FAR 91.115 — Water Right-of-Way

FAR 91.115 sets the right-of-way rules when you're operating an aircraft on the water — for example, a seaplane taxiing, taking off, or landing on a lake or harbor. The general principle is that aircraft must stay clear of boats and avoid getting in the way of their navigation whenever possible.

The specific rules are:

• General duty: Keep clear of all vessels and give way to any aircraft or vessel that has the right-of-way under this section.
• Crossing: When two aircraft, or an aircraft and a vessel, are on crossing courses, the one on the other's right has the right-of-way.
• Head-on: When approaching head-on or nearly so, each shall alter course to the right to keep well clear.
• Overtaking: The craft being overtaken has the right-of-way; the overtaking aircraft or vessel must alter course to stay clear.
• Risk of collision: When a collision risk exists, each craft must proceed with careful regard to existing circumstances, including the limitations of each craft.

This matters operationally because seaplanes maneuver slowly on water, have limited braking, and share the surface with boats that may not understand aviation rules — so cautious, predictable handling is essential.