The National Transportation Safety Board has determined that the probable cause of the crash that killed Senator Ted Stevens and four others “was the pilot’s temporary unresponsiveness for reasons that could not be established from the available information.” Contributing to the investigation’s inability to determine more precisely what caused the crash in the mountains near Aleknagik, Alaska, was the lack of a cockpit recorder system with the ability to capture audio, images, and parametric data, NTSB officials said.
“One of the greatest lessons from this tragedy is the powerful reinforcement of the need for onboard crash resistant recorder systems,” said NTSB Chairman Deborah A.P. Hersman. “With onboard recorders, we can learn so much more from crashes like this one to prevent future tragedies and loss of life.”
According to the recently released NTSB report, on Aug. 9, 2010, at about 2:27 p.m., the de Havilland turbine Otter floatplane flown by Theron Smith, 62, a 28,000-hour pilot, departed a private lodge on the shore of Lake Nerka en route to a remote fishing camp approximately 52 miles southeast on the Nushagak River. The pilot was highly experienced and familiar with the route, the report noted. “However, during the flight, the airplane turned toward the east-northeast, away from the intended destination, and crashed into mountainous terrain at about 2:42 p.m.,” it continued.
While Stevens and Smith, along with three other passengers, were killed, four passengers survived, including former NASA chief Sean O’Keefe and his teenaged son.
NTSB investigators point to the pilot’s medical history, which included an intracerebral hemorrhage on March 3, 2006, as a possible cause. His most recent first-class medical certificate was issued Dec. 1, 2009. “This tragedy also highlights inadequate FAA guidance related to the medical certification of pilots who have had a cerebrovascular event,” Hersman added.
As for the airplane, it was equipped with a variety of avionics designed to assist the pilot with navigation, situational awareness, and terrain avoidance. However, like most GA aircraft, the Otter was not equipped with a cockpit voice recorder, flight data recorder, or other crash resistant flight recorder. Minutes prior to the crash, the last position report showed the plane on course. “What we do not know, and can never know, is what happened in the last three minutes of that fatal flight,” Hersman said.
Recommendations arising from the accident include revising the FAA’s issuance of medical certificates after an ischemic stroke or intracerebral hemorrhage; correcting any deficiencies with Automated Weather Sensor System stations to ensure they provide accurate, real-time information; and calling on the FAA to require “all existing turbine-powered, non-experimental, non-restricted-category aircraft” to have crash-resistant flight recorder systems for cockpit audio, “a view of the cockpit environment” and flight data.
A synopsis of the NTSB report, including the probable cause, conclusions, and safety recommendations is available at: NTSB.gov/Events/2011/Aleknagik_AK/synopsis.htm. The NTSB’s full report will be available online in several weeks.