A close call between a United Airlines flight departing San Francisco International Airport and a Cessna 182 over the weekend has the aviation world busy trying to figure out what happened that allowed the two airplanes to get so close. According to the pilots, the aircraft came within an estimated 300 feet of each other. Both aircraft were communicating with the control tower at the time.
The National Transportation Safety Board has released the audio from the control tower that includes the communication between the tower, the United 777 bound for Beijing and the Cessna. The NTSB is investigating the incident and said in a statement it is taking "strong measures to make sure something similar does not occur in the future."
It is routine and legal for small aircraft to fly near large airports such as San Francisco International. Many large airports, including Los Angeles International, have published routes known as a VFR corridors that allow smaller aircraft to safely navigate through the busy airspace.
Aviation expert and veteran flight instructor Max Trescott does a great job of explaining the incident with an analysis of the airspace rules surrounding the area. As Trescott explains, the controller was in contact with both airplanes, but it is unclear whether or not the instructions were given in a timely enough manner.
It appears the pilots of the United briefly leveled off their departure after their onboard traffic collision avoidance system (TCAS) alerted them to the Cessna's position. In the audio, the controller can be heard handing off the United flight to the next air traffic controller (Norcal Departure), indicating nothing unusual had occurred. The United pilot replies that the incident had set off the TCAS and follows up with, "we need to talk," indicating something more serious had occurred.
The NTSB will likely take several months to investigate the incident before releasing a final report.
Photo of San Francisco International Airport: caribb/Flickr
