The pilot of a Mitsubishi cargo plane and faulty air traffic control procedures share the blame for the fatal crash of the aircraft near Centennial Airport in August 2005, according to the final federal safety report on the accident.
The crash killed pilot Sam Hunter, the plane’s sole occupant.
The probable cause of the accident was “the pilot’s failure to fly a stabilized instrument approach at night, which resulted in controlled fight into terrain,” the National Transportation Safety Board said in the final report.
Hunter hit a hill at an elevation of 6,350 feet, about four miles south of Centennial.
NTSB said contributing factors to the accident included “the inadequate design and function” of Centennial’s Minimum Safe Altitude Warning System and the Federal Aviation Administration’s inadequate procedure for conveying updated safe-altitude information to air traffic controllers.
Radar data showed Hunter’s plane was low as it made a final approach to Centennial about 2 a.m. on Aug. 4.
About a minute before the plane hit the hill, visual and audible low-altitude alerts activated in the FAA’s approach control facility near DIA, yet Centennial’s air traffic tower got only a visual alert on a controller’s computer screen, the NTSB said.
Visual alerts in towers are not fail-safe warning tools because controllers often are looking out tower windows instead of monitoring screens, the agency said.
Air traffic procedures at the time of the accident triggered an audible alarm in the tower only when planes were within five miles of Centennial.
Such an alarm sounded in August 2005, but the plane crashed as the controller radioed an urgent low-altitude warning.
As a result of the accident, the FAA changed procedures to ensure that the audible alarm rings in the tower when a plane is within 10 miles of the airport instead of 5.
Even though the air traffic facility near DIA – which controls aircraft roughly within a 50-mile radius – had earlier warnings that Hunter’s plane was low, controllers there were not required to pass that information on to counterparts in Centennial’s tower, NTSB said.
That also has changed. Now, when approach controllers at DIA get low-altitude alerts, they must call towers with the information as safety backup, according to the FAA.
Staff writer Jeffrey Leib can be reached at 303-954-1645 or jleib@denverpost.com.
