Which type of approach requires the controller to notify the pilot of the straight-in MDA?

The approach that requires the controller to notify the pilot of the straight-in Minimum Descent Altitude (MDA) is the ASR (airport surveillance radar) approach. In the context of ASR approaches, controllers provide radar guidance to the aircraft, and it is standard procedure for them to inform pilots of the MDA, which is crucial for safely executing the approach. The notification of MDA is essential in maintaining situational awareness and ensuring that pilots are prepared to descend safely during the approach when visual references are insufficient.

In ASR approaches, the controller might provide specific altitude information as part of the radar service, highlighting the need to be aware of the MDA for safe operation. In contrast, precision approaches and visual approaches have different operational parameters, where MDA notification is either not required or is managed through different methods. Non-precision approaches also incorporate MDAs but may not require the same active notification from controllers in the same way as ASR approaches do.