Mesa Airlines Bombardier Inc CL-600-2D24 incident

This incident occurred after the local controller (LC) cleared SkyWest Airlines (dba United Express) flight 5326 (SKW5326) for takeoff from runway 33 at Bob Hope Airport (BUR) and instructed Mesa Airlines (dba American Eagle) flight 5826 (ASH5826) to continue its approach to land on the same runway. At the time of takeoff clearance, ASH5826 was 1.6 miles from the threshold of the same runway. Shortly after SKW5326 began its takeoff roll, the flight crew of ASH5826 determined the separation was insufficient and initiated a go-around. At this time, SKW5326 was at a groundspeed of 27 kts and accelerating across the runway threshold, and ASH5826 was 4,200 ft from the threshold at an altitude of 300 ft above ground level (agl).

The LC instructed ASH5826 to climb and maintain 4,000 ft, and fly the runway heading, which put their airplane on a converging course with SKW5326, who was on the assigned standard instrument departure (SID) heading of 270. Twenty-seven seconds later, the LC instructed ASH5826 to turn right, heading 270 then changed it to turn left, heading 270 which put the two airplanes on parallel headings. Forty-seven seconds later, the crew of ASH5826 reported they were responding to a TCAS RA [traffic alert and collision avoidance system resolution advisory], and the LC instructed them to turn right 30 degrees, then changed the instruction to a left 30-degree turn. The airplanes’ closest point of separation was 1,680 ft during the left turn. After that, the separation began to increase and both airplanes were handed off to Southern California Terminal Radar Approach Control.

Federal Aviation Administration (FAA) Order 7110.65Z, Air Traffic Control, Chapter 2, section 1, paragraph 2-1-6, Safety Alert, requires controllers to “issue a safety alert to an aircraft if they are aware the aircraft is in a position/altitude that, in your judgment, places it in unsafe proximity to terrain, obstructions, or other aircraft.” However, for this event, the local controller did not issue a traffic advisory or safety alert, as required, to either of the flight crews immediately after ASH5826 reported going around, or during the following minutes when both airplanes were in an unsafe proximity to each other.

Prior to the incursion, at 18:53:06, the LC instructed SKW5326, which was on the ground departing Burbank, to turn right onto runway 33 and to Line Up and Wait (LUAW). The aircraft performance study found that at this time, ASH5826, was 7.9 NM (9 statute miles) from the threshold, at 2,800 ft above ground level (agl), and approaching runway 33 at BUR. According to FAA Order 7110.65Z, Air Traffic Control, Chapter 3, section 9, paragraph 3-9-4, the intent of LUAW” is to position aircraft for an imminent departure.”

About 19 seconds later, ASH5826 checked in with BUR tower, and the local controller advised the crew that traffic (SKW5326) was holding in position on runway 33, and they were instructed to continue their approach. SKW5326 entered runway 33 and by 1854:30 the airplane was aligned with the runway heading and stopped behind the runway threshold waiting for a takeoff clearance.

Around this time, the LC instructed an uninvolved visual flight rules (VFR) Cirrus airplane to perform a go-around on runway 26. During a postincident interview, the LC stated the go-around was issued because the airplane was too high for the approach. However, the LC did not inform the Cirrus pilot of the reason for the go-around, but the pilot complied immediately with ATC instructions. The LC then instructed the Cirrus pilot to turn base for runway 33 and follow a regional jet (ASH5826) on a 2-mile final. Several transmissions were conducted between the Cirrus pilot and the LC because there was confusion on which cross wind traffic pattern leg the pilot should fly.

The LC’s communications with the Cirrus may have been a distraction that delayed the takeoff clearance for SKW5326, which would have reduced separation between the two airplanes. Further, the focus on the Cirrus may have prevented the LC from performing an adequate scan of the runway and airport environment to determine the positions of SKW5326 and ASH5826 before issuing a takeoff and landing clearance, respectively.

FAA Order 7110.65Z, paragraph 3-10-3, Same Runway Separation, instructed a controller to “separate an arriving aircraft from another aircraft using the same runway by ensuring that the arriving aircraft does not cross the landing threshold until…the other aircraft has departed and crossed the runway end.”

At the time of the incident, the BUR airport traffic control tower did not have surface detection equipment which would have allowed air traffic controllers to track the movement of aircraft and vehicles on airport surfaces and on final approach. This type of system would provide controllers with visual and aural warnings when a potential conflict existed. Had BUR tower been equipped with this technology, it would have alerted the controller to the reduced separation between the two airplanes prior to the SKW5326 takeoff clearance. It likely would have also detected the potential conflict during the initial portion of the ASH5826 go-around. These warnings would have likely allowed the controller to prevent these conflicts altogether or reduced their severity.

Verbatim NTSB analysis and probable cause from the NTSB dataset