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:

1. A

   1 only

   1 only: This option states that Black Boxes carry a beacon emitting red light pulses to facilitate underwater detection. This is incorrect because the underwater locator beacon emits acoustic pulses (ultrasonic sound waves), not red light pulses, to help locate the device in deep water.

2. B

   2 and 3 only

   2 and 3 only. Statement 2 is correct because modern flight recorder systems comprise both a Cockpit Voice Recorder (CVR) and a Flight Data Recorder (FDR). Statement 3 is correct because the internal memory units of flight recorders are encased in heavy-duty materials like stainless steel or titanium to withstand extreme impact and high-temperature fire conditions.

3. C

   1 and 2 only

   1 and 2 only: This option includes statement 1, which is incorrect regarding the beacon emitting red light pulses instead of acoustic signals.

4. D

   1, 2 and 3

   1, 2 and 3: This option includes statement 1, making it incorrect since underwater locator beacons rely on acoustic frequencies rather than light emissions.

Summary. Official key is (b). The correct combination highlights that Black Boxes record flight data and voice communications, and their memory cores are protected by robust stainless steel or titanium casings, while statement 1 is false due to relying on acoustic rather than light pulses.