In January last year, as the sun had started to sink on a picturesque Saturday afternoon, a red Mustang II aerobatic taildragger took off from the Big ‘T’ residential airpark (64GA) snuggled in the Georgia countryside. A skilled, experienced pilot at the controls. In the right seat, a happy 13-year-old boy. A video recording shows idyllic aviation images as the Mustang II flies by fast above the manicured turf runway. Then six barrel rolls. Then disaster.
It was tail flutter. A metal part had failed. Possibly dating from a 2005 repair, a forward attach bolt may have been missing. The vertical stabilizer quickly separated from the airframe. After that, the canopy departed. The plane turned nose down, 150 feet in the air, 200 knots. The horizontal stabilizer came off. Both occupants died in the high-energy crash half a mile from the runway.
While few people saw the accident, news spread quickly, as the pilot was one-half of the famous Twin Tigers aerobatic display team. Many of us have seen their exciting routine at airshows, two orange- and black-striped Yak-55’s flying in an awesome demonstration of precision and excitement. Heartbreakingly, the young passenger was the son of the Mustang II’s owner, the founder and other display pilot of the Twin Tigers.
After the accident, the National Transportation Safety Board (NTSB) conducted an extensive investigation. Maybe the high profile of the pilot and owner allowed its tight budget some flexibility. The Board recently released its final report explaining what happened, including the mechanical details of the tail failure. And to come closer to how it happened, the human-factors details of the accident, Plane & Pilot recently talked with the Mustang’s owner. He’s a respected, 24,000-hour major airline captain licensed in jets, helicopters and powered parachutes.
In October 2019, he was looking to buy a fast single-engine piston plane with an eye to a proposed national air-race circuit. The Airshow Racing League would have two planes competing against each other at the same time around a marked course. An ad for a plane in Canada caught his eye:
MUSTANG II · $37,000 · BEST DEAL EVER! · the most beautiful and the fastest is available for you, professionally built with all the options, engine lycoming io-360 fuel injection 200hp 40smoh, propeller c/s Hartzell, tank in the wings 40gal tt, cruise 235mph at 8gph, night flight, easy to fly, elt 406.
In photos, the little red two-seater looks sharp. It’s similar to an RV-7, but I think it looks faster. Long pointed nose and clean aerodynamic lines over a big engine. If the plane was in flying shape, it was a great price. Not wanting to buy a trailer-load of parts, the Twin Tigers founder struck a deal to buy the plane if the Canadian owner flew it to the U.S. The new owner would then open the Mustang II up and inspect it before ever racing it. Winter weather interrupted the plans, and it was the start of 2020 before he saw the plane flying.
The Mustang II is a popular, sleek, tapered-wing experimental kit. Designed and supported by Mustang Aeronautics in Troy, Michigan, it has side-by-side comfort for long cross-countries and two sticks for aerobatics. The kit manufacturer lists the airplane as fully aerobatic, with G limits of +6 and -4.5. This one was built in 1980 and had passed through several owners, none of whom seemed to fly it a lot.
Upon examining it a week before the accident, the prospective owner found that it appeared to have a lot of Piper parts. The recent “major engine overhaul” might have been only a top overhaul, but the prop was new. It had a 1970s-looking panel chock full of white-needle/black-background clockwork instruments.
On a 15-minute pre-purchase flight in Florida, the soon-to-be owner noticed the airspeed indicator seemed to be reading about 20 knots faster than his handheld GPS indicated. The airspeed indicator had no maximum speed red-line marking but did have a red line at 87 mph. It was there, he was told, when the Canadian owner bought the plane. A reminder to not fly slower than 90 mph indicated airspeed because the airplane tended to “drop a wing” when slower than that. It was also unclear if a tail mod had been properly completed. There was some hangar damage history. Years of disuse. The canopy latch wasn’t great. But the price was right, so he bought the plane. Right away, he ordered a new airspeed indicator for $150 that he’d install once they got the Mustang II to his home hangar in Georgia.
The new owner planned on trucking it home for inspection, but his close friend and airshow partner wanted to get to know the plane and proposed flying it to Georgia. That pilot ended up flying it a few times with his girlfriend and then ferried it to Georgia on the day of the accident. He landed at the Big ‘T’ airport in the afternoon after a high-speed low pass. He used to live there, so he was confident in the local area and seemed eager to show his old friends the new plane.
The 43-year-old pilot grew up flying his dad’s Cessna in South Africa. Now he had about 11,000 hours and was a B-737 pilot for a major airline. He had been a member of the U.S. Unlimited Aerobatic Team and still flew aerobatics in his Extra. As part of the Twin Tigers airshow team, he won the 2019 Bill Barber Award for Showmanship. People called him an assured, hard-working pilot with exceptional flight handling skills. Others thought he might have been over-confident and shared stories of the kinds of flying that a more careful aviator might decline.
“How fast were you on that pass?” he was asked at the airpark after his solo arrival shortly before the accident. With a smile, he said, “249.” The FAA speed limit below 10,000 feet is 250 knots. The nominal maximum indicated airspeed for the Mustang II is listed as 230 mph, but since it is an experimental aircraft, the actual placarded limit could be whatever the operator decided during flight test. We are outside the normal category FAA certification process with these aircraft. The previous owner told the NTSB that on the pre-purchase flight, the accident pilot flew it at an indicated speed of about 270 mph.
The new owner, the pilot’s airshow act partner, wasn’t home at the time, but his wife and kids were. After loading one of the boys onboard, the pilot and the child went for what was intended to be a quick hop around the sky.
One side of hindsight risk assessment sees that the expert pilot was highly skilled and had safely flown the aircraft that week and that day. The weather was excellent. The area well-known. Gentle positive-G maneuvers. Aircraft fully insured. The 13-year-old had grown up around aviation, with 250 hours already logged.
The other side says it was a just-purchased 1980 homebuilt that hadn’t yet been fully inspected. There were known issues with the airspeed indicator. There were unknown issues with a 2005 tail repair and recommended canopy frame and canopy latch modifications. It had been deregistered in Canada but not yet on the FAA registry. The pilot allegedly had a history of risky flying. He liked to please a crowd. There were only a few gallons of gas left in the tank. He and his passenger were not wearing parachutes.
The NTSB found the vertical stabilizer failed “along the internal edge of the aft doubler rib, consistent with stress and multiple fatigue cracks. Based on the evidence, it is likely that the pilot previously exceeded the airplane’s structural limits, which led to the in-flight separation of the vertical stabilizer.” The report added the detail that the canopy, “separated due to overstress and that it did not have reinforcing gussets installed per a kit manufacturer canopy frame revision issued in 1984.”
If the pilot or owner had trucked the Mustang II to the hangar before flying it, checked all the recommended service bulletins, looked inside the tail, maybe things would have been different. If the pilot had been more conservative, maybe things would have been different. In flying, we have to respect red lines, even if they’re not marked on the instruments.
It’s been over 18 months of unimaginable pain for the Mustang’s owner and the father of the boy who died in the crash. A highly experienced pilot and mechanic who didn’t want to take the homebuilt aloft before looking closely inside, he shares flying advice that is hard-earned: “Pay attention to details. When you operate at elite envelope aerobatics, the last thing you want is an accident that is preventable. Learn a new airplane. Take the time. Airplanes talk to us. If something is not normal, step back.”