Published: Apr 22, 2011 6:41 PM EDT
Updated: Apr 22, 2011 3:42 PM EDT

JUNEAU, Alaska (AP) - Witness and survivor accounts released Thursday paint a dramatic picture of the aftermath of the plane crash that killed former U.S. Sen. Ted Stevens and four others last August, but give no clear indication of the cause.

The National Transportation Safety Board plans to release its probable cause findings next month.

The hundreds of pages of documents that the NTSB released Thursday stem from its investigation into the Aug. 9 crash in southwest Alaska, ranging from the pilot's medical history to a review of weather conditions and analysis of the plane. Stark images of the aftermath also were released, including pictures of the amphibious aircraft with its wings peeled back and parts of the aircraft crumpled like a crushed soda can.

Some of the information has been discussed before, including questions about weather conditions at the time of the crash. But there are also newly released witness and survivor accounts, providing details about the events surrounding the crash.

For example, in one interview, Robert Himschoot, who was among the first people on the scene, recounted helping two emergency medical technicians to the site to assist a doctor who was already there, and finding two others later who had been lost and unable to help that night.

Poor weather also hindered further rescue attempts and supply drops; the survivors were brought off the mountain the following morning.

Stevens and former NASA chief Sean O'Keefe were among eight guests at a General Communications Inc. lodge flying to a salmon fishing camp the afternoon of Aug. 9, about 52 miles away. NTSB estimates the accident happened about 15 minutes into the flight.

Perishing were Stevens, 86; pilot Theron "Terry" Smith, 62, of Eagle River; William "Bill" Phillips Sr.; Dana Tindall, 48, an executive with GCI; and her 16-year-old daughter Corey Tindall.

NTSB said the plane wasn't officially reported overdue to the FAA's Flight Service Station in Dillingham until 6:59 p.m., just before the lodge manager said they were expected back for dinner. NTSB said the flight left at 2:27 p.m.

Several interviews given to NTSB indicate the weather earlier in the day was dreary but had improved by lunchtime, when plans were made to take the trip.

The lodge manager told NTSB he had seen Smith check the weather several times on the computer. Computer data analyzed for the agency showed weather sites checked between 7:40 a.m. and 11:33 a.m. though it's not clear who was checking the sites.

A weather information broadcast, cited by NTSB as current until after the accident time, indicated light rain and mist at the Dillingham airport, about 18 miles south of the crash site. It cited forecasts for isolated moderate turbulence and did not recommend visual flight rules, which is how Smith flew that day.

Dani Bowman, the wife of GCI executive Ron Duncan and the doctor who was on scene the night of the crash, said she and Duncan flew in the general area of the crash site, without knowing it, not long after Stevens' group had left. She described the visibility as "good."

The four survivors, in interviews with NTSB, did not report anything alarming before the accident. At least one said that all passengers were wearing life preserver vests. Another said the weather was unremarkable and that Smith made several turns to avoid terrain, which he called "characteristic" Alaska flying. He said Smith made a left turn, going up a hill just before impact but didn't consider the angle unusual or hear any change in engine sound before the crash.

Smith's former employers and others who knew him spoke highly of his skills; results of toxicology reports released by NTBS show no drugs or carbon monoxide detected in his blood, and at least two of the three autopsies performed on Smith, excerpted in the NTSB file, determined the cause of his death was blunt force trauma. The state medical examiner determined that was the cause of death of all the victims.

Smith was grounded from flying from March 2006 to April 2008 due to a stroke, according to NTSB. Medical records later reviewed by NTSB indicated he was "fully recovered" but also found an "extensive" family history of "intracranial hemorrhages at young ages."

NTSB said Smith's applications for medical certificates from the Federal Aviation Administration in 2008 and 2009 did not mention his visits to a naturopathic practitioner for a left-side facial twitch said to have started before the stroke and worsened with stress or fatigue. It said Smith told the practitioner he'd undergone dental work before the twitch started.

As for the airplane, NTSB found "no pre-existing failures or discrepancies that would preclude normal operation of either the engine or the propeller prior to impact. All the damage to the engine and propeller were consistent with impact forces."

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