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Summary

Summary

The pilot of the Lancair 320 aircraft planned to fly, with a passenger, from Archerfield to Rockhampton and return. The aircraft was refuelled at Rockhampton and after an hour's stopover, they departed for Archerfield, on climb to the planned cruise altitude of 5,500 ft above mean sea level. The aircraft left controlled airspace at 1403 Eastern Standard Time. At 1428 Brisbane Flight Service received a Mayday transmission from the aircraft. The pilot indicated that the engine had lost all oil pressure, and that she intended to land on a road. This was the last recorded transmission from the aircraft. The crews of searching aircraft did not hear any transmissions from the missing aircraft's emergency locator transmitter (ELT). The crew of a search aircraft sighted the wreckage at 1815.

The pilot held a commercial pilot licence, and a medical certificate limited to private operations. She had been taught to fly the aircraft type in July 1994, and up to December 1997 had gained 104 hours experience on type. The pilot met the 90-day recency requirement specified in the Civil Aviation Regulations pertaining to the carriage of passengers. However, with the exception of a 30-minute flight on 13 December 1997, the only flying experience gained by the pilot in the last 90-days was the 3 hours flown on the day of the accident. The passenger held a private pilot licence but was not experienced on the aircraft type.

The wreckage was located about 380 m south of a dirt road aligned 080/260 degrees M. The road was new and unusually wide due to the recently constructed clearway through the coastal forest. it had a natural surface and was suitable for an emergency landing. The surface wind at the time of the accident was an easterly at about 15 kts.

Examination of the accident site revealed that the aircraft struck the ground at an angle of 45-50 degrees nose-down and banked approximately 90 degrees left. The left wingtip struck the ground first. The aircraft then cartwheeled, traversed a windrow of felled trees, and came to rest inverted, aligned approximately 345 degrees M, 22 m from the initial impact point. The engine, firewall and instrument panel had separated from the fuselage in one piece. The empennage had separated in a whiplash action and had come to rest 8 m beyond the fuselage, also aligned approximately 345 degrees M. The landing gear was locked in the extended position and the wingflaps were retracted. A significant quantity of oil had escaped from the engine during flight, as evidenced by oil along the lower fuselage. A search of the area where the aircraft was parked at Rockhampton found a small pool of fresh oil consistent with engine oil dripping from the engine cowling during the stopover. It could not be established if oil had been added to the engine at Rockhampton.

The ELT was mounted in the rear of the fuselage but was disconnected from its aerial due to impact forces. The unit was turned off 42 hours after the accident. Later specialist examination found that the near-new batteries were almost depleted, indicating that the unit had been operating but not radiating effectively without its aerial.

The engine was removed to an engineering workshop and dismantled under the supervision of BASI investigators. Approximately 1 L of oil was recovered from the engine and there was no sign of seizure damage to any engine component. Specialist engineering opinion was that the engine was serviceable before impact. Destruction dynamics of the wooden-bladed, variable-pitch propeller assembly indicated that the engine was producing power at impact. During removal of the engine ancillary components, a high-pressure oil hose was found to be holed. The braided steel, rubber-lined hose had been resting on the Number 1 cylinder exhaust pipe and had worn through due to vibration and heat.

The oil hose had been fitted to replace the engine manufacturer's stainless steel line between the propeller hub and the propeller governor at the rear of the engine crankcase. Replacement of the stainless steel line with a braided steel hose was authorised by Civil Aviation Safety Authority (CASA) Airworthiness Directive (AD) AD/LYC/86 Amdt. 1 issued on 12 July 1990. The AD referred to Textron Lycoming Service Instruction 1435, which specified a Type D, teflon hose with steel braiding/fire-sleeving, and instructions on clamping/routing. The item fitted to the aircraft was a Type A, steel-braided, rubber hose of lower specifications than the Type D hose and was clamped/routed incorrectly. The aircraft was amateur-built by its previous owner. The hose had been installed before the aircraft's initial airworthiness inspection prior to being placed on the Australian Aircraft Register.

Forty flight-hours before the accident, the engine's cylinders had been removed/refitted during unscheduled maintenance. The aircraft had also undergone a periodic inspection at the same maintenance organisation 19.4 flight hours before the accident.

Although the engine did not show any signs of seizure and some oil remained, the length of time that the engine may have continued to operate could not be determined. Bundaberg aerodrome, 72 km from the accident site, was the nearest suitable aerodrome. Considering the loss of oil pressure, the pilot's decision to carry out a precautionary landing on a road in an area devoid of other suitable landing sites was appropriate. The circumstances of the approach could not be determined. Although the wingflaps had not been configured for landing, the disposition of the wreckage was consistent with a right-base position for landing into wind. The attitude of the aircraft at impact was consistent with a loss of control at a height from which recovery was not possible.

Comparison of limitation data contained in the aircraft flight manual and the flight test results contained in the aircraft files held by CASA revealed a discrepancy in the documented aerodynamic stalling speeds. The stall speeds specified in the aircraft flight manual were lower by 2 kt when compared with the relevant flight test power-off stalling speeds.

Although not implicated in the accident sequence, two other discrepancies were found which involved the fitment of an automotive engine oil filter to the engine, and a right-angle drive adaptor for the rear mounted propeller governor. Neither was covered under an Australian Engineering Order or Supplemental Type Certificate for the Textron Lycoming engine.

During the course of the investigation it was reported that maintenance by unqualified personnel had been performed on the propeller system following the last periodic inspection. This could not be substantiated.

 
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