The National Transportation Safety Board Tuesday determined that a combination of flight crew and air traffic control deficiencies led to the crash of an air ambulance near San Diego.
"The Board has seen too often in its investigations where the flight crew and/or controllers are not performing their duties as they should," said NTSB Acting Chairman Mark Rosenker. "We can not emphasize enough the importance of following the appropriate procedures to help ensure safety."
On October 24, 2004, a Learjet 35A operated by Med Flight Air Ambulance, crashed into mountainous terrain shortly after takeoff from Brown Field Municipal Airport, near San Diego. The captain, the copilot, and three medical crewmembers were killed. The airplane was destroyed.
The Board determined that the probable cause of the accident was the flight crew's failure to maintain terrain clearance during a visual flight rules (VFR) departure, which resulted in controlled flight into terrain, and the air traffic controller's issuance of a clearance that transferred the responsibility for terrain clearance from the flight crew to the controller.
The Board's investigation revealed that according to the Federal Aviation Administration's (FAA) Aeronautical Information Manual (AIM), the recommended procedure for departing under VFR at night in areas of mountainous terrain is to adhere to the airport's takeoff minimums and departure procedures for instrument flight rules (IFR). The accident captain and copilot did not follow the recommended departure procedure and instead flew the airplane straight out on a heading toward the mountains and leveled off at an altitude of 2,300 feet, presumably to maintain VFR below the cloud ceiling.
The controller identified the airplane on the radar screen, provided the flight crew with a heading, and instructed the crew to maintain VFR and expect an IFR clearance above 5,000 feet. The captain acknowledged the heading instructions; however, the heading issued by the controller resulted in a flight track that allowed the airplane to continue directly toward mountains. This was also the time, the Board noted, that the controllers computer system generated aural and visual MSAW alerts on the display, yet the controller took no action to warn the flight crew about the MSAW alerts.
The Board pointed out that although the flight crew is responsible for maintaining terrain clearance while operating under VFR, FAA rules state that, when an aircraft is operating under VFR below minimum IFR altitudes and the flight crew requests an IFR clearance, the controller should ask the crew if they would be able to maintain terrain and obstruction clearance during the climb to the minimum IFR altitude. It was reported to the Board that the controller was unaware of this responsibility. The controller had the knowledge and opportunity to alert the flight crew to an unsafe condition, but failed to take appropriate action to do so, the Board concluded.
Contributing to the accident was the pilots' fatigue, which likely contributed to their degraded decisionmaking, the Board stated. At the time of the accident, the captain had been awake about 17.5 hours, and the co-pilot had been awake about 16 hours, and both pilots had accumulated about 11 hours duty time. The Board noted that although the duty and rest times of both flight crewmembers were in compliance with Part 135 rules, the accident flight departed about 3 hours past both crewmembers' normal bedtimes at the end of a long duty day.
A synopsis of the report can be found on the Board's website, www.ntsb.gov.
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