TCAS Not Working in Citation CJ1, 777 Near Midair

 - September 9, 2010, 12:02 PM

The UK’s Air Accidents Investigation Branch (AAIB) yesterday released its incident report on the near midair of a German-registered Cessna Citation CJ1 and a Turkish Airlines Boeing 777 on the afternoon of July 27, 2009, after the business jet crew climbed too quickly after taking off from London City Airport. According to the report, the Citation was barely half a mile from the 777 and between 100 and 200 feet below it when the CJ1 crew took evasive action. Investigators found that the Citation’s traffic collision avoidance system was not functioning at the time of the incident, but that the 777’s TCAS had given traffic alerts and three resolution advisories. The Citation had been cleared to depart London City with an initial climb to 3,000 feet. The pilot read back the clearance as 4,000 feet, and the controller in the airport tower did not correct this error. The 777 was cleared to descend to 4,000 feet on its approach to London Heathrow Airport. The AAIB issued five safety recommendations in its final report on this incident.