What Caused The 2019 Jacksonville Boeing 737 Runway Excursion?

Over two years have passed since a Miami Air International 737-800 overran a wet runway in Jacksonville, Florida. The incident was blamed on an “extreme loss of braking friction.” With the US’ National Transportation Safety Board (NTSB) recently releasing its full 32-page accident report, let’s take a look at the findings of the investigation.

737 runway excursion
The incident took place on May 3rd, 2019, at Jacksonville Naval Air Station. Photo: NTSB

Incident details

With so much time having passed since the incident occurred, let’s first take a look at what happened before we go over the NTSB’s findings.

On May 3rd, 2019, a 737-800 operated by Miami Air International was chartered to fly from Leeward Point Field in Guantanamo Bay, Cuba (NBW) to Jacksonville Naval Air Station, Florida (NIP). Onboard were two pilots, four flight attendants, one mechanic (in the jumpseat), and 136 passengers. The aircraft had been chartered to transport US Department of Defense personnel from Guantanamo Bay.

Touchdown of the 737 occurred at 21:41, about 20 ft right of centerline, 1,580 ft past the displaced threshold. The Captain reports that he applied brake pressure after touchdown, but the airplane did not decelerate, nor did he notice any antiskid activation.

737 Excursion
The aircraft was unable to come to a stop before the end of the runway, hitting the airport’s seawall. Photo: NTSB

The Captain also states that the No. 2 engine thrust reverser was deployed, applying enough pressure to the thrust reverser lever “that it left a mark on his fingers.” The airplane began to “slide a little to the right,” which was corrected with the rudder to get the airplane back on the centerline.

Despite all of the efforts made to slow the aircraft down, the aircraft departed the paved surface and impacted the seawall of Jacksonville Naval Air Station. Ultimately, one minor injury was reported, with the remainder uninjured. Sadly, several animals carried in the cargo compartment died in the accident.

The airplane was substantially damaged, with portions of the engine cowlings, the radome, and both main landing gear separated during the accident sequence. These parts ended up in the water adjacent to the airplane or on the rock embankment. Three life rafts were recovered in the water around the airplane.

NTSB’s final conclusions

Having had time to analyze the aircraft’s flight data recorder, inspect the aircraft post-accident, and interview all crew involved, the NTSB has finally issued its conclusions via a 32-page report.

The independent federal agency cites an “extreme loss of braking friction due to heavy rain and the water depth on the ungrooved runway, which resulted in viscous hydroplaning” as the official cause of the accident.

Viscous hydroplaning is defined as “the buildup of water pressure under the tire due to viscosity in a thin film of water between a portion of the tire footprint and the runway surface.”

The NTSB also adds the following:

“Contributing to the accident was the operator’s inadequate guidance for evaluating runway braking conditions and conducting en route landing distance assessments.”

An unstabilized approach was caused by several factors, according to the report:

  • The captain’s plan continuation bias (defined as an unconscious cognitive bias to continue with the original plan despite changing conditions.)
  • An increased workload due to the weather and performing check airman duties.
  • The first officer’s lack of experience.
Miami Air 737
A photo of the aircraft that was taken in 2012. Photo: Tomás Del Coro via Wikimedia Commons 

The accident report clearly states that the flight crew did not follow procedures, “including continuing an unstabilized approach, landing the airplane at an excessive approach speed, and delaying [the] deployment of the speedbrakes.”

The NTSB’s investigators, however, conclude that even if none of the above errors occurred, the airplane still would not have stopped on the ungrooved runway due to the rate of rainfall, noting that the characteristics of the runway contributed to water depths that caused the aircraft to hydroplane.

The investigation also found that the operator, Miami Air International, “failed to provide its flight crews with adequate guidance for evaluating braking conditions for landing on wet or contaminated runways.”

Miami Air International filed for Chapter 11 Bankruptcy protection on March 24th, 2020. Less than two months later, on May 8th, 2020, the airline ceased operations.

What’s your reaction to this incident and the NTSB’s findings? If you’re reading this as a pilot, what experiences have you had with wet and ‘contaminated’ runways? Share your experiences with us by leaving a comment.