specification. What the case shows is that the specification bounds the search, which is why some installations now carry 90-day beacons and a low-frequency airframe beacon detectable at greater range.

Answer: D

A wrong conversion produces a believable trace rather than an obviously broken one, which is exactly why readouts are anchored to known events. Touchdown, gear selection and radio calls all provide that independent reference.