The Boeing 737-33A aircraft, registered VH-CZQ, departed Townsville at 1805 EST on a scheduled passenger service to Brisbane. Soon after levelling at flight level (FL) 330, the flight crew observed that the master caution light, the cabin pressurisation auto-fail light and the pressurisation standby light had illuminated. The crew completed the non-normal procedure and, as cabin pressurisation was being maintained, they decided to continue the flight to Brisbane.

At about 1909, the flight crew experienced physiological sensations, which indicated that the flight deck was depressurising. The crew donned their oxygen masks and the copilot noticed that the cabin rate of climb indicator was displaying a rate of climb of 4,000 fpm. Shortly afterwards, as the cabin altitude climbed through 10,000 ft, the crew observed that the master caution light and passenger oxygen `on' light had illuminated and heard the cabin altitude warning horn. The flight crew completed the non-normal procedure for a rapid depressurisation and emergency descent and advised air traffic control that the aircraft had left the cruising level due to a depressurisation. The pilot in command advised the cabin crew on the public address system (PA) of the descent.

The cabin in-flight service had been completed and the four flight attendants were at the front of the aircraft when the oxygen masks dropped from overhead passenger service units (PSU) throughout the cabin. When the oxygen masks dropped, the cabin supervisor returned to his seat at the forward left entry door, donned an oxygen mask and removed the PA handset from its receptacle. Another flight attendant also returned to his crew seat at the forward left door and donned an oxygen mask. The two remaining flight attendants, standing at the front of the aircraft when the oxygen masks dropped, returned to their crew seats at the rear left entry door.

Some passengers were assisted by a flight attendant as she walked to the rear cabin. When the flight attendant reached the rear crew seat she found that the crew oxygen masks had not automatically deployed from the overhead stowage. She released the masks by activating the manual release on the overhead panel, and was seated just as the second flight attendant reached the crew seat.

The flight attendants reported that the floor angle during the emergency descent seemed no different than a normal descent and they did not notice any movement of cabin or galley items. One flight attendant reported that she did not feel in danger. Her ears were `popping', but there were no indications of depressurisation such as those taught in emergency procedures training. The flight attendants reported that they `weren't short of breath, felt [they] had time, there were no objects flying in the cabin or cabin misting'.

The flight data recorder information showed that at 09:08:55, while in cruise at FL330, the cabin altitude warning activated indicating that the cabin altitude had exceeded 10,000 ft. Thirty-six seconds later at 09:09:31, the emergency descent was initiated with the thrust levers being closed and the autopilot level change mode being selected. The pitch attitude then decreased from 3.2 degrees nose up to 4.4 degrees nose down and the aircraft began to descend at a rate of 4,600 feet per minute. At 09:11:01, the speedbrake was deployed as the aircraft descended through FL276 at a rate of 4,500 feet per minute, with a pitch attitude of 3.7 degrees nose down.

The maximum nose-down pitch attitude during the emergency descent was 4.4 degrees for a 6-second period as the aircraft descended through FL 285 at 5,000 feet per minute. By the time the aircraft reached FL199, the pitch attitude had reduced to 1.4 degrees nose down, with a rate of descent of 3,400 feet per minute. By way of comparison, the pitch attitude during a normal descent of a B737-300 series aircraft is about 2 degrees to 3 degrees nose down above FL260, reducing to about 1 degree nose down during the latter part of the descent.

When the aircraft levelled at 10,000 ft, the pilot in command advised the passengers by PA that oxygen masks would no longer be required, and instructed the cabin crew to commence follow-up actions. The cabin supervisor went to the flight deck to confirm instructions and advise the pilot in command of the conditions in the cabin. The flight attendants reported that, although all passengers were calm, three or four passengers needed reassurance, but additional oxygen was not required. The flight crew continued the flight to Brisbane at 10,000 ft and landed at 1953 without further incident. There were no injuries.

The flight crew later reported that they felt a slight movement on the rudder pedals on two occasions during the descent into Brisbane. The crew considered the rudder pedal movements to be minor and did not take any further action. About the same time, the crew also noticed that the map display on the Electronic Horizontal Situation Indicator (EHSI) was incorrect. The aircraft position depicted on the EHSI differed from the position indicated on the other navigation instruments.

Operator's Operations Manual

Volume B3 of the operator's Operations Manual contained information about the safety equipment and procedures. Section 5.1 included information about cabin depressurisation and actions to be taken by the flight crew and cabin crew following a depressurisation event. The manual used the term decompression when referring to depressurisation.

The manual stated that there were two types of decompression, gradual and rapid (explosive). The information provided in section 5.1 related primarily to the rapid type of decompression. The manual stated that `the angle in the cabin will become very steep as the aircraft descends at an approximate rate of 6000 ft per minute (normal rate of descent is approximately 2000 ft per minute)'. The manual also contained a warning that required the immediate use of oxygen by all crewmembers following the deployment of drop out oxygen masks in the passenger cabin. The manual advised cabin crew that the effects of a decompression event on the aircraft were:

1. Sudden boiling of liquids;
2. Loud noise as air escapes;
3. Air becomes thin, cold and dry;
4. Fog forms in cabin (should not be confused with smoke);
5. Dust and objects blown about;
6. Smoke alert devices in toilets may be activated; and
7. Flight crew may initiate an emergency descent causing the angle in the cabin to become very steep.

Aircraft examination

Following the incident, the electrical/electronic (E/E) bay was inspected and water was found to be dripping from the forward galley floor into the bay. There was also evidence of moisture leakage under the forward passenger door and service door. Moisture stains were found on the racks and ducting within the bay. The inspection also revealed that the moisture shroud was missing from above the E1 rack in the forward part of the bay.

A number of avionics units were removed from the aircraft, including the pressurisation controller, yaw damper coupler, auto-throttle computer and two stall warning computers. These units exhibited evidence of water damage, including moisture staining of component casings and corrosion of connector pins. There was no record of the maintenance staff finding moisture contamination in the E/E bay prior to the incident.

The operator stored beverages in polystyrene ice containers that were stowed in the forward galley. The containers were partially filled with crushed ice that melted during flight. The flight attendants on the incident flight did not recall any water spillage occurring from the ice containers, nor did they recall any turbulence that may have caused a spillage. The flight attendants reported that on previous flights on various aircraft there had been spillage from the ice containers, usually during landing.

Component testing

The manufacturer of the pressurisation controller inspected the unit and subjected it to a series of tests. A visual inspection of the outer case of the unit and the circuit boards did not find any damage or anomalies and a series of functional tests did not reveal any faults. Although there were indications of moisture staining on the outer case, there was no evidence of any residual damage to the unit due to water contamination. The manufacturer was aware of other instances where water had entered pressurisation controllers and caused problems in one or more of the operational modes.

An inspection of the yaw damper coupler found that the electrical filter was shorting out. After the filter was replaced the unit operated satisfactorily. A dent was also found on the top cover of the outer housing of the coupler, but it did not affect the operation of the unit. An inspection of the rudder power control unit found that the transfer valve was unserviceable due to an open electrical circuit.

Aircraft information

The aircraft was acquired from another Australian operator during October 2001 and underwent a pre-delivery inspection prior to commencing passenger operations on 1 November 2001. The operator's contracted maintenance provider conducted the inspection that was intended to ensure compliance with airworthiness directives and service bulletins.

The previous operator had purchased the aircraft from the United Kingdom and it was entered onto the Australian civil register on 3 December 2000. Between December 2000 and January 2001 the aircraft underwent modification and heavy maintenance work at an overseas engineering facility before entering revenue operations in Australia. The modifications included the removal of an airstair from under the forward passenger entry door. During that work the airstair drip pan and the cloth moisture shroud were removed from the E/E bay.

The documentation covering the removal of the airstairs specified that the moisture shroud was to be replaced following the modification work. However the shroud was not installed because the kits were temporarily unavailable from the manufacturer. One of the operator's engineers, authorised by the Civil Aviation Safety Authority to approve a design modification or repair, assessed that the absence of the moisture shroud would not affect the safety of the aircraft. On 29 January 2001, the engineer approved an amendment to the engineering release that permitted the installation of the shroud within 12 months of receipt of the parts.

The aircraft was subsequently operated on Australian domestic passenger services between February and September 2001 without the moisture shrouds being fitted. An order was placed with the manufacturer for the shroud kits and the delivery of the kits was due in November 2001. The moisture shrouds were not fitted to the aircraft when it was delivered in October 2001 to the current operator, who was unaware that the shrouds had not been fitted to the aircraft.

During the investigation, the aircraft manufacturer provided the following advice:

`Boeing advises that these shrouds are required in order to ensure the airworthiness of the airplane. 737 airplanes should not be used for revenue flight with these moisture shrouds not installed.'

`The 737 MMEL/DDPG does not provide any relief for these items to be removed from the airplane. Furthermore, the purpose of these shrouds is to protect the electronic equipment from moisture ingress. There have been several reports of 737 airplanes experiencing uncommanded flight movement due to moisture ingress into certain electronic components in the E/E Bay.'

On 18 April 2002, another Australian registered Boeing 737-33A, VH-CZR, sustained a depressurisation incident during a scheduled passenger service from Auckland to Christchurch, New Zealand. The incident occurred soon after top of descent when the crew selected the pressurisation system to the standby mode. The aircraft had a history of pressurisation controller problems when being operated in the AUTO mode, until approximately three weeks prior to the incident when the controller was replaced. The pressurisation controller fitted to the aircraft at the time of the occurrence failed during post incident testing, as the selection of standby mode resulted in the cabin outflow valve moving to the fully open position.

VH-CZR had a similar service history as CZQ, having been purchased by the same previous operator and undergoing similar airstair removal modifications at the overseas engineering facility prior to entering service in Australia. The aircraft also had not been fitted with moisture shrouds following the removal of the airstairs and the moisture shield over the E1 rack was not installed on the aircraft at the time of the occurrence in New Zealand.

The pilot of the Piper PA 32-260 was conducting the return sector of a charter flight for five passengers from Rottnest Island to Jandakot, WA.

The pilot reported that a strong and gusty southerly wind was blowing almost directly across the runway, but favoured a departure from runway 27. He used the indications from the aerodrome's windsock to assess the wind strength and determined that it was within acceptable limits for his aircraft.

Shortly before 1600 WST, the pilot taxied the aircraft to the threshold of runway 27. The pilot reported that he used a conventional crosswind technique for the take-off, with full aileron deflection into wind and use of rudder to maintain the aircraft on the runway centreline. The pilot reported that the airspeed indicator was reading about 65 - 70 kts when he positively rotated the aircraft nose for the initial climb. However, the aircraft did not respond to these control inputs and started drifting to the right. Despite applying full deflection of the rudder and aileron controls, the pilot reported that he was unable to maintain directional control of the aircraft.

The aircraft continued to diverge from the runway centreline, departing to the right of the runway strip and passing over a sealed taxiway and sandy scrub terrain. The right main landing gear collided with a tree stump on the edge of a shallow salt-water lake adjacent to the aerodrome. The aircraft briefly became airborne before coming to rest in the lake, in water that was less than 1 m deep. The pilot and passengers were not injured and vacated the aircraft without assistance. Although the aircraft was carrying an inflatable life jacket for each person on board, nobody was wearing one at the time of the accident and nor was this required by regulation.

Examination of the aircraft did not reveal any defect that could have affected its normal operation. Damage to the propeller blades was consistent with the engine operating at a high-power setting on impact with the water. Marks on the lower surface of the right wingtip were consistent with the tip of the right wing dragging across a hard sealed surface. The outboard portion of the right aileron also exhibited evidence of contact with a hard sealed surface.

The passengers recalled that the aircraft started to become airborne at a ground speed that seemed slower than the speed achieved during take-off from Jandakot earlier that day. They also reported that the ground roll along the runway seemed shorter. One of the passengers also described seeing a flashing red light on the instrument panel during the take-off attempt.

The pilot reported that following the accident he returned to the terminal building and was watching the aerodrome's windsock. During this period, he reported that the wind direction occasionally seemed to favour a departure from runway 09.

Examination of the runway revealed marks that indicated the aircraft commenced diverging from the runway centreline approximately 270 m from the threshold of runway 27. The aircraft's ground track was evident as it departed the runway strip and crossed the sealed taxiway. The ground track included abrasion marks from the tip of the right wing and the trailing edge of the right aileron, together with the track of the right main wheel. The marks on the right wingtip indicated that the aircraft was in a sideslip at the time and the nose was displaced right of the actual track across the ground. The aircraft came to rest about 530 m from the runway threshold and 120 m to the right of the runway centreline.

The aerodrome forecast issued by the Bureau of Meteorology (BoM) and current at the time of the accident forecast a wind from 190 degrees true (T) at 25 kts. BoM also issued routine half-hourly weather reports of the recorded conditions at the Rottnest Island automatic weather station (AWS). The report issued at 1530 indicated that the wind was 190 degrees T at 30 kts, gusting to 38 kts. These conditions were consistent with other reports issued on the afternoon of the accident.

The AWS for Rottnest Island is situated approximately 2 NM to the west of the aerodrome, on higher terrain about 160 ft above the aerodrome elevation. The site for the AWS is an exposed part of the island, and consequently, the recorded wind speeds could be expected to exceed those that would be experienced at the aerodrome.

Information from the AWS was not broadcast on either a discrete very high frequency radio or the Rottnest Island non-directional beacon navigation aid. The half-hourly reports issued by BoM could be obtained by pilots during pre-flight briefing and on request in-flight from air traffic services' Flightwatch frequency.

Minute by minute data from the Rottnest Island AWS indicated that during the 5 minutes prior to the accident, the maximum recorded wind speed was 38 kts, minimum wind speed 25 kts, from directions between 181 and 198 degrees T.

The east-west orientation of the runway at Rottnest Island and a series of sand hills to the south of the runway can significantly influence operations at the aerodrome, particularly at times when strong southerly winds prevail. This can include the effects of low-level wind shear, low-level turbulence in the lee of the sand hills and other conditions due to the behaviour of strong winds as they flow over and around the terrain.

Climatology studies of Rottnest Island conducted by BoM indicate that the runway is not aligned with the prevailing winds, and consequently, pilots can expect to frequently encounter crosswind conditions when operating at the aerodrome. In general terms, the strongest southerly crosswind components are more prevalent during the afternoons of the summer months. Strong northerly crosswinds appear to be more prevalent during the afternoons of the winter months. Records indicate that the runway crosswind component regularly exceeds 20 kts.

The pilot reported that he did not obtain a weather forecast for the day of the accident, but had received an operational briefing by telephone from the company chief pilot, prior to departing Jandakot on the first flight of the day. This briefing had included information obtained by the chief pilot on the weather conditions forecast for the day. The pilot did not obtain additional information or update the briefing received from the chief pilot during the course of the day.

The investigation calculated that the aircraft's operating weight at the time of the accident was below the maximum permitted take-off weight, with the centre of gravity in the vicinity of the published aft limit.

Forces acting on the aircraft during the initial stages of its take-off roll would cause the nose to yaw to the left as engine power was applied. In addition to this effect, at low speed during a crosswind take-off, the stability of the aircraft was such that the fuselage had the tendency to weathervane into wind. Control of the aircraft in those conditions required the application of a crosswind take-off technique to safely control the aircraft. From the perspective of aircraft controllability, a crosswind from the left (as was the case for the accident flight) was the more significant. This was due to the tendency of the aircraft nose to yaw left due to the crosswind, combining with the tendency of the aircraft nose to yaw left due to the application of engine power. The tendency of the aircraft nose to yaw is counteracted by the pilot applying right rudder, with the required amount of rudder input generally reducing as the aircraft accelerates and the rudder becomes more effective. During the later stages of the take-off roll, some left rudder input may have been required to maintain the aircraft on the runway centreline.

The investigation could not positively determine the airspeed of the aircraft at the time the pilot attempted to rotate the aircraft's nose to initiate the climb from the runway.

The US Federal Aviation Administration approved flight manual for the PA32-260 indicates that the demonstrated take-off or landing crosswind component is 20 miles per hour (17 kts). The Civil Aviation Safety Authority approved flight manual for the aircraft type stipulates a maximum permissible crosswind component of 20 kts.

The DHC-8-201 (Dash 8) aircraft was being operated on a scheduled passenger service from Sydney to Lord Howe Island. Overhead Lord Howe Island, when the flight crew was preparing for landing, the main landing gear failed to extend following normal selection. The crew then broadcast a PAN (radio code indicating uncertainty or alert), notified air traffic services (ATS) of a main landing gear problem, and requested a diversion to Port Macquarie. Radio transmissions between the aircraft and ATS were intermittent and radio relays from other aircraft in the area were employed. The request for diversion was granted and the aircraft tracked, first for Coffs Harbour, then Port Macquarie while the crew reassessed their fuel reserves. Enroute to Port Macquarie, the flight crew estimated that there was sufficient fuel on board for a diversion to Sydney, so they requested and received a clearance to track direct to Sydney.

Enroute to Sydney, when within very high frequency radio range, the flight crew contacted the operator on the company radio frequency and attempted to troubleshoot the main landing gear anomaly. Maintenance personnel suggested a check of the position of the landing gear inhibit switch. The switch was found to be in the INHIBIT position, rendering the gear unable to extend. The flight crew repositioned the switch to the NORMAL position and normal landing gear operation resumed. The aircraft continued to Sydney and completed an uneventful landing.

Prior to the flight, maintenance personnel replaced contact pins on the main hydraulic pressure transmitter connector to resolve a number 2 hydraulic system low pressure indication. During that maintenance, the landing gear inhibit switch had been placed in the INHIBIT position. Following maintenance, the maintenance engineers completed a hydraulic system operational check to return the aircraft to flight status. The check did not include a cycling of the main landing gear system, nor was there a requirement to do so. The number 2 hydraulic system retracted and extended the main landing gear.

Landing gear inhibit switch

The two-position (NORMAL and INHIBIT) landing gear inhibit switch was guarded (plastic cover to confirm position) to the NORMAL (OFF) position. The INHIBIT position provided an open electrical circuit to the landing gear down solenoid of the gear selector valve, preventing normal operation of the gear and also preventing illumination of the LDG GEAR INOP caution advisory light. Selecting the landing gear inhibit switch to the INHIBIT position idled the normal landing gear extension system actuators to ensure unhindered operation during alternate extension. Alternate extension of the landing gear used the freefall characteristics of the landing gear, and was used for emergency extension of the gear. The landing gear inhibit switch was also selected in flight crew training to provide the crew with realistic practice in using the alternate landing gear extension system.

Aircraft return to service and flight crew checklists

The operator reported that the maintenance procedures for returning the aircraft to service after maintenance included a requirement to check the landing gear inhibit switch position. They reported that the post-maintenance checks were not thoroughly completed because the maintenance personnel were interrupted by the flight crew during the task.

The operator checklists for the aircraft type were required to be conducted using the challenge and response method. The aircraft manufacturer's NORMAL PROCEDURES checklist, required that the landing gear inhibit switch was checked for selection to the NORMAL position. The operator's Civil Aviation Safety Authority approved ORIGINATING BEFORE START/ BEFORE START and NORMAL (originating) checklists included a check to confirm that the landing gear inhibit switch was in the NORMAL position. The BEFORE START checklist used by the crew, did not have such a requirement. The operator required that the ORIGINATING BEFORE START/ BEFORE START checklist be actioned following maintenance, other than ramp activity, of the aircraft. Under existing requirements, the ORIGINATING BEFORE START/ BEFORE START checklist was not required to be completed by the flight crew prior to take-off.

The manufacturers ALTERNATE LANDING GEAR EXTENSION/ LANDING GEAR MALFUNCTION (with illumination of landing gear inoperative caution light or loss of number 2 hydraulic system pressure) checklist included a check of the landing gear inhibit switch for the INHIBIT position. That checklist was not actioned as the landing gear inoperative caution light did not illuminate, nor was there a loss of number-2 hydraulic system pressure indicated during the flight. The operator reported that the crew decision to not use the alternate landing gear extension system once overhead Lord Howe Island was based on operational considerations.

As the Boeing 717-200 (B717) aircraft was levelling off in cruise flight at flight level 250, the crew noticed a 'MAP FAIL' message on the co-pilot's navigation display. This was followed by the same message on the pilot in command's (PIC) display along with a flight management system (FMS) double failure indication. After a short pause to allow the versatile integrated avionics (VIA) units to stabilise, the PIC selected 'STBY NAV' and reverted to the aircraft's very high frequency omni-directional radio (VOR) system for navigation.

The co-pilot then noticed that his FMS had become available once again; however, the flight plan information had been lost and required reloading. The PIC's FMS also became available and was re-instated. The flight then continued to Melbourne with no further anomalies.

A subsequent maintenance check of the aircraft revealed that both VIA units had indicated software faults. The aircraft had recently undergone a system software upgrade. The upgrade had been installed to prevent software faults that had resulted in previous FMS failures on this aircraft type. The aircraft's avionics system manufacturer was informed of the failure.

FMS reset

The software manufacturer advised that the loss of the FMS function (known as a reset) occurred under certain conditions when a secondary flight plan had been entered into the FMS. The normal procedure was to copy the primary flight plan to the secondary so it could be utilised for late changes once en route. However, if altitude adjustments during the flight were made using the altitude setting function on the autopilot glare shield controller, with the system selected to the EDIT mode, the primary flight plan data of the FMS would be updated automatically, but the secondary flight plan data would not. This would have created a conflict between the primary and secondary flight plans resulting in an FMS reset.

FMS software upgrade

The aircraft was fitted with the latest FMS software upgrade (VIA-905), which had addressed previously encountered problems associated with the system, and provided a number of improvements to the aircraft's operation. Although a dual reset resulting from the use of a secondary flight plan was experienced, the upgrade did allow the FMS to be reinstated after a built-in test equipment (BITE) test had been conducted.

The Boeing 767-300ER aircraft had departed Sydney for Honolulu on a scheduled passenger service. While on climb through flight level 105, the left engine fire warning light illuminated. The crew carried out the fire drill, shutting down the engine and discharging the engines' fire bottle number 1. Fire bottle number 2 was discharged shortly after due to the reactivation of the left engine fire warning. The fire warning lights continued to fluctuate on and off.

Air traffic control was advised of the emergency and issued a clearance for the aircraft to return to Sydney. After landing at Sydney, rescue and fire fighting services followed the aircraft to the parking area but were not required.

An examination by the operator revealed that a high-pressure duct (Wye-Air Cooling Part No 1456M55G03) had fractured transversely through the shorter of two stub-sections. High-pressure, high-temperature air that had escaped from the cracked duct, impinged on wiring to the engine fire detection loop. The insulation of the wires was damaged, and the wires disrupted. The duct that ruptured was part of the engine's stage 11 cooling system. Air is ducted from stage 11 of the high-pressure compressor to cool the stage 2 high pressure turbine nozzles.

Examination of the duct by the Australian Transport Safety Bureau determined that the duct rupture was a result of fatigue cracking consistent with high-cycle, vibratory loads. The crack initiated at the base of a reinforcing strap brazed to the duct neck. There was evidence of a misalignment of approximately 2 degrees in the connection of the fractured stub section to the adjoining section. There was no evidence of material or manufacturing defects.

The ruptured duct was replaceable with either of two later part numbers introduced by the engine manufacturer's Service Bulletins (SB) 72-757 and 72-761. A further option was introduced by SB 75-0156, dated February 2001, that replaced the duct with individual pipes. None of the service bulletins had been actioned by the aircraft operator, nor were they required to be actioned.

The engine was fitted with a "Kidde" fire warning loop that relies on changes of resistance of the internal thermistor material. When subjected to heat, the resistance of the material decreases to a pre-set point which then activates the cockpit warning system. Once the source of heat is removed, the resistance of the material returns to the original value and the fire warning ceases.

The Boeing 767-300ER engine fire extinguishing system has two fire bottles located in the fuselage which are both available to either engine. The engine fire drill required that if an engine fire warning light remained illuminated after activation of the number 1 fire bottle, the crew wait for 30 seconds before they discharge the second fire bottle. As the light remained on, the second fire bottle was discharged. That action meant that the entire fire extinguishing system for both engines was exhausted.

The operator advised that the engine fire detection loop was inspected after the incident and found to be fully serviceable. Temporary repairs were effected to the damaged wiring and the wires were subsequently replaced. Photographs of the damaged and disrupted wires, and the corresponding wire loom on another aircraft, are available on the ATSB website, www.atsb.gov.au, or from the Bureau on request. The continued fluctuation of the fire warning was due to damage and disruption of the wires to the engine fire detection loop, rather than a signal from the loop itself.

Individual wires to the engine fire warning loop were in a loom and the loom was positioned between the duct, pipes and the compressor outer case. Compliance with SB 75-0156, that removed the duct altogether, would still not remove the pipes that carry the high-pressure, high- temperature air through the area.

The Piper Chieftain was being flown as a single-pilot operation to conduct a scheduled passenger flight from Adelaide to Kingscote. The Chieftain was one of six aircraft being used by the operator on the route at the time. The other aircraft were involved in passenger charter operation. The six aircraft departed Adelaide at about the same time for Kingscote and the Chieftain was the first to approach the airfield.

The pilot reported that he decided, based on the Kingscote Automatic Weather Service reports and the weather forecast for the area, to descend to the sector's Lowest Safe Altitude. He intended to descend clear of cloud and approach the airfield to land on Runway 19 via a 5 NM straight-in visual approach. He had also planned to conduct a Sector A Global Positioning System (GPS) instrument arrival should the aircraft not break clear of cloud in sufficient time for a normal visual approach. Due to the weather conditions, the pilot decided to make the Sector A GPS arrival. The pilot reported that during the descent and approach, the pilots of the other aircraft were querying him about the cloud base and weather so that they could plan their arrivals.

The pilot reported that, during the GPS arrival, he had configured the aircraft in accordance with the operator's requirements and aircraft checklist, including lowering the landing gear. The aircraft broke clear of cloud at about 1,000 ft and 2 NM from the airfield. The pilot decided that the aircraft would require excessive manoeuvring to land directly from the approach and chose, instead, to conduct a left circling approach to Runway 19. He reported that he raised the landing gear to reduce the chance of large power changes that may have alarmed the passengers. He then flew the circling approach but did not lower the landing gear.

While the pilot was answering queries from other pilots about the weather conditions on the MBZ frequency, he was also listening to radio traffic on the ATC frequency. He also reported that there was light rain falling and running along the windscreen, reducing visibility and increasing his workload.

The pilot reported that late in the landing flare, he heard the landing gear warning horn and the scraping of the aircraft on the runway. He initiated a go around and advised the following aircraft of the event, however he did not receive a reply because the aircraft's VHF antennas had been damaged during the scrape on the runway. He then lowered the landing gear and landed without further incident on Runway 24 to help ensure separation from the following aircraft. The Chieftain sustained damage to both propellers, the VHF radio aerials on the underside of the aircraft fuselage and the inboard sections of the flaps.

The pilot was in a high workload situation, manoeuvring the aircraft in order to set it up for landing, and was probably distracted by the radio broadcasts and weather conditions at the time, which resulted in him forgetting to lower the landing gear before landing.