Precarious position of a flightseeing plane at Denali National Park/NPS

A "flightseeing" plane that crashed into a ridgeline in Denali National Park, killing all five aboard, will not be recovered because of the precarious position it is in and the threat that poses to potential rescuers, the National Park Service has decided.

"The crevasse where the wreckage sits is a dangerous and potentially fatal terrain trap should even a small avalanche occur. The aircraft is broken in half behind the wing, and the tail section of the fuselage is actively pulling down the aircraft towards a glacier 3,500 feet below," park staff said. "Additionally, more than two and a half feet of new snow has fallen at the crash site and loaded the nearly 45-degree slope just above the aircraft."

The plane, a de Havilland Beaver, crashed August 4 not far below the summit of 10,920-foot Thunder Mountain, which stands more like a ridgeline than a mountain. While some of those on board -- the pilot and four visitors from Poland -- survived the crash, they all perished before Denali climbing rangers reached the wreckage on August 6. A ranger who was lowered to the wreckage from a rope dangled from a helicopter determined that there were no survivors, but only had about five minutes to assess the wreck.

Location of crashed flightseeing plane at Denali National Park/NPS

On Friday, following several days of heavy cloud cover, rangers returned to the wreckage with a larger helicopter that allowed another ranger, still tethered to the whirlbird via a line, to spend about an hour at the crash site.

While the Park Service identified the pilot as Craig Layson, who was able to radio his company, K2 Aviation immediately after the crash to say there were some survivors, the names of the Polish passengers were withheld at the request of the Consulate General of the Republic of Poland in Los Angeles.

"Hazards at the crash site include, but are not limited to, avalanche danger, steep snow/ice, crevasses, unstable seracs (blocks of ice loosely attached to the mountain) and aircraft-related concerns such as protruding pieces of jagged metal," park staff said in announcing the decision to leave the plane where it lies. "Recovering the bodies and the aircraft under the current conditions would require an extremely complex and unfeasible recovery operation. NPS looks at three primary factors when evaluating risk: severity, probability and exposure. Due to the unique challenges posed by the steepness of terrain, the crevasse, avalanche hazard and the condition of the aircraft, NPS has determined that recovery of the deceased and/or removal of the aircraft exceed an acceptable level of risk in all three factors and will not be attempted."

The chief of the Alaska region of the National Transportation Safety Board agreed with the Park Service's decision.

"It's a tough decision, but I support the (National Park Service's) decision 110 percent," Clint Johnson told the Anchorage Daily News. "We're used to working in tough spots, but this is out of our league."