A pilot flying in the area of this week's Alaska plane crash that killed former Sen. Ted Stevens and four others has estimated that clouds were as low as 600 feet (200 meters) at the time of the crash, the National Transportation Safety Board's chairwoman said on Saturday.
That is well below previous estimates of between 1,000 and 2,000 feet (300-600 meters), Chairwoman Deborah Hersman said at a news conference. The pilot of the small plane also told investigators that visibility was between five and seven miles, she said. The cause of Monday's crash on a remote mountainside in southwest Alaska hasn't been determined.
Investigators have spoken with two of the four survivors, and one survivor has told officials he didn't notice any changes in the plane's pitch or hear any unusual engine sounds right before the plane went down.
The group delayed their scheduled Monday morning trip from a corporate-owned lodge to a fishing camp 50 miles (80 kilometers) away because of poor weather, but decided to fly to the camp in the afternoon when conditions had improved, one of the survivors has told officials.
Hersman hasn't identified the survivors who spoke with officials. She said Saturday that the conditions of the other two survivors has prevented investigators from interviewing them.
Former NASA chief Sean O'Keefe, his son and two other passengers surived the crash. Pilot Theron Smith was killed, along with Stevens and three others.
Smith's wife told investigators that she had several telephone conversations with her husband in the days before the crash and noticed nothing out of the ordinary in his demeanor, Hersman said. Investigators were trying to construct the last 72 hours before the crash, and investigators routinely look at whether human fatigue was a factor, Hersman said.
The badly damaged plane has been lifted in pieces from the rugged mountain slope and laid out on the floor of the hangar in Dillingham, where it awaits examination, Hersman said. The engine was also in the hangar and was to be transported to a Honeywell International Inc. facility. The company, which made the engine, will then perform a "teardown" to look at possible causes of the crash, Hersman said.
Of particular interest to investigators is whether a system on the 1957 DeHavilland DHC-3 Otter plane meant to alert the pilot that terrain was near, or if the alarm function had been suppressed, she said.
The plane also wasn't required to have a cockpit voice recorder or flight data recorder, but investigators were hoping to glean some information from cell phones and other devices and instruments aboard the plane, Hersman said.
She estimated a final report could take more than a year.