Under which condition is single-engine taxi allowed?

Under which condition is single-engine taxi allowed?

• A. During engine start in RVSM operations
• B. When engine oil level is not critical
• C. As directed by maintenance
• D. Relocating on uneven ramp to check affected engine oil level

Answer: (D)

Single-engine taxi is a tightly restricted maneuver that’s only allowed for a specific maintenance-related purpose, not for normal taxiing. In this case, it’s permitted to relocate the aircraft on an uneven ramp so that maintenance can accurately check the oil level on the affected engine. The uneven surface creates a situation where you need to move the airplane to a position that allows a proper oil level check, and doing so with one engine running keeps the operation within a controlled maintenance task rather than a routine flight operation. The other options don’t provide a valid, safety‑driven maintenance exception: starting engines in RVSM isn’t a permissible taxi scenario, oil level being non-critical isn’t a reason to maneuver on one engine, and simply following a maintenance directive without a specific relocation/maintenance-check context isn’t the approved exception.

Single-engine taxi is a tightly restricted maneuver that’s only allowed for a specific maintenance-related purpose, not for normal taxiing. In this case, it’s permitted to relocate the aircraft on an uneven ramp so that maintenance can accurately check the oil level on the affected engine. The uneven surface creates a situation where you need to move the airplane to a position that allows a proper oil level check, and doing so with one engine running keeps the operation within a controlled maintenance task rather than a routine flight operation. The other options don’t provide a valid, safety‑driven maintenance exception: starting engines in RVSM isn’t a permissible taxi scenario, oil level being non-critical isn’t a reason to maneuver on one engine, and simply following a maintenance directive without a specific relocation/maintenance-check context isn’t the approved exception.