What is the lower limit for Control Areas defined in aviation?

In the context of aviation, Control Areas (CTAs) are defined as airspace in which air traffic control service is provided to all flights. The lower limit for Control Areas is specifically set at 700 feet above ground level (AGL) in New Zealand. This altitude ensures that the controlled airspace begins at a safe height above the minimum altitude for safe operation of aircraft, particularly for those operating under visual flight rules (VFR).

Establishing the lower limit at this height helps to minimize the risk of collisions with terrain and obstacles while allowing for effective management of air traffic. It creates a buffer zone where pilots are ensured a level of safety and air traffic controllers can monitor aircraft more efficiently in areas with higher traffic density.