On entering downwind for runway 06 the crew of VH-FKA saw an aircraft on the taxiway. The aircraft was then observed to enter the runway, backtrack and take off on runway 06.

No communications could be established with the departing aircraft on either the area frequency or the Mandatory Traffic Advisory Frequency (MTAF). There was no loss of separation.

With the assistance of company personnel on the ground the crew of VH-FKA were able to establish the registration of the departing aircraft was VH-PMT.

Significant factors

The following factors were considered relevant to the development of the incident:

1. The pilot of VH-PMT did not follow the radio communication procedures for operation in an MTAF. The reason for this was not determined.

When the pilot attempted to add power to correct an undershoot on short final for landing, he discovered that the throttle had jammed. As he manoeuvred the aircraft to avoid a fence, it stalled from about 10 feet. The aircraft landed heavily and the landing gear collapsed.

Subsequently it was found that the throttle inner cable had broken and jammed in the outer cable.

Significant Factors

The following factors were considered relevant to the development of the accident:

1. The throttle cable broke in flight.

2. The pilot was unable to increase power to correct an undershoot.

3. The pilot stalled the aircraft while trying to avoid a fence.

VH-KTF [Beech76] was proceeding on an instrument flight rules [IFR] training flight from Goulburn to Canberra and was being radar vectored by Canberra Approach control [APP] for a right downwind leg for runway 35. The pilot was maintaining 6,000 feet being the last assigned altitude.

VH-CZP [Boeing 737] was proceeding on a regular public transport flight from Melbourne to Canberra and was being radar vectored by APP for a left base to runway 35. The pilot was also assigned 6,000 feet by Air Traffic Control [ATC].

APP was being performed by a trainee controller who had completed four weeks of a proposed twelve week training period. This controller was supervised by a suitably qualified training officer.

At 1406 hours VH-KTF was given a left turn onto a heading of 320 degrees with the intention by ATC of using this turn to provide 5NM separation with VH-CZP who was to be given a left turn onto the localiser ahead of VH-KTF.

As VH-CZP was approaching the centre line the training officer realised that the trainee was leaving the issuing of the turn instruction a little late and decided to instruct the trainee to turn VH-CZP immediately. At 1408 hours the trainee issued the turn instruction using the callsign CZF. The captain of VH-CZP then queried this instruction and with this further delay the ATC training officer decided to take over and issued instructions to both VH-CZP and VH-KTF which placed the two aircraft on diverging headings. During these manoeuvres the horizontal distance between the aircraft reduced to 2.5NM with no vertical differential.

The weather conditions were such that both crews were in cloud throughout the occurrence and no pilot saw another aircraft.

The required separation standard was either 5NM horizontally or 1,000 feet vertically.

Significant Factors

1. The trainee approach controller allowed VH-CZP to get too close to the localiser before implementing a turn onto final.

2. The trainee approach controller used the wrong callsign when issuing VH-CZP with a turn instruction.

3. The training officer allowed the traffic situation to develop to a point where he was unable to guarantee separation once the trainee made an error.

The flying instructor advised that at 300 feet, after taking off to the north from the eastern grass at Moorabbin, he first heard an odd noise and then felt a violent vibration through the airframe. He also noticed that rotor RPM had begun to diminish. Immediately he lowered the collective, closed the throttle, and carried out an autorotation into an area just outside the airfield boundary. The engine continued to idle from the moment of closing the throttle.

Engineers found that the aft bearing on the lower pulley assembly had disintegrated internally, and the forward bearing was rough. (This pulley assembly is part of the drive train which transmits engine power to the main gearbox via eight rubber belts.)

The bearing (part number 269A5050-78) which failed was lifed at 1800 hours. It failed at 741 hours total time in service and 246 hours since it was last inspected/greased. There was no evidence of lack of grease or overheating of the bearings.

Significant Factor

The following factor was considered relevant to the development of the incident:

1. The lower pulley aft bearing failed in flight.

VH-MFS was inbound to Darwin and cleared to maintain 1,500 feet by Darwin Approach Control, then subsequently instructed to call Darwin Tower.

When the pilot contacted the tower, he was advised of traffic, VH-BYK, a Cessna 210 on downwind for runway 36. This aircraft was sighted about two kilometres in front and 100-200 feet below. VH-MFS passed directly over VH-BYK.

The pilot of VH-MFS was advised by the RAAF controller that an error of judgement on their part had resulted in the confliction.

Safety Action

Deficiencies identified during this and other investigations involving procedures by Darwin RAAF controllers are the subject of further analysis in conjunction with the Directorate of Flying Safety - Air Force.

The pilot of the Fokker F-50 VH-FNA reported that when he was lined up on Runway 24 at Ballina and about to commence take-off, a Piper Arrow suddenly appeared overhead the airfield, crossing the intended take-off path. Its undercarriage was extending and the aircraft appeared to be joining the circuit for landing. A taxiing call had been made by the pilot of VH-FNA, and contact had been made with another transiting aircraft on the Mandatory Traffic Advisory Frequency. No calls were heard from the arriving aircraft by the crew of VH-FNA or by the transiting aircraft.

The unannounced aircraft was observed turning base for Runway 24 when VH-FNA departed.

VH-HYC was under the control of Melbourne Sector one on track from Oodnadatta to Woomera cruising at Flight Level (FL) 380. The pilot requested a climb to FL390. The aircraft was cleared to FL390, but the coordination of level change was not passed onto Adelaide Control which was the next controlling authority.

The sector controller advised that there was more than 15 minutes to the adjoining airspace boundary when the aircraft requested a climb which meant he did not have to coordinate with Adelaide Control prior to approving the level change. He believes that he cocked the VH-HYC flight strip as a reminder to coordinate with Adelaide after approving the level change. It is possible that while processing two other flight strips, he may have inadvertently knocked the strip for VH-HYC back into its normal position thereby removing his memory cue for the need to coordinate with Adelaide.

Air Traffic Services (ATS) management personnel have subsequently formalised a procedure for marking flight strips which should facilitate scanning techniques and help guard against items being overlooked.

Significant Factors

The following factors were considered relevant to the development of the incident:

1. The controller probably inadvertently lost his reminder cue to coordinate the aircraft's change of level with Adelaide ATS.

The aircraft had been engaged on a target towing exercise involving live firing of ground-to-air missiles in a military restricted area north of Adelaide.

The target had been deployed at the full 5240 metre extension of the cable. The aircraft and target carried out 10 tracking runs before one missile was fired at the target, without hitting either the target or the cable. After this firing the Army firing point advised the aircraft to recover the target and depart the area.

The operator commenced reeling in the target as the pilot banked the aircraft 30 degrees to the left and began a climb. With 4920 metres of cable still deployed the cable tension indication fell to zero indicating that the cable had broken. The cable cutter was activated to ensure that no cable was trailing behind the aircraft, and the aircraft was returned to Edinburgh.

The 4920 metres of cable landed along the main street of a fishing village creating some disruption to electrical services, but without causing any other damage or injuries.

The cable probably failed when the armour wrap covering a splice became jammed in the reel unit, over stressing the cable. The reel unit was serviceable, and the cable had been subjected to 14 flights with no abnormal loads or stresses. The normal life of a cable is 20 flights.

The pilot reported that during cruise, the engine had a tendency to overspeed when the power lever was retarded but was operating normally at high power. He elected to proceed to the destination with high power set. When power reduction was required for landing a precautionary engine shut down was carried out and a single engine landing was made.

Investigation revealed that the concentric control shafts at the fuel control unit were binding and causing mutual interference. The shafts were lubricated and the overspeed defect disappeared. The aircraft had been washed recently. Failure to reapply lubrication after the wash probably contributed to the defect.

Significant factors

• The FCU concentric control shafts were not lubricated after the aircraft was washed.

Circumstances

VH-TJR [Boeing 737] had departed Melbourne for Canberra at 1529 hours and was on a 10NM final for runway 35 at Canberra airport. The crew had been cleared to make the approach by Air Traffic Control [ATC].

VH-TCO [Cessna 150] was performing circuit training with a student pilot at the controls being supervised by an instructor. The aircraft was instructed by ATC to make a right orbit when on downwind leg and as the trainee was completing the manoeuvre ATC instructed the crew to sight and follow a B737 on an 8NM final. They looked to their left and saw a twin engined jet passenger aircraft that looked like a B737 and acknowledged the ATC instruction as they turned their aircraft onto base leg. The aircraft they saw was an Airbus Industries A320 which was carrying out an approach to runway 35 ahead of VH-TJR.

As VH-TCO was proceeding on its base leg the instructor realised that the aircraft they saw was not at the 8NM final position that was indicated by the Aerodrome Controller [ADC]. He then looked to his right and saw a second twin engined jet passenger aircraft, VH-TJR and calculated that his present track and altitude would take his aircraft above and behind that aircraft. At this point the ADC again issued traffic information to VH-TCO as he observed the two aircraft closing on one another.

As the relative tracks of the two aircraft closed the captain of VH-TJR looked to his left and saw VH-TCO in a position that appeared to be on a collision course and immediately took evasive action by turning his aircraft to the right. After diverging about 0.5NM, the aircraft then re-joined final approach and made an uneventful landing.

The crew in VH-TCO did not take evasive action, as the instructor watched the B737 pass clear, in front and below his aircraft. He had maintained visual contact with VH-TJR continuously from the time he had first seen it. The aircraft came within 300 metres and 300ft of each other.

Significant Factors

1. The crew of VH-TCO initially sighted the wrong aircraft and selected a flight path based on this incorrect sighting.

2. The crew of VH-TCO realised their error while on base leg and elected to continue with that track having correctly sighted the B737.

3. Separation between the aircraft reduced to the point where the crew of VH-TJR considered that evasive action was necessary to maintain adequate clearance from VH-TCO.