Serious weather a factor in killing Greenacres pilot

NTSB says fast-rising upward drafts may have led to malfunctions.

A new report on the death of a Greenacres pilot suggests just how much may have gone wrong over the Illinois skies. A shredded wing. Freakishly strong updrafts. And a wing pushed so hard it bent one way, and then another, and may have spun around.

The National Transportation Safety Board’s newest report on the July 2016 crash does not attempt to say how the wreck began. But it confirms that the twin-engine Piper Comanche broke up in mid-air, scattering some pieces of debris a mile away from others.

The only person on the plane, pilot Garry Thomas Bernardo, 58, was killed. No one on the ground was injured from the crash, which started a fire.

Radar imagery and a computer model suggest the airplane was hit with fast-rising winds. The computer model showed updrafts, called convective available potential energy, capable of pushing upward at a rate of a football field per second. Upward drafts in the area were estimated at 4,207 joules per kilogram, with downdrafts of 1,194. Moderate values are considered 736, the NTSB reported.

A computer model suggested the airplane pitched about 20 degrees up for several minutes,

rising several thousand feet and bleeding off airspeed. It slowed to as little as 48 knots, about 55 miles per hour, slower than the airplane’s stated stall speed. The plane began losing altitude and spiralling down, before going faster than the manufacturer said it should go.

Witnesses said weather resembled a fast-forming thunderstorm. So much lightning was detected around the crash site in a 90-minute period that a report fills five pages. The NTSB said Bernardo did not get a weather briefing for the leg of his flight over Illinois. Forecasts called for a marginal risks with “isolated severe thunderstorms possible.”

Besides weather, the report lists other significant problems, but does not attempt to say how the accident started or what failures led to other problems.

Less than a year before the crash, Bernardo had some of the left wing’s skin replaced, the NTSB reported, including portions of the leading edge, the part that goes most directly into the wind. The NTSB found that nearly 7 feet of the left wing’s leading edge skin separated.

The parts of the left wing that work like its bones were bent in two directions and shattered. The evidence was “consistent with the outboard wing rotating,” the NTSB reported. The agency also found evidence that rivets, which are supposed to hold the wing together, may have been installed incorrectly and failed to share the load.