Cessna Aircraft 310R, VH-COQ, Groote Eylandt, Aero. 25 March 2003

The damage to the rod end was consistent with failure during the
retraction of the landing gear after takeoff at Gove. Disconnection
of the left main gear from its push-pull tube meant that the
gearbox was unable to extend or retract that gear. It also meant
that the emergency gear extension was ineffective. Fatigue cracking
within the rod eye section was the principal factor behind the
separation of the push-pull tube and the subsequent failure of the
landing gear to operate correctly.

The investigation was unable to determine why the rod end
failed. It is possible that an increase in transmitted loads
resulting from excessive system friction, system rigging problems
or the failure of interrelated components could have contributed to
the initiation of the rod end cracking.

The pilot was confronted with the high workload of maintaining
control during night circuits and trouble shooting a landing gear
malfunction. The night conditions meant that people on the ground
were of limited help, at least initially, in determining the status
of the landing gear. Landing the aircraft with the gear retracted
allowed for some directional control during the landing slide and
probably limited damage to the aircraft.

The release of the emergency exit on final approach had the
potential to inflict serious damage to the tailplane with possible
control problems resulting.

The pilot of a Cessna 310R made a night departure from Gove, NT,
at 1900 Central Standard Time for Groote Eylandt, NT. After takeoff
he noticed two unusual thumps near the end of the landing gear
retraction cycle. Normal landing gear up indications were observed
and there were no unusual handling characteristics during the
flight to Groote Eylandt.

The pilot reported that on arrival in the circuit area he
selected the landing gear down. The landing gear operated but the
left main landing gear down light did not illuminate at the end of
the cycle. The pilot changed the down light bulb without change to
the indication. He then cycled the landing gear by selecting up
then down, which resulted in the left main and nose landing gear
down lights not illuminating. The pilot spoke to ground personnel
by radio and made a few low passes along the runway to allow them
to observe and report on the condition and position of the landing
gear. However, they were unable to see the position of the landing
gear due to the darkness.

The pilot manoeuvred the aircraft in an unsuccessful attempt to
free the landing gear. Further cycling of the landing gear and a
manual landing gear extension were attempted without success.
Emergency services, notified by air traffic services, attended and
were able to provide enough illumination of the aircraft for
observers to report that the nose gear was not extended, the left
main gear was at an angle and the right gear appeared to be in the
down position.

After consultation with a pilot on the ground and briefing the
passengers, the pilot made an approach to runway 28 with the gear
selected up and the flaps down. While on final approach the pilot
unlatched the emergency exit and cabin door. The emergency exit,
which consisted of the pilot's side window and associated frame,
detached from the aircraft.

The aircraft made a smooth touchdown and slid on the runway. The
pilot selected the mixture control to idle cut off and the fuel,
magnetos, alternators and battery to off. The passengers exited
through the cabin door and over the right wing and moved away from
the aircraft. There was no fire, but the propellers and the
underbelly of the aircraft were damaged.

Inspection of the aircraft by engineering personnel revealed
that the rod end on the outer end of the left main gear inboard
push-pull tube had separated, effectively disconnecting the left
main landing gear assembly from the actuating mechanism.

Laboratory examination by the ATSB revealed that rod end
separation had occurred under predominantly tensile forces after
fracturing through one side of the eye section. Detailed
examination of the fracture surfaces found characteristic evidence
of fatigue cracking, originating from the outer corners of an
integral lubrication port within the eye body. The examination
found no evidence of any material or manufacturing defects having
contributed to the failure.

There were no reports of previous landing gear problems.

The electro-mechanical landing gear system utilised a gearbox,
driven by an electric motor, to turn two bellcranks that extended
or retracted a push-pull tube to each landing gear assembly. A
landing gear hand-crank provided an alternative manual means to
drive the gearbox.

In the sub-section titled `EMERGENCY LANDING PROCEDURES', the
Cessna 310R pilot's operating handbook (POH) specified unlatching
of the cabin door prior to flare-out. However, there was no
reference to in-flight unlatching of the emergency exit in any of
the emergency checklists.