EAA Sport Aviation - September 2011

A Warning
Sign Ignored

Installing inadequate stop blocks

IT’S NOT OFTEN THAT the passenger involved in an accident resulting from aerobatics gone wrong is around to provide details of what happened. But the person riding in the second cockpit of an Acroduster II was unusually lucky.

The passenger told NTSB investigators that, after the pilot had
performed a very thorough preflight of the homebuilt biplane, they
took off and flew to a practice area to perform aerobatics. The
report does not mention what maneuvers, or how many, the pilot
flew, but he did ask the passenger if he wanted to perform what
sounded like “a tail slide.”
The passenger said they climbed to 3,500 feet, and the pilot
initiated the maneuver. The passenger told investigators that
“after falling for a few seconds, [the PIC] then attempted to
bring the airplane back to straight and level for a second with
full power (not sure if it was full power but it seemed like it).
At that point, the airplane started rolling to the left, then to
the right, up and down, and I heard the pilot begin loudly
announcing that we had problems with the airplane, which I
believe he repeated three times. It was very difficult to hear
with the speed we were at and with the airplane starting to
lose control.”
The passenger further stated that the airplane seemed to be
out of control “as it was going to the left, the right, towards the
ground.” He heard the pilot tell him to bail out of the airplane.
The passenger unbuckled and jumped. The parachute functioned
properly, and while under canopy the passenger scanned the sky
for the airplane or for another chute and saw neither.

The passenger landed in treetops, and his chute snagged the branches. While suspended by the trees he continued to look for the airplane or the pilot’s parachute and could not see either. He managed to get to the ground and walked to a nearby house for help. The Acroduster crashed inverted in a heavily wooded area, killing the pilot.

The 31-year-old private pilot had been flying for about eight years. The NTSB did not locate an exact total of his flying experience but believed it to be between 900 and 1,000 hours. The accident report did not include any information about aerobatic or other flight training the pilot had received.

The Acroduster II is one of the classic amateur-built designs. The biplane is made using conventional airframe techniques with fabric covering. The accident airplane was built in 1980, and the builder submitted data from the plans showing that limit loads were plus and minus 6g’s. Ultimate load was reported to be plus and minus 9g’s. The airplane was powered by a Lycoming IO-360-A1B rated at 200 hp.