A US investigation into a hazardous proximity incident involving a JetBlue Airbus A320 and a Bombardier Learjet 60 in April 2012 has pointed to a lack of procedures to ensure separation in the event of a go-around on runways with intersecting flight paths.

In its report released on 13 March, the US National Transportation Safety Board (NTSB) said the lack of such procedures was the probable cause behind the incident that took place at Las Vegas airport on 27 April 2012. No one was injured and neither aircraft was damaged in the incident.

In the incident, the A320's flight crew was conducting a visual approach to runway 25L at the airport while the Mexican-registered Learjet 60 was simultaneously being cleared for take-off from runway 19L.

The A320's pilots chose to execute a go-around and came into dangerous proximity with the Learjet 60 as it was departing, said the NTSB. The A320 made an "evasive turn" to the left while the Learjet 60 initiated a rapid climb.

The closest proximity of the two aircraft was 100ft (30.5m) vertically and 0.3nm (0.56km) laterally. "After the pilot of the A320 executed the go-around, neither local controller was able to provide control instructions to separate the two aircraft," said the NTSB.

The two runways were non-intersecting converging runways with intersecting flight paths.

The NTSB said the two aircraft were being controlled by different air traffic controllers who were simultaneously routing aircraft to land on 25L and take off from 19L. Such a procedure was not prohibited by the US Federal Aviation Administration, said the NTSB. "There were no FAA-prescribed separation minima or procedures for air traffic controllers to follow when conducting simultaneous independent converging runway operations in the event a pilot elected to execute a go-around," said the NTSB.

"This resulted in the aircraft going around coming into close proximity with the departure aircraft where the flight paths intersected."

In its report, the NTSB said that while the two runways do not physically intersect, the flight paths of the runways intersect approximately 0.32 nautical miles past the departure end of 19L.

The airport has four runways: 19L/R and 25 L/R. During the day of the incident, runway 25L was being used for arrivals, runway 25R was being used for departures and runways 19L/R were being used for both arrivals and departures.

Source: Air Transport Intelligence news