Flight Data Recording Questions and Answers

Answer: A

It records the measured state of the aircraft and its systems over a long period. Voice and ambient sound belong to the cockpit voice recorder, which is a separate unit with its own duration and its own regulatory requirements.

Answer: B

The area microphone picks up warnings, switch clicks and airflow noise as well as speech, and that ambient channel is often as valuable as the words. Correlating it with the data recorder is how an investigation reconstructs a sequence.

Answer: C

Solid state memory survives impact far better than tape, which could stretch or break, and it needs no transport mechanism. The change also allowed far more parameters to be held at higher sampling rates in the same volume.

Answer: D

The casing is a high visibility orange with retro-reflective tape so it can be found among wreckage. The popular name is a misnomer that probably comes from early wartime electronics rather than from any recorder's actual colour.

Answer: A

An acoustic pulse at that frequency propagates well in sea water and is detected by a towed or hand-held hydrophone. Radio frequencies such as 121.5 and 406 megahertz belong to emergency locator transmitters and do not travel through water.

Answer: B

Correct answer: 30 days after activation

The underwater locator beacon must transmit for at least 30 days from activation, which sets the window a search has to find it acoustically.

The figure has proved tight in deep-water accidents where the site was uncertain, and some installations now carry beacons specified for 90 days, with a low-frequency airframe beacon detectable at greater range. The period is bounded by battery capacity in a sealed unit that must also survive the crash and the pressure at depth.

Answer: C

Correct answer: Immersion in water

A water-activated switch closes when the beacon is submerged, so it starts transmitting on immersion and not before. That is what preserves the battery: a beacon triggered by impact or by power loss would run down on an accident ashore where it is not needed.

Nothing from the flight deck is involved, and it must work with the aircraft's electrical system destroyed. The design is deliberately simple, with no logic to fail - contact with water is the whole of the activation.

Answer: D

It gathers signals from sensors and buses, converts them to a common format and assembles the data frame the recorder writes. A fault here can corrupt or lose parameters while the recorder itself is entirely serviceable.

Answer: A

The frame structure gives each parameter a fixed slot, so a parameter appearing once per subframe is sampled once a second. Reading the data back requires the frame layout document for that aircraft, which is why the layout is controlled.

Answer: B

Sampling rate is chosen to match how quickly a parameter can meaningfully change. Sampling a slowly varying quantity rapidly wastes capacity, while under-sampling a fast one loses exactly the detail an investigation needs.