1989 Hurricane Hunters NOAA 42 incident

On September 15, 1989, a Lockheed WP-3D Orion operated by the National Oceanic and Atmospheric Administration (NOAA) experienced an engine fire and nearly crashed while flying through the eyewall of Hurricane Hugo. The crew managed to extinguish the fire and safely return to Barbados.

Background

Following the 1943 Surprise Hurricane, the National Hurricane Center began doing routine reconnaissance missions into hurricanes, known as "Hurricane Hunter" missions. Among the planes used was a WP-3D Orion serviced by the NOAA and nicknamed Kermit (callsign N42RF). In 1989, this plane had been deployed to Barbados alongside another WP-3D Orion as part of a research experiment coordinated by the Hurricane Research Division. The goal of the mission (termed the Hurricane Energetics experiment) was to gather data related to the hurricane (such as wind speeds and the location of the hurricane) which would help predict future hurricanes before they occur and thus save lives. Leading up to 1989, only one plane had crashed in the Atlantic during a reconnaissance flight: Snowcloud Five in 1955, which flew into Hurricane Janet at 700 ft and crashed in the eyewall with a loss of all 11 passengers (though there had been several other crashes in the Western Pacific).

Incident

According to the latest satellite estimates at the time of the flight, Hurricane Hugo was believed to be at Category 3 strength. Thus it was decided that the first reconnaissance mission into the storm would fly in at 1,500 feet (460 m) to study the low-level environment (such a move had been done earlier in the year with Hurricane Gabrielle) while another mission would fly at 20,000 feet (6,100 m) to study the large-scale environment. Takeoff went without any issues and the plane easily climbed to 10000 feet.

After takeoff, the plane's belly radar failed, depriving the crew of valuable data on the strength of the storm, but it was fixed after 20 minutes. This problem, however, left only 5 minutes to examine the radar before they had to begin the descent. Flight director Dr. Jeff Masters briefly examined the radar and determined that the storm was still likely Category 3 strength and went through with the descent. As they began to fly through the rainbands, the turbulence in the storm was not unusual and as they approached the eyewall the winds fell to unusually low values making the crew believe the storm was actually weaker than a Category 3, so they decided go ahead and fly in at 1,500 ft, but plan on ascending to 5,000 ft if it got too rough. In reality, they had failed to notice that the eyewall was maxing out the radar scale they were using at multiple points, a sign of a much stronger storm.

Upon entering the eyewall, the pressure began to fall rapidly as the winds began rising much faster than expected, eventually increasing to Category 5 intensity with winds near 200 mph. At first the turbulence wasn't terrible, but it took both pilots to control the plane. After one minute, the plane then began to experience severe updrafts and downdrafts, with the crew going through periods of being slammed into their seats at multiple gs of force to feeling weightless. An updraft of 20 mph was then followed by a downdraft of 22 mph causing unsecured objects to fly around in the cabin. Shortly after, the plane was hit by a 45 mph updraft, but at this point it began to brighten up outside signaling the eye was close. But right before they entered the eye, dark clouds reconsumed the plane and 3 consecutive intense drafts of wind hit the plane causing it to begin a dive toward the ocean and the 200 lb life rafts to break loose, hitting the ceiling of the plane and permanently denting it while other equipment drawer locks failed causing everything from soda cans to tapes to hit the ceiling and rain down on the crew. The violent winds created in the eyewall put enormous g-forces on the plane, reaching +5.8 g's and -3.7 g's, far greater than it was built to withstand. The crew noticed that the number 3 engine had been overheating, and it now caught fire. Finally the crew made it to the eye.

Once in the eye, the dive was stabilized just 880 ft above the water at 17:28 UTC. However, complicated by the attention needed to shut down the flaming number 3 engine, and requiring tight turns to stay circling within the eye, they chose the wrong direction initially and nearly reentered the eyewall a second time. Finally with a precariously steep turn the pilots were able to establish a course consistently within the eye. A damage inspection showed that not only was the number 3 engine out of commission, but the deicing boot on the number 4 engine had started to detach. If the boot broke free and damaged that engine, they could lose all power from that side of the aircraft. To avoid overworking the three remaining engines, the pilots continued to orbit the 9 mi wide eye of Hugo for an hour and slowly ascending. To lighten the load and gain more height, fuel was ejected from Kermit lower fuselage and a suite of now-superfluous ocean sensing instruments were fired off. After finishing the dumps, Teal 57, an Air Force C-130 reconnaissance plane, arrived in the storm flying at 10,000 ft. The crew of this flight did multiple passes around NOAA 42 to look for any other outside damage, finding none. Teal 57 then started eyewall penetrations to seek a safe passage for NOAA 42 to fly out of. NOAA 43 also arrived at 15,000 ft, but NOAA 42 was unable to climb that high due to their damaged engine. The eastern and southern parts of the eyewall were found to not be safe, but on the third pass made by Teal 57 they found a better option in the northeast side. NOAA 42 was able to climb to an altitude of 7,000 ft before departing the eye via that northeast course safely (losing the deicing boot in the process). NOAA 43 followed NOAA 42 out, while Teal 57 remained in the eye to continue their mission. The two planes finally landed safely at Grantley Adams International Airport in Barbados with no further incidents. Miraculously, there were no injuries on the flight.