National Park Service photo

The current National Park Service cabin at Swikshak Bay is due to be replaced. The missing NPS crew was preparing a site for the new cabin and awaiting the arrival of cabin construction supplies.

With hopes dimming for three young employees of the National Park Service and a pilot missing since Saturday, a small air force organized by the federal agency was back in the air over Katmai National Park and Preserve Tuesday.

Under blue skies and with search conditions optimum, agency officials had hoped to find some sign Monday of the missing, single-engine deHavilland Beaver flown by 47-year-old Marco Aletto, but they found nothing. Aboard the floatplane with the pilot when it left the outer coast of the Katmai park Saturday afternoon were Mason McLeod, 26, and two brothers, Neal Spradlin, 28; and Seth Spradlin, 20.

The Spradlins grew up in Indiana where their father is a minister. Like many young men, they came to Alaska looking for adventure. Neal Spradlin has lived and worked Alaska for the park service for seven years. Brother Seth, a budding wildlife artist, was working for the second summer as a park service seasonal employee to make money to go to college. Their friend McLeod is a native of Jacksonville, Fla., who has worked for the park service both in the Everglades and at Katmai, a park just north of Kodiak Island along the Gulf of Alaska.

All three had flown with Branch River Air Service from King Salmon to the coast to work on rebuilding an old Katmai ranger station at Swikshak Lagoon. King Salmon is a community of about 400 about 300 miles west of Anchorage. The three park workers were with Aletto on a return flight to the community when their plane disappeared.

It's disappearance was immediately noted upon the arrival of another airplane from Swikshak. That flight had left 15 minutes after Aletto's with another party of park service employees working on the ranger station project. The pilot of the second flight reported the weather rapidly deteriorating along the flight route from the coast.

A search for the missing plane began almost immediately, but three days of searching found nothing. Search efforts Tuesday were shifting to the northeast part of the 4-million-acre national park, particularly the several river valleys that drain into Kamishak Bay, according to a park service press release. The expectation is that the plane flew up one of the valleys there looking for a route through the Aleutian Range mountains to King Salmon.

Ten aircraft -- four helicopters and six fixed wing -- are officially involved in the search, which has drawn support from the U.S. Fish & Wildlife Service, the Alaska State Troopers, U.S. Coast Guard, Alaska Air National Guard, Branch River Air, and Egli Air Haul, a freight hauler in the King Salmon area.

Air-taxi operators flying fishermen and bear viewers into the area have also informally joined the search, the park service said.

The missing plane was fitted with an emergency location transmitter, but it has remained silent, as has the aircraft's radio.

Contact Craig Medred at craig(at)alaskadispatch.com.