What is the effect of not releasing the manual parking brake for a sufficient amount of time?

The answer you provided identifies a key aspect of aircraft towing operations. Not releasing the manual parking brake for a sufficient amount of time can lead to improper aircraft movement. When the parking brake is engaged, it restricts the wheels from rotating freely. As a result, the aircraft will not move as intended during towing operations, which can cause issues in maneuverability and control.

In towing, it is crucial for the aircraft to be able to roll freely to avoid strain on the towing vehicle and ensure safe and efficient movement from one location to another. If the brakes are not fully released, the wheels may be locked up, leading to a situation where the aircraft either remains stationary or moves with great difficulty, impacting the overall operation.