What is the correct sequence to initiate the automatic engine start?

What is the correct sequence to initiate the automatic engine start?

• A. Master switch to ON, then Mode Sel IGN/START
• B. IGN/START, then Mode Sel to ON
• C. Mode Sel to IGN/START, then Master switch to ON
• D. Mode Sel IGN/START, then MASTER switch to ON

Answer: (D)

The key idea is that the ignition/start logic must be armed before the start power is applied. Moving the Mode Selector to IGN/START primes the system—the ignition and start sequence are prepared and the FADEC can control the start. Then turning the Engine Master switch ON supplies power to the start circuit and allows the starter to turn the engine once the armed mode detects the proper conditions. If you energize the start circuit (Master ON) before the ignition/start mode is selected, you’re powering the start system without a valid start command, which won’t initiate a start and can waste electrical power or trigger protections. So the correct sequence is to set the Mode Selector to IGN/START first, then switch the Master ON.

The key idea is that the ignition/start logic must be armed before the start power is applied. Moving the Mode Selector to IGN/START primes the system—the ignition and start sequence are prepared and the FADEC can control the start. Then turning the Engine Master switch ON supplies power to the start circuit and allows the starter to turn the engine once the armed mode detects the proper conditions.

If you energize the start circuit (Master ON) before the ignition/start mode is selected, you’re powering the start system without a valid start command, which won’t initiate a start and can waste electrical power or trigger protections. So the correct sequence is to set the Mode Selector to IGN/START first, then switch the Master ON.