Final answer:
In an electronically-timed fuze, the arming vane is replaced by a Safe and Arm (S&A) device, which electronically controls the timing of the explosives. This improves safety and reliability.
Step-by-step explanation:
In an electronically-timed fuze, the arming vane is replaced by a Safe and Arm (S&A) device:
The arming vane in a mechanically timed fuze is a spinning device that aligns with the airflow to arm the fuze. In an electronically-timed fuze, the S&A device is used to electronically control the timing of the explosives. It ensures that the fuze is armed at the right moment and prevents accidental detonation.
By replacing the arming vane with an S&A device, the electronically timed fuze allows for more precise control over the timing, increasing safety and reliability.