JUNEAU, Alaska (AP) -- The National Transportation Safety Board examination into the plane crash that killed former Sen. Ted Stevens has raised questions about whether the pilot should have been cleared to fly after suffering a stroke.
The NTSB at a hearing in Washington on Tuesday found no definitive cause for the crash that killed Stevens, the pilot and three others after the amphibious plane slammed into a mountainside. The probable cause, however, was determined to be the "temporary unresponsiveness" of 62-year-old pilot Theron "Terry" Smith "for reasons that could not be established from the available information," according to the board.
The finding took the Federal Aviation Administration to task over its guidelines for clearing pilots to fly after suffering strokes, saying the agency's guidance for medical certification in such cases was inadequate. The board also said it doesn't address the risk of recurrence or recommend formal cognitive testing to check pilots for possible impairments -- an issue the FAA was advised to address.
Investigators said they went through a number of possible scenarios about the pilot: Was he depressed or distracted? Was he tired or stressed by recent major events in his life that included including the loss of his son-in-law shortly before the crash? Did he suffer a seizure or otherwise become incapacitated?
Smith, an experienced pilot familiar with the flight path the day of the crash, was described as being in a good mood on the day of the crash, the NTSB's Malcolm Brenner said.
Results of toxicology reports previously released by the NTSB showed no drugs or carbon monoxide detected in Smith's blood.
The plane was equipped with a terrain awareness and warning system that would have notified Smith when he was approaching treacherous mountain areas. But the warning system was disabled.
That means Smith had as little as four seconds to respond as the plane approached the mountain it eventually slammed into, as opposed to an alert of up to 30 seconds had the system been turned on, the NTSB said.
Jim Morhard, who was sitting behind Smith on the plane, said he didn't notice anything unusual before impact. He said a metal bulkhead blocked his view of Smith.
"I just wish there was a more definitive finding as to why or how it happened," Morhard, 54, said in a phone interview. "I'm disappointed that it wasn't more than what it was, but I also know that the NTSB has a process and they followed the process. It is what it is."
According to NTSB, Smith had been grounded from flying from March 2006 to April 2008 due to a stroke, and medical records reviewed by the agency showed he had an "extensive" family history of "intracranial hemorrhages at young ages."
The NTSB has said Smith's applications for medical certificates from the FAA in 2008 and 2009 did not mention visits to a naturopathic practitioner for a facial twitch said to have started before his stroke and to have worsened with stress or fatigue.
FAA spokesman Les Dorr said his agency changed its policy following a March 2010 summit and now requires a neuropsychological evaluation -- essentially formal cognitive testing -- for any pilot that has suffered a "significant" stroke.
That requirement wasn't in place when Smith received his medical certification and the board said it's not clear that a "sufficiently thorough aeromedical evaluation" would have rendered him ineligible for that certification. However, "a more rigorous decision-making process for evaluating this pilot with a history of intracerebral hemorrhage would have decreased the potential for adverse consequences," the board found.
The passengers in the plane included Stevens and former NASA chief Sean O'Keefe and his son, who was in the copilot's seat and asleep at the time of the crash. Four people, including O'Keefe and his son, were injured.
Stevens and O'Keefe were among the guests at a General Communications Inc. lodge flying to a salmon fishing camp the afternoon of Aug. 9. The other victims who died were William "Bill" Phillips Sr.; Dana Tindall, 48, an executive with GCI; and her 16-year-old daughter, Corey Tindall.
Phillips' son was also on board and survived.
Stevens' family thanked the NTSB and those involved in the rescue effort. The family also cited Stevens' commitment to improving aviation safety -- a cause he fought for, given Alaskans' heavily reliance on flying to get around, during his 40 years in the Senate. The family said it hoped the board's recommendations will help further the goal of better aviation safety.
Efforts to reach Smith's widow weren't immediately successful.
Last month, NTSB released hundreds of pages of documents stemming from its investigation, ranging from the pilot's medical history to a review of weather conditions. Several interviews given to NTSB indicated the weather was dreary earlier the day of the crash but had improved by lunchtime. Investigators could not determine weather conditions at the crash site at the time of the accident.
There was no indication the plane had mechanical problems before the trip.
(Copyright 2011 by The Associated Press. All Rights Reserved.)