The search for a missing aircraft continued yesterday. There have been no radio or emergency locator transmitter transmissions to date. The NPS Alaska Incident Management Team, lead by incident commander Richard Moore, is assisting Katmai National Park by managing the search efforts for the missing aircraft and the persons on board. On Wednesday, aerial efforts to locate the plane and missing employees moved to a grid pattern. Initial operations were driven by topography and the need to follow all routes of highest probability for the flight path of the missing plane. Searchers focused on all recognized low elevation passes, both to the north and south. Operations have now moved to a broader saturation model, based on a grid defined by air miles rather than terrain. This methodical path of using a grid system is based on the same method used by the Civil Air Patrol and will cover all areas regardless of geographical features. The Coast Guard continues to search the coast and the Civil Air Patrol is working on the northern search areas. The single engine floatplane, a deHavilland Beaver operated by Branch River Air Service in King Salmon, carried the pilot and three National Park Service maintenance employees and has been missing since Saturday afternoon. The missing employees are Mason McLeod, 26, and brothers Neal Spradlin, 28, and Seth Spradlin, 20. The pilot is Marco Alletto, 47, from King Salmon.