Which situation should be avoided when issuing taxi instructions?

Issuing taxi instructions should be handled with utmost caution, particularly when small aircraft are nearby. The presence of small aircraft can introduce potential safety risks, as these aircraft often have different performance characteristics and may be less visible to pilots of larger aircraft. If a larger aircraft is taxiing and not adequately aware of the small aircraft's position, there is a heightened risk of a collision or an unsafe situation.

While other factors like heavy aircraft using normal taxiing power, high traffic volume, and low visibility conditions certainly present their own challenges, the interaction between different types of aircraft requires heightened awareness and careful management to ensure safety on the ground. In contrast, issuing either clearances or instructions where small aircraft are involved necessitates additional vigilance on the part of controllers and pilots alike.