What action should be taken when a glider and an airplane are on a head-on collision course at the same altitude?

When a glider and an airplane are on a head-on collision course at the same altitude, the appropriate action is for both aircraft to give way to the right. This adheres to the aeronautical rules that require pilots to alter course or speed to avoid a collision when two aircraft approach each other head-on. By both turning right, they create a predictable and safe outcome, allowing for better clearance between the two aircraft.

This maneuver is grounded in the fundamental principles of avoiding collisions among aircraft and ensures that each pilot is aware of the other's actions. The right-turning rule is part of the "Rules of the Road" in aviation and helps standardize responses to prevent misunderstandings during encounters in the airspace. Thus, both pilots executing the same maneuver significantly reduces the risk of an accident in this scenario.