Are speed restrictions when 'cleared' for an arrival mandatory?

When an aircraft is 'cleared' for an arrival, any speed restrictions that are issued in conjunction with that clearance are mandatory. This means that pilots are required to adhere to the specified speed limits as part of their compliance with air traffic control instructions. These restrictions are established for various reasons, including maintaining safe separation between aircraft, ensuring efficient traffic flow, and accommodating specific runway conditions or configurations at the destination airport.

For example, if air traffic control instructs an aircraft to reduce speed to a certain threshold upon arrival, failing to comply can lead to unsafe situations, such as too close of separation with the preceding aircraft or complications with traffic management during landing. Therefore, adherence to these speed restrictions is crucial for maintaining organized and safe operations in the airspace surrounding the airport and during the landing phase.