What is the primary reason for adhering to the prescribed duty cycle of a pneumatic starter?

Adhering to the prescribed duty cycle of a pneumatic starter is primarily focused on preventing overheating. The duty cycle defines the limits within which the starter can operate without exceeding safe temperature thresholds. Pneumatic starters generate substantial heat during operation due to the compression and expansion of air and mechanical work involved. If the starter is used continuously or beyond the specified limits, it can lead to excessive heat buildup, which may damage the components or lead to failure.

Maintaining the correct duty cycle ensures that there are adequate intervals for the starter to cool down, thereby prolonging its lifespan and ensuring it operates reliably during the engine start sequence. This practice is crucial for maintaining both the performance and safety of the aircraft systems reliant on the pneumatic starter. While factors like noise reduction, starting efficiency, and fuel consumption are associated with starter performance, they are secondary concerns compared to the fundamental requirement of preventing overheating.