Runway 17 was nominated as the duty runway, with runway 12 available for departures only. Aircraft movements included VH-DUP, flying practice Instrument Landing System (ILS) approaches for runway 35, and VH-TQN and VH-KDV, both to depart from runway 35 for Sydney. Before these two aircraft departed the tower co-ordinator attempted to pass to the approach controller a departure clearance for VH-AVS for departure from runway 35.

The approach controller initially did not acknowledge acceptance of this clearance, instead advising he did not hold details for this aircraft. Shortly after the approach controller obtained the details and also got the clearance from the tower controller for AVS. This was for a runway 35 radar departure tracking via Shelleys at 5,000 ft. The approach controller then passed to the tower the departure instructions for AVS which included a 90 deg right turn after take-off.

A short time later the approach controller passed the approach sequence to the tower. This was for TQQ and EKN, both inbound from Sydney for runway 17 and for HYD, inbound from Melbourne for an ILS approach for runway 35. The crew of TQQ were initially told by the approach controller to take up a heading of 260 degrees to position for the final leg of the runway 17 VOR/DME approach. Shortly after this they reported visual and were given a visual approach. TQQ was then flown on a south-westerly track, with the aim of intercepting the extended centreline of runway 17.

AVS then became airborne off runway 35 and when the pilot contacted the approach controller he was instructed to cancel the right turn and to maintain runway heading. The approach controller then realised a conflict existed between TQQ, which was closing on the extended centreline for runway 17 and AVS which was flying on the runway 35 extended centreline in the opposite direction. The controller assessed that TQQ would pass behind AVS, but with less than the required radar separation of three miles. The pilot of AVS reported sighting TQQ but no traffic information was passed to the crew of TQQ. The two aircraft passed with a lateral separation of about two miles and about 400 ft vertical separation. In a situation where the minimum lateral separation of three miles does not exist the minimum required vertical separation is 1000 ft.

The instructions for the use of runways at Canberra did not preclude the use of reciprocal runways. Following this incident amended instructions were issued. These included the following:

'The duty runway nominated on the Canberra ATIS, or the runway nominated in the runway agreement, are the only runways that shall be used for departing and arriving aircraft. The runway agreement shall not include reciprocal ends of the same runway. The only exception to the above shall be an aircraft with an operational requirement to use another runway.'

The existing instructions did not exclude the use of reciprocal runway directions. The traffic situation was significantly complicated by the use of reciprocal runway directions for both departing and arriving aircraft. The procedures adopted by the approach controller did not provide for separation assurance and thus a loss of separation occurred.

The aircraft was engaged in chemical spraying operations. Before the first flight the pilot fuelled the aircraft to the 3/4 tab in both wing tanks. Prior to each subsequent operation the pilot refuelled only the left-wing tank to the 3/4 tab, as further chemical was loaded with the engine running. The pilot subsequently reported that on the fourth operation the engine momentarily lost power during a spray run. The fuel contents gauge indicated just above empty, but he could not recall which tank was indicating at the time. He decided to land and refuel, but the engine flamed out and the aircraft was substantially damaged in the ensuing forced landing.

Inspection of the aircraft determined that the left tank contained a substantial amount of fuel. However, only a small amount remained in the right tank. The fuel filter and header tank were only half full. The pilot reported that he had refuelled via the left tank only as the tanks were interconnected and designed to self level, and that it was a common practice on other agricultural aircraft he had flown. The pilot was trained and endorsed on Thrush aircraft, which automatically qualified him on the Air Tractor. His experience on the Air Tractor was relatively limited and he had not received training on system differences between the two aircraft types. The fuel systems of the two aircraft differ primarily in the design of the header tanks and tank interconnection. The Thrush has a header tank of approximately 20-L capacity, gravity fed by a single line from each wing tank. The tanks self level through the header tank and interconnections. Engine fuel is drawn from the lowest point in the header tank.

The Air Tractor's cylindrical header tank holds only 4.5 L, and is also gravity fed by a single line from each wing tank, designed to be self levelling. Engine fuel is drawn through a line positioned halfway up the rear face of the header tank. By refuelling through the left tank only during the rapid ground loading operations, it is likely that fuel did not flow to the right tank as quickly as the pilot had expected. Also, the continual racetrack pattern being flown, coupled with any skid induced during turns, may have further exacerbated the imbalance in fuel quantities between the tanks. The right tank fuel quantity probably reduced to the point where any fuel sloshing in the tank uncovered the outlet, allowing air to be drawn into the header tank, resulting in a momentary loss of power. With the engine supply line positioned at the rear of the header tank, it is likely that the nose low approach attitude of the aircraft caused any remaining air in the tank to enter the supply outlet, causing the engine to flame out.

Safety Action

As a result of the investigation into this occurrence, and of a similar event (BASI No. 9401685, VH-ODR), the Bureau of Air Safety Investigation forwarded the following Safety Advisory Notice to the Civil Aviation Safety Authority on 01 July 1996.

'SAN 960052

The Bureau of Air Safety Investigation suggests that the Civil Aviation Safety Authority, in consultation with the US Federal Aviation Administration, review the fuel system design of aircraft conforming to Type certificate A17SW to ensure the adequacy of the fuel system with all applicable airframe/engine combinations.'

The Civil Aviation Safety Authority responded on 18 July 1996, stating in part: 'I have written to the President of Air Tractor, and the Small Airplane Directorate of the Federal Aviation Administration, advising them of the fuel starvation incidents in Australia and asking for their comments. I will advise of the responses when I receive them.'

The Bureau is addressing pilot systems training in another accident investigation (BASI 9600323, VH-BRN).

The pilot reported he was making an approach to land on the 090 deg grass strip in nil wind conditions. The approach to this strip is over a steep gully. The pilot said that approaching the flare the sink rate suddenly increased and airspeed washed off. He applied full power but not in time to prevent the aircraft landing heavily. The left main landing gear collapsed, the propeller and left wingtip struck the ground, and the aircraft slid for about 100 metres, coming to rest at the left edge of the strip.

The pilot reported that as he was preparing engine settings for descent, he noticed a very large bird ahead of the aircraft. Insufficient time remained to initiate avoidance, and the bird struck the left-wing leading edge. The flight continued without further incident and the aircraft made an uneventful landing at the planned destination. Post flight examination found the wing leading edge was deformed outboard of the left engine and a wing rib was damaged.

The take-off was being conducted in a northerly direction along a curving sea channel when the float-equipped aircraft struck a sandbar in the channel. It nosed-over and came to rest inverted. All five occupants received minor injuries: three sustained head and neck injuries.

From the information provided by the pilot and passengers it was determined that the aircraft was correctly loaded, and the centre of gravity was within limits.

The pilot reported that there was a light crosswind and the tide was low which created a narrower than usual channel for the take-off.  However, he was familiar with the prevailing conditions having operated the aircraft along the same channel, in the same direction, with similar loadings, on several previous occasions. The planned take-off path followed the channel to the north west before changing to a north easterly direction. This meant that the first part of the take-off would have a quartering tailwind which would change to a quartering headwind after the aircraft rounded the first bend. From experience the pilot expected the aircraft to become airborne soon after rounding the bend.

The pilot reported that once the aircraft was on the step it continued to accelerate normally, and all power indications and flight controls were normal during the take-off. As the aircraft approached the first bend in the channel the pilot decided to abandon the take-off because the sandbar appeared to be larger and the bend tighter than usual. After closing the throttle, the pilot held back pressure on the control column, but was unable maintain enough rudder directional control to prevent the aircraft from floating onto the sandbar. The aircraft skidded along the sandbar until the floats entered a depression, causing the aircraft to nose over. The pilot assisted the passengers to vacate the aircraft through the left cockpit door.

Passengers reported that the pilot had given a pre-take-off safety briefing. A passenger who had occupied the rear cabin seat said that he had not fastened his seat belt because he could not find the end of the belt. He said that he did not inform the pilot about the seat belt because he had previously taken a similar flight which was uneventful, and he was confident that nothing would happen on this occasion.

Significant factors

1. The pilot misjudged the distance available to the sandbar during the take-off run.
2. The decision to reject the take-off was taken too late to avoid impact with the sandbar.

The aircraft departed from Parafield with three persons on board. The pilot estimated the aircraft weight was within tolerance, being just below the allowable maximum all up weight for the aircraft type.

The destination airstrip had a steep uphill gradient in the landing direction to the north. A 20 kt to 30 kt northerly wind was blowing at the time. The pilot assessed the situation, but because the wind was not generating a great deal of turbulence, he believed it to be lighter, but he still decided to make a shallow approach at a slightly faster speed. On final approach, as the aircraft descended through about 500 ft above ground level (AGL), the pilot believed it experienced windshear, with the airspeed decreasing from 70 kt to 60 kt, and an increase in the rate of descent.

On short final the pilot reduced power, then flared for the landing but too high. He felt the aircraft sink but did not increase power to arrest the descent, with the result the aircraft struck the ground heavily on its main wheels, bounced, then turned to the left impacting the ground again with the left main wheel, left wingtip, nose wheel, and propeller. The nose gear separated, and the left main gear fractured.

A witness on the ground reported that a stronger wind gust occurred just as the aircraft was on short final and commencing to flare at about 20 ft AGL. It then sank rapidly to the ground.

The pilot probably misjudged the flare height due to the steep incline of the airstrip, allowed the airspeed to decay, then failed to apply power to prevent the subsequent high sink rate. The heavy aircraft weight, and the wind roll over effect in the lee of the hill, would have contributed to the rapid rate of descent.

The pilot of VH-RQF reported "ready" for runway 03L and was instructed by the air traffic controller to line up. The pilot of VH-KGP, conducting crosswind landing practice on runway 08L, received a clearance for a touch-and-go landing.

The air traffic controller observed VH-KGP complete the landing and commence to take-off. He then noticed that VH-RQF was also taking off and attempted to instruct the pilot to stop but used the call sign of another aircraft operating in the circuit area, with the result that the instruction was ignored.

As both aircraft became airborne the air traffic controller gave a warning to the pilot of VH-KGP, who then saw VH-RQF and dived to pass beneath it. Both aircraft had climbed to about 100 ft above ground level and passed at the intersection of the two runways.

The pilot of VH-RQF stated that he had been involved in discussing the take-off technique with the student pilot, and thought he heard his take off clearance being given. When airborne he saw VH-KGP, and noticed that it had commenced to descend, so he climbed his aircraft as steep as possible to increase separation.

FACTUAL INFORMATION

History of the flight

The aircraft was the third in a stream of five company aircraft departing the Tangalooma Resort airstrip at two-minute intervals on a clear moonlit evening. Following a routine departure at 2105 EST, the aircraft was climbed to 3,000 ft for the flight back to Coolangatta. Early in the cruise phase of the flight, the pilot found that the fourth aircraft was catching up to his and he elected to descend to 2,000 ft to ensure continued separation.

At 2127 EST, the pilot reported to Coolangatta Approach Control that the aircraft had severe problems, but did not inform the controller of the nature of his emergency. However, the controller activated the airport emergency procedures when he observed on his radar display that the aircraft was losing altitude. The pilot had his second VHF radio transceiver tuned to his company frequency and was answering transmissions received from other company pilots on this frequency while transmitting on the Coolangatta Approach frequency.

The pilot later said that after the aircraft passed the seaway at Southport, the right engine surged, which resulted in the aircraft yawing. After he switch the electric fuel pump to "on", the symptoms disappeared. About a minute later he switched the pump off, then on again.  He said that when the engine began surging again, he shut the engine down, feathering the propeller. Left engine power was increased, and the aircraft maintained 1,500 ft in level flight. He switched the left engine's fuel supply to the right main tank, believing that this action would ensure supply from both main fuel tanks.

The pilot said that after the aircraft passed Burleigh Heads, many things appeared to go wrong at once. The left engine began to splutter and did not respond to the throttle. He recalled attempting to restart the right engine. This proved to be unsuccessful.  As the descent continued, he planned to land on a beach.

The pilot selected a stretch of beach for a forced landing. During late final approach, aided by bright moonlight, he noticed that any overrun would take the aircraft into a crowded car park. He changed his aim point to the stretch of beach south of the Currumbin Lifesavers Clubhouse. Following the flare for landing, the right wing struck a low rocky outcrop, and the aircraft crashed into the surf.  The entire wing assembly separated from the fuselage, which came to rest on its left side. Some of the nine passengers, and the pilot, escaped from the semi-submerged fuselage while bystanders rescued others.

Personnel information

The pilot was 45 years of age and had commenced flying training in October 1990. He was issued with a commercial pilot licence on 30 June 1993. He continued his training and, on 3 June 1994, gained a grade 3 instructor rating valid for single-engine aircraft. He was appropriately endorsed to fly the Britten-Norman Islander BN-2 series of aircraft. The pilot held a current command instrument rating valid for multi-engine aircraft. He satisfied the recency requirements for single-pilot flight under instrument flight rules, as contained in Civil Aviation Order 40.2.1. The pilot had a total flying experience of 881 hours, of which 606 were as pilot in command. He had recorded about 373 hours in multi-engine aircraft, of which 177 were on the Britten-Norman Islander aircraft. In the previous 30 days he had flown a total of 38 hours, all on the aircraft type.

The pilot had been employed by the company on a part-time basis until February 1996, when he became a full-time pilot. During his employment as a part-time pilot, he had worked in the maintenance hangar as a general hand assisting the licensed aircraft maintenance engineers who serviced the company's aircraft.

Medical information

The pilot's class 1 medical certificate was without restriction and was current until 7 May 1996. The pilot reported that he was not suffering from any illness and that he was fit to undertake the flight.

Aircraft information

The aircraft, a model BN-2A-21, Serial No. 415, was manufactured by Britten-Norman Limited in England in

1974.  It was a high-wing, twin-engine, propeller-driven aircraft with a maximum allowable take-off weight of 2,994 kg. The aircraft was imported from Singapore in 1995 and placed on the Australian Aircraft Register on 25 October 1995 when Airworthiness Certificate AFD/10663 was issued. Maintenance Release Certificate No.

PA/51001, issued on 11 January 1996, was valid until 11 January 1997, or 6,020.8 hours total time in service (TTIS). The aircraft TTIS was 6,013.4 hours at the time of the accident.  There were no identified outstanding maintenance requirements. The aircraft was fitted with forward facing seats and certified to carry 11 persons.

The aircraft was powered by two Avco Lycoming IO-540-K1B5 engines driving Hartzell fully feathering propellers. These components were within their mandatory service lives. The design of the propellers provides a feathering spring and dome air pressure to drive the blades into the feather position when the control is selected to feather. The blades may also go to feather when oil pressure has been lost if the blade pitch is on the coarse pitch side of the propeller stops. The propeller stops prevent the propeller from moving to feather during engine shutdown in normal operations.

The pilot flew the aircraft on the outbound flight earlier in the day. He did not report any defects.

Fuel system

The aircraft fuel system included four individual wing tanks: two integral main tanks located outboard of each engine, and two auxiliary tanks at the wingtips. The two main tanks have a total capacity of 518 L, and the two auxiliary tanks 223 L. Two main fuel tank selector valves provide for selection of OFF, PORT, and STARBOARD. When the selector is positioned to the opposite wing named on the selector, the engine uses fuel from that main tank only, in crossfeed. Two auxiliary fuel switches provide for selection of MAIN or TIP, which can also be crossfed in the same way by selecting the wing named on the selector and operating on TIP.

Before departure from Coolangatta in the morning, the aircraft was refuelled to 240 L in the main tanks and 100 L in the auxiliary tanks. The flight to Tangalooma and return required approximately 120 L.

Engine handling during cruise

The operator of the aircraft required pilots to set the engine fuel mixture after the aircraft had levelled out in cruise. The normal technique was to lean the engine fuel mixture to peak exhaust gas temperature and then enrich the mixture to lower the exhaust gas temperature by 50 degrees (two divisions on the exhaust gas temperature gauge).

Weight and balance

The aircraft weight at the time of the accident was calculated at 2,749 kg, 245 kg below the maximum allowable take-off weight. The centre of gravity was within allowable limits.

Propeller controls

The manufacturer restricted the propeller controls for normal operations by offsetting the rear segment of the slots to prevent inadvertent feathering which would otherwise be possible when selecting coarse propeller pitch. To select feather, the pilot has to move the lever sideways slightly to bypass the 2-mm notched stop or detent.

Meteorological information

The Bureau of Meteorology prepared an analysis of wind conditions in the Coolangatta area. The low-level wind was a light northerly, less than 5 kts at the surface and increasing to about 10 kts at 2,000 ft. The Coolangatta Automatic Terminal Service reported a light north-westerly wind at 4 kts, a temperature of 21 degrees C, and a QNH of 1,018 hPa.

Witnesses reported that the night was clear, with a near-full moon about 20 degrees above the eastern horizon. Visibility was in excess of 10 km. The tide was about 1 hour short of high tide, which led to high cresting waves washing over the wreckage.

There was no evidence that weather conditions contributed to the accident.

Aids to navigation

The aircraft was equipped with very high frequency omni-directional radio range (VOR), automatic direction finding (ADF) and distance measuring equipment (DME) navigation aids. The flight was planned to operate under instrument flight rules; however, the weather was such that visual navigation was possible. The pilot did not report any navigation aid defects or difficulties.

Communications

The aircraft was fitted with two very high frequency (VHF) radio transceivers appropriate to the flight. Both radios were in use, monitoring air traffic control (ATC) and the company frequency at the same time. However, only one transmitter at a time could be used. The pilot had communicated without difficulty with Brisbane Flight Service, Brisbane Approach, and Coolangatta Approach before reporting problems.

The sound of an engine operating at high revolutions per minute was audible in the background of 17 subsequent transmissions. Engine noise was not apparent in the last transmission at 2137:37 but an aural warning tone could be heard. A stall-warning horn was the only aural warning device fitted to the aircraft.

Communications recorded on the ATC automatic voice recorder (AVR) tapes

All communications between the aircraft and air traffic services were recorded on automatic voice recorders in Brisbane and Coolangatta. The first indication of any significant problem was when the pilot transmitted at 2127:34 that he was experiencing severe problems with the aircraft. However, the pilot did not elaborate on the problems. A series of unnecessary transmissions were made by the pilot throughout the emergency sequence, some in answer to unrecorded questions received on his second radio which was monitoring the company frequency.

At 2131:05 the pilot reported that he seemed to have the aircraft under control again. At 2132:01 he transmitted "I'm having problems maintaining height with whatever this configuration is" and 50 seconds later, "OK guys, I'm just going to try a restart". This was the first indication to the Coolangatta approach controller that the aircraft was operating on one engine. The aircraft was then at approximately 600 ft. At 2133:05 another company pilot asked whether he had lost one (engine) or both. The pilot's answer indicated that the aircraft was operating on one engine which was not delivering the power he expected. The last transmission made by the pilot was at 2137:37 in which he said that he was going to land the aircraft on the beach.

Safety equipment

An emergency locater transmitter was not installed in the aircraft.

The restraint harnesses appeared to have effectively restrained all passengers and the pilot. The serious injuries received by both front-seat occupants were probably due to the cockpit structure collapsing, thereby reducing the occupiable space.

The Civil Aviation Orders required that the aircraft, which was authorised to carry more than nine passengers, be equipped with life jackets for each occupant where the take-off or approach paths extended over water. The aircraft was not equipped with life jackets on this flight.

Wreckage and impact information

The right wingtip separated when it struck a low rocky outcrop. The aircraft yawed right and landed in waist-deep water in the surf some 10-15 m further on. The force of impact of the fixed main gear with the sand and water caused the wing assembly to separate from the fuselage. The fuselage came to rest on its left side. Both engine/propeller combinations remained attached to the wings. Both propellers were bent. The wing flaps were fully retracted. Wave action exacerbated the impact damage and filled the structure with sand.

Aircraft maintenance documentation

The aircraft logbooks and maintenance work sheets were examined. In the period from November 1995 to late February 1996, the records showed that there were six reports of low engine power, mostly involving the right engine. The last report of low engine power was on 24 February 1996, when no fault was found. The aircraft had operated since then without any apparent engine defects requiring rectification. The recording of defects by maintenance personnel was incomplete due to omissions. Pilots had not recorded defects in the aircraft's maintenance release but had annotated a whiteboard in the chief pilot's office which was periodically checked by the chief licensed aircraft maintenance engineer. Defects which required urgent attention were also directly referred (verbally) to the engineer.

Aircraft systems examination

Approximately 100 L of fuel were recovered from the right main and left auxiliary (tip) tanks. The fuel, apart from salt water in the tip tank, was clean avgas. The main fuel-feed and vent lines were inspected and found to be free of any blockages. The left main tank was ruptured. The right auxiliary tank had separated, and the cap was off. Neither tank contained fuel. The fuel manifold of both the right and left engines contained fuel. The left fuel gascolator was found to be full of clean fuel.  The right gascolator was loose, having sustained impact damage. It contained salt water and sand.  The inlet filters in both left and right fuel control units were clean.

Due to the separation of the overhead panel from the fuselage, an examination of the main fuel selectors could not determine the settings. The two auxiliary fuel switches were set to MAIN. This selection was confirmed by the position of the electromechanically activated fuel valve in each wing.

The engines and propellers were dismantled and examined. The investigation gave considerable attention to the fuel injectors due to previously reported problems evident from the aircraft's maintenance history.  No evidence of contamination or blockage was found with the injectors, other than some minor salt and sand deposits in two injectors from the left engine, consistent with immersion in the surf.

The condition of each engine was consistent with a low power setting at impact.  Both propellers were bent, and each was found to be within its normal pitch range. The fuel control units from each engine were functionally bench tested and later dismantled. No fault was found with either unit. Both magnetos from each engine were examined and found to be functional, apart from saltwater damage.

The airframe, avionics and instrumentation were examined, but no pre-existing defects were found. Both left engine magneto switches were on but only the left magneto switch of the right engine was on. This is consistent with an incompleted air start attempt as the manufacturer recommends the use of only the left magneto during start. No other useful information was obtained from the engine controls located in the centre console due to the break-up of the wreckage.

Tests and research - aircraft performance

Test flights were arranged to determine certain aircraft performance parameters not available from the manufacturer's data. The pilot conducting the tests was a qualified experimental test pilot. The aircraft used was a Britten-Norman BN-2A-20 with similar performance to that of the accident aircraft and was ballasted to replicate its weight. The temperature was 19 degrees, within 2 degrees of the temperature at the time of the accident. The Owners Handbook specifies 65 kts as the best single-engine rate of climb speed (blue line on the airspeed indicator). The manufacturer indicated that this speed represents the speed at maximum allowable weight at which the margin of engine power in excess of that required for flight is greatest. The manufacturer indicated that the aircraft should be flown at this speed following an engine failure during the critical initial climb after take-off.

The following parameters were noted:

1. At 65 kts, to maintain level flight at 2,000 ft, flaps up and right propeller feathered; power (left engine) required was 19 inches manifold air pressure [MAP] (propeller in full fine pitch).
2. At 2,000 ft, to maintain level flight, flaps up, left engine at full power, right propeller feathered; stabilised speed was 102 kts.
3. At 2,000 ft, to maintain level flight, flaps up, left engine at full power, right propeller windmilling (fuel mixture closed); stabilised speed was 80 kts.

The test pilot found that at an air speed greater than 80 kts level flight was not possible with one propeller windmilling. The aircraft would descend at the approximate rate of 200 ft/min. for a 10-kt increase in air speed.

The test flights were conducted in daylight and in visual meteorological conditions with a distinct horizon as an aid to aircraft attitude control. These conditions were significantly better than those on the accident flight. The test pilot found that in order to obtain the best possible performance, fine attitude control was necessary. A significant rate of descent was easily set up by minor attitude deviations and the elevator required careful trimming until stabilised speeds were obtained.

Comparison of automatic voice recorder information

A further flight was conducted in the test aircraft to establish the engine power settings heard in the background of transmissions from the accident aircraft recorded on the Coolangatta AVR tape. A series of transmissions was broadcast from the test aircraft to Coolangatta Surface Movement Control. Each transmission was made with the left engine at a specific power setting and the right propeller windmilling. The power settings varied from cruise power to full rated power. The test transmissions were recorded on the Coolangatta AVR tape and were compared with those from the accident AVR tape. The result of this comparison indicated that the accident aircraft was operating on one engine, and that the engine was operating in excess of 2,590 RPM and at greater than 25 inches MAP from 2127:49 until just before impact at 2137:37.

In-flight engine start procedure

The pilot reported that he attempted to start the right engine when he realised that it was unlikely that the aircraft would reach the aerodrome at its current performance. He was unable to restart the engine. Subsequent research found that the manufacturer's Owners Handbook was found to contain a procedure for air-starting an engine which was applicable to the Avco Lycoming O-540 carburetted engine and not the IO-540 fuel injected engine as fitted to this aircraft. The investigation did not reveal whether the pilot used this checklist on the night.

During a test flight the Owners Handbook emergency checklist was used in an attempt to start the right engine, propeller feathered. The test pilot was unable to start the engine using the procedure in the checklist. When the correct start procedure in the Avco Lycoming Operators Manual was used, the engine started immediately. The propeller did not unfeather until the engine started. The aircraft manufacturer confirmed that unfeathering was not possible without an engine start.

The aircraft manufacturer confirmed that the Avco Lycoming Operators Manual procedure was the correct procedure to use in an air start. The manufacturer also said that the Owners Handbook was not an approved document and was provided for advice only. The introduction in the first edition of the Owners Handbook, dated February 1971, states in part that more detailed information is contained in the flight and maintenance manuals.

Information from the pilot

The pilot was aware of incidents involving power losses, including one where a gascolator came loose and sprayed the wing with fuel. As pilot, he was involved in one incident where some fuel injectors to the right engine were blocked. He left the propeller windmilling on that occasion because the aircraft was only 3-4 minutes from landing. The engine stopped during the landing roll, but the pilot was able to restart the engine for the taxiing phase.

Observation of pilot's instrument rating renewal test

On 3 July 1996, a Civil Aviation Safety Authority flying operations inspector (FOI) observed an instrument rating renewal test on the pilot. During debriefing the significance of the best single-engine rate of climb speed was discussed. The FOI reported that the pilot did not understand the effects on aircraft performance if the speed deviated from the best single-engine rate of climb speed.

Information from witnesses

Some passengers reported that they saw the right propeller rotating before the final impact.

Witnesses near the beach said that the wind was almost calm. They heard engine noise as the aircraft approached and, when they looked towards the source of the sound, saw the aircraft with its landing lights on. About 10-15 seconds before impact, all engine sound ceased.

Recorded radar data

A secondary surveillance radar transponder with an altitude encoder was fitted to the aircraft. Consequently, aircraft pressure altitude, position and ground speed, as well as time, were recorded on the radar tape. The recorded radar data has been converted to altitude above mean sea level, local time and airspeed. However, the normal performance for this type of aircraft is 126-130 kts indicated airspeed in cruise, and all these aircraft were achieving approximately 130 kts groundspeed.  Given this, the winds on the night of the accident flight were probably lighter than assessed by the Bureau of Meteorology.

The radar data showed that the accident aircraft was the slowest aircraft in the cruise phase, at 3,000 ft, compared to the other aircraft.  Later, during and after descent to 2,000 ft, airspeed increased to about 130 kts and the other aircraft had airspeeds ranging between 126 kts to 135 kts. The first indication of a problem was at 2127:34 when the pilot transmitted that he had severe problems.  Radar recorded that the aircraft descended from 2,000 ft at 2127:53, to approximately 200 ft at 2135:16.  The airspeed during this period was approximately 90 kts and the rate of descent averaged 245 ft/min.

In the 1 minute 50 seconds before the aircraft disappeared from radar, the rate of descent reduced to an average of 55 ft/min and the aircraft airspeed progressively reduced from 87 kts to 70 kts.

ANALYSIS

Engine handling

From the pilot's evidence, the right engine surged a number of times. However, no defects were discovered which could explain the symptoms of the right engine surging. Such symptoms would be consistent with air or water in the fuel. Due to the damage to the aircraft, neither possibility could be established.

During level flight at 3,000 ft, the radar data showed that the aircraft was initially travelling at approximately 120 kts. The aircraft's speed increased to approximately 130 kts during and after descent to 2,000 ft. This higher speed continued in cruise and was probably due to the pilot setting a power setting greater than cruise power. Normal company procedure required pilots to lean the fuel mixture at cruise power once the aircraft was stabilised in level flight. If the pilot had not increased the fuel mixture to the engines to compensate for the increased power setting and lower altitude, the resulting over-lean mixture could have caused rough running. There is no evidence that the engine problem was of such severity that it should have been shut down. The pilot's intention to restart the engine later indicated that his earlier action in shutting the engine down was premature.

The pilot had been involved in a previous incident involving this aircraft when the right engine lost power due to the blockage of two fuel injectors. On that occasion he elected not to feather the propeller. This incident and the pilot's knowledge of the aircraft's maintenance history may have predisposed him to expect problems with the right engine and to conclude that the injectors were blocked again.

Propeller feathering

The pilot said that he had shut the right engine down by feathering the propeller, yet evidence indicated that the propeller was windmilling during the emergency sequence. The propeller was found to be in the normal operating range at impact and some passengers confirmed that the right propeller was rotating more slowly than the left propeller during the emergency. The pilot could not restart the engine when he attempted to do so. This information, together with the fact that the propeller cannot be unfeathered without an engine start, proved that the propeller was not feathered when the pilot thought he had done so. He probably brought the propeller lever back into the coarse pitch detent only, instead of fully back into the feather range.

Aircraft handling and performance

The series of test flights confirmed that level flight was possible with the right propeller windmilling or with it feathered, provided that the left engine produced sufficient power. These tests indicated that the flight could have been concluded safely had the pilot flown the aircraft near the recommended best single-engine rate of climb air speed. The radar data showed that the pilot did not fly the aircraft at or near the single-engine best rate of climb speed until just before impact.

The transmission made by the pilot at 2132:01 which included the comment "whatever this configuration is", indicated that the pilot did not understand the reason for the aircraft's apparent poor performance. Following a flight test, the pilot demonstrated that he was not aware that the best flight performance that could be obtained with one engine inoperative was at the best single-engine rate of climb speed.

The pilot's impression that the left engine was not delivering power was probably due to his rationalisation of the aircraft's apparent poor performance. His impression of low power was not supported by the performance profile of the aircraft as shown from recorded radar data, or by the analysis of engine sound during 17 transmissions over a 10-minute period which showed that the engine was operating close to rated power. The pilot would have been aware that the aircraft was capable of level flight at 90 kts with a feathered propeller, the speed maintained during the emergency sequence. However, the propeller was not feathered.

Engine restart

The attempt to restart the engine was made late and at a time when the pilot needed to concentrate on flying the aircraft to its best performance. The reason for the pilot's inability to restart the engine was not conclusively established. Had he used the electric fuel pump while the engine windmilled, it is likely that the engine would have been flooded.

Pilot knowledge and workload

The pilot was a qualified flying instructor. He was also the holder of a command instrument rating for twin-engine aircraft. However, the pilot appeared to demonstrate a lack of understanding of certain aspects of the aircraft's operation, including performance limitations of operating a twin-engine aircraft on one engine, and necessary details of the aircraft's fuel system. This lack of knowledge would have increased the pilot's difficulties in dealing with the apparent engine and performance problems.

During the emergency period, the pilot appeared to be experiencing a high workload. In addition to the difficulties in identifying the nature of the aircraft's performance problems, there were a large number of radio transmissions made to and from other company aircraft. This workload would have contributed to the pilot's difficulties in dealing with the apparent engine and performance problems.

SIGNIFICANT FACTORS

1. The pilot shut down an engine following surging but did not feather the propeller.
2. The aircraft was not flown at (or near) its best single-engine performance speed after the right engine was shutdown.

SAFETY ACTION

The Bureau of Air Safety Investigation is continuing its investigation into the incorrect air start procedure appearing in the Owners Handbook as supplied by the aircraft manufacturer.  The results of any recommendation action that may subsequently arise will be published in the Quarterly Safety Deficiency Report.

FACTUAL INFORMATION

The Saab 340 aircraft was inbound from Orange for a landing at Sydney and the crew had been instructed to track via the Sydenham locator for a left circuit to runway 16L. The Saab had been cleared to descend to 6,000 ft. At about the same time a Mooney aircraft, en route from Bankstown to Tobins Gap, was on climb to 5,000 ft while tracking north from overhead the Sydney Very High Frequency Omni-Directional Radio Range (VOR) navigation aid to Williamtown.

The approach controller was aware of the possibility of conflict between the aircraft due to the limited displacement (approximately 2.5 NM) between the Sydenham locator and the Sydney VOR. Consequently, he used a function of the radar display to highlight the symbol and label of the Mooney to assist in monitoring the aircraft's track. However, due to the close proximity of the terminal radar antenna and the VOR, the Mooney passed through the radar overhead cone of silence (an area immediately above the antenna where the radar is unable to detect aircraft) as it overflew the VOR. Consequently, the Mooney's symbol and label disappeared from the controller’s radar display.  The radar display does not retain controller inputs for lost tracks and subsequently did not re-highlight the symbol and label when the aircraft emerged from the cone of silence. Consequently, the controller was not provided with the visual cue to assist in monitoring the aircraft's symbol after it passed over the VOR.

The controller intended to instruct the pilot of the Saab to turn downwind after passing overhead the Sydenham locator, an action that would ensure separation was maintained between the Saab and the Mooney.  However, this instruction was not passed to the pilot as the controller commenced a handover/takeover to a new controller. As the Saab passed overhead the locator, the pilot maintained an easterly heading which was a converging course with the Mooney. The controller could not confirm whether or not the Saab's symbol and label were continuously displayed on the radar screen. The radar recording system showed a continuous plot for the aircraft; however, such a recording does not replay individual radar screen presentations and consequently, the actual radar display provided to the controller could not be confirmed.

The pilot of the Mooney had been instructed, by a controller on an adjacent control position, to turn north to track to Williamtown and climb to 8,000 ft. As separation between the aircraft reduced, the two controllers conducting the handover/takeover were alerted to the situation by a controller at an adjacent control position. The latter queried the track of the Saab as the aircraft was about to infringe his airspace. The new on-duty controller instructed the pilot of the Saab to turn left while the pilot of the Mooney was given traffic information and instructed to turn right for separation. Traffic was busy but not abnormal for the time of day and the weather was fine with unrestricted visibility.

The aircraft passed with approximately 1.5 NM horizontal separation and 100 ft vertical separation. The required standard was 3 NM horizontally or 1,000 ft vertically. There was a breakdown in separation.

ANALYSIS

Controllers were aware of the problem with the radar display not retaining controller inputs for lost tracks. This had become apparent with the advent of new procedures for parallel runway operations. The actual radar cone of silence is very narrow, and approach controllers sometimes transfer aircraft early to either of the Directors (East or West as appropriate) to ensure aircraft tracking via the Sydenham locator do not enter the cone. The directors operate on a larger scale display and consequently are better able to monitor aircraft clear of the cone and maintain aircraft symbols on the display.

In this incident the controller elected to retain the aircraft and then became distracted while conducting a handover/takeover. The provision of separation assurance techniques would have ensured separation between the two aircraft while they were in close proximity to the cone of silence. This was not done. Alternatively, the controller could have tracked the Mooney via a route which would have ensured that the aircraft did not enter the radar cone of silence and, consequently, the system would have maintained the track on the display.

The situation was compounded by the inability of the radar and display systems to continue plotting the track of the Mooney as it passed through the overhead cone of silence. Secondary surveillance radar data from the Sydney terminal area is available from two sources and the use of multi-radar tracking would eliminate the blind spot due to the cone of silence. However, this facility is currently not available at Sydney. Additionally, the system was unable to maintain controller display inputs to re-highlight the track. While not major factors in the incident, the lack of these functions reduced the defences available to the air traffic system.  New equipment being provided by Airservices Australia will address this deficiency.

SIGNIFICANT FACTOR

Separation assurance techniques were not adequately utilised.

SAFETY ACTION

Safety deficiencies involving handover/takeover aspects are being addressed through Occurrence 9600800.

On final approach to land the helicopter in a clearing to refuel, the engine misfired and stopped. During the subsequent autorotation, the pilot managed to restart the engine. The engine faltered again on late final approach. The pilot attempted to stretch the glide to the clearing and managed to land the helicopter clear of the trees. The run-on landing was heavy. The pilot who was the only occupant, was able to exit the helicopter safely.

The skid gear and lower fuselage of the helicopter were damaged. The tail rotor drive was struck by the main rotor during the run-on landing.

The pilot confirmed that the helicopter had run out of fuel.