plane sailing

method of calculating a ship's position as though the ship were on a plane surface instead of the curved surface of the earth 平面航法（将地球曲面视作平面测定船的位置）.

plain, plain clothes (esp of police officers), plain dealing, plain flour, plain-clothes man, plain-spoken, plainchant, plainly, plainness, plains, plainsman, plaint, plaintiff, plaintive, plaintively, plaintiveness, plait, plan, plane, plane geometry, plane-table, planet, planetarium, planetary, plangency, plangent, plangently, plank, planking, plankton, planned, planning, plant, plantain, plantation, planter, plaque, plasma, plaster, plaster cast,