Avoid clearances that ___.

• A. hold aircraft short of taxiways
• B. taxi aircraft across active runways
• C. allow helicopters to hover-taxi across an active runway
• D. require super or heavy jet aircraft to use greater than normal taxiing power

Answer: (D)

The main idea being tested is that taxi clearances should not force an aircraft to use more engine power than is normal for ground movement. For heavy and super jets, even taxiing at low speeds already produces strong thrust and jet blast. If you issue a clearance that requires them to use greater than normal taxiing power, you create safety risks for people on the apron, ground vehicles, and nearby aircraft or equipment, and you can kick up debris that could cause damage. So the safest and most appropriate clearance is one that avoids pushing pilots to apply extra thrust beyond what’s typical for taxiing.

The other options involve actions that aren’t about power settings in the same way. Holding short of taxiways is a routine safety measure to prevent runway incursions. Having helicopters hover-taxi across an active runway involves helicopter operations, which have different dynamics and aren’t about demanding extra taxi power from a jet. Taxiing across an active runway is a traffic separation issue, not a question of requiring more thrust on the ground. The key point is to keep ground movement within normal, safe power levels, which is why the statement about avoiding clearances that require greater-than-normal taxi power is the best choice.