The National Transportation Safety Board (NTSB) has published a preliminary report concerning a runway excursion incident involving United Airlines flight 2477 (UA2477). The event occurred on the morning of March 8, 2024, at George Bush Intercontinental Airport (IAH), when the Boeing 737-8 MAX, registered as N27290, veered off the runway while transitioning to a taxiway after its arrival from Memphis International Airport (MEM). The incident led to the aircraft’s left main landing gear striking a submerged concrete structure and detaching.

Remarkably, despite the severe circumstances surrounding the incident, all 166 individuals on board, including 6 crew members and 160 passengers, were evacuated safely with no injuries reported. The flight, operating under Part 121 as a scheduled domestic passenger service, thus averted what could have been a far more catastrophic outcome.

The NTSB, alongside parties including the Federal Aviation Administration (FAA), United Airlines, The Boeing Company, and the Air Line Pilots Association (ALPA), promptly initiated an investigation into the events leading up to the accident. These investigations have revealed critical moments and decisions that played pivotal roles in the incident.

Critical Moments and Decisions Unveiled

The preliminary findings offer a detailed account of the flight’s final moments. The aircraft’s captain, acting as the pilot flying, alongside the first officer, encountered unexpected slippery conditions upon landing, contrary to the anticipated dry runway conditions. Despite an uneventful touchdown and the deployment of speed brakes and thrust reversers, the decision to manually brake late in the landing sequence, coupled with a last-minute effort to exit the runway onto taxiway SC, culminated in the aircraft’s slide off the pavement.

A notable revelation from the report is the disparity between the captain’s expectations and the actual runway conditions, exacerbated by the captain’s decision to expedite the deceleration process for passenger comfort, which ultimately compromised the aircraft’s stopping capabilities.

Investigative Focus and Ongoing Analysis

The NTSB’s thorough examination extends to the crew’s actions, the aircraft’s mechanical status, and environmental factors at the time of the incident. The captain, with extensive experience, particularly on the B-737, and the first officer, though less experienced, were both deemed highly qualified. However, the interaction of human decisions, aircraft performance, and environmental conditions remains a focal point of the investigation.

Further analysis of UA2477’s flight data recorder (FDR) and cockpit voice recorder (CVR) information, along with ADS-B data, will provide additional insights into the precise dynamics of the flight’s landing and runway excursion.

The NTSB’s investigation into UA2477 is ongoing, with further updates anticipated as new information becomes available.

About the aircraft

The aircraft at the center of the incident, registered as N27290, is a Boeing 737 MAX 8 that was constructed in Renton and is approximately 4.39 years old. Its first flight took place in October 2019, amid the grounding of the 737 MAX fleet. The delivery to United Airlines was completed on June 8th, 2023. This aircraft carries the Manufacturer’s Serial Number (MSN) 44309.