Incident Overview
An airplane flying at 3,000 feet in level flight toward its destination airport received a traffic advisory from air traffic control, directing a turn away from approaching traffic located 500 feet below. Simultaneously, the airplane's traffic collision avoidance system (TCAS) alerted the crew and issued a resolution advisory (RA) to climb. The first officer initiated a climb to 3,500 feet, then descended back to 3,000 feet after complying with the RA. During the climb and subsequent descent, a cabin attendant sustained a serious injury.
Flight Crew Response
Data from the flight data recorder showed that the flight crew applied a pitch-up attitude of 14 degrees, resulting in a sustained g-load of 2 g's. This response was significantly more aggressive than recommended by regulatory and manufacturer guidance.
Regulatory and Manufacturer Guidance
Federal Aviation Administration Advisory Circular 120-55b recommends an initial response with no greater than 7 degrees of vertical pitch and a resultant g-load of approximately 0.35 g's. It further advises that the pilot not flying should inform the pilot flying about progress in achieving the vertical rates commanded by TCAS. The manufacturer's airplane operator's manual states that compliance with pitch guidance on the primary flight display should require a maneuver of no more than 0.75 g to 1.25 g (±0.25 g).