What adjustment should pilots make if instructed by ATC to deviate from VNAV?

When pilots are instructed by Air Traffic Control (ATC) to deviate from Vertical Navigation (VNAV) procedures, they must manually adjust their altitude settings. This is crucial because the VNAV system is programmed based on the flight plan and any associated constraints. If a pilot receives a deviation instruction, it can either mean an immediate change in altitude or a different flight path that requires a reassessment of the planned vertical profile.

Manually altering altitudes allows pilots to ensure compliance with ATC's directives while maintaining control over the aircraft. ATC's instructions may not consider the VNAV's original constraints, so it's essential for pilots to actively gauge their altitude settings accordingly. This step promotes a safer and more coordinated response during the flight, especially in dynamic airspace situations.

This choice emphasizes the responsibility of the pilot to assess and respond to ATC commands effectively while ensuring the aircraft stays safely within aviation regulations and operational parameters.