Excessive Avoidance Maneuver Led To Fall

According to a National Transportation Safety Board (NTSB) probable cause report published last week, the pilot of a corporate jet was at fault for the October 2006 injury to a flight attendant during a flight from Washington's Dulles International Airport to Teterboro Airport in New Jersey.

The report stated while receiving radar vectors for an instrument approach, the pilots of the Bombardier CL-604 Challenger received a traffic advisory from the airplane's Traffic Alert and Collision Avoidance System (TCAS). The report notes the pilot-in-command "yanked the controls" out of the copilot's hands, and began a climbing left turn that resulted in an 800 foot increase in altitude. 

The sudden movement caused the flight attendant in the cabin to fall and break her left leg.

Air Traffic Control issued traffic information to the Challenger crew, advising them of traffic at their 2 o'clock position, 1 mile northwest bound, at 2,800 feet unverified but did not consider the airplane to be on a collision course. Later, ATC reported the aircraft triggering the TA to be a Cessna 172 flying under Visual Flight Rules, transmitting a transponder code of 1200, and not in voice communication with any ATC facility.

Neither pilot made visual contact with the triggering aircraft. The Challenger landed without further incident, and the flight attendant was transported to a nearby hospital for treatment.

The NTSB's analysis of the flight data recorder airplane's flight data recorder indicated a maximum angle of attack of 15.6 degrees, a maximum bank of 32 degrees, and an altitude increase to 3,778 feet in 16 seconds. The entire maneuver lasted 40 seconds, rate of climb peaked at 2,628.75 feet per minute, and maximum acceleration reached 2.3 Gs.

In the report, the NTSB found the pilot's maneuver to be excessive, and well beyond the recommended procedures outlined by the operating company in response to a TCAS alert.

According to the Probable Cause report, the operator also warned "maneuvers based solely on TCAS traffic advisories (TA), without visual acquisition of the intruder were not recommended, and that, 'certain vertical speeds were not safe' and that the flight crew should monitor their vertical speed indicator (VSI) and keep the VSI pointer out of the 'red prohibited area.'"

The operator also noted pilots should "be prepared to maneuver" should TCAS then issue a resolution advisory (RA), adding those manuevers should be done "promptly and smoothly."

FMI: Read The Probable Cause Report