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.

The student was landing at the completion of a solo training flight. After an apparently normal touchdown, the aircraft suddenly swung to the right and tipped forward on to its nose, collapsing the nose gear leg in the process. The pilot reported that, after landing, she applied right rudder to correct the aircraft back to the centreline but inadvertently applied right brake. This resulted in her losing directional control of the aircraft.

Findings

1. The pilot inadvertently applied right brake while attempting to control direction by the application of right rudder.

2. The pilot lost directional control of the aircraft. 3. The pilot's flying experience level was low.

Boeing 767, CF-BEG, had departed Sydney at 1352 hours on a regular public transport flight to Auckland and was climbing to Flight Level (FL) 370. The aircraft was being controlled by Sydney Arrivals North who maintained it at FL 270 due to the presence of an opposite direction aircraft. When the controller was able to radar separate these aircraft he climbed CF-BEG to FL 290 as other arriving traffic precluded the use of a higher level at that time. Arrivals North then handed over the control of CF-BEG to Sector 5 who immediately asked how separation was being achieved with N68065, a Douglas DC10 aircraft maintaining FL280, which was inbound to Sydney from Auckland and on the reciprocal track to CF-BEG.

The Arrivals controller claimed to have no knowledge of N68065, and immediate checks were made of the aircraft altitudes. This check revealed that CF-BEG was maintaining FL 290 and therefore a 1,000 ft separation standard had been achieved. The arrivals north flight progress strip had been placed on the console, but the controller had not placed it in the flight progress board to indicate the confliction. The arrivals controller was performing the combined duties of Arrivals North and Arrivals South at the time due to a comfort break requirement of the other controller.

Sector 5 was being performed by a controller under training supervised by a suitably rated check controller. The trainee had recognised the conflict between N68065 and CF-BEG and had twice attempted to pass a separation requirement to Arrivals North. Each time the arrivals controller was busy, and the co-ordination was unsuccessful. As the sector traffic situation increased in workload due to poor weather and several aircraft diversions, the trainee forgot to make a third attempt to pass this information, and the check controller was unable to arrange for it to be done.

The approach procedural controller had received the co-ordination on N68065 from sector 5 and had updated the information on the flight progress strip and passed it to the arrivals north controller who did not immediately place the strip in the flight progress board. The strip was still in front of the arrivals controller at the time of the occurrence. Workload was considered to be moderate.

Findings

1. Arrivals north controller was on combine and his workload was considered moderate.

2. The arrivals north controller had not placed the flight progress strip for N68065 onto the flight progress board and was thus unaware of its operation.

3. Due to the moderate workload at the arrivals north position, the controller was unable to accept incoming verbal communications which would have alerted him to the possibility of a conflict between N68065 and CF-BEG.

The aircraft and instructors from an aero club were based at Eulan Downs to train a group of five students to the general flying progress test (GFPT) standard. The instructor and student had planned to carry out an upper air sequence prior to returning to Fairfield to commence circuit training. After the completion of the upper air flying the instructor decided to demonstrate a practice forced landing. The forced landing was commenced at 2500 feet above mean sea level (the elevation of the airstrip is 600 feet amsl).

During the descent the instructor found it necessary to adjust his circuit, to ensure a landing on the airstrip, such that a base turn was commenced approximately abeam the threshold and the aircraft aligned on final at about 20 feet above the ground. The instructor reported that the indicated airspeed was 60 knots and the flaps were still selected up when the aircraft was aligned on final. The aircraft stalled at this point and landed heavily on the airstrip. All three legs of the landing gear were torn off and the aircraft slid for about 20 metres before coming to rest.

As the landing gear was retracted after take-off, the baggage door warning light illuminated and a noise consistent with a propeller strike was heard. The aircraft returned for a landing on runway 34, and on inspection the nose locker door was found open. A piece of baggage was missing. A bag was found on the runway and there was evidence of propeller slash marks on it. The pilot stated that he had checked the nose locker door prior to starting engines and it was locked. The door may have become unlocked due to baggage pressure on it. The lock has been replaced as a precautionary measure.

During the pre-flight check at Los Angeles, when the Standby Power switch was selected to Battery, the captain's electronic navigation displays went blank, the upper Engine Indication and Crew Alerting System (EICAS) display transferred to the lower screen, and an additional message 'Standby Bus Main' was displayed. It was later determined that the standby inverter was missing from the aircraft. Investigation determined that the inverter had been removed in Sydney on the previous day, to service another aircraft.

Maintenance engineers involved with the removal did not raise the appropriate documentation as they were unaware of the requirements of the company Policy and Procedures Manual. No formal shift handover was conducted, consequently subsequent shift personnel were unaware of the missing component and released the aircraft for service. The aircraft was then flown to Los Angeles.

During the departure preflight cockpit check at Sydney, the correct responses were displayed when the standby power test was performed but the crew were not alerted to the additional 'Standby Bus Main' message as the checklist does not mention it. EICAS display transfer to the lower screen was not noticed as the cockpit was sunlit and the captain's navigation instrument displays were selected to low intensity at the time.

Significant factors

1. The maintenance crew was unaware of the required documentation procedures.

2. The maintenance crew did not conduct a formal shift handover.

3. The cockpit checklist was deficient with regard to testing the standby power system.

Safety action

As a result of this investigation the operator advised that they had initiated the following safety actions in respect to the deficiencies relating to the training of certifying engineers on the requirements of the company Policy and Procedures manual:

1. The course notes for the LAME Introduction Course were distributed to all LAMEs including those at line stations. A where to find it booklet was also given to AMEs. These actions were completed by the end of August.

2. Maintenance Memo Number M1884 was issued to alert all LAMEs to their responsibility to follow approved procedures. It provided information as to which volume would be relevant to the particular work area.

3. In conjunction with item 2, Department Heads checked and, in some cases, improved the availability of the appropriate P.&P. Manuals in their areas. This was completed prior to the end of August.

4. In order to provide a concise and accurate analysis of incidents for those persons who need to know we have introduced a Quality Alert Bulletin. The objective of which is to ensure all benefit from the lessons learned. The information is depersonalised for obvious reasons.

5. While there was nothing wrong with the existing procedure for serviceable transfer (Vol. 5 chapter 3-40-05) we took the opportunity to emphasise its existence when it was revised.

Maintenance Memo M1880 refers.' The Bureau of Air Safety Investigation made the following interim recommendations on 9 February 1994:

IR940015

The Bureau of Air Safety Investigation recommends that the Civil Aviation Authority liaise with the Boeing Commercial Airplane Company, in conjunction with the Australian operator, to amend the B747-438 Flight Deck Preparation Checklist to include reference to additional EICAS messages that will be displayed when an unacceptable condition exists with the standby power system.

The CAA response stated, in part: 'The Authority believes that the abnormal indication of the Captain’s display blanking and EICAS transfer to the secondary screen should have been sufficient indication that there was a problem with the aircraft systems. We do not believe it is reasonable to expect aircraft systems to compensate for abnormal maintenance actions and the range of inappropriate actions that are possible would make such an approach difficult to address. Nevertheless, the Authority will raise the matter of amendment to the B747-400 Flight Deck Preparation Checklist to highlight that further investigation of any unusual indications during flight deck preparation checks is necessary.'

The operator response stated: 'I have enclosed a copy of a revised page for the 747-400 Operations Manual. This revision has been written as a result of the referenced A.S.I.R. The revision is highlighted by a margin line bar and will be processed as part of a general revision to go to printing at the end of the week. Rather than make the comment specific to the Standby Power check, I have included it as part of the preamble to the whole flight deck preparation. I feel that this is more appropriate as there are potentially other areas where a similar problem could occur should these circumstances ever arise again.

IR940016

The Bureau of Air Safety Investigation recommends that (the operator) conduct a review of policy relating to shift handover procedures to include directions for individuals as well as supervisors.

The operator response stated, in part: 'The reason the static inverter was not fitted to VH-OJB was that the engineer who removed the inverter failed to carry out the requirements of the Policy and Procedures manual in regards to not entering in the aircraft log book or work package that the inverter had been removed from the aircraft to service the other aircraft. By making an entry as required the person removing the item is also fulfilling the requirements of an individual handover as this entry has to be acquitted prior to the Maintenance Release being certified.

After the investigation of this incident the engineer involved was counselled and disciplinary action was effected against him. As well the Policy and Procedures manual reference to the actions required when cannibalising aircraft components has been amended to clarify the requirements when carrying out this function. These procedures have since been widely distributed to all Sydney Line Maintenance staff.'

A surf competition was being held. Teams with their equipment were on the beach. The pilot made a landing approach from over the sea, with an estimated 15 knot tailwind, towards the designated helicopter landing site where two other media helicopters had already landed. The pilot was being guided into the landing site by another helicopter pilot on the ground.

On short final he realised that his rotor downwash had diverted to the right front of the helicopter and was dislodging equipment on the beach. He immediately aborted the approach and landed elsewhere. The diverted downwash lifted a surf boat which struck and injured a female competitor.