Which of the following statements with regard to Black Boxes used in modern aircrafts is/are correct ? 1. They carry a beacon emitting red light pulses to facilitate underwater detection. 2. They record both the cockpit voice and flight data. 3. Their memory units are made using either stainless steel or titanium. Select the answer using the code given below :

(a) 1 only
(b) 2 and 3 only ✓ UPSC's answer
(c) 1 and 2 only
(d) 1, 2 and 3

Why the answer is (b)

• A 'black box' is actually two bright-orange units: the Flight Data Recorder, logging hundreds of parameters such as altitude, speed and control positions, and the Cockpit Voice Recorder, capturing crew speech and cockpit sounds — statement 2 is correct.

• The crash-survivable memory unit is encased in stainless steel or titanium and insulated to survive impacts of about 3,400 g, fires of 1,100 °C and deep-sea pressure — statement 3 is correct.

• Statement 1 is wrong: the underwater locator beacon emits ultrasonic 'pings' at 37.5 kHz for at least 30 days, detectable by sonar; light would be useless in deep water.

• Recorders are usually mounted in the tail, the part most likely to survive a crash.

• Hence 2 and 3 only, option (b).

Why the other options are wrong

(a) 1 only: Statement 1 is wrong: the beacon emits ultrasonic pings, not red light; statements 2 and 3 are correct.
(c) 1 and 2 only: Statement 1 is wrong: underwater detection uses acoustic, not optical, signals.
(d) 1, 2 and 3: Statement 1 is wrong, so all three cannot be correct.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2026, held on 24 May 2026. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.