If an aircraft is in lateral tolerance but out of longitudinal tolerance, what action does the computer take?

If an aircraft is in lateral tolerance but out of longitudinal tolerance, what action does the computer take?

• A. Cancels the current flight plan and requests pilot input
• B. Declares loss of radar contact
• C. Switches to a different sector
• D. Calculates a new flight plan position, issues updated times, and remains in FLAT track

Answer: (D)

When the system sees you are staying within the horizontal path limits but behind or ahead along the route (longitudinal position out of tolerance), it doesn’t abandon the plan or chase a different sector. Instead, it updates its internal estimate of where you are on the flight plan, recalculates a new position along the plan, and issues updated times (like ETAs) based on that new position. It then keeps guidance on the original track, i.e., remains in FLAT track, so the flight plan continues to be followed without switching sectors or canceling the plan. This approach makes sense because vertical and lateral adherence are still acceptable, so there’s no need for a corrective action that would change routes or alert the pilot. The system simply realigns the timing and position to reflect your current along-track status while preserving the intended path.

When the system sees you are staying within the horizontal path limits but behind or ahead along the route (longitudinal position out of tolerance), it doesn’t abandon the plan or chase a different sector. Instead, it updates its internal estimate of where you are on the flight plan, recalculates a new position along the plan, and issues updated times (like ETAs) based on that new position. It then keeps guidance on the original track, i.e., remains in FLAT track, so the flight plan continues to be followed without switching sectors or canceling the plan.

This approach makes sense because vertical and lateral adherence are still acceptable, so there’s no need for a corrective action that would change routes or alert the pilot. The system simply realigns the timing and position to reflect your current along-track status while preserving the intended path.