The aircraft were operating on the same air route within controlled airspace under the jurisdiction of Jakarta control sector. Although Jakarta was providing control and separation services within the Jakarta Flight Information Region (FIR), Perth Flight Information Service International (FIS INT) was monitoring the common international high frequency (HF) aeromobile facilities being used by both aircraft and Jakarta.

G-BPFV was southbound at FL370 estimating LAMOB at 1914 hours and had established HF Primary Guard with Perth FIS INT.

VH-EAM was northbound, 10 NM right of track, at FL350 until passing waypoint LAMOB at 1858 when a flight planned climb to FL390 was requested from Jakarta.

FIS INT 1 intercepted Jakarta's approval for VH-EAM to climb to FL390 and recognised the potential for a traffic confliction with G-BPFV. FIS INT 1 immediately advised Perth control Sector 1 of the situation and provided traffic information direct to VH-EAM.

Almost simultaneously, Jakarta instructed VH-EAM to maintain FL350, but the aircraft had already climbed to FL365 prior to resuming FL350.

The aircraft had established the required 2,000 feet vertical separation again by approximately 1904, two minutes prior to the point of closest approach, which was approximately 60 NM north of LAMOB, within the Jakarta FIR. It was later established that G-BPFV had been authorised by Jakarta to track 10 to 15 NM west of track.

Neither the amended track for G-BPFV nor the change of level for VH-EAM were co-ordinated with Perth Sector or FIS INT for relay. There was a breakdown of the required separation standards.

The pilot reported that he made a normal approach and landing to the wet runway, touching down at around 60 knots. During the landing roll the aircraft began to veer to the right. Attempts to stop the yaw using both rudder and brake were unsuccessful. The aircraft left the sealed runway and the nosewheel was damaged when it entered a soft area.

The wind was blowing at 30 knots with gusts of up to 15 knots and a crosswind of 8 knots from the right.

The precise reason for the loss of control could not be determined but it is possible that it was the result of the combination of the wet runway and the strong and gusting crosswind.

VH-AJJ was climbing to Flight Level (FL) 370 (37,000 feet) whilst VH-WGJ was climbing to FL350, and the aircraft were under the procedural (non-radar) control of the Perth Sector 1 air traffic service controller. The aircraft were on reciprocal tracks and a vertical separation of 2000 feet was required at least 10 minutes before the aircraft passed. The climb profiles of the aircraft meant that the required separation would not be achieved by 10 minutes prior to passing. The controller did not recognise the potential confliction.

Nine minutes prior to the aircraft passing, VH-AJJ requested an amended level of FL350 but was given FL330 because the controller assumed VH-WGJ was already at FL350.

Seven minutes prior to passing, the controller ascertained that VH-WGJ was passing FL320. He then realised a conflict existed and instructed VH-WGJ to descend to FL310. VH-WGJ started its descent back to FL310 as VH-AJJ reached FL330 on the climb. The aircraft reached the standard vertical separation requirements approximately three minutes prior to passing.

Although the controller was an experienced procedural sector controller he had not been involved in this type of control for about 12 months and had only recently been re-categorised.

The pilot extended the landing gear but failed to get a down and locked indication from the single green indicator light on the instrument panel. The pilot recycled the gear twice, checked the indicator light was in the day mode but still did not get a down and locked green light.

The pilot raised the gear, proceeded to the west of the airfield and reduced speed, and then carried out a manual extension of the gear. He still did not obtain a green light. The pilot advised that during the manual extension he was unable to push the extension lever to the stop and the handle felt slightly spongy.

The pilot was advised that a visual inspection of the landing gear from the control tower showed that the gear appeared to be fully down, however, during the subsequent landing the gear collapsed.

Later investigation showed that the green light bulb was loose in its socket. After it was properly secured the green light illuminated satisfactorily.

The manual landing gear extension system was found to have been not correctly manipulated. For the gear to be successfully manually lowered, two actions are required; the electric motor must first be disconnected and then the gear must be manually lowered. It was found that the motor release arm used to disconnect the electric motor had not been pushed fully forward and the motor was still partially engaged. Consequently, the emergency gear handle was unable to be pushed fully forward to its stop. This meant that the gear was not able to be locked down, and the restriction caused by the partially disconnected electric motor led to the spongy feel reported by the pilot.

Significant Factors

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

1. The landing gear down and locked globe was loose in its socket.

2. The pilot did not get a safe indication when he extended the landing gear normally, even though the gear was most probably locked down.

3. The pilot retracted the landing gear and then attempted to manually lower it.

4. The manual extension system was not able to lock the gear down because the electric motor was still connected.

Shortly after carrying out a touch-and-go landing, at night on runway 29, a loud 'chuffing' sound was heard. Safety checks were begun, but the cockpit commenced to fill with smoke with no obvious sign of fire. Fresh air vents were closed, and a close circuit was carried out for a normal landing.

It was subsequently found that a number of exhaust pipe slip joint bolts were missing. One exhaust pipe had become detached and the escaping hot exhaust gases had burnt through the lower cowling.

Safety Action

As a result of the investigation into this and other similar occurrence (OASIS 9201731), the Bureau of Air Safety Investigation met with the Civil Aviation Authority Airworthiness (Powerplants) staff and discussed the apparent deficiencies with the exhaust clamping arrangements.

The CAA researched the available data and located a SOCATA Service Bulletin (SB), SB 10-073-78, which had been released in January 1994. The CAA subsequently isssued Aerospatiale (SOCATA) TB9, TB10 and TB20 Airworthiness Directives (ADs) AD/TB10/20, AD/TB10/21 and AD/TB20/27 effective 26 May 1994 mandating compliance with the manufacturers SB within 50 hours of time of service.

This prompt action by the CAA, in full consultation with the Bureau of Air Safety Investigation, obviated the need for any formal safety output.

1. FACTUAL INFORMATION

Sequence of events

The aircraft was involved in Civil Search and Rescue Unit training at the time of the occurrence and the trainee drop master was undertaking his first live dispatch of a twin raft training pack under the supervision of an instructor. The aircraft was being flown at 120 knots and 200 feet above sea level for the exercise.

The drop proceeded normally until the first raft pack was dispatched after which the trainee retained his grip on the second raft pack beyond the point in time when the second pack should have been dispatched. As the rope reached full length a tug was felt and shortly afterwards the first raft pack entered the water placing a much greater load on the rope causing the second raft pack to be pulled from the trainee's grip.  It struck the rear door frame before exiting the aircraft, causing substantial damage.

Raft dropping procedures

Raft packs connected by 440 m of rope are normally dispatched from the aircraft at six second intervals allowing the rope to be pulled completely from special containers attached to each raft pack. The raft packs are normally located one on top of each other and protrude through the door. They are pushed outwards and downwards by the dispatcher to ensure they remain clear of the aircraft. The drop master may also use an alternative procedure by waiting until he feels a tug on the rope before dispatching the second raft. During training, raft packs made from a solid wooden cylinder and webbing are used in lieu of rubber rafts. The training pack has less elasticity than the actual pack.

When an actual raft is dropped it begins to inflate during its descent and will not generally contact the water before the second raft is released. However, a training raft pack does not inflate and therefore it falls at a faster rate, entering the water sooner than an actual raft. On this flight the early entry into the water of the training pack led to the uncontrolled release of the second raft and the subsequent damage to the aircraft. The twin raft deployment system does not include a weak/frangible link to protect the aircraft from damage resulting from such circumstances.

Pre-flight training/briefing

The trainee drop master had been trained and subsequently briefed for a single raft drop. On the day of the occurrence the aircraft to be used for the single raft training became unserviceable and the exercise was re-scheduled for a twin raft drop. He had not been trained or briefed for the twin drop until immediately prior to departure. Before each flight the crew normally received a briefing from the pilot-in-command on the procedures and calls to be used during the drop.

During the preflight briefing by the pilot-in-command, it became evident that the trainee drop master was not familiar with the twin raft drop procedures. The briefing was discontinued to allow the trainee drop master to be given instruction on twin raft drops by the drop master instructor. The preflight briefing was subsequently resumed but the drop master instructor did not attend this briefing as he had become occupied with other duties. The trainee did not carry out any dummy runs to practise the twin raft drop procedures.

During the flight the drop master instructor introduced procedures that had not been explained during the preflight briefing. In addition, the intercom between the drop master and pilot failed and hand signals (a normal alternative procedure) were used.  Additionally, the clock, used for timing the drop sequence, was stopped during the live drop run causing the drop master to lose his timing reference.

3. CONCLUSIONS

Findings

1. The trainee drop master was inadequately prepared for the twin raft sequence due to insufficient instruction and a lack of dummy training runs.
2. There was a breakdown in standardisation and communication because the drop master instructor did not attend the preflight briefing given by the pilot-in-command.
3. The twin raft deployment system does not include a weak/frangible link to protect the aircraft from damage should there be a hang-up and one raft pack enters the water.

Significant Factors

1. The training system in use was not mature enough to cope with a last-minute change in the program caused by an aircraft unserviceability.
2. Training staff did not ensure that drop master training was adequate and that procedures were clearly understood prior to departure for the flight.
3. The design of the training raft packs was deficient in that it did not provide a failsafe system in the event of a hang-up during normal dispatch.

4. SAFETY ACTION

4.1 The Civil Aviation Authority suspended all training using the twin raft system pending the results of an investigation into the safety of the system.

4.2 The Bureau of Air Safety Investigation issued Safety Advisory Notice SAN 940076 on 29 March 1994, suggesting that the Civil Aviation Authority review the Search and Rescue twin life raft system to ensure:

1. that a weak/frangible link is included between the two rafts for twin unit deployments;
2. that ab-initio trainee drop masters undertake at least one practice drop run before attempting an actual deployment; and
3. that communication and teamwork between flight crew and the drop crew is improved on SAR training flights.

The Civil Aviation Authority responded on 7 June 1994 advising that:

1. in future there will be no change of the supply drop process during a planned training program for an ab-initio drop master trainee;
2. ab-initio trainee drop masters will undertake a minimum of ground training drop simulation and one airborne practice drop prior to an actual life raft/dummy unit deployment;
3. the Drop master and Pilot SAR Manuals will be amended to delete the use of the tug on the rope as an alternate indication to an elapsed time of 6 seconds for the release the second raft;
4. the drop master instructor and the pilot tutor will attend the preflight briefing given by the pilot in command, prior to each training flight and all crew members will attend the preflight brief given to the trainee drop master;
5. where possible training is to be conducted with rubber compound units, - Technical Services Division (TSD) are about to place an order for the manufacture and supply of rubber compound units, which will replace the wooden logs currently in use. A time frame for delivery and replacement is not known; and
6. TSD have developed a weak link for use on all training equipment (Single, Twin and Multi-unit drops). Testing of this weak link is presently being conducted.

Status of response: Closed - accepted.

The pilot reported that while flying at 350 feet above ground level, maintaining 50 knots, the engine started to vibrate violently and lose power until it stopped. Prior to the power loss, all temperatures and pressures were normal. The pilot entered autorotation but due to the unsuitable terrain he had to make a very steep descent to put the aircraft onto a suitable landing site. In doing this, he made a heavy touchdown which resulted in a main rotor blade striking the tail boom causing substantial damage.

The engine failure was later determined to have been caused by failure of the number two connecting rod assembly. The failure of the assembly was caused by fatigue crack growth in the connecting rod cap. The factors that contributed to the fatigue crack initiation were not determined.

ASOR Summary

The aircraft was to depart via a Wollongong One Standard Instrument Departure (SID) after taking off from runway 16. After this instruction had been passed to the aircraft, the duty runway was changed to runway 07. This information was passed to the aircraft along with the instruction that the Wollongong One SID was to be flown. (The Wollongong One SID from runway 16 is different to the Wollongong One SID from runway 07.) In the event, the aircraft was observed on radar after take-off from runway 07 to commence to fly the Wollongong One SID applicable to runway 16. The aircraft was then instructed to track direct to Wollongong.

Safety Action

The Bureau of Air Safety Investigation recommends that the Civil Aviation Authority:

(a) review the presentation of standard departure instructions in order to ensure that they are clearly laid out to make them easily assimilated, and

(b) review the instructions for each runway so that they are contained on individual charts or, are clearly delineated on each chart.

The helicopter was tracking coastal at about 500 feet AMSL when the pilot saw a crocodile on a riverbank and commenced a descent to enable photographs to be taken. He made a right turn to position the helicopter into wind while descending to a height of about 100 feet and decelerating to 10-20 knots.

As the helicopter came out of the turn the pilot applied normal up collective control and left anti-torque pedal to regain level flight which was immediately accompanied by a severe vibration. The helicopter began to rotate rapidly to the right and the pilot applied full left pedal, but with no response, the feel on the pedals being as if they were detached from the tail rotor system.

The pilot lowered the collective and applied forward cyclic in an attempt to control the rotation and vibration. Although the rotation rate slowed, the helicopter rotated through another 2-3 turns and descended to about 30 feet above the sea. The pilot realising that he would be unable to effect a successful recovery, landed the helicopter in the water with a forward speed of about 10-20 knots in a tail low attitude while still rotating to the right.

The helicopter rolled inverted and floated upside down for 3-4 minutes. All occupants evacuated the helicopter and swam ashore. The helicopter sank, but after a while it resurfaced then floated out to sea on the tide and was recovered the next day. The tail boom was found to have been severed behind the horizontal stabiliser, the vertical fin, tail rotor gearbox and tail rotor being lost in the sea.

Subsequent investigation revealed that the tail rotor drive forward short shaft had failed due to torsional overload. The severed tail boom, when matched to a serviceable helicopter of the same type, showed that the damage and impact marks were found to align with the tail rotor blades. The tail rotor drive long shaft had only slight impact damage and had uncoupled intact off the splines at the tail rotor gearbox, indicating that a main rotor blade impact had not caused the tail boom to fail.

The tail boom was severed by a direct strike from a tail rotor blade under power, which then caused the tail rotor drive short shaft to fail under load. It was not possible to determine the reason why the tail rotor blade struck the tail boom.

The student pilot/owner and an experienced private helicopter pilot, who was not endorsed on type and did not hold a valid medical certificate, decided to ferry the helicopter. Enroute, they elected to enter an autorotation to practise a forced landing from about 1,000 feet above the ground. When attempting a power recovery near the ground, they realised that the engine had stopped. During the autorotative touchdown the main rotor cut through the tail boom. The landing gear skid assembly broke, and the helicopter rolled onto its left side.

No mechanical failure of the airframe or engine has been found which may have contributed to the accident.

At the time of the flight the relative humidity was about 88% and the outside air temperature about 13 degrees Celsius; conditions were ideal for the formation of carburettor icing. The engine is water cooled and is fitted with a water jacket on the carburettor. If the tap adjoining the carburettor is turned on, hot water will circulate to warm the carburettor and thereby counteract carburettor icing. On the standard Rotorway EXEC 90, the tap must be turned on before flight because there is no means to turn it on from the cockpit. On VH-YCP, the tap was turned off.

Subsequent to the accident it has been noted that the carburettor air temperature gauge fitted to the console reads about 10 degrees celsius colder using the external air scoop, which is an Australian modification, as opposed to the original Rotorway design. Since the accident, the Civil Aviation Authority has amended the permits to fly. Until the matter of carburettor heat is resolved, the induction anti-icing system must be turned on for all flights in conditions of outside air temperature below 24 degrees Celsius; and flight in conditions of outside air temperature 10 degrees or below in visible moisture is not permitted.

Significant Factors

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

1. The carburettor heat water jacket was not turned on before the flight.

2. Prevailing conditions were conducive to the formation of carburettor icing.

3. The engine probably failed due to carburettor icing.