A controller should avoid clearances that ___________.

• A. could cause an aircraft to exceed speed restrictions
• B. require greater than normal taxiing power for all categories
• C. violate minimum required wake turbulence separation
• D. requires category A through D aircraft to use greater than normal taxiing power

Answer: (D)

On the ground, keeping taxi engine power at normal levels helps maintain predictable speeds, reduce jet blast, and preserve safe spacing between aircraft and ground personnel. Forcing every aircraft to use greater than normal taxiing power creates an across-the-board hazard: it can surprise pilots, increase ground-level noise and debris, and make it harder to control movements and braking, which in turn raises the risk of collisions or runway incursions.

The best choice expresses this across-the-board risk: a clearance that would require every aircraft in categories A through D to use more than normal taxiing power. That kind of instruction is unsafe because it imposes nonstandard thrust settings on all traffic, compromising safety and flow on the taxiways. Other options touch on related concerns (speed limits, wake turbulence, or specific categories), but they don’t capture the broad safety issue as clearly as the across-the-board requirement for higher-than-normal taxi power.