7700 mode A or C
Sat my air law exam today for my ATPL ground exams i had two question which asked about the use of the transponder in an emergency and hijacking had the obvious correct for emergency of 7700 and 7500 for Unlawful interference but it wanted me to state whether it was on Mode A or C unfortunately i picked Charlie as i thought it gave more information which would be relevant for the emergency. the correct answer was mode A can anyone let me know why this would be the case?