Five years ago Thursday, a fully armed Air National Guard F-16 plunged through the roof of a warehouse adjacent to Interstate 215 in Riverside, triggering a massive public safety response that prompted closure of the freeway and an extensive operation to recover the jet’s missiles — all of which happened because a bad valve allowed hydraulics to leak out of the Fighting Falcon.
The chain of events leading to the May 16, 2019, crash began when two F-16s from the 175th Fighter Squadron based at Sioux Falls, South Dakota — but temporarily assigned to March Air Reserve Base — departed the Riverside military installation on a simulated scramble alert issued by the North American Aerospace Defense Command shortly after 2 p.m.
The fighters traveled to a military operations area 120 miles east and performed maneuvers before heading back toward March. The wingman to the principal pilot flying the sortie began receiving warning bells in the cockpit as he crossed the Coachella Valley, but the two-flight formation continued, according to a report issued a year later by the U.S. Air Force Aircraft Accident Investigations Board.
“The pilot checked the hydraulic pressure gauges and noted low pressure in (one) system,” the report stated.
As he set up for final approach to March, the jet’s second hydraulic system went on the blink, and the airman declared an emergency but set up for a landing on one runway, while the lead pilot in the formation broke away and landed uneventfully on a separate runway.
The ensuing dual hydraulic system failure caused the second Falcon to start rolling to the left, and when the pilot tried to counter the roll, “the aircraft responded by rolling hard to the right,” according to the AAIB.
The F-16 became uncontrollable, and the pilot ejected, parachuting unhurt onto a runway. The out-of-control fighter flew another two seconds, crossing over I-215 and crashing wheels first through the See Water Inc. warehouse at 22220 Opportunity Way, tearing an enormous hole in the roof and smashing water pipes, as well as aisles full of electronics accessories, aluminum awnings and other products. Everyone in the warehouse escaped injury and safely evacuated.
There was a small blaze, but March Air Reserve Base Fire Brigade and Riverside County Fire Department personnel quickly knocked it down. Over 100 firefighters from multiple agencies converged on the area, followed by the sheriff’s bomb squad, whose then-commander, Robert Epps, told later City News Service that he had been monitoring public safety radio traffic when the accident happened, and his team immediately assembled and went to the scene.
While a hazardous material unit began working to mitigate the fuel and hydrazine spills from the jet, the bomb squad and Air Force technicians initiated a search to secure the F-16’s four missiles and nose-mounted 20mm Vulcan cannon. One missile was found broken in two on the roof of the facility, while the others were found inside, near the jet, Epps said.
According to authorities, they had not fired or detonated because the jet’s armament panel had not been switched on, and the fire in the warehouse lacked the intensity to cause them to explode.
The March Explosive Ordnance Disposal Team disarmed and transported the cannon back to the base.
Epps and his crew, along with U.S. Marine explosives experts from Camp Pendleton, spent hours locating and securing the missiles, he said.
The California Highway Patrol shut down a 4-mile stretch of I-215 in both directions for 24 hours after the crash as a safety precaution, and businesses near the warehouse were evacuated, while residents in nearby homes were asked to shelter-in-place.
The missiles were all removed from the warehouse and taken to the nearby Ben Clark Public Safety Training Center, where Epps, March ARB command staff and others coordinated disposal of the weaponry.
“We buried them in the ground in holes … 4 feet wide, 12 feet deep and 10 feet long,” the sergeant said. “We used all the dirt from the holes to mitigate the noise and fragmentation, then planted blocks of C4 down the lengths of the holes.”
The C4 was detonated early on the afternoon of May 17, 2019, destroying the missiles.
“That was pretty much it for our part,” Epps said. “It was all pretty interesting.”
In the investigation conducted by the AAIB, a panel discovered that an integrated servo actuator, or ISA, that had been overhauled by Air Force techs at Hill Air Force Base in Utah was not put back together correctly.
ISAs are critical because they govern the flow of hydraulics that control an F-16’s flight devices — ailerons, elevators — to enable the nimble fighters to turn, climb, roll and everything else. The investigators found that a check valve screw cap on the ISA had not been properly refitted, allowing hydraulics to leak out.
Further inquiry uncovered evidence of poor inventory control that caused the wrong parts to go into the overhaul.
The deficient device was placed in the ill-fated F-16, and the plane managed to fly 16 hours before the complete hydraulic failure occurred, according to the report.
The cost of repairs to the warehouse, as well as cleanup operations, totaled just under $4 million.