Investigators Reveal Cause Of Near Miss Between Delta A330 & Ryanair 737

Investigators Reveal Cause Of Near Miss Between Delta A330 & Ryanair 737

• A Delta Air Lines Airbus A330-300 narrowly avoided a collision with a Ryanair Boeing 737-800 at Barcelona El Prat Airport.
• Miscommunication and procedural errors by the local arrivals controller and ground movement controllers contributed to the near-miss incident.
• The investigators recommended improving the airport’s lighting control and monitoring system.

The Spanish Civil Aviation Accident and Incident Investigation Commission (Comisión de Investigación de Accidentes e Incidentes de Aviación Civil, CIAIAC) revealed that a Delta Air Lines Airbus A330-300 missed a Ryanair Boeing 737-800 by 700 feet (213.3 meters) while the former was departing Barcelona El Prat International Airport (BCN) on flight DL 169. Both aircraft suffered no damage during the incident and continued to their destinations after the event.

First departure after arrival/departure runway configuration switch

CIAIAC detailed that BCN changed its runway configuration from east to west, which resulted in runway 24R and runway 24L being used for arrivals and departures, respectively, at 15:54 local time. The local arrivals controller (LCL ARR) coordinated with the Barcelona Final Sector 06 approach controller (Final Sector 24 after the runway configuration change) to arrange a take-off for the Delta Air Lines aircraft.

The investigators noted that the Airbus A330-300, registered as N803NW, was supposed to take off as per the previous runway arrival/departure configuration or a non-preferential take-off when the assigned runway is used for landings. However, when the LCL ARR controller contacted the Delta Air Lines crew and asked whether they would be ready for an immediate take-off after reaching their designated holding point, the Airbus A330-300 pilots responded that they would need a minute at 15:58.

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At the same time, the Ryanair Boeing 737-800 requested a pushback from its parking stand to taxi to runway 24L, a parallel runway located at the bottom of the airfield. At 16:00, the Delta Air Lines crew confirmed to LCL ARR that they were ready for departure, yet the controller told the Final 24 controller that the Airbus A330-300 was unable to depart at 16:01, which is why it would leave BCN following an ITA Airways aircraft.

Subsequently, LCL ARR told the Delta Air Lines pilots that there would be three landings before they could depart. Two minutes later, the Ryanair flight crew were informed about their taxi route, which included taxiing through an extension on the taxiway S bypass. The bypass is located on the left of runway 24R.

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Further traffic issues ensued. A medical aircraft was supposed to taxi across the runway, but an easyJet flight, which landed on runway 24R and exited via P5 at 16:05, blocked the medical aircraft’s taxi path. As a result, the medical aircraft taxied for longer than anticipated and could not cross the runway as scheduled. Air Traffic Control (ATC) decided that the Delta Air Lines flight would depart earlier, and at 16:06, LCL ARR cleared the A330-300 for its takeoff from BCN.

Taxiing beyond a stop bar

However, LCL ARR did not coordinate the departure with the north ground movement controller (GMC N). According to the CIAIAC, a non-preferential takeoff procedure has a checklist. The investigators stated that after the delay in the departure of flight DL 169, the arrival controller failed to restart the checklist and skipped a few steps, including the failure to inform GMC N about the approved departure of the A330-300.

BCN’s ground movement controllers are split into three areas of operation: north, central, and south. GMC N is responsible for the northern area, with the controller having already told the Ryanair aircraft to taxi up to DS, which was the boundary of his area of responsibility. The central ground movement controller (GMC C) was responsible for the central area, while the ground movement controller south (GMC C) was responsible for the southern taxiways at BCN.

Furthermore, at that point, the Ryanair Boeing 737-800 was already beyond the S14 stop bar, which lights up to prevent the aircraft from taxiing into the path of a departing aircraft. The airport’s procedures do not allow aircraft to cross taxiway S/M if another aircraft is departing runway 24R since “this obstacle limitation surface would be breached if an aircraft with a height of more than 7m [22 ft – ed. note] crosses the runway extension using the S/M taxiway.” The Boeing 737-800 is 12.5 m (41 ft 3 inches) high.

The investigators revealed that the only reason the Ryanair aircraft stopped was because GMC C alerted GMC N that the Delta Air Lines A330 was already departing at 16:07. At that point, the aircraft was already accelerating on the runway for its departure, reaching a ground speed (GS) of 120 knots, while the Boeing 737-800 was now stationary on the extension of runway 24R, having crossed the S14 stop bar.

Shortly after GMC C advised GMC N about the departing Delta Air Lines aircraft, LCL ARR turned on the stop bar at S14, yet the Ryanair pilots were beyond it, meaning they could not see it. GMC N immediately told his supervisor that he was not aware of potential traffic or a request to stop traffic on taxiway S. The supervisor responded that he would check in with LCL ARR, with the investigators stating that he was not aware of it either, yet at that point, the stop bar was already on.

This resulted in the Delta Air Lines Airbus A330-300 overflying the Ryanair Boeing 737-800 with a vertical separation of 700 ft (213.3 m). The report noted that the Ryanair pilots informed ATC “that they would be reporting the incident as they believed an irregularity had been committed.”

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The incident is still under investigation.

Failure to follow procedures

The CIAIAC concluded that the incident resulted from LCL ARR failing to follow the airport’s procedures and failing to inform GMC N about the Delta Air Lines takeoff. As such, this resulted in the near-miss event.

In addition, the investigators pointed out two contributing factors: an inefficient design of the non-preferential take-off checklist and the ergonomics of the lighting control and indicating system. The CIAIAC has not recommended amending the former since ENAIRE, the air navigation services provider in Spain, is already modifying it.

Still, the CIAIAC advised AENA, the operator of BCN, to collaborate with ENAIRE to improve the lighting control and monitoring system at the airport, making it viewable from the controller’s principal working position. The investigators also said it would benefit ENAIRE to work with AENA to improve the same system, enabling the controller to monitor it from their main working position.

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