History of the flight
Two days later, on the day of the accident, the pilot again
attempted to depart Moorabbin for Archerfield. The pilot stated
that shortly after takeoff, as the aircraft climbed through
approximately 1,600 ft, the engine appeared to cut out but then
immediately operated normally again. Soon afterwards, the engine
lost all power.
The pilot conducted a forced landing onto a stretch of road that
was clear of vehicles. The aircraft was substantially damaged
during the accident sequence when it collided with various
obstacles, including powerlines, poles, a tree and a fence. The
occupants of the aircraft were not injured, but were unable to open
the doors. While exiting the aircraft through broken windows, both
passengers sustained minor injuries.
Wreckage examination
Damage to the propeller indicated that the engine was rotating
on impact, but not under power. A subsequent examination of the
engine established that the magneto timing was between
approximately 20 and 25 degrees after top dead centre. The correct
timing for the engine was 25 degrees before top dead centre. The
magneto gear was missing three teeth. The idler gear that drove the
magneto gear and the engine-driven fuel pump, was no longer secured
in either the accessory housing or the crankcase. At the accessory
housing end, the mounting boss had cracked away from the housing
and most of the fracture surfaces had worn smooth. At the crankcase
end, the mounting bore had been substantially worn, and remnants of
a bush remained in the bore. During normal operations, both idler
gear mounts were subject to significant side loads from the
engine-driven fuel pump drive cam.
Further examination of the idler gear shaft boss and bore
established that the crankcase idler gear shaft bore had been
repaired. This repair involved drilling out the bore and subsequent
installation of a bush. The bush had not been secured to the
crankcase bore and the metal used to manufacture the bush was
commercially pure aluminium, a metal with low resistance to plastic
deformation.
History of the aircraft
The aircraft was exported to Australia from the United States in
early 1989. The Lycoming IO-540 engine installed in the aircraft at
the time of the accident had been overhauled in 1988 in the USA,
just prior to the aircraft being exported to Australia. According
to the aircraft logbooks, in December 1989 the Australian company
that imported the aircraft replaced the crankcase with an
overhauled crankcase supplied by a USA crankcase repair company.
There was no record of the reason it was replaced.
The USA company that supplied the overhauled crankcase had
detailed its requirements for idler gear shaft bore repairs in its
Federal Aviation Administration approved repair scheme. The repair
involved drilling out the bore to a diameter of 0.813 inches,
installing a bush to an interference fit and welding the bush to
the crankcase. The repair scheme did not specify the material from
which the bush should be manufactured.
The engine manufacturer issued a number of service instructions
related to bushed repairs of idler gear shaft bores. The most
recent of these, number 1417 issued 1 October 1982, required that
the bore be drilled out to a diameter of 0.812 to 0.813 inches and
that the outside diameter of the bush be machined to 0.814 to 0.815
inches. The instruction also stipulated that the bush be fixed to
the crankcase by dowels and that the bush should be manufactured
from AMS 4118 aluminium alloy. AMS 4118 referred to an alloy of
aluminium and 3.5% magnesium. This alloy had a higher resistance to
plastic deformation than commercially pure aluminium.
The crankcase idler gear shaft bore repair in the accident
aircraft had not been conducted in accordance with either the
Lycoming approved repair scheme or the US crankcase overhaul
company repair scheme.
Maintenance
At the time of the accident, the engine had approximately 114
hours to run before it was due for overhaul. The aircraft was being
maintained using the Civil Aviation Safety Authority Maintenance
Schedule detailed in Schedule 5 to the Civil Aviation Regulations
1988. Section 2 (4)(c)(ii) of that schedule required that if a
cartridge full-flow oil filter was fitted, that maintenance
personnel should remove, open and inspect the filter at each
periodic inspection. Because oil filters remove particulate
contamination, such as metal, from engine oil, internal inspections
of oil filters can provide an indication of the engine's
condition.
The aircraft's engine was equipped with a cartridge full-flow
oil filter, and periodic inspections were being conducted at 100
hourly intervals. The engine manufacturer recommended that the oil
and oil filter be changed at 50 hourly intervals. The aircraft
documentation indicated that the aircraft had been operating for
approximately 83 hours since the last periodic inspection. There
was no record that the oil and oil filter had been changed since
the periodic inspection.
Personnel information
At the time of the accident, the pilot held a Private Pilot's
Licence and had accumulated approximately 270 hours of flying
experience. He had completed approximately 9 hours in the accident
aircraft, his only experience in Piper PA32R-300 aircraft.
The pilot's training on the aircraft type involved two check
flights, conducted a week before the accident. The aircraft engine
ran roughly during taxi, however increasing the engine RPM and
leaning the mixture cleared the problem. The pilot was told that
the engine used a lot of oil and that the rough running and oil use
related to the age of the engine.