Approach and Landing Workload
The approach and landing phases are recognized as periods of elevated workload. This workload can escalate significantly when unexpected errors occur, compounding the challenges faced by the flight crew.
Altitude Selector Error
The pilot flying (PF) did not press the altitude selector correctly and subsequently failed to check that the intended flight mode change had been registered on the Flight Mode Annunciator (FMA). This oversight led to a substantial increase in the PF's workload as the approach progressed.
Loss of Situational Awareness
As a result of the higher workload, the PF lost awareness of the aircraft's descent profile, particularly the relationship between altitude and distance to the landing point. This loss of situational awareness was compounded by a preconception that the aircraft should not become high on the profile during positioning for final approach.
Descent Below Clearance Limit
The combination of diminished descent profile awareness and the preconceived notion led the PF to initiate a descent below the published altitude limit of 3,000 ft, which was required to be maintained until the aircraft was established on final approach. The PF recognized the error and began leveling the aircraft just before air traffic control (ATC) notified the flight crew that they had breached the descent clearance limit.
Pilot Monitoring Role
The pilot monitoring (PM) has a responsibility to maintain awareness of the PF's actions and the aircraft's flight profile relative to altitude clearances and approach procedure limitations. Although the PM had not flown this particular approach before, the monitoring duties during the approach were not effectively executed.