ATPL: In the ATC flight plan Item 10 (equipment), the letter to indicate the carriage of a serviceable transponder - mode A (4 digits-4096 codes) and mode C, is:
Question 102, Flight Planning and Monitoring - ATPL - Airline Transport Pilot license
Explanation: In the ATC flight plan Item 10 (equipment), the letter to indicate the carriage of a serviceable transponder - mode A (4 digits-4096 codes) and mode C, is: