How many igniters are used with most turbine engines?

How many igniters are used with most turbine engines?

• A. One
• B. Two
• C. Three
• D. Four

Answer: (B)

Ignition system redundancy is the idea being tested here. In most turbine engines, a pair of igniters is used to start and reliably light the fuel–air mixture in the combustor. Having two igniters provides a backup if one spark source or its wiring fails, which greatly reduces the chance of a no-start. The igniters are positioned so they cover different areas of the combustor, helping ensure flame initiation under varying conditions, such as lean mixtures or different airflows during start and hot starts. Using a single igniter would leave a greater risk that a fault could prevent ignition, while having more than a pair is not typical for most engines, since two provides the needed redundancy with less weight and complexity.

Ignition system redundancy is the idea being tested here. In most turbine engines, a pair of igniters is used to start and reliably light the fuel–air mixture in the combustor. Having two igniters provides a backup if one spark source or its wiring fails, which greatly reduces the chance of a no-start. The igniters are positioned so they cover different areas of the combustor, helping ensure flame initiation under varying conditions, such as lean mixtures or different airflows during start and hot starts.

Using a single igniter would leave a greater risk that a fault could prevent ignition, while having more than a pair is not typical for most engines, since two provides the needed redundancy with less weight and complexity.