The Boeing 737 (B737) was in cloud overhead Hamilton Island at 3,000 ft and the crew were cleared to track outbound on the 325 radial for a VOR/DME approach to runway 14 by the aerodrome controller. The 325 radial was the outbound leg of a "teardrop pattern" approach. The crew were instructed to report when commencing the turn inbound. The co-pilot was the flying pilot and the pilot in command was monitoring the approach and making the radio calls.

The pilot of a Cessna 182M Skylane departed Shute Harbour (12 NM west-north-west of Hamilton Island) and requested an air traffic control clearance for a parachute dropping operation. The aerodrome controller told the pilot that he would "have one for you in a moment" but did not instruct the pilot to remain outside controlled airspace. The controller was required to obtain an airspace release from the Tabletop controller, who was located in the Brisbane Centre. An airspace release was subsequently obtained from the Tabletop controller for an area encompassing a 5 NM radius of Shute Harbour up to and including 10,000 ft.

The B737 crew reported turning inbound and that they were visual. The aerodrome controller told them to continue approach to runway 14. The profile of the runway 14 VOR/DME approach restricted the descent of aircraft to not below 2,300 ft until inside 8 NM from Hamilton Island.

Less than 1 minute later, the Skylane pilot was issued with a clearance by the aerodrome controller to operate within a 5 NM radius of Shute Harbour not above 10,000 ft and to report ready for the drop. Since first contact with the aerodrome controller, the pilot had been steadily climbing and was established inside controlled airspace at about 2,100 ft when the clearance was issued. Seconds later, the pilot and parachutists in the Skylane sighted the B737 in a left banking turn, in their relative 2 o'clock position and at the same level. The Skylane pilot estimated the B737 passed alongside them with less than 100 m of lateral separation.

The B737 crew were unaware of the near mid-air collision with the Skylane. Their traffic alerting and collision avoidance system (TCAS) did not alert them to the proximity of the Skylane because the Skylane's transponder, although fitted, was not switched on and operating. The pilot of the Skylane was required to have the transponder activated and selected to code 1200 in accordance with Aeronautical Information Publication (AIP) Australia ENR 1.6-8.

At the time of the occurrence, the Skylane was about 10 NM north-west of Hamilton Island, where the 9-12 DME control area step had a Class D airspace lower limit of 1,500 ft. Analysis of the radar data showed that the B737 was below 2,300 ft beyond 8 NM of Hamilton Island, which was below the altitude profile for the approach. The recorded radar altitude of the B737 was consistent with the altitude reported by the pilot of the Skylane.

The control tower did not have a Local Instruction or any lateral separation diagrams that plotted separation points between the final approach path of the runway 14 VOR/DME approach and the Shute Harbour parachuting area.

The EMB-120ER Brasilia was cruising at Flight Level 190, en route from Darwin to Tindal. Just prior to top-of-descent, the crew reported that they heard a loud bang from the right side of the aircraft, and the aircraft simultaneously yawed to the right. Suspecting an engine failure, the pilot-in-command disconnected the autopilot and re-trimmed the aircraft, noting that a considerable amount of rudder trim was required to maintain directional control.

Observation of the engine instruments by the crew confirmed a right engine failure, with the right engine torque gauge indicating 1%. A burning smell and fine smoke then became evident in the cockpit, and the crew put on their oxygen masks. Communications between the two pilots proved difficult with the masks fitted, due to a faulty right oxygen mask microphone. The crew positioned the right engine power lever to flight idle and commenced a descent. The flight attendant also indicated to the crew that smoke had begun to enter the cabin area.

The smoke immediately began to dissipate, following the reduction in engine power. The crew then shut down the right engine in accordance with company operating procedures, and broadcast to Air Traffic Control requesting that emergency services be made available on arrival at Tindal. Air Traffic Control declared a distress phase.

The crew removed their oxygen masks as the smoke had dissipated from the cockpit, however, they still fitted the masks intermittently due to the residual strong burning smell.

By that time the flight attendant had completed the company emergency plan actions, and following approval from the pilots, conducted the emergency briefing. During the briefing, some of the passengers indicated that they were experiencing difficulty hearing the details of the pre-recorded instructions, and the flight attendant had to stop the presentation several times to repeat unheard information. After the flight attendant's briefing, the pilot in command used the public address system to inform the passengers of the right engine problem.

After the single-engine landing, the crew stopped the aircraft on the runway. Emergency services indicated that there was a fuel leak from the right engine cowling. As a precaution, the crew shut down the left engine and instructed the flight attendant to disembark the passengers onto the runway through the main cabin entrance door.

The operator conducted an initial inspection of the failed Pratt and Whitney PW118A engine. This inspection revealed extensive damage to the engine's power turbine and a jammed low-pressure compressor. The reduction gearbox also appeared to have decoupled from the engine, with internal damage to the reduction gearbox case. The engine oil filter bypass indicator had activated, with evidence of metal contamination in the oil filter and on the reduction gearbox chip detector.

The Australian Transport Safety Bureau (ATSB) then quarantined the engine, and delivered it to Pratt and Whitney Canada (PWC) for an investigation supervised by the Transportation Safety Board of Canada. The PWC investigation found that the in-flight shut down had occurred due to the decoupling of the reduction gearbox drive from the power turbine rotor. This was considered to be a direct result of the fracture of the reduction gearbox input shaft by torsional overload. (Refer to Annexes A and B attached to this report).

Maintenance

The following PWC Service Bulletins (SB's), were considered to be relevant to this investigation:

* SB 20246 - Replacement of reduction gearbox (RGB) oil transfer tube arrangement; modification of RGB housing set.

* SB 21323 - Replacement of RGB input shaft.

The aircraft was maintained in accordance with the operator's Civil Aviation Safety Authority (CASA) approved system of maintenance; the operator utilising the engine manufacturer's `high utilisation' periodic inspection requirements as detailed in the maintenance manual.

Listed in those periodic inspection requirements was an engine reduction gearbox input shaft (pinion) borescope inspection, which was required at an interval of 3,000 hours maximum since new, or total time since overhaul, or since input shaft (pinion) replacement. Thereafter, the shaft was to be subjected to an ongoing borescope inspection at a maximum interval of 600 hours. If `unacceptable spalling' was detected on the gear teeth surface, an inspection was to be carried out at an interval of 300 hours maximum. A description of `unacceptable spalling' was included in chapter 72-00-00 of the manufacturer's maintenance manual.

A `Note 5' that applied to the borescope inspection, had been placed in the maintenance manual by the manufacturer in May 1996. This note indicated that the borescope inspection was not required for `non floating layshaft' type reduction gearboxes with SB 20246 incorporated. `Note 5' applied to the reduction gearbox assembly fitted to the failed engine.

The first stage input shaft had been installed in the engine, during the last overhaul in May 1997, after having been assessed as serviceable in accordance with PWC's, Cleaning, Inspection and Repair manual requirements. The shaft had previously been removed from another engine, following the incorporation of SB 21323 into that engine. SB 21323 introduced a new input shaft to the system, with a larger tooth fillet radius and an increased carburised case hardening depth on the shafts' surface. This service bulletin had been issued following the fatigue failure of some reduction gearbox input shafts with insufficient carburised case depth. When the shaft was removed from the previous engine it had accrued 10,180 hours time in service.

At the time of failure, the shaft had accrued a further 2,565.2 hours. During that time, the operator reported that they had carried out all required oil filter servicings and completed daily operational checks of the engine and reduction gearbox chip detectors. No contamination had been noted during those checks.

The operator had been conducting a Spectrometric Oil Analysis Program (SOAP) on the engine. However, the program had been discontinued following the receipt of advice from a PWC field representative that it was not required.

The flight crew oxygen mask microphone could not be faulted during maintenance ground testing, however, as a precaution both masks were replaced.

Following this incident, the operator engaged a cabin safety specialist to conduct an audit into the cabin issues highlighted during the occurrence, and the operator's general aircrew procedures. The audit identified several areas for improvement, which were subsequently acted upon by the operator.

A Beech 200 (Beech) was on an instrument flight rules (IFR) category flight from Wilcannia to Adelaide. The flight was to be initially conducted in non-controlled airspace up to flight level (FL) 165, then across a Class E controlled airspace (CTA) corridor (above FL165 between Dubbo and Broken Hill), prior to entering Class C CTA above FL200. The pilot was required to request a clearance from a Melbourne sector controller before entering CTA.

The aircraft departed Wilcannia and climbed to FL190 prior to the pilot requesting a clearance from Melbourne Centre. The sector controller estimated that the aircraft had entered the Class E corridor without a clearance. There were two formations of military aircraft in the area at FL170 and FL180 respectively that could have conflicted with the Beech. A subsequent check established that there had not been an infringement of separation standards.

The Class E corridor had been implemented on 3 December 1998 and was depicted on the Aeronautical Information Publication (AIP) chart L5 (3 December 1998). The width of the corridor was promulgated as 5 NM either side of the Dubbo-Broken Hill air route, and was depicted on the chart to scale. However, the width of the Class E corridor was increased to 25 NM either side of the route by a Notice to Airmen (NOTAM) on 8 March 1999. The chart was not due for amendment until 17 June 1999. Consequently, pilots who used the chart for operations in proximity to the corridor needed to be familiar with the NOTAM, and to draw the increased corridor width on the chart for reference, and/or remember to include the increased width in any navigation calculations.

The pilot of the Beech was undergoing a check on the day of the occurrence and had the appropriate charts, NOTAMs and weather information for the flight. The pilot was aware of the amended width of the Class E corridor and had regularly flown the route taken. A number of flights had been planned for the day but were subsequently cancelled. The pilot was therefore required to submit a new plan for the flight that was subsequently undertaken. Although the pilot submitted the new flight plan by facsimile, this was not received by the Melbourne briefing office. When the pilot departed Wilcannia he was advised by air traffic service staff that there were no details held for the flight. Consequently, the pilot was required to re-submit the plan. It was during this period of the flight that the pilot believed he may not have taken into account the amended width of the Class E corridor when estimating the time and point at which the aircraft would enter CTA. He was using a chart and graduated rule and suspected that he may have used the distance between Wilcannia and the corridor as depicted on the chart (approximately 46 NM) for his calculations instead of that actually available due to the amended corridor width (approximately 15 NM).

The combined demands of cockpit workload associated with the particular phase of flight, some self-imposed stress due to being under check, and having to re-submit the flight plan while airborne, probably resulted in the pilot being near to task saturation. Consequently, despite his previous awareness of the need to consider the amended width of the corridor, he forgot to take that into account in his calculations.

An infringement of the 3NM radar separation standard occurred at 0606 western standard time approximately 5NM to the northeast of Perth. The aircraft involved were a British Aerospace 146 (BAe146) that departed Perth on a RWY 03 BIU2 standard instrument departure (SID) followed shortly after by a Boeing 737 (B737) that departed on a RWY 06 PEPPA3 SID.

The 03 BIU2 SID is designed to provide system separation with military airspace to the north of Perth and, as a consequence joins the 06 PEPPA3 SID at position REDIL, 8NM to the northeast of Perth. Military airspace was not active at the time of the incident.

The aircraft were under the control of the Perth Departures (DEP) controller at the time. The responsibility for the provision of separation of aircraft on these two SIDs was defined in Perth Local Instructions as the responsibility of the DEP controller.

The DEP controller was monitoring a trainee controller on DEP who was approaching the final stages of rating training. The controller did not use an "override" box that would have allowed him to override the trainee and transmit instructions to the crews.

The aerodrome controller (ADC) advised the trainee DEP controller that the B737 was next for take-off. The trainee DEP controller issued the ADC an unrestricted clearance for the B737 to depart.

The crew of the BAe146 heard the B737 being cleared for take-off and realised that the two aircraft were on conflicting departure routes. The crew asked the trainee DEP controller for a clearance direct to Ballidu in an attempt to resolve the situation. The controller advised the crew that he "would advise" when the direct clearance was available.

The B737 departed and the crew contacted DEP control and advised that they were leaving 1,800 ft. The crew of the BAe146 monitored the proximity of the B737 visually and on the Traffic Alert and Collision Avoidance System (TCAS). The TCAS equipment did not provide a traffic or resolution advice.

The DEP controller did not intervene directly and prompted the trainee to turn the BAe146 away from the B737. The trainee then issued an instruction to the crew of the Bae146 to cancel the SID and track direct to Ballidu. The DEP controller then instructed the trainee to give the crew of the BAe146 a heading in order to resolve the situation. The trainee responded by instructing the crew of the BAe146 to turn left heading 360 degrees for separation. The trainee then instructed the crew of the B737 to turn right heading 090 degrees for separation.

Traffic information was not passed to either crew, nor was the word "immediate" used in passing heading instructions. There was no relay of the urgency of the situation to either crew by phraseologies used by the trainee. At that time the training officer utilised the APP console handset to contact the ADC on the hotline. The ADC was asked by the DEP controller "can you just monitor", to which the response from the ADC was "Yes I'm monitoring". The DEP controller later reported that in his mind it was a request for the ADC to provide visual separation between the aircraft. He also reported that the response received from the ADC indicated to him that the ADC had been providing separation throughout the event by visual monitoring of the aircraft.

The ADC was monitoring a trainee controller by use of a headset. The "B", or training system handset, was not being utilised. The ADC was unable to override the trainee without actually taking over the ADC handset from the trainee.

The DEP controller was not aware of the training on the ADC position and the ADC controller was not aware of the training on the DEP position.

Recorded radar data indicated that separation reduced to 1.4NM with a vertical separation of 200ft. The aircraft were separated by 1.5NM while at the same level. Minimum required radar separation for these aircraft while not 1,000ft vertically separated was 3NM.

The procedures in use were the standard procedures applicable for the use of runways 03/06 for departing aircraft prior to first light. These procedures required the issue of departure instructions for aircraft departing at night or in IMC to be in the form of a SID. It was not permissible for a controller to cancel a SID and issue a radar departure instruction while the aircraft is on the ground prior to first light. It was only permissible in these circumstances to cancel the SID after the aircraft was airborne and had reached the Minimum Vectoring Altitude (MVA). In the case of the 03 BIU2 SID, this situation provided a very short window of opportunity between the aircraft reaching the MVA and commencing a right turn off runway heading. Reliance on controller intervention to cancel this SID and issue a maintain runway heading instruction in order to maintain separation with SID departures from RWY 06 provided no separation assurance.