United Airlines Boeing 737 Collides with Deicing Trucks at Denver Airport

This article is based on an official preliminary report from the National Transportation Safety Board (NTSB).

On April 9, 2026, the National Transportation Safety Board (NTSB) released its preliminary report detailing a March 6 ground collision at Denver International Airport (DEN). The incident involved a United Airlines Boeing 737-800 and two deicing trucks operated by ground contractor Aeromag.

According to the NTSB’s initial findings, the collision resulted in substantial damage to the commercial aircraft and minor injuries to one ground worker. Fortunately, zero injuries were reported among the passengers or flight crew. The event highlights the critical nature of communication protocols during winter weather operations, particularly in airport zones where air traffic control does not actively manage aircraft movement.

We are reviewing the sequence of events outlined by federal investigators, which points to a premature taxiing decision following a misunderstood radio clearance between the flight deck and the deicing team.

The Incident and Sequence of Events

Deicing Operations at Pad C

The incident occurred on Friday, March 6, 2026, at approximately 8:30 a.m. local time. United Airlines Flight 605, a scheduled service from Denver to Nashville International Airport (BNA), was positioned at Deice Pad C, Spot C5. According to the NTSB preliminary report, the Boeing 737-800 (registration variant 737-824) had 136 total occupants on board, comprising 130 passengers, two pilots, and four flight attendants.

The aircraft was actively receiving Type 4 deicing fluid to combat the heavy snowfall brought on by a winter weather advisory in Colorado. The NTSB notes that four Aeromag trucks were servicing the plane: trucks designated MAG 94 and MAG 95 were positioned forward of the wings, while MAG 28 and MAG 30 were positioned aft of the wings.

Communication Breakdown and Collision

The preliminary findings point toward a critical miscommunication as the catalyst for the collision. According to flight crew statements provided to the NTSB, the pilots were engaged in a conversation when the first officer heard a post-deice briefing over the radio. The captain was reportedly unsure if the clearance was intended for their specific flight. However, the first officer acknowledged the brief and read back the details, stating that all deice vehicles were behind the clearance lines.

Believing they were clear to proceed, the flight crew conducted their post-deice checks, received standard taxi clearance from Air Traffic Control (ATC), and began to move the aircraft forward. Ground deicing agents observed the plane moving but were unable to halt its progression.

The aircraft’s left wing struck truck MAG 94, and the right wing struck truck MAG 95, pushing MAG 95 onto its side.

Sequence of events as detailed in the NTSB preliminary report.

The flight crew felt the impact, immediately stopped the aircraft, and contacted the deicing team via radio. The ground team then informed the pilots that they had not been cleared to exit the pad and had struck two vehicles.

Aircraft Damage and Emergency Response

Assessing the Boeing 737

The NTSB reported that the Boeing 737 sustained “substantial damage” during the ground collision. Post-accident examinations documented extensive damage to multiple components of the aircraft. According to the official report, the impact damaged the left winglet, the left wing lower skin, slats number 1, 5, 6, 7, and 8, the right wing lower skin, and the right aileron.

Passenger and Crew Handling

Following the collision, the Denver Fire Department and local paramedics quickly responded to Deice Pad C. The injured Aeromag deicing operator was secured on a backboard and transported to a local hospital for treatment of minor injuries. Because of the substantial damage, the aircraft was immediately taken out of service. Passengers safely deplaned via air stairs, were bused back to the terminal, and were re-accommodated on a replacement aircraft later that afternoon.

Industry Context and Safety Protocols

Operating in Non-ATC Controlled Areas

The Federal Aviation Administration (FAA) noted that the collision occurred in a designated deicing pad area where Air Traffic Control does not actively manage or oversee aircraft movements. In these specific zones, pilots must rely entirely on direct radio communication and visual signals from ground crews to ensure the safety envelope around the aircraft is clear before advancing the throttles.

Deicing is a high-pressure, fast-paced necessity during winter weather events. Strict adherence to communication protocols is required to prevent ground accidents, especially when visibility is reduced by heavy snowfall and multiple heavy vehicles are operating in close proximity to aircraft wings.

AirPro News analysis

The ongoing NTSB and FAA investigations will likely heavily scrutinize the radio communication protocols between airline flight decks and third-party ground contractors. This incident underscores a known vulnerability in aviation ground operations: the handoff between ground service providers and flight crews in non-ATC controlled areas. Because the captain expressed initial doubt about whether the clearance was meant for their aircraft, investigators will likely examine whether call-sign verification procedures were strictly followed. We anticipate that the final NTSB report may lead to new safety recommendations regarding how clearances are verified and visually confirmed before an aircraft is permitted to move in an active deicing zone.

Frequently Asked Questions

What flight was involved in the Denver ground collision?

The incident involved United Airlines Flight 605, a Boeing 737-800 scheduled to fly from Denver International Airport (DEN) to Nashville International Airport (BNA) on March 6, 2026.

Were there any injuries reported?

Yes. One ground worker operating an Aeromag deicing truck suffered minor injuries and was transported to a local hospital. There were zero injuries reported among the 136 passengers and crew members on board the aircraft.

What caused the collision?

According to the NTSB’s preliminary report, the collision was preceded by a communication breakdown. The flight crew believed they had received clearance from the ground team that all trucks were behind the clearance lines, prompting them to taxi forward prematurely while trucks were still actively positioned near the wings.

Sources: NTSB Preliminary Report