Pilot error led to two F-16s colliding on the runway at Nellis Air Force Base, Nevada, in 2015, which left one pilot with life-threatening injuries, according to an accident investigation report released Monday.
After completing an orientation flight during the Red Flag training exercise at Nellis Aug. 15, 2015, the two aircraft attempted to land. The first F-16 landed without incident but did not clear the landing zone of the runway quickly in a timely manner, according to the report released by the Air Combat Command Accident Investigation Board.
The second aircraft then landed at too great a speed, "had the engine above idle power" and "did not aerobreak within prescribed limits," the report said.
The two aircraft closed on each other, and both pilots attempted to turn their aircraft to the right to avoid the collision. The second aircraft was unable to stop in time, however, and rear-ended the plane in front of it. According to the accident report, the rear pilot became pinned under the wing of the front craft, and the ejection seat fired. Both aircraft were soon on fire.
The pilot of the front craft was able to get out of the cockpit without injury. The pilot of the rear craft was taken to the base hospital with life-threatening injuries, but survived.
The damage done to the front aircraft was estimated at $5.4 million. The damage to the rear aircraft was $64 million and the plane was considered a complete loss, the report said.
Both aircraft were assigned to the 457th Fighter Squadron at Naval Air Station Fort Worth Joint Reserve Base, Texas.
The two F-16s had returned from an overview mission to orient themselves with Nellis and the surrounding area in preparation for the Red Flag exercise, one of the Air Force's largest training events. The front F-16 in the crash had the call sign Bleed 1 and the rear plane was Bleed 2.
Investigators said Bleed 1 landed without incident, except that the plane then "stayed on the hot (landing) side of the runway" and didn't make a prompt exit.
Just 15 seconds later, Bleed 2 landed 15 seconds later 3,052 feet behind Bleed 1, which investigators said is standard for F-16 landings. However Bleed 2 was traveling much faster, at 181 knots ground speed versus Bleed 1’s 163.
Upon landing, Bleed 2 didn't fully deploy his aerobrakes and didn't use his wheel breaks "sufficiently," the report said, "thus creating a substantial closing velocity" between the two aircraft.
Bleed 2 then noticed the aircraft in front of him and hit his breaks, contacting the Bleed 1 pilot and telling him to move the front aircraft to the right.
But the aircraft ahead was still drifting to the left, the accident report said, so Bleed 2 called again. At this point the forward pilot took action and steered his craft toward the right of the runway.
However, the Bleed 2 pilot "perceived [the pilot in front of him was] staying on the left side of the runway and abandoned normal runway de-confliction," according to the report. Bleed 2 then turned his aircraft to the right. This led to both F-16s turning right and colliding with each other at an estimated speed of 60 knots.
According to the accident report, the trailing edge of Bleed 1's right wing forced Bleed 2's panel against the ejection seat lever, triggering the ejection sequence. The canopy and drogue chute blew, but the Bleed 2 pilot was still pinned in his cockpit.
"The seat traveled up the seat rails but did not leave the aircraft because the impact wedged the lower right leg guard behind a section of cockpit panel," the report said.
In quick succession both the left and right fuel tanks on Bleed 2 burst, and the aircraft became engulfed in flames, the report said.
The accident board commended the emergency crews and firefighters who responded to the accident, especially the crew of a fire truck identified as "Crash-7." The driver drove the truck across the open ground between runways, getting to the accident 17 seconds faster than if the truck had stayed on the paved runways and access roads.
"Given the compounding nature of injury in sustained fire, each second was critical in saving [the Bleed 2 pilot's] life," the accident board wrote.
The crew began using the truck's cannons to spray water and foam as they neared the accident scene, even before the truck came to a stop, according to the report. The fire truck was on scene, putting out the fire, just 68 seconds after the collided planes came to a rest.