Buzzing things on the ground is just a bad idea. It doesn’t matter how good a pilot you are or how quick and responsive your aircraft, extremely low altitudes leave no margin for error. Momentary distractions can be fatal; if something happens that you didn’t expect, there’s little or no time in which to react. Buzzing things below ground level is even worse.
On July 24, 2008, an amateur-built Cozy Mark IV flew down into a limestone quarry near Midlothian, Texas. With cruise speeds in the 180-knot range, the standard Mark IV design is fast for a piston single-engine aircraft, and this particular example seems to have been even more of a hot rod: It had a 220-hp engine instead of the recommended 180 hp, and retractable gear rather than the fixed gear of the stock configuration. It was being flown by its builder, a 13,700-hour air transport pilot, who had put 81 hours on the airplane since its completion.
The NTSB report describes the quarry as being about a mile wide and 100 feet deep. Witnesses working inside the quarry said the airplane flew through it “at high speed” about 20 to 30 feet above its floor. One said that the airplane flew directly at his bulldozer; he waved to the pilot as it passed by, about 30 feet off the floor. He then saw it bank right and nose up to avoid a pile of dirt before smashing headfirst into the quarry wall, killing the pilot instantly and scattering debris up the slope and some 350 yards into the adjoining field.
Most of the wreckage was too heavily damaged to allow investigators to establish continuity between the cockpit and the flight controls; it wasn’t even possible to tell whether the pilot’s shoulder harness had been fastened. However, the gear were retracted, the fracture signatures on the propeller fragments suggested that the engine was making power at the moment of impact, and the witness accounts describe an aircraft under positive control. So what happened?
The NTSB found the probable cause of the accident to be “[t]he pilot’s failure to maintain clearance from the wall of the rock quarry.” But why was he down there in the first place, and why did a veteran professional pilot fail to pull up in time to climb over the rim? The NTSB report does not address whether the pilot knew the quarry workers, though the bulldozer operator’s wave suggests he might. Confronted with an airplane unexpectedly flying straight at them, most people would probably have taken cover.
What is clear is that the pilot was deliberately cutting it close in the most unforgiving surroundings. At 180-plus knots, the Cozy would cross a mile-wide excavation in less than 20 seconds, and 70 feet below the rim, visual references would likely have been unfamiliar. Perhaps that threw off his estimate of the distance, or perhaps he was distracted a second too long waving back to the man on the bulldozer. Maybe he wanted to make things look really good by slipping over the rim at the last possible instant.
Whatever his reasons, this veteran pilot chose to take risks that were not only great, but completely unnecessary. The price he paid was high.