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."