During a hung start, the engine must reach idle Ng speed within how many seconds from start initiation before an EPECS abort is commanded?

• A. 60 seconds
• B. 80 seconds
• C. 100 seconds
• D. 120 seconds

Answer: (B)

In a hung start, the system monitors how quickly the engine accelerates after the start is initiated. The engine must reach idle Ng within a defined time window; if it hasn’t, the Electronic Propulsion and Engine Control System (EPECS) automatically aborts the start to protect the engine from damage due to a prolonged light-off or fuel-washed condition. For the PC-12 NGX, that cutoff is 80 seconds from the moment the start is initiated. Reaching idle Ng within 80 seconds means the engine is starting properly and can proceed to normal operation. If it hasn’t reached idle by 80 seconds, the start is aborted to prevent potential issues, whereas shorter or longer time limits would either prematurely abort a marginal light-off or delay protection during a difficult start.