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A Boeing 747-48HE registered VH-OEB (OEB) was en-route from Los Angeles, USA to Auckland, New Zealand was maintaining flight level (FL) 330 as assigned by Tahiti air traffic control (ATC). A Boeing 747-4H6 registered VH-OED (OED) was en route from Auckland to Los Angeles and was also maintaining FL330. The crew of OEB reported that they observed, on their traffic alert and collision avoidance system (TCAS), another aircraft that was on a reciprocal track at the same level (OED). The crew of OEB turned their aircraft right 15 degrees and descended to FL325. The crew of OED later reported that they observed, on their TCAS, another aircraft that was on a reciprocal track at the same level (OEB), and climbed their aircraft to FL333. A third aircraft, a Boeing 747, was en-route from Los Angeles to Auckland at FL340. The crew of OED also observed an indication of that aircraft on their TCAS.

The vertical separation standard was 1,000 ft. The vertical distance between OED and OEB reduced to 800 ft, and to 700 ft between OED and the third aircraft. There was an infringement of separation standards.

The crews of OEB and OED were communicating with Tahiti ATC via both Controller-Pilot Data Link Communications (CPDLC) and high frequency (HF) radio. CPDLC was a 'means of communications between a controller and pilot using data link for [Air Traffic Control] communication' (ICAO Doc 4444 ATM/501 14.1.1). Messages were compiled and initiated either by the crew of the aircraft or by ATC and were, in this case, pre-formatted. The use of pre-formatted messages was 'intended to reduce the possibility of misinterpretation and ambiguity' (ICAO Doc 4444 ATM/501 14.3.4).

The crew of OEB had requested climb from FL320 to FL340 but that request was denied. About ten minutes later the crew of OED requested climb from FL330 to FL350. Tahiti ATC asked the crew of OED, via CPDLC, when they could reach FL350 and then denied the request for climb. The French Bureau d'Enquetes et d' Analyses pour la Securite de l'Aviation Civile (BEA) produced a report on the occurrence. The BEA reported that the crew of OED then contacted Tahiti ATC via HF radio and advised that they could reach FL350 by time 1140 universal coordinated time. The controller responded via HF radio and instructed the crew of OED to maintain FL330. The crew of OEB then requested, via CPDLC, climb to FL330. The CPDLC response provided to the crew of OEB was 'climb to and maintain FL330 due to traffic' even though FL330 was not available. The message was selected by the controller from the menu of pre-formatted messages available in the system.

The South Pacific Operations Manual (SPOM Part 5.5) stated that 'when a clearance request is denied, the controller shall use the element "UNABLE" in the uplink message'. The SPOM detailed the procedures and requirements applicable in the South Pacific flight information regions (FIRs) for CPDLC equipped aircraft and applied within the Tahiti FIR. The SPOM (Part 5.1) also stated that `generally, when a CPDLC aircraft is operating within a CPDLC FIR, CPDLC will be the primary means of communication'.

Subsequent to the occurrence OEB returned to FL320 and OED returned to FL330. The crews then reported to Tahiti ATC at those respective levels. The controller had not intended to assign FL330 to the crew of OEB and did not realise that they had been assigned FL330, or that they had climbed to FL330 and subsequently returned to FL320. When the crews reported at FL330 and FL320 respectively, after the occurrence, that information was consistent with the information the controller had recorded on the flight progress strips. The controller was not aware that there had been an infringement of separation standards.

The BEA reported that the controller believed there were possibly two reasons why a climb instruction had unintentionally been assigned to the crew of OEB:

1. In reply to the request by OEB for climb to FL330, the controller pre-selected the wrong pre-formatted CPDLC message and sent the message without checking it, or

2. The controller confused the two aircraft because of their similar callsigns.

The BEA reported that four controllers had been rostered for the period between 1900 hours and 0700 hours (Papeete local time) and were rostered to cover the aerodrome control position, the approach control position and the area control position. The event occurred at 0050 Papeete local time. The controller involved in the occurrence was alone in the tower at the time of the occurrence and was performing all three functions. That controller considered that the workload was high due to poor quality HF radio, increased coordination with other centres in relation to aircraft using 'flexible routes' and difficulty validating CPDLC messages with OED.

The controllers at Tahiti had been trained in France but that training had not included the use of CPDLC. Initial training on the use of CPDLC was incorporated into a one-week training program in Papeete that included CPDLC with other local training requirements. Ongoing CPDLC training was incorporated into on-the-job training which could take controllers around 57 weeks to complete. Controllers reported that the initial training was essential but they had not been exposed to the system sufficiently during training to master all aspects of the system.

The controller involved in the occurrence had been working Tahiti Oceanic Controlled Airspace for approximately three and a half years and was qualified on the three ATC positions being managed at the time of the occurrence.

A Boeing 737-376 aircraft was being taxied for a departure from runway 20 at Christchurch on a scheduled service to Auckland. The Automatic Terminal Information System indicated that the surface wind was from 200 degrees at 10-15 kts, the temperature was 6 degrees Celsius and the dewpoint was 5 degrees Celsius. The visibility was 10 km reducing to 3,000 metres in rain and drizzle. During the taxi, the crew observed that the weather was fine and that the taxiway was wet after recent rain.

The route to the threshold of runway 20 included a 1,600-metre straight section of the main taxiway which ran parallel to runway 02/20, and which had a slight downhill grade. Analysis of flight data recorder (FDR) data revealed that the aircraft was on that section of the main taxiway for 2.3 minutes and that the speed of the aircraft gradually increased from 11 kts until it reached a maximum of 29 kts. The operator's flight crew training manual (FCTM) contained the following information regarding taxi procedures:

"To the pilot, the airplane appears to be moving slower than it actually is due to the flight deck height above the ground. Consequently, the tendency is to taxi faster than desired.

"Taxi speed should be closely monitored during taxi out, particularly when the active runway is some distance from the departure gate.

"Avoid taxi speeds greater than 30 kt on long taxi routes.

"Allow for decreased braking effectiveness on slick surfaces."

Although it was not included in the most recent edition of the FCTM, previous text stated that when approaching a turn, the aircraft should be slowed to the appropriate speed for the conditions. On a dry surface, approximately 8 kt to 12 kt was recommended. The aircraft manufacturer inadvertently removed that maximum recommended cornering taxi speed, when the Boeing 737 FCTM was extensively rewritten.

At the end of the main taxiway, the route to the threshold of runway 20 required that the aircraft be steered to the left, through approximately 60 degrees, onto taxiway "alpha". The pilot in command began braking the aircraft before reaching that turn point, but the aircraft had only slowed to 25 kt when the turn was commenced.

During the turn the nosewheel started "scrubbing", indicating excessive steering angle and/or taxi speed for the surface condition. Lacking traction, the nosewheel moved sideways and directional control was lost. That was followed by loss of traction on the main gear. As the aircraft moved sideways, the right main gear slid off the paved surface and onto the grassed area adjacent to the taxiway. The aircraft came to a halt with the right main gear settled slightly in the soil.

A maintenance engineer attended the aircraft, assessed that there was no obvious damage and then marshalled the aircraft back onto the taxiway. The aircraft was then taxied back to the terminal where a detailed inspection of the landing gear, the brakes and the engines was carried out. That inspection did not reveal any damage and the aircraft was released back into service.

The technical crew of the Boeing 737 consisted of a pilot in command and a co-pilot; both of whom were very experienced on the aircraft type. The airline operator had only recently commenced operations from this airport; the crew's local experience was therefore limited. The Boeing 737 nose wheel steering system was only controllable from the left control seat. Therefore, the pilot in command always taxied the aircraft. Either pilot could have used the ground speed readout on the pilots' electronic attitude director indicator (EADI) to monitor the taxi speed. The airline's normal procedure was for the co-pilot to bring to the attention of the pilot in command, any unsafe speed. During the airline operator's subsequent investigation of the incident, both pilots expressed surprise at the high speed recorded by the FDR during the turn.

The taxiway in question was treated during February 2001 with a surface enrichment treatment that resulted in making the surface more slippery. A notice to airmen (Notam) was issued on 20 March 2001 that advised poor braking action was possible when the surface was wet. That Notam was subsequently cancelled on 27 May 2001, when it was considered that the taxiway surface had weathered sufficiently for friction levels to return to normal.

During August 2001, a different airline operator reported another two minor skid events at that same location. Neither of those incidents resulted in the aircraft leaving the sealed area. As a precautionary measure, the airport operator re-issued the Notam that warned of the possibility of poor braking action. The taxiway surface was subsequently roughened by water blasting. That action removed the smooth bitumen top layer and exposed the aggregate for a better friction surface.

Shortly after take-off, the crew of the Boeing 747 aircraft received a number four engine fire warning advisory. The crew actioned the non-normal checklist, secured the number four engine, and discharged two engine fire bottles before the fire indication extinguished. The crew then jettisoned fuel and completed an uneventful landing at the departure airport.

Initial inspection by operator maintenance personnel revealed evidence of charring and discolouration around the engine combustion area. Maintenance personnel removed the engine from the aircraft and the engine was then test run on an engine test cell. The test run revealed a fuel leak from the left and right fuel manifold connectors. The connectors were confirmed as being secured with safety lockwire, but subsequent torque checks revealed a lower value of torque than that required by the engine manufacturer's maintenance manual. The fuel manifold connectors were re-torqued and another test run completed. The resulting test run at high power settings revealed no discrepancy. A decision was made by the operator to have the engine overhauled before being put back into service.

During cruise, the Boeing 767 (B767) crew noticed that the fuel consumption was 230 kg per hour more than normal. After the cargo had been unloaded at the destination, the crew had the cargo re-weighed. The actual cargo weight was more than 3,400 kg greater than the weight stated on the manifest.

The operator reported that its investigation revealed that four pallets had been carried from Honolulu to Sydney and that all were heavier than the weights recorded on the manifest. The discrepancies were 2,277 kg, 887 kg, 220 kg, and 10 kg.

The two pallets with the greatest weight discrepancies had been transported from mainland USA in a freight aircraft operated by a US operator, and had been transferred at Honolulu to the B767 for onforwarding to Sydney. The weights stated on the pallet tags for the internal US leg were in pounds, but the B767 operator required the weights to be in kilograms. The agent who handled the freight for the US operator at Honolulu converted the weights from pounds to kilograms and pencilled in the converted weights on the deadload sheet for the Honolulu-to-Sydney flight.

When the agent who handled freight at Honolulu for the B767 operator received the pallet weights, she did not check the figures against the loadsheet issued by Load Control. Consequently, she did not realise that the weights stated on the loadsheet had already been converted to kilograms, and applied the conversion a second time. Also, as the agent for the US operator was confident that she had passed the correct weights to the B767 agent, she did not recheck to ensure that the B767 agent had received the correct weight information.

The 220 kg and 10 kg weight discrepancies affecting the other two pallets were probably the result of weighing or recording errors.

The B767 operator has since amended procedures for its agent at Honolulu. Under the new procedures, only the supervisor will carry out weight unit conversions and liaise with other operators' agents. This should minimise the risk of erroneous information being passed between agents and help to ensure that all required checks are carried out.

The B767 operator is monitoring the effectiveness of the new procedures.

A Boeing 747-400 was enroute from Los Angeles to Melbourne, cruising at FL320 in a south-westerly direction on airway R576 in the Oakland Flight Information Region. A McDonnell Douglas MD-11 departed Honolulu and was climbing in an easterly direction to FL350. The aircraft were on converging tracks.

The Honolulu Air Traffic Control Facility was responsible for providing positive separation between the aircraft. The radar separation standard was 5 NM lateral, or 1,000 ft vertical.

A controller subsequently recognised that, without intervention, the tracks of the two aircraft would come within 5 NM when less than the required vertical separation existed. The controller instructed the MD-11 crew to "...fly heading 020 ..." to change the aircraft's track. The crew responded by broadcasting "... Air 205, now right, right heading...". The controller did not clarify the required turn direction, and then instructed the B747 crew "...fly 180, vectors on traffic". Those instructions were passed 60 seconds and 49 seconds respectively, prior to the aircraft passing each other.

The B747 crew correctly read back the instruction to fly 180 degrees. Immediately after receiving that instruction, the crew received a traffic advisory alert from the aircraft's traffic alerting and collision avoidance system (TCAS). The alert was followed by a TCAS annunciation of a resolution advisory (RA) to descend. The crew advised air traffic control, "... heading 180 and TCAS descent", as they descended the aircraft, in accordance with standard operating procedures. The crew had the MD-11 in sight for the duration of the incident.

Analysis of the continuous data recording plot indicated that the MD-11 did not commence the left turn until after the aircraft had passed. There was no indication that the B747 turned onto a heading of 180 degrees. A minimum of 700 ft vertical separation existed when there was less than 5 NM between the aircraft. An infringement of separation standards had occurred.

The MD-11 crew apparently misunderstood the instruction to fly heading 020 as "right" heading 020 degrees. A right turn would have been confusing to the crew as the aircraft was tracking approximately 090 degrees. The direction of turn onto a new heading would normally be flown via the shortest arc distance; in this case, a turn onto a heading of 020 degrees would normally involve a left turn. Thirty-three seconds later the MD-11 crew sought confirmation that a left turn to heading 020 degrees was required.

The crew of the B747 may not have turned as instructed due to their response to the TCAS alert, and their visual observation of the conflicting traffic. It could not be established whether standard separation would have been achieved if one or both crews had turned their aircraft when instructed to do so.

There was no evidence that the controller applied the principle of separation assurance in the control of these aircraft. Rather, the controller had relied on aircraft performance to achieve separation.