Subelement C: Equipment Operations— Topic 14: VHF Channel Selection
Question 1-14C2
Element 1 (MROP)What is the aircraft frequency and emission used for distress communications?
Explanation
Aircraft distress communications primarily use Amplitude Modulation (AM) for voice. The emission designator A3E specifically denotes Amplitude Modulation, telephony (voice). The internationally recognized frequency for civilian aircraft distress is 121.500 MHz, monitored by air traffic control, military, and other aircraft.
Therefore, **D) 121.500 MHz - A3E** is correct, combining the standard civilian aircraft distress frequency with the correct AM voice emission type.
Option A is incorrect because 243.000 MHz is primarily a military aeronautical distress frequency, and F3E is FM voice, which aircraft do not typically use for standard communications. Option B uses the correct frequency but the incorrect emission type (F3E, FM voice). Option C is incorrect as 156.525 MHz is the marine VHF Channel 16 distress frequency, and F1B is a data mode (RTTY), not voice.
Related Questions
1-13C6 Why must all VHF Distress, Urgency and Safety communications (as well as VTS traffic calls) be performed in Simplex operating mode?1-14C1 What channel must VHF-FM-equipped vessels monitor at all times when the vessel is at sea?1-14C3 Which VHF channel is used only for digital selective calling?1-14C4 Which channel is utilized for the required bridge-to-bridge watch?1-14C5 Which channel would most likely be used for routine ship-to-ship voice traffic?