Aircraft was on a test flight just after maintenance carried out by RA.
Two of the three owners of the aircraft were on board, Ngaire Moxley,
senior female flying instructor with the Royal Queensland Aero Club,
and a Kevin Brown, an experienced pilot of about 30 years mainly as a
preacher flying in North Queensland a few years back. Both pilots seem
to be in their late 50's. Time just before last light, good visibility
and the aircraft seemed to be airborne for about 4 minutes.

Two Eyewitness reports:
Aircraft was observed taking off on Runway 10L and then commenced a
shallow left turn almost immediately. There was dual dark smoke trails
issuing from the left engine. No bang was heard. The aircraft continued
onto downwind at about 100ft with the undercarriage still not retracted.
An "agitated" female voice was heard over VHF telling Brisbane that
there was an engine problem. The aircraft impacted the ground vertically
and adjacent to and about 200yds north of the 10L threshold.

News Desk View:
Seems there was an "over rich" condition on the left engine which may or
may not have been a complete engine failure. Why two very experienced
pilots tried to carry out a circuit at 100 ft with the gear down and
pass up an opportunity to land on the grass runway 22, which they flew
past, is beyond comprehension.

Conclusion:
It was either a below Vmc condition or "low level G
pull" or both that resulted in the accident.

AirCentre News Desk May 24, 2001 @ 1300hrs.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

November 4, 2002
ASTB Final Report Released

http://www.atsb.gov.au/aviation/occurs/occurs_detail.cfm?ID=446

FACTUAL INFORMATION

Sequence of events

The co-owners of the Piper Twin Comanche aircraft, both of whom were pilots,
were conducting the flight to test a newly fitted left propeller governor.

At about 1650 EST, one of the owners telephoned the aircraft refueller and
requested fuel for VH-CNZ. When the refueller arrived at the aircraft a
short time later, he was requested by the other pilot to refuel the aircraft
to full tanks. The refueller reported that this pilot appeared to be
conducting a preflight check of the aircraft while the other pilot was
seated in the cockpit, possibly in the left seat. The refueller noticed
that the fuel filler flap covers were open and that the fuel tank filler
caps, two on each wing, one on either side of the engine nacelles, had each
been removed and placed on the wing adjacent to the filler points. After
adding fuel to the right auxiliary fuel tank, the refueller placed the cap
in the filler port. The pilot who was doing the external inspection
approached him and said that he would secure the caps because they had a
locking mechanism that was different from those fitted to many other
aircraft types. The refueller then filled the right main tank and placed
the cap in the filler port. As he moved away, he saw the pilot move to the
tank. The refueller then moved to the left side of the aircraft and filled
the left auxiliary and left main tanks, again placing the caps in the filler
port of each tank. He did not secure the caps and left the flap covers open.
At this stage, he saw the pilot lying beneath the fuselage, apparently
conducting a fuel drain check. The refueller recorded in the refuelling
register that 179 litres of fuel had been added to the aircraft at 1700.
He then told the pilot seated in the aircraft the amount of fuel he had added,
and reminded her that he had not secured the fuel caps. The refueller then
moved to refuel another aircraft.

A short time later, the aircraft taxied for takeoff. Visual meteorological
conditions existed with scattered light cloud at 3500 feet. The wind was from
the southeast, gusting to 5 knots. Sunset on the day of the accident was at
1658. At the time of the accident, the sun was 3.5 degrees below the horizon,
bearing 292 degrees True.

The following is a summary of the pertinent communications between the aircraft
(CNZ) and Archerfield Tower (Tower), which commenced at 1714.14.

1714.14 (CNZ) Archer Tower Twin Comanche Charlie November Zulu is ready runway
10 right departing to the southeast (male voice).
1714.26 (Tower) Charlie November Zulu Tower runway right cleared for takeoff.
1714.31 (CNZ) Runway right cleared for takeoff Charlie November Zulu (male voice)
1715.21 (Tower) Charlie November Zulu there is smoke coming from one of your
engines (pause) it's the left engine.
1715.31 (Tower) Charlie November Zulu did you copy.
1715.36 (CNZ) Charlie November Zulu affirm we're shutting it down and request
a left turn back for landing (female voice).
1715.43 (Tower) Charlie November Zulu left turn approved.
1715.45 (CNZ) Charlie November Zulu (female voice).
1716.23 (Tower) Charlie November Zulu clear to land.
1716.27 (CNZ) Clear to land Charlie November Zulu (female voice).

Several witnesses observed the progress of the aircraft. Their observations
confirmed that a cloud of what appeared to be 'greyish black smoke' coming from
both sides of the left engine. The aircraft yawed sharply left and right just
after becoming airborne and then commenced a left circuit at very low level,
estimated to have been 100 ft above ground level. The landing gear remained
extended throughout the circuit. Approaching the western boundary of the
airport, the aircraft entered another left turn, passing low over some
buildings. Part way through the turn, the aircraft's angle of bank suddenly
increased and it descended rapidly into the ground. Both occupants were
fatally injured.

Wreckage and impact information

Initial examination at the accident site revealed that the fuel filler flap
covers of the two left wing tanks were open, and both filler caps were
missing. The caps were recovered the following day from runway 10 right and
the adjoining clear way. Fuel wetting was evident on the ground below the
open fuel caps of the inverted left wing. A total of approximately 35 litres
of fuel was recovered from the damaged right wing fuel tanks. The recovered
fuel was confirmed as the correct type and grade for the aircraft.
The accident aircraft was the thirteenth of sixteen refuelled from the same
batch and tanker on the day. The records show that the fuelling agent had
sample tested the fuel on three previous occasions throughout the day. Given
that there were no reports of fuel related problems from any other aircraft
and because of the obvious level of performance from the right engine. The
quality of the fuel as a factor in the development of the accident was
discounted.

The aircraft wreckage was located in an open area adjacent to the western
boundary fence of the aerodrome, approximately 250 metres north-northwest
of the threshold of runway 10 left. Impact marks indicated that the aircraft
was inverted and rolling left when it struck the ground. The aircraft
attitude was 55 - 60 degrees nose down and 25 - 30 degrees left wing low.
The main wreckage came to rest about 17 m beyond the initial impact point.
The tail section was right way up and the main wing section was folded back
on top of the rear fuselage. The cabin area was severely distorted, with the
instrument panel and cockpit floor displaced rearward.

Specific points noted during the wreckage examination included the following:

There was no evidence of either pre-impact or post impact fire including to
the left engine. (PA30-160 aircraft, along with most other light twin engine
aircraft, were not equipped with fire detection or suppressant systems.)
The landing gear was locked in the extended position and the wing flaps were
fully retracted. Impact damage prevented the serviceability of the stall
warning system being assessed.
The nature and extent of damage to the cockpit engine control pedestal
prevented any useful witness mark information being obtained regarding
the pre-impact position of the controls.
Ground contact marks and the condition of the right propeller blades
indicated that the right engine was developing significant power at impact.
Ground contact marks and the condition of the left propeller blades indicated
that the left propeller was rotating at impact but that the engine was not
developing power.
The constant speed governor from the left engine was recovered; the only
obvious damage being slight bending to the control-input shaft which was
consistent with impact damage. The governor was functionally tested at an
approved overhaul facility. The tests met all the manufacturer's
specifications, with the exception of the maximum RPM setting that indicated
2285. This was 45 RPM below the specification. Specialist opinion was that
this discrepancy could be attributed to the damage to the control-input shaft.

Disassembly of the left and right propellers found no evidence of any
pre-existing fault or defect. Disassembly of the left propeller confirmed
the blades were at fine pitch and not in the feathered position at impact.
Disassembly of both engines did not reveal any pre-existing fault or defect
that would have affected normal engine operation.

Fuel tank filler points

The two fuel tank filler points on each wing were located on either side of
the engine nacelles. The filler points consisted of filler port, a cap to
seal the port, and a flap covering the cap access. The cap consisted of a
black rubber insert that compressed to seal the fuel filler tank port by
the action of a screw grip on top of the cap. The flap cover was secured
with a winged slotted 'dzus' type fastener and, when locked, was flush
with the upper surface of the wing. Locking the flap cover required
deliberate action, and could not be achieved by slamming the cover down.
The flap covers were hinged parallel to the longitudinal axis of the
aircraft, and opened away from the engine nacelles. The slotted 'dzus'
fasteners had to be locked for the flap covers to be closed flush with
the wing surface. If not locked, the flap covers would stand slightly
proud of the wing surface.

The left and right wing filler points, inboard of the engine nacelles,
were visible from the left and right cockpit seats, respectively. They
may have been visible in the pilot's peripheral vision, depending on the
pilot's seating position. With the flap covers open, there was a high level
of contrast between the white painted upper surface of the wing and the dark
underside of the flap covers and filler cavity. In reduced light conditions,
the level of contrast would have been lower.

When in the open position, the outboard flap covers were partly visible from
the cockpit. If those covers were down, but not locked, they were not visible
from the cockpit.

The 'dzus' fastener locking mechanism for the flap covers on the left wing
tanks functioned normally. Aside from damage caused to one cap when it was
struck by an aerodrome mower operating on the runway 10R flight strip on
the morning following the accident, both fuel caps from the left wing tanks
were in a serviceable condition.

The pilots

Both pilots were appropriately licensed and held current medical certificates.

Toxicological and Post-mortem analysis did not reveal the presence of any
compound or pre-existing medical condition that may have affected the
performance of either pilot.

Aerodrome information

Runway 10 Right was 1100 m long. Beyond the runway end was a flat area extending
for more than 400 m, and free of major obstacles, to the aerodrome boundary fence.
The distance from a position on the runway abeam the control tower to the
boundary fence was about 800 m.

The control tower cab was 65 ft above ground level. The controller reported
that when the aircraft passed abeam the tower, its level appeared to be
slightly below that of the tower cab. With respect to the control tower, the
remaining light or glow from the sun was behind and slightly left of the
position of the aircraft, as it became airborne.

Aircraft performance

The aircraft flight manual performance charts indicated that, in the prevailing
conditions, the take-off ground run distance required was about 350 m,
depending on the flap setting used. The observations of the tower controller
indicated that the actual take-off performance of the aircraft was not
substantially different from that figure.

The landing distance over a 50-ft obstacle was approximately 500 m,
depending on the aircraft flap setting and approach speed.

Single engine performance

The sea level single engine climb performance of light twin engine aeroplanes
certified in accordance with United States Federal Aviation Regulation 23
requirements can be up to 70 to 90 percent less than the twin engine
performance. Many factors can contribute to this performance loss such as
aircraft age and condition, leaving the landing gear extended, not
feathering a propeller, not maintaining the correct airspeed, and not
turning towards the live engine.

The Pilot's Operating Manual for the aircraft included information on
propeller feathering procedures and single engine flight. That information
included the statement that, when climbing with one engine inoperative,
the landing gear and wing flaps must be retracted. 

ANALYSIS

The aircraft took off with the fuel caps for the left wing tanks not secured,
and the flap covers unlocked. It could not be established if the flap covers
remained in the opened (up) position where they were left by the refueller,
or whether they moved to the closed/not locked position because of aircraft
movement or vibration, or airflow.

There may have been some perceived time pressure regarding the pre-flight
inspection because of the deteriorating light. Further, the light may have
reduced the visual prominence of the open flap covers. Either, or both of
those influences could have contributed to the pilots not being aware that
the left wing fuel caps were not secured.

As the aircraft accelerated during the takeoff roll, the caps fell from the
left wing filler ports, probably as a result of vibration and/or aerodynamic
forces. The 'smoke' observed by the tower controller and a witness was fuel
venting from the open tank filler ports. It was unlikely that any other
interpretation of the venting fuel would reasonably have been made in the
circumstances, particularly in the deteriorating ambient light conditions,
coupled with the position of the filler ports on either side of the engine
nacelle.

Other than the tower controller's transmission regarding the 'smoke', it
could not be determined what other information the pilots of the aircraft
used in reaching the decisions to shut down the left engine and attempt a
left turnback. However, based on the examination of the left engine and
propeller, there would most probably have been no indication from the
cockpit instruments that the left engine was malfunctioning in any way.
Whether the pilots were able to observe the 'smoke', or became aware of
the situation regarding the fuel caps, could not be determined.

It was apparent from the record of communications with the control tower
that the pilot who initiated communications with the air traffic controller
prior to take off was not the same person who communicated with the tower
controller following the advice that there was 'smoke' coming from the left
engine. However, which pilot manipulated the aircraft controls during that
period could not be determined.

At the time the aircraft passed abeam the control tower, there was adequate
runway and overrun distance available for the aircraft to land and decelerate
significantly before reaching the boundary fence. Whether the pilots
considered the option of landing straight ahead after being notified of the
'smoke' could not be determined.

The flight path taken by the aircraft (the turn away from the live engine)
and the aircraft configuration at impact (left propeller not feathered,
landing gear extended) indicated that aspects critical to maintaining single
engine performance were not accomplished. The final flight path and impact
attitude of the aircraft were typical of what might be expected following
loss of control when the airspeed falls below the minimum single engine
control speed. 

SIGNIFICANT FACTORS

The left wing fuel tank filler caps were not secured before takeoff.
Fuel vented from the left wing fuel tanks and had the appearance of smoke
coming from the left engine.
The pilot(s) did not take the appropriate actions to maintain aircraft
performance after shutting down the left engine.

The pilot(s) were unable to maintain control of the aircraft.