The aircraft was cruising 1000 feet above ground level, to remain clear of cloud, when the windscreen was suddenly covered with oil. The pilot transmitted a MAYDAY call and attempted to make a forced landing on the Great Eastern Highway.

During an attempt to expedite the landing, because of approaching traffic, the pilot forgot to lower the landing gear and the aircraft touched down with the landing gear retracted before skidding off the road and into the bush. The oil had been released through an unsecured oil filler cap.

The aircraft was cleared to climb to Flight Level (FL) 390. After departure, and when on Brisbane Approach (South) frequency, the pilot requested FL 370. This was approved and co-ordinated by the Approach (South) controller with the Brisbane Sector 1 Radar controller. Prior to this, the Sector 1 Procedural controller had co-ordinated the original level clearance for the aircraft with the Brisbane Sector 2 Procedural controller as FL 390.

The Sector 1 Radar controller annotated FL 370 on the flight strip. Normally, the Sector 1 Procedural controller would then have co-ordinated this change with the Sector 2 Procedural controller. However, this was not done and was not detected by the Sector 1 Radar controller. He later handed off the aircraft to the Sector 2 Radar controller without reference to the level. (This is the correct procedure when the current level assigned has been co-ordinated procedurally.) The aircraft was transferred to Sector 2 and reported on climb to FL 370 to the Sector 2 Radar controller.

However, the discrepancy with the co-ordinated level was not detected and when control of the aircraft was transferred to Sydney Sector 2 the level was co-ordinated as on climb to FL 390. Later, while the aircraft was still in the Brisbane FIR, the Sydney Sector 2 Radar controller noticed that the aircraft was maintaining FL 370. This was queried with Brisbane and the oversight was discovered. An examination of the voice tape recording showed that when the aircraft called Sector 2 reporting on climb to FL 370, the Sydney Sector 2 Radar controller was coordinating a handoff to the Brisbane Sector 2 Radar controller and the two transmissions over-ran. This made the transmission from the aircraft difficult to hear clearly.

However, the Brisbane Sector 2 Radar controller did not confirm the level from the aircraft but assumed it to be FL 390 as that was the level shown on the flight strip. The Sector 1 Radar controller, after writing FL 370 on the flight strip, did not follow this up with any coordination checks as was standard procedure. The controller indicated that an aspect relating to the control of a military aircraft was on his mind around the time of the omission. This may have been a level of distraction sufficient to cause the omission.

SIGNIFICANT FACTORS

1. The Sector 1 Radar controller failed to pass a change of level to the next sector, possibly because he was distracted.

2. The Sector 2 Radar controller failed to confirm the aircraft's level.

SAFETY ACTION

On 19 August 1993, an instruction was issued by the Manager Brisbane AACC amending the procedural requirements so that controllers are now required to provide an adjacent unit or position with advice of an amended level whilst affecting handover.

In response to this, and other recent incidents in this area, the Bureau of Air Safety Investigation, in co-operation with the Civil Aviation Authority, have conducted further investigations, resulting in the publication of BASI Investigation Report BS/930154 titled, "An Investigation of Systemic Factors Underlying Air Safety Occurrences in the Brisbane Area Approach Control Centre."

The aircraft departed Maroochydore on climb to a cleared level of flight level (FL) 260. After being transferred to Brisbane Approach (North), the aircraft requested an amended level of FL 240. The Approach (North) controller cleared the aircraft to maintain FL 240. Later, on transfer to Brisbane Sector 1, the aircraft reported on climb to FL 240. However, the Sector 1 controller had not been notified of the level change and was expecting the aircraft at FL 260.

Before the aircraft departed Maroochydore, there was a request for the aircraft to track direct to Singleton instead of the usual route via Farrel (a reporting point south-east of Maroochydore). The direct track took the aircraft close to overhead Brisbane during its climb. The Approach (North) controller agreed with the request. Potential conflictions with the aircraft included two aircraft inbound to, and two outbound from, Brisbane.

The request for the amended level was made while these aircraft were being processed and the controller annotated FL 240 on the flight strip but neglected to co-ordinate this information with Sector 1. It appears possible that the increased workload resulting from the aircraft being cleared direct to Singleton might have been sufficient to cause the controller to omit to conduct the co-ordination with Sector 1. There was no requirement for the controller to approve the level change requested by the aircraft.

At the time of the request, the aircraft was some distance from top of climb and the controller could have controlled his workload better by deferring the request.

SIGNIFICANT FACTORS

1. The controller agreed to a request for direct tracking which had a significant impact on his workload.

2. The controller unnecessarily approved a request from the aircraft for a level change at a time of high workload.

3. Probably as a result of 1. and 2. above, the controller failed to co-ordinate the change of level with the next sector.

SAFETY ACTION

On 19 August 1993, an instruction was issued by the Manager Brisbane AACC amending the procedural requirements so that controllers are now required to provide an adjacent unit or position with advice of an amended level whilst effecting handover.

In response to this, and other recent incidents in this area, the Bureau of Air Safety Investigation, in co-operation with the Civil Aviation Authority, have conducted further investigations, resulting in the publication of Investigation Report BS/930154 titled, "An Investigation of Systemic Factors Underlying Air Safety Occurrences in the Brisbane Area Approach Control Centre."

The Boeing 747 was cleared to descend to flight level 200 with a requirement to reach flight level 200 by Bindook. This requirement was to achieve separation with a Boeing 737 which had a requirement to reach flight level 210 before Bindook. When the B747 passed Bindook the aircraft was observed by radar to be at flight level 220, and this was confirmed by the pilot. The aircraft was immediately put on a heading to achieve separation with the 737 and no separation breakdown occurred.

The Sydney Sector One controller observed VH-OXD pass Singleton without deviating to avoid the restricted airspace R546B which was notammed active up to flight level 135. Headings were passed through Flight Service to the aircraft to avoid the restricted area. The pilot stated that he was aware of the activated restricted airspace and was intending to track clear of it. He accepted the heading provided by Flight Service which took him east of the boundary.

VH-OJJ had departed Cairns and was climbing through Flight Level (FL) 120 when it received a TCAS (Traffic Alert and Collision Avoidance System) warning. The subject of the alert was P2-AND, which was on descent inbound to Cairns from the north-east. Both aircraft took avoiding action, with VH-OJJ following the Resolution Advisory directions of the TCAS and adopting a descent.

The crew of P2-AND saw VH-OJJ and arrested their descent. The closest point of approach between the two aircraft was 1.14 NM laterally and 900 ft vertically. Both aircraft were under radar control by Cairns Approach at the time. The minimum separation standard under these circumstances is 3 NM laterally or 1,000 ft vertically.

The Approach Control console was manned by a controller who was being refamiliarised by another rated air traffic controller, following a period of absence. VH-OJJ had departed Cairns via a SID (Standard Instrument Departure) that left the aircraft on a climb-out track of 020 degrees. During the SID, the clearance was amended to allow the aircraft to track direct to the first enroute reporting point at AKTEL.

The aircraft turned and tracked about 330 degrees to comply with the amended clearance. The supervising controller advised the operating controller that the track adopted would, in his opinion, not provide enough separation with P2-AND. The operating controller then gave VH-OJJ a heading of 330 degrees to steer.

The supervising controller allowed the situation to continue as the aircraft were still separated by some 25 NM, expecting the operating controller to take adequate steps to resolve the potential confliction. Approach Control was busy, having approximately 10 aircraft on frequency with several awaiting clearance to enter the control zone. When the supervising controller saw that a confliction was imminent, if the two aircraft continued on their present headings, he told the operating controller to turn VH-OJJ to the right, expecting a significant turn onto 020/040 degrees.

However, because of radio transmissions from other aircraft, some 20 seconds elapsed before the controller was able to instruct VH-OJJ to turn to a heading of 360 degrees. As VH-OJJ straightened on the new heading, the TCAS Resolution Advisory warning was received by the crew. The control technique used by the operating controller, and allowed to continue by the supervising controller, was flawed because it left the two aircraft in conflict from the time the crew of VH-OJJ was instructed to steer 330 degrees.

The controller had the option of using a failsafe technique by turning VH-OJJ early and further so that it would pass behind P2-AND. The option of applying altitude restrictions on both aircraft to achieve vertical separation was not considered. During the sequence, the supervising controller was sitting behind and to one side of the operating controller.

He was provided with a facility to listen to communications but was unable to directly issue instructions to aircraft. The supervising controller was surprised at the small turn given to VH-OJJ when the confliction was imminent, but it was then too late to take action. Later he said that he should have taken action earlier but the controller at the console was more experienced in the position. As a result, he was reluctant to interfere with the other controller's method of operation. Prior to this shift, the operating controller had been absent from work for 25 days. This period included recreation leave followed by sick leave. Unbeknown to his shift supervisor, he was under considerable stress due to illness in his family and had not fully recovered from influenza. Refamiliarisation can be undertaken under the supervision of any rated controller, even if the latter has only himself or herself just been rated. Other training is carried out by a training officer who has at least six months experience in the position or has received training in instructional techniques. A refamiliarisation officer is not required to have received training in instructional techniques.

SIGNIFICANT FACTORS

1. The operating controller was unfit for duty due to his own illness and stress caused by family problems.

2. He did not inform his supervisor of the problems.

3. The supervising controller did not take timely action to resolve the confliction.

4. The operating console was inadequate for training/familiarisation in that there were no facilities for the supervising controller to communicate directly with aircraft.

SAFETY ACTION

During the course of the investigation the Bureau issued the following recommendation R930236:

It is recommended that the Civil Aviation Authority include complete and comprehensive documentation on the operation of TCAS in the Manual of Air Traffic Services and Australian Aeronautical Information Publication to provide:

(i) flight plan, progress strip and radar data tag indications when serviceable TCAS equipment is carried.

(ii) samples of unambiguous phraseology for aircrew to notify only TCAS TA and RA events to ATS.

(iii) samples of unambiguous phraseology for aircrew to use when diverting from and resuming flight profiles following an RA event.

A reply was received from the Civil Aviation Authority which stated, in part: 'The general comments on TCAS have been noted and are confirmed by our own information. I also advise that the recommendations listed have already been acted upon or are in the process of activation.

The Civil Air Operations Officers' Association of Australia have expressed the view that they are "convinced that the carriage of TCAS should be the subject of specific flight plan notification" and "that notification should be displayed for controller reference". (U.S. controllers receive flight plan notification and the information is also shown on radar data tag and/or flight progress strip.) District Offices have been asked for comment on the inclusion of the ICAO statement in MATS or otherwise given the Civil Air and BASI position.

Copies have been made of 2 videos; the first deals with the operation of TCAS from a pilot's perspective (30 minutes) and the second deals with the controllers side (10 minutes). Both were produced by the FAA. These videos have been distributed to the CAA District Offices for controller education. "Standard phrases" both for pilots and controllers are being devised for inclusion in AIP and MATS.

It is expected that these phraseologies, which are based on UK CAA and FAA phrases in use, will be included in the next AIP/MATS amendment. In conclusion it is agreed that it is important to raise both pilot and controller awareness of TAS. and the effect that it will have.' Other deficiencies identified during this investigation, including console modification and training considerations, are being analysed in order to formulate appropriate safety actions.

As the aircraft approached the holding point for runway 19, the Tower Controller issued a line up clearance. A Boeing 767 aircraft was on base for runway 19. The controller then judged that the sequence may be too close and told the taxiing aircraft to hold short of the runway. The crew of this aircraft were taxiing over the holding point and managed to stop just beyond the marked line.

The controller then had the option of sending around the Boeing 767, now on a two mile (3.7km) final approach, or asking the crew to accept a slightly infringed flight strip. The crew of the Boeing 767 decided to continue the approach and landed safely.

The pilot was carrying out his first solo flight. During the landing he lost directional control and the aircraft left the runway. The nose gear collapsed and the propeller struck the ground.

During the landing as the main wheels touched down, the aircraft began to shudder severely and pulled to the right. All attempts by the pilot to regain directional control were unsuccessful and the aircraft ran off the side of the runway. After entering the lightly grassed flight strip, the turning effect increased, and the aircraft began to slide sideways.

The abnormal side loadings imposed during the slide caused the left main landing gear to collapse. The investigation found that a substantial amount of the threaded section of the nut which secures the right main landing gear torque link tie bolt had stripped allowing the two halves of the torque link to separate. The right main wheel assembly was then free to oscillate up to ninety degrees to the direction of travel as the landing loads were applied. The pilot was not able to apply enough steering control to overcome the effects of the oscillations. The investigation also found that the left and right main landing gear torque links were installed incorrectly. The left set was fitted to the right landing gear and vice versa.

This incorrect fitment had the effect of placing excessive tension loads on the link shear nut assembly causing it to fail by stripping the nut threads. Furthermore, neither of the torque link tie bolt assemblies were of the type specified by the manufacturer for this torque link installation. The bolts and shear castellated nuts were of the type used with the original torque links fitted to this aircraft model. The design of the original torque links was significantly different to the modified type fitted to the accident aircraft. With the original links, all torque stresses were borne against the mating surfaces of the link halves and the tie bolt assembly carried only shear loads. The later modified links require the tie bolt to carry some of the torque loads in tension.

The incorrect fitment of the failed torque links caused a substantial increase in the normal tension loads on the tie bolt assembly. The shear nut and link bolt assembly was not able to withstand these additional tension loads. In July 1986 the Australian Department of Aviation issued an Airworthiness Directive (AD) based on information contained in the manufacturers Service Bulletin (SB) 746A.

The AD required operators to inspect all aircraft models which were not fitted with the torque link replacement kit called for in SB 746A. This AD also recommended that the replacement kit be fitted at the earliest opportunity. Subsequent to the issue of the Australian AD the manufacturer issued two updates to the SB 746A as SB 746B dated 11 June 1991 and SB 746C dated 15 September 1992. SB 746B required the replacement of the torque link connecting nut and bolt to prevent the original shear nut from stripping. The Australian AD had not been revised to reflect the later information contained in SB 746B and SB 746C. SB 746C required the inspection of the torque links for cracks within ten hours.

If any cracks were found the torque links were to be replaced with torque link kit 765-155 revision G before further flight. If no cracking was detected the links were to be replaced within the next 100 hours of operation. Both SB 746B and SB 746C stated that "compliance is critical". The accident aircraft met compliance with the Australian AD but not with the SB 746 parts B or C. The aircraft logbooks indicated that the modified torque links were probably fitted to the aircraft prior to July 1990 when it was imported into Australia.

Three other aircraft of the same type were inspected during the initial stages of the investigation, and it was found that they met compliance with the manufacturers original SB 746A as required in the Australian AD but not SB 746 parts B or C. The investigation was unable to obtain a current, appropriately amended manufacturer's Maintenance Manual or Illustrated Parts Catalogue for this aircraft type that would show the correct method of fitment for the modified torque links.

The manufacturer's Australian distributor indicated that the only way such instructions and illustrations could be obtained was for the operators to purchase a total kit number 765-155 revision G which included fitment details. Several local maintenance organisations and operators stated that they had been unable to procure appropriate updated amendments for their Maintenance Manuals or Illustrated Parts Catalogues for several years.

The same situation was said to apply to the amendment service for Service Bulletins and Service Instructions. In each case where the torque links were fitted incorrectly or where the shear nut assembly was still in service the operator or maintenance organisation was not in receipt of either SB 746B or SB 746C.

SAFETY ACTION

As a result of the investigation the Bureau made the following interim recommendation IR930188 to the Civil Aviation Authority on 24 August 1993. It stated:

The Bureau recommends that the Civil Aviation Authority:

1. initiate inspections of all aircraft to ensure compliance with Aerostar Service Bulletin 746C;

2. amend AD/TSA-600/33 Amendment 4 to reflect the latest issue of Aerostar Service Bulletin 746C; and

3. assess revisions to manufacturers data which are quoted in Australian Airworthiness Directives and determine the requirements for subsequent amendment to the relevant Airworthiness Directive.

[The Bureau had previously recommended similar action. BASI Report B/913/1009, VH-TPM, Recommendation 1 refers].

In response to this recommendation, the Civil Aviation Authority Published Airworthiness Directive AD/TSA-600/33 Amendment 5 effective 15 September 1994.

However, this Airworthiness Directive amendment did not require compliance with Aerostar Service Bulletin SB 746C which the aircraft manufacturer classifies as "compliance critical" and that SB 746C "supersedes and voids SB 746, SB 746A and SB 746B".

In further correspondence with the Civil Aviation Authority the Bureau requested a further review of the Airworthiness Directive to ensure that it accurately reflects the aircraft manufacturers compliance requirements. The Civil Aviation Authority's response to this correspondence stated in part:

"This Authority does not agree with your assessment of amendment 5 to AD TSA-600-33".

The Bureau has classified this response as CLOSED/NOT ACCEPTED.

The pilot reported that he was carrying out a circuit and landing on runway 34 with crosswind from the right. The aircraft bounced after touchdown and began to "porpoise". During successive bounces the nosewheel steering was damaged and the aircraft ran off the runway and collided with an open culvert.