Sliding Off The Runway In Hard Rain, Part 1
It was the night of May 3, 2019, and a hard rain was falling in Jacksonville, Florida. The rain was coming down so hard that the runway was slippery and probably flooded, so hard that landing distance numbers were just wishful thinking. It was also the night the captain and crew of a chartered Boeing 737 came in, intent on landing. The flight’s landing coincided with some of the heaviest rainfall, resulting in the airplane’s almost frictionless slide off the end of the runway and into the St. John’s River. While there were no serious injuries to any of the 143 people aboard, several animals in the cargo hold drowned and the airplane was substantially damaged.
The accident once again raised the old question of how can a pilot know when the runway is so flooded or slick that the airplane can’t be stopped once it’s on the ground. It made us ask how reliable are landing distance numbers, how shall we adjust them, and when should we doubt them.
The accident investigation took a detailed look at weather reporting and braking performance and turned some conventional wisdom on its head.
The flight’s captain was a newly appointed aircrew program designee (APD), and the first officer (FO) was a new hire 18 flight hours into his first airline job. They were at the end of a long, problem-filled duty day, feeling the need to get on the ground and transfer their 136 passengers to another airplane.
The charter flight was Miami Air 293, a Boeing 737-800, N732MA. The plan was to fly from Jacksonville Naval Air Station (KNIP) to Leeward Point Field in Guantanamo Bay, Cuba (MUGM), and return, then continue on to Norfolk Naval Air Station, Virginia (KNGU). If the original schedule had held together, they would have arrived in Norfolk at 7:30 p.m. after an 11 hr., 35 min. duty day. That didn’t happen. Delays accumulated and the company had to call another charter company to subcontract out the last leg. That airplane had arrived at KNIP and was parked on the ramp, awaiting the flight.
Start of the Day
The Miami-based crew took a commercial flight to Jacksonville on May 2 and remained overnight. The next day, they were scheduled to depart at 9:25 a.m. Problems began when they first arrived at the aircraft. The number-one thrust reverser (TR) light was illuminated, and the mechanic who was traveling with them could not reset it. They deactivated the TR and deferred the repair under the company’s approved minimum equipment list (MEL).
Next, when they taxied out for takeoff, they found that the pneumatic duct pressure for both engines was zero, meaning they couldn’t pressurize or air condition the airplane. After taxiing back to the ramp and troubleshooting the problem, they deferred both engine bleed-air shutoff valves and used the auxiliary power unit (APU) for engine start and pressurization. The APU is a small turbine engine that can provide air to an air-conditioning pack, but it does not provide enough volume to completely replace the air from an engine. The MEL for that problem restricted the flight to fly no higher than 17,000 ft.
The warm, humid weather conditions, the low-altitude cruise and the minimal air volume to the cabin would have made the airplane uncomfortably warm. When 136 passengers boarded for the return flight, it must have been stifling.
The mechanical problems delayed the takeoff from KNIP by 4 hr. The flight time to and from MUGM was 2 hr., 20 min. The revised schedule had them arriving back in to KNIP at 8:10 p.m., but even that was optimistic. It was about 9 p.m. when the flight got in range of Jacksonville and prepared to descend.
The return flight had been uneventful. About 1 hr. before landing, the crew began deviating around cumulus buildups and the captain called his dispatcher to inquire about the destination weather. The dispatcher reported the wind was 120 deg. at 4 kt. with visibility of 10 sm, temperature 26C, and cumulonimbus clouds (CB) in the distance to the south and west. Based on the weather forecast information, the flight crew set up the area navigation (RNAV) GPS approach to Runway 10 in the flight management system (FMS).
When the FO checked in with Jacksonville (JAX) approach control, the controller told them to expect the RNAV approach to Runway 28 and to expect moderate to heavy precipitation. He also said precipitation was building on the approach to Runway 10, starting about 5 mi. out. The crew re-entered the approach, this time to Runway 28, in the flight management computer (FMC).
The controller then said “Biscayne two nine three just talked to Navy JAX tower, he said both runways look pretty ah, pretty bad, or pretty socked in, showing moderate to heavy precipitation east and west of the airport. Do you want to try to go for RNAV two eight?” The captain replied, “Yes, whatever looks better.”
About 5 min. later, the controller said, “and Biscayne two nine three--as you head northbound the precip is heading eastbound, you wanna try one zero--that might be better?” Once again, the captain agreed, and again reloaded the FMC.
After vectors to the west of the airport, ATC cleared the flight for the RNAV Runway 10 approach and directed the crew to contact a Navy precision approach radar (PAR) frequency to monitor their flight path. At 9:40 p.m., more than 13 hr. after starting their duty day and 2 min. before they touched down, they were cleared to land. The reported winds had shifted to 240 deg. at 10 kt.
Just as the captain called for flaps 30, the Navy radar monitor said, “You’re well above glidepath.” The captain disconnected the autopilot and increased the airplane’s descent rate to 1,400 fpm. The airplane began to deviate to the right of the inbound course and the ground speed, pushed along by an increasing tailwind, reached 180 kt. Six enhanced ground proximity warning system (EGPWS) “sink rate” alerts sounded. The airplane crossed the threshold high, fast and sinking 1,450 fpm. Just before touchdown, the tailwind increased to 12-13 kt. The airplane touched down about 1,580 ft. beyond the displaced threshold and 20 ft. to the right of the runway centerline.
The captain of the waiting 737 was seated in her cockpit and watching the runway. She said there was “blinding rain” when she noticed the Miami Air flight come across the threshold. Based on the landing lights, she said they seemed high, and seeing the plane’s position when it passed her, she had a bad feeling about the outcome of the landing.
After touchdown, the captain deployed the number-two engine thrust reverser. At first applying maximum reverse thrust on the number-two engine, the captain then reduced thrust and stowed the TR, only to re-command max reverse for another 10 sec., then reduce thrust again. As the airplane swerved to the right, left rudder corrected the swerve, but the nose of airplane continued to swing up to 8 deg. left and right of the runway heading while the airplane slid.
The speed brakes, which had not been armed for automatic deployment, deployed after 4 sec. The auto brakes activated but were immediately disconnected by the captain’s manual braking. The captain did not sense any anti-skid action and did not feel the airplane decelerate.
The airplane was about 55 ft. right of the centerline when it crossed the end of the runway, still traveling at 98 kt. It struck the seawall, which was 1,164 ft. beyond the runway end, and dropped into the river.
The flight attendants felt two crashes. On the first, one of the ovens flew out of its galley compartment. The oxygen masks dropped in one galley and then the airplane went dark. There was no announcement, but the captain exited the cockpit and ordered an evacuation. The emergency exit lights came on, but it was pitch black outside.
Both of the escape slides at the front of the airplane on the left and right malfunctioned and the purser began to direct passengers back to the overwing exits. The captain jumped into the water in an attempt to rescue some pets in the cargo bin, and found the water was shallow enough to stand in. The passengers began to assemble on the wings and board inflatable rafts that the flight attendants launched. One raft deflated with people in it, but two men jumped into the water and pushed it to shore. The captain, the mechanic and one of the flight attendants did a final walkthrough of the cabin before departing.
The next part of this article series will look at the accident investigation.