'Mayday mayday mayday' - NTSB releases report from fatal F-16, Cessna crash

MONCKS CORNER, S.C. (WCIV) — "Mayday, mayday, mayday!"

Those were the words of an U.S. Air Force F-16 pilot, seconds after the jet collided with a private Cessna over Moncks Corner on July 7, 2015.

The National Transportation Safety Board today released its final report of the crash that killed a father and son on board the Cessna.

In ruling the crash an accident, the massive report shows the two planes were most likely unable to see one another until one to four seconds before the crash 1,400 feet above ground. The F-16 was traveling at 282 mph; the Cessna 78 mph.

Michael Johnson, 68, and his 30-year-old son Joe, both of Berkeley County, died in the mid-air crash. The F-16 pilot, identified as Maj. Aaron Johnson of the 20th Fighter Wing from the Shaw Air Force Base in Sumter, survived after ejecting safely.

The NTSB report says the F-16 was on an operational check flight and was returning from Myrtle Beach International Airport when it contacted Air Traffic Control at 10:52 a.m. and asked to perform a practice tactical air navigation system.

The Cessna 150M took off from the Berkeley County Airport at 10:57 a.m. and was headed to the Grand Strand Airport in North Myrtle Beach.

The report says the controller noticed the Cessna and initially thought, because local traffic typically stayed beneath 1,000 feet, it would do the same.

At 10:59:49 the Cessna passed 1,000 feet. The Cessna's pilot did not contact air traffic control but was not required to.

At 11:00:16, the F-16 was flying at 1,570 feet at 253 knots. The Cessna was at 1,200 feet and climbing at a rate of 240 feet per minute.

The controller told the F-16 (Death Four One) that another plane was in the area.

“Death Four One, traffic 12 o'clock two miles opposite direction, 1,200 indicated type unknown."

The F-16 pilot responded. "Death Four One looking."

Controller: "Four One, turn left heading 1-8-0 if you don't have that traffic in sight."

F-16 pilot: "Confirm two miles?

At 11:00:34 the controller told the pilot, "Death Four One if you don't have that traffic in sight turn left heading 1-8-0 immediately."

The F-16 pilot responded but the transmission was garbled and unreadable.

The F-16 began gradually turning to the south. It dropped from 1,595 feet to 1,467 feet as it made the turn. The Cessna climbed 200 feet to 1,466 feet during the same time.

At 11:00:52 the controller reached out to the F-16. “Death Four One traffic passing below you one thousand four hundred [feet].”

The F-16 responded with a broken transmission, “Death four one (unintelligible) that traffic is uh (unintelligible).”

At 11:01:09 the controller replied “Death Four One unable to read you. Say again.”

Ten seconds later the F-16 pilot called out "Death Four One. Mayday, mayday, mayday."

That was the last the controller would hear from the pilot. The F-16 flew about 10 more miles before ejecting.

"I felt an impact," Maj. Johnson told the NTSB. "My aircraft took -- I don’t know what kind of damage -- but I lost the info in the HUD. I had problems with FLCS -- probably some significant hydraulic damage, I didn’t look at my hydraulics. And I looked -- I started a left turn direct to Charleston and I looked back over my shoulder to see what happened to the other aircraft and I saw the aircraft out of control, but I couldn’t turn back to assist because my plane was very low on thrust. I went to afterburner trying to maintain some type of altitude, the whole time the plane was direct at Charleston and, again, probably a good part of the bottom of my jet was gone so I wasn’t going to have any gear anyways so there was no way I could make it. I was trying to give myself a little more time."

Searchers found most of the jet right away near the Lewisfield Plantation. The search for the Cessna was much wider, as parts were strewn about.

USAF personnel interviewed did not believe the radar on the F-16 would locate a small Cessna aircraft at takeoff or climb speed. Air traffic controllers at Charleston International Airport say the technology they use to track planes isn't up to date.

The study indicates that each plane would have remained a relatively small object in the other plane's window until about five seconds before the crash. It says the Cessna might have been obscured from the F-16 pilot's field of view because of the jet's display or instrument panel.

The report says the F-16 would have remained out of the Cessna pilot's field of view until about 1 second before the collision, partially obscured by the Cessna's left wing strut.

This is a developing story. Check back with ABC News 4 as more details are added.