N995CA

On July 21, 2004, at 0815 eastern daylight time, a Bombardier CL-600, N995CA, operated by Comair Airlines Inc., as flight 5645, was not damaged during a climb to avoid traffic near Snow Hill, Virginia. The two certificated airline transport pilots, and two non-revenue passengers were not injured. One flight attendant was seriously inured. Visual meteorological conditions prevailed for the flight that departed from the Charleston International Airport (CHS), Charleston, South Carolina, destined for the John F. Kennedy International Airport (JFK), New York, New York. An instrument flight rules flight plan was filed for the scheduled passenger flight conducted under 14 CFR Part 121.

According to the first officer (FO), while in cruise flight at flight level (FL) 290, the crew received an audible traffic advisory (TA) alert from the traffic collision avoidance system (TCAS). The multi-functional display depicted an aircraft at the 12-to 1-o'clock position, about 2,000 feet below, and climbing about 500 feet per minute. As the conflicting aircraft reached approximately 1,400 feet below the CL-600, the first officer visually observed the airplane, announced "traffic in sight, " and alerted the captain to the traffic.

At the same time as the captain instructed the FO to climb, the crew received an aural resolution advisory (RA) warning to "CLIMB, CLIMB" from the TCAS. The FO then disconnected the autopilot and initiated a climb, while advancing the thrust levers. The captain continued his instruction to climb and the vertical speed indicator displayed a rate of ascent of 1,500 feet per minute.

The captain then announced he was taking the controls and proceeded to pitch the airplane at a greater angle. Once the TCAS announced, "clear of conflict," the captain leveled the airplane at 30,000 feet. He then returned the controls to the FO, and the airplane was descended back to FL 290.

After the airplane was level, the captain was informed that the flight attendant was hurt. The flight continued to JFK, where the flight crew requested that paramedics meet the flight to assess the flight attendant's injury.

According to the flight attendant, she was performing a walk-through of the cabin, when she "felt pressure on herself, " and fell to the floor. Two jumpseating passengers in the cabin assisted her to a seat, and retrieved ice for her ankle. After landing, she was transported to an urgent care facility, and diagnosed with a broken ankle.

A review of radar data and air traffic control information provided by the Federal Aviation Administration (FAA), revealed that the Comair flight was climbing at a rate of 2,500 feet per minute and an airspeed of 483 knots. The airplane which caused the traffic alert for the Comair crew was an MD-80, which was climbing at 2,000 feet per minute, and an airspeed of 433 knots. The closest proximity between the two aircraft was 1.54 nautical miles and 1,500 feet.

According to the Comair CL-600 Flight Standards Manual, "the correct response to a corrective RA is to fly from the red zone into the green zone. This maneuver requires a response within 5 seconds of the advisory using approximately a 0.25g maneuver. Listed below [is one] possible corrective RA aural warning:

- 'CLIMB, CLIMB,' - Climb at the rate shown on the VSI, normally 1,500 FPM."

A performance review of the radar data revealed the flight crew response to the TCAS alert included a 1000-foot climb, followed immediately by a descent back to the airplane’s assigned altitude. The entire maneuver lasted about a minute and a half. While the nature of the radar data that tracked the flight did not allow the load factors in the cabin to be computed with certainty, the maneuver described by the radar data could be performed using an initial 1.15 G pull-up to start the climb, followed by a 0.05 push-over to arrest the climb and start the descent, followed by a 1.4 G pull-up to level the airplane at the assigned altitude. In this sequence, the time between the 0.05 G push-over and the 1.4 G level-off was about 5 seconds.

According to Comair training documents, flight crews receive initial TCAS training, during simulator LOFTs. During recurrent training, TCAS training/demonstrations may be built into specific LOFT scenarios.