21Any helicopter provided by the inspected State Party shall be large enough to carry at least two members of the inspection team and at least one member of the escort team. Inspectors shall be allowed to take and use on overflights of the inspection site any of the equipment specified in paragraph 15 of this Section. The inspection team shall advise the escort team during inspection flights whenever it intends to take photographs. A helicopter shall afford the inspectors a constant and unobstructed view of the ground.