Sequence of events
The Cessna Silver Eagle aircraft, a turbine-powered, pressurised
Cessna 210, was conducting a private flight from Maroochydore to
Bankstown under the Instrument Flight Rules (IFR), cruising at
flight level (FL) 160. Meteorological conditions conducive to icing
had been forecast for the route.
While enroute, the pilot faced adverse weather and requested a
diversion around the weather. Air traffic control (ATC) cleared the
aircraft to divert then, when clear, to track direct to Mount
Sandon. The pilot requested, and was approved to, climb to FL 180.
Twenty four minutes later, the pilot told ATC that he required a
descent to FL 140 due to icing. Six minutes after that, the pilot
stated that he required a further descent to FL120 due to icing,
and four minutes later, requested descent to 10,000 ft due to
icing.
Two minutes later, the pilot reported an engine failure. One
minute and 43 seconds later he reported that he had lost generator
power and that the aircraft was descending through 8,500 ft. ATC
then asked the pilot to activate the emergency locator transmitter
(ELT). A Distress Phase was declared and, after further attempts to
communicate with the pilot were unsuccessful, search and rescue
(SAR) action was started.
Several hours later, search aircraft found the wreckage on steep
mountainous terrain, 380 m south-east of its last position showed
by radar. The accident was not survivable.
Wreckage examination
Onsite investigation revealed that the right wing had failed
before impact, both at midspan and at the fuselage attachment
point, because of aerodynamic forces that exceeded the wing
structural load limits. The empennage had also separated from the
fuselage before impact. The right horizontal stabiliser and
elevator were not present at the accident site. Objects thought to
be parts of the missing empennage were sighted from the air. Their
location was 330 m from the main wreckage site, and on the northern
slope of a ridge. The main wreckage was on the southern slope. The
wreckage trail was consistent with the direction of flight as
recorded on radar.
The fuselage, with the engine and left-wing still attached, had
impacted the ground in a steep nose-down, inverted attitude. The
cabin section of the fuselage comprising the pressure hull, had
remained intact until impact with the terrain. The landing gear and
wing flaps were found to be in the retracted position.
The evidence showed that the propeller was still attached to,
and was being driven by, the engine at impact. The engine and
cockpit firewall, with most of the instrument panel attached, had
separated from the fuselage during the impact sequence and had been
destroyed by post-impact fire. Most of the left-wing was also
destroyed by post-impact fire. The intensity of the fire suggested
the aircraft was carrying a significant fuel load at impact. There
was no evidence of any pre-impact fire.
The aircraft had been fitted with a fixed and two portable ELTs,
all of which had been destroyed by impact forces.
The engine was subsequently stripped and inspected. The
inspection revealed that the engine was producing significant power
at impact. The wreckage examination did not reveal any pre-existing
technical fault that would have contributed to the accident.
Aircraft
The aircraft was registered in the USA and was maintained to US
Federal Aviation Administration requirements. It was fitted with an
Allison 250-B17F/2 turbo-propeller engine. Section 2 page 5 of the
approved flight manual supplement for the aircraft stated:
"For flight at ambient temperatures of 4 degrees Celsius and below,
the fuel used in this aircraft MUST have an anti-icing additive in
compliance with MIL-I-27686D or E or Phillips PF A55MB,
incorporated or added into the fuel during refuelling in accordance
with the additive manufacturer's instructions."
Section 2 page 9 of the approved flight manual supplement for
the aircraft stated:
"Flight into known icing conditions is prohibited."
The engine-driven generator installed in this aircraft was
designed to automatically shed all electrical load when engine
compressor revolutions per minute (RPM) fall to 70%.
Inspection of the aircraft technical logbooks revealed
compliance with all applicable Airworthiness Directives and Service
Bulletins.
Fuel
The aircraft was refuelled before departure from Maroochydore.
No evidence was found to suggest that anti-icing additive had been
added to the fuel at that time.
On the day of the accident, several other aircraft, including
one high-capacity regular public transport aircraft, had been
refuelled from the same fuel supply as N62J. None of the pilots of
these aircraft reported any problems with fuel.
Pilot
The pilot held a US commercial pilot certificate with a valid
Class 2 medical certificate, a command instrument rating, and was
endorsed for the aircraft type. His total experience was 3,229
hours with 629 hours on the aircraft type. He was reported as being
a cautious pilot who planned his flights carefully and correctly
applied inflight procedures. He was aware of the aircraft
limitations about flight in icing conditions.
Pathological and toxicological examination did not reveal any
evidence of any medical condition affecting the pilot that could
have prevented him from safely operating the aircraft.
Weather
The amended area forecast showed rain and thunderstorms with a
freezing level of 10,000 ft; moderate icing in the tops of large
cumulus, altocumulus and altostratus cloud, temperatures of 2
degrees C at 10,000 ft and minus 6 degrees C at FL 140.
The actual freezing level was approximately 11,500 ft with
severe icing and turbulence in thunderstorms. Conditions in the
area at the time the pilot reported the engine failure were
conducive to airframe and engine intake icing. Interpretation of
the enroute weather reports suggested that the aircraft might have
passed through a line of showers and thunderstorms.
