N316PF – The Boeing Company 737-800 – 2026-06-20 NTSB Accident Report

On June 20, 2026, about 1134 eastern daylight time (EDT), Delta Air Lines flight 2351 (DAL2351), an Airbus A319, and American Airlines flight 3161 (AAL3161), a Boeing 737-800, were involved in a runway incursion that resulted in a go-around of DAL2351 at General Edward Lawrence Logan International Airport (BOS), Boston, Massachusetts. There were no injuries reported to the 131 passengers and 5 crewmembers on board DAL2351 or the 176 passengers and 6 crewmembers on board AAL3161. There was no damage to either airplane.

DAL2351 was a scheduled domestic passenger flight operating under the provisions of Title 14 Code of Federal Regulations (CFR) Part 121 from Dallas Fort Worth International Airport (DFW), Dallas-Fort Worth, Texas, to BOS. AAL3161 was a scheduled domestic passenger flight operating under the provisions of Title 14 CFR Part 121 from BOS to Charlotte-Douglas International Airport (CLT), Charlotte, North Carolina. At the time of the runway incursion, DAL2351 was descending to land on runway 33L when AAL3161 began its takeoff roll on runway 27. After the go-around, DAL2351 landed in BOS without incident while AAL3161 continued their takeoff and completed their flight to CLT without incident.

As part of the investigative process, the NTSB invited qualified parties to participate in the investigation. Parties to the investigation include the Federal Aviation Administration (FAA), National Air Traffic Controllers Association (NATCA), Delta Air Lines, American Airlines, Air Line Pilots Association (ALPA), Allied Pilots Association (APA), and Boeing. In accordance with the International Civil Aviation Organization (ICAO) Annex 13, the Bureau d’Enquêtes et d’Analyses pour la Sécurité de l’Aviation Civile (BEA) of France, representing the State of Design of the Airbus A319 airplane, was notified of the investigation. The parties were formed into specialized investigative groups led by NTSB group chairmen in the areas of Air Traffic Control (ATC), Operations, and Human Performance. Additionally, NTSB specialists in the areas of Meteorology, Aircraft Performance, and Recorders were assigned to the investigation.

At the time of the incident, a local control west (LCW) controller, a local control east controller (LCE), a ground control (GC) controller, a clearance delivery (CD) controller, and an operations supervisor (OS) were present in the BOS ATC tower cab. The LCW controller was responsible for aircraft departure and arrival operations on runways 27 and 33L. The LCE was responsible for traffic coordination, monitoring the LCW position, writing flight strips, and local helicopter traffic. See figure 1 below for a BOS airfield diagram.

Figure 1. BOS airfield diagram showing runways 27 (highlighted blue) and 33L (highlighted yellow). A red arrow points to the runway intersection for this incident.

Certified ATC audio recordings and Automatic Dependent Surveillance-Broadcast (ADS-B) data for the incident were provided by the FAA. Table 1 provides key transmissions between the LCW controller and the flight crews of DAL2351 and AAL3161 as well as key events from ADS-B data.

Table 1. Key transmissions between the BOS ATC tower LCW and the flight crews of DAL2351 and AAL3161. All times are approximate and presented in EDT.

Time (EDT)

Event

1132:21

LCW instructed AAL3161 to “line up and wait” on runway 27 and advised that traffic was landing on runway 33L. Crew of AAL3161 subsequently acknowledged instruction.

1132:35

LCW provided landing clearance to DAL2351 for runway 33L and that traffic is holding on runway 27. Crew of DAL2351 subsequently acknowledged instruction.

1133:14

AAL3161 positioned at the threshold of runway 27.

1133:33

Tradewind Aviation flight 82 (GPD82), a Pilatus PC-12, crossed the threshold of runway 33L and subsequently landed.

1133:43

LCW provided takeoff clearance to AAL3161 for runway 27.

1133:46

Crew of AA3161 acknowledged the takeoff clearance. Additionally, GPD82 crossed the intersection of runways 33L and 27.

1134:02

LCW instructed GPD82 to turn left on taxiway T and to expedite its taxi because traffic was on a 1.25-mile final. Crew of GPD82 subsequently acknowledged.

1134:06

AAL3161 velocity began to increase from zero, but then decreased to zero 8 seconds later.

1134:20

LCW instructed GPD82 to continue on runway 27 and turn left on taxiway T.

1134:31

LCW provided GPD82 with additional taxi instructions.

1134:33

GPD82 exited runway 27 onto taxiway T.

1134:37

AAL3161 velocity began to increase.

1134:45

Crew of DAL2351 began to communicate to the LCW that they were initiating a go-around due to AAL3161.

1134:50

LCW queried AAL3161 on where they are going. Crew of AAL3161 subsequently replied to the LCW that they had been cleared for takeoff.

1135:05

LCW provided go-around instructions for DAL2351.

A preliminary estimate of the closest proximity between DAL2351 and AAL3161 determined they were about 670 ft apart, as shown in figure 2.

Figure 2. Profile view of the DAL2351 and AA3161 flight tracks. The yellow arrows point to the locations of the two airplanes at the time of their closest proximity to each other, which was about 670 ft.

Airport Surface Detection Equipment – Model X (ASDE-X)

BOS was equipped with Airport Surface Detection Equipment – Model X (ASDE-X), a system that provides ATC controllers with visual and aural alerts to runway conflicts through predictive system logic. BOS was also equipped with Runway Status Lights (RWSL), an automated system that provides situation awareness to flight crews and vehicle operators regarding potential conflicts at runway and taxiway intersections that are detected using surface radar surveillance. The RWSL system at BOS included takeoff hold lights (THL) on runways 9/27 and 15R/33L. The THL illuminate red when the system control logic determines it is unsafe to depart the runway due to a predicted conflict and extinguish when there is no predicted conflict.

A preliminary review of the ASDE-X data from the incident by the FAA determined that the system generated an aural and visual alert for a predicted conflict involving converging targets, specifically DAL2351 and AAL3161. Additionally, a preliminary analysis by the FAA of the performance of the RWSL determined that the THL for runway 27 had illuminated while AAL3161 was lining up at the threshold of runway 27 and GPD82 was approaching runway 33L to land. After GPD82 had landed and was about to cross the intersection with runway 27, the THL for runway 27 extinguished.

The THL for runway 27 illuminated red again when DAL2351 was on final approach to runway 33L, and subsequently extinguished when DAL2351 was crossing the intersection with runway 27.

Both DAL2351 and AAL3161 were each equipped with a cockpit voice recorder (CVR) that recorded a minimum of 2 hours of cockpit audio. By the time investigators requested the CVRs be quarantined for each airplane, the CVR data for the incident flight had been overwritten. The digital flight data recorder (DFDR) from each airplane still contained flight data from the incident. These data are currently being analyzed by investigators.

Delta Air Lines Flight 2351 (DAL2351) Flight Crew Statements

Postincident statements provided by the DAL2351 flight crew revealed the first officer (FO) was the pilot flying and the captain was the pilot monitoring. The captain stated that, once Tradewind Aviation flight 82 (GPD82), a Pilatus PC-12, passed through the intersection of runways 33L and 27, they heard AAL3161 receive a takeoff clearance and their understanding was that AAL3161 would depart and be clear of runway 33L before their arrival. The captain recalled seeing AAL3161 move forward slightly, and then stopped and remained stationary. The captain told the FO he would monitor GPD82 until it cleared runway 33L as well as the progress of AAL3161 through the runway intersection.

The captain recalled seeing AAL3161 initiate its takeoff roll at about 500 ft, and as AAL3161 approached the 1,000-ft markers on runway 27, the captain instructed the FO to initiate a go-around, which the FO stated he immediately executed. The FO stated he was unable to see AAL3161 during initiation of the go-around due to obstruction from the cockpit window pillar that was within his field of view. The captain stated they did not receive a traffic alert and collision avoidance system (TCAS) alert at any time during the incident.

American Airlines Flight 3161 (AAL3161) Flight Crew Interviews

Postincident interview of the AAL3161 flight crew revealed that the taxi to runway 27 was uneventful. The FO was the pilot flying and the captain was the pilot monitoring. When AAL3161 was cleared to take off, the FO advanced the engine thrust levers to 40% power. After the engines stabilized, the FO pressed the takeoff/go-around (TOGA) button and then received a takeoff configuration warning; the FO immediately pulled engine power back to idle. The captain checked the flaps, trim, parking brake, and speedbrake to verify that the takeoff configuration was correct.

After the flight crew concluded the takeoff configuration warning was likely erroneous, the FO advanced the thrust levers for take off. When approaching the intersection of runways 27 and 33L, the captain stated he saw DAL2351 initiating a go-around. The AAL3161 flight crew determined they would not be in further conflict with DAL2351 and elected to continue their takeoff. Both the captain and FO stated they did not see any RWSLs illuminated.

Boston Air Traffic Control Tower Interviews

Postincident interviews of the BOS ATC tower LCW, LCE, and OS revealed that there were no notable distractions or anomalies within the tower cab during the time leading up to the runway incursion. The controllers interviewed characterized both the traffic and complexity as moderate-to-low at the time of the incident. The LCW recalled that, after seeing GPD82 land, he cleared AAL3161 for takeoff and thought he saw the airplane begin its takeoff roll. Believing that AAL3161 would continue its takeoff, and not receiving further communication from the crew of AAL3161, the LCW stated he subsequently focused his attention back on GPD82 to ensure they would vacate runway 33L in time for DAL2351 to land.

The LCW recalled hearing the ASDE-X alert, looked out the tower cab window, and recalled feeling confused since GPD82 was exiting runway 33L at that time. The LCW stated he normally canted the flight strip on the strip bay after giving a takeoff clearance, but saw the flight strip for AAL3161 was not canted when the runway incursion occurred, leading him to believe that he must not have cleared them for takeoff. The LCE recalled that, during the time leading up to the runway incursion, he was writing flight strips for the LCW and was also monitoring GPD82 as the LCW was providing them multiple taxi instructions.

The LCE stated he became aware of the runway incursion when DAL2351 began to communicate they were going around, after which the ASDE-X alerted, and he saw DAL2351 performing a go-around while AAL3161 was rolling down runway 27. The OS stated that, prior to the incident, he was contacted by a supervisor at the Boston Consolidated Terminal Radar Approach Control (TRACON) about a prior pilot deviation. The OS was looking through their logs to research this prior pilot deviation when he heard the LCW instruct GPD82 to expedite their taxi on runway 33L. The OS recalled looking at the intersection of runway 33L and taxiway T when he saw the nose of DAL2351 rise up, after which the ASDE-X alerted.

The NTSB’s incident investigation is ongoing.