What bank angle should be used prior to final for a no-gyro approach?

In a no-gyro approach, pilots do not receive the typical visual or instrument guidance to maintain a stable turn; instead, they rely on a predetermined bank angle to facilitate safe navigation. A standard rate turn is defined as a bank angle that results in a rate of turn of 3 degrees per second, which is generally around a 15-degree bank angle depending on the airspeed.

Using a standard rate bank allows pilots to maintain altitude control while establishing the correct flight path during the final stages of the approach. It helps in managing the aircraft's performance, maintaining situational awareness, and ensuring a smooth transition to landing. This approach minimizes the risk of over-banking or under-banking, which could lead to undesirable flight attitudes or inadequate spacing from the runway.

The other options presented involve varying degrees of bank angles that are either too steep or not sufficiently effective for ensuring adequate control during final approach, making them less suitable for this critical phase of flight.