Part 4: Visiting Australia & Pacific

Welcome again everybody on this round the globe trip flying the A330-200 aircraft and visiting the vast virtual world. We've already seen various landscapes and tackled many technical aspects of our flight, but there is still much more to see. Through lack of time, and so as to limiting the articles size, however, some scheduled destinations will unfortunately have to be cancelled in the future of this project. That should not garble the variety of regions to be visited and the global flight path introduced in Part 1 should remain almost the same. For example, stops in Bali, Indonesia and Adelaide, Australia were scheduled between Hong Kong and Sydney. We'll fly directly from Hong Kong to Sydney in the following leg, that will be in the meantime the first long range route of our trip.

Leg 17: Hong Kong, PR of China – Sydney, Australia

Though being also efficient on medium haul routes, the A330 wide body airliner is first of all a long range aircraft. We'll then fly a true long range sector now, with a 9 hours flight.

From HONG KONG INTL (HKG/VHHH) to SYDNEY/ KINGSFORD SMITH INTL (SYD/YSSY) Alternate YSCB CANBERRA VHHH SANDI1D SANDI DOVAR A583 ZAM A461 AMN R340 TASHA A464 OMUBI B587 NBR UH209 SCO H39 BOREE BOREE3 YSSY

Distance 4110 nm (7600 km) Cruise alt. FL 350 Cruise spd. Mach 0.82

The aircraft Zero Fuel Weight calculation was introduced in Part 2. Let's see now how to calculate the fuel quantity we need for this flight. To do this, we'll use the PSS fuel planner – a very easy to use software, a simplified tool designed for flight simulation only.

First, the route and alternate distances are provided by the MCDU, once a flight plan is completed or loaded:

The alternate distance is simply the distance between the destination and alternate airports (as shown by the blue dotted line on the ND), since we cannot specify any alternate flight plan with the MCDU modeled by PSS. We just read: route distance: 4109 nautical miles (rounded to 4110) and alternate: 127 miles (rounded to 130). Next, the APU Time is the estimated running time of the APU. Taxi Time should be far less than 20 minutes since we'll leave Hong Kong at dawn, before the rush hour, but the higher is the estimation, the higher will always be the safety margin. I always set the same 20 min Holding Time at the destination, but knowing that MSFS default ATC doesn't handle holdings... Route Contingency is a further additional enroute time which could occur because of nearby traffic avoidance or serious weather skirting. I always leave 0 there: offline flying doesn't provide much ATC or weather surprises... Additional fuel Reserves is though filled (5 tonnes set), as well as the scheduled cruise altitude. Setting the weather myself, and usually only surface winds, the 'Prevailing Winds' section is often ignored. The very last thing to do in real life, when this is perhaps the most important thing in flight planning, and in particular in the cross-Atlantic flights, where high altitude streams may have a dramatic impact on fuel burn. The aircraft Zero Fuel Weight, which was calculated in Part 2, is the last figure filled. Clicking 'Calculate Required Fuel' will compute the fuel quantity we need for the flight. The 61949 kg result will be rounded to 62000 kg or 62 tonnes. The PSS utility also computes Taxi, Takeoff and Landing weights (that will also be done by the MCDU) – if TOW or LW were above MTOW or MLW, they would be displayed in red. Because the PSS fuel utility is unfortunately independent of FS2004, we have to use the latter's default aircraft Fuel & Payload utility to fill the tanks.

Lower ECAM Fuel page just after engine start. The 62 tonnes of fuel could be filled in the wing tanks, the center tank is still remaining empty for this flight.

Taxiing out while Hong Kong is awaking – 6:10 local time.

Lining up runway 25R for an immediate takeoff

Prior to taking off for the 17th time, let's focus a while on the very special Airbus thrust levers and autothrust system.

Though looking like any other airliner controls, the Airbus thrust levers have an unique way to work. They move between different detents called gates. Four gates are available: IDLE (0), CL, FLX/MCT and TO/GA. The range between the IDLE and CL gate is called the manual range and works like on any other airliner, with engine thrust being proportional to lever angle. But as we will see, it may not be used during flight, and then only on the ground while taxiing the aircraft or monitoring the engines just before applying take off power. Maximum takeoff power is available through the TO/GA (Take off/Go around) gate, while the FLX/MCT gate will provide a reduced thrust takeoff. In that case, computed FLEX thrust will be based on an assumed temperature (always greater than the current ambient temperature) at which the needed (and then lower) takeoff thrust is calculated. Reduced thrust takeoffs will always be preferred for economical and structural reasons when runway length, TOW and airfield situation permit. Moving the levers to the FLX or TO/GA gate will automatically arm the autothrust (A/THR) system, and 'A/THR' will appear in blue on the PFD's Flight Mode Annunciations. With autothrust armed or active, the A/THR button on the FCU illuminates. At thrust reduction altitude, usually set to 1500 feet AGL, 'LVR CLB' will flash on the PFD and the levers are retarded to the CL gate. Autothrust then automatically comes active ('A/THR' turns to white on the PFD) and will automatically control thrust according to any thrust demand. This is why the levers are normally left in the CL gate throughout the whole flight. The levers will then NOT move as the thrust is automatically adjusted like on Boeing and other airliners. Through the CL gate, several autothrust modes are available following the flight phase and pilot's choice. The CLB mode (THR CLB will appear on the PFD) will be automatically used during climbs. CLB thrust will be equal to the climb thrust available at the current ambient conditions.

In the SPEED / MACH mode autothrust will control the engines to maintain selected or managed airspeed / mach number, following the altitude. The approach speeds can also be entirely managed through the SPEED mode and MCDU Approach Phase, we'll see that later in a following leg. Finally, the IDLE (THR IDLE) mode commands idle thrust and is used during Open descents. Just before touchdown, 10 feet above the runway, the cockpit voice will announce 'RETARD!', the levers must then be retarded to the IDLE gate. Doing this will automatically de-activate the autothrust system and provide idle engine rate. In the meantime, the A/THR button will go out. Moving the levers through the REV range will apply desired reverse thrust after landing. Thrust reverse is usually cancelled once the aircraft has decelerated to 60 knots.

Flight envelope protection is provided by Alpha floor autothrust mode, which will engage regardless of A/THR status and commands TO/GA thrust to aid recovering the aircraft from low speed and too high angle of attack conditions. Let's hope that we will not have the 'opportunity' to illustrate this in the following flights!

The thrust levers moved to the FLX/MCT gate for a reduced thrust takeoff.

On the PFD flight mode annunciations, 'MAN FLX 42' confirms that a FLEX take off is performed, with a 42°C assumed temperature. This temperature is also visible on the upper ECAM, where the computed FLEX thrust is also displayed with EPR = 1.69. We see that current EPR is 1.60 (for engine 1), and increasing to the 1.69 value commanded by the autothrust system, as shown by the blue command arcs. On the PFD speed tape, the arrow extends to the speed that will be attained in 10 seconds at present acceleration. A quick calculation shows that the latter is then equal to 2 m/s², meaning only 0.2 g. Not really the acceleration of the lifting off space shuttle anyway!

At thrust reduction altitude (which defaults to 1500 feet AGL), 'LVR CLB' is flashing and thrust levers must be retarded to the CL gate.

Thrust reduction altitude, as well as FLEX take off based temperature, are specified on the MCDU Take off performance page (see Leg 18).

Take off is completed. The PFD now shows the expected 'THR CLB' autothrust climb mode. Note that the A/THR annunciation in the autoflight status column is now white, meaning that autothrust is active. We've just passed the thrust reduction altitude: the engines EPR is now decreasing to the computed thrust limit value (EPR = 1.46) associated with the climb mode. Note that the blue 'CLB' above the thrust limit figure will not turn to 'CRZ' once reaching cruise altitude like on Boeing planes: the thrust limit is strictly linked to the thrust lever gate and will only appear if autothrust is active, that means with the levers moved to the CL, FLX or TO/GA gates.

Farewell to Hong Kong, left turn heading South on the SANDI 1D departure.

Still climbing and already cleared to our cruise altitude

The PFD shown when the managed cruise speed of Mach 0.82 is reached, with autothrust MACH mode active.

Sydney, as well as other destinations that will be found in this fourth part, was already visited in a first round the world trip in 2003. Since the aircraft and sceneries that were used in that time now seem to date back to the stone age, it should be interesting to come back to those places and see how they look today.

The ILS rwy 16R, the most usual approach to Kingsford Smith Int'l, will be performed. With its 13000 feet or 3962 m, runway 16R is one of the longest of the Southern hemisphere; it it said to be a 'diversion' landing facility for the above-mentioned space shuttle. The destination, which has a 2 hours time lag with Hong Kong, was reached just before sunset. Another thing to point out here, the equator was crossed for the first time in the trip.

Final for the 'City of Brides' @ 2500 feet

Cannot miss the typical shape of the Opera with this shot – now @ 2000 feet, 7 miles more to go

Close the the 'One hundred' radio altimeter call, note that autothrust is still active. 21240 Kg of remaining fuel, this is very comfortable.

Leg 18: Sydney, Australia – Agana, Guam (USA)

Already back for a while to the northern hemisphere with a second crossing of the equator, in this leg we'll focus on aircraft performance, controlled through the MCDU. The route to Guam, a Micronesian island belonging to the United States and located near the Mariana trough, will include Brisbane on Australia's Gold coast, then Port Moresby in Papua New Guinea. Quite a long leg again with a route distance of 2967 nautical miles or 5490 km.

Flight Plan

From SYDNEY/ KINGSFORD SMITH INTL (SYD/YSSY) to GUAM INTL (GUM/PGUM) Alternate PGSN SAIPAN INTL YSSY KAMPI1 KAMPI ENTRA H133 CAS H66 JCW H185 BN O26 CORAL O18 KELPI B220 PY B586 ZEEKE PGUM

Aircraft performance is an important step in the cockpit preparation process and will also be managed by the MCDU. The flight is divided into several phases with each phase having its own performance page: TAKE OFF, CLIMB (CLB), CRUISE (CRZ) , DESCENT (DES), APPROACH (APPR) and GO AROUND. Pressing the PERF key on MCDU calls up the performance page for the current flight phase. Next phases are also available using the 'NEXT PHASE' prompt, but phases already flown are not.

Though each flight phase can then be separately called up, aircraft global performance can be controlled through one single parameter called the cost index (CI). With an effective range of 0...100, cost index is used in economy speed computation. Lower values result in lower speeds and lower fuel consumption, higher values gives higher speeds and then increased fuel costs. MCDU's default cost index value is 50, I'll set 80 for this flight. The cost index can be specified on the INIT page, as well as on the CLB, CRZ and DES performance pages.

MCDU INIT page #1, where the Cost Index and Cruise flight level are entered. If temperature at the cruise flight level is not entered by the pilots, the FMS automatically calculates it using a standard atmosphere model.

In Part 2, we have seen how the Zero Fuel Weight and Block fuel were calculated and entered on the INIT page #2.

With the Cost Index, Cruise FL, ZFW, Block fuel and assumed temperature as main entries, the FMS will automatically compute engine thrust and flight envelope limits, economy speeds for all phases of flight and all the parameters required for automatic flight.

The TAKE OFF performance page is where the take off speeds, departure airport transition altitude, thrust reduction altitude, take off flaps setting and assumed temperature for FLEX take off are entered.

The take off speeds V1 (take off decision speed), VR (rotation speed) and V2 (takeoff target speed) are not automatically computed and must be entered by the pilots following performance tables. If not entered, a red 'SPD SEL' flag is displayed above the PFD speed scale.

Hopefully, PSS will kindly compute the T/O speeds here if the user clicks on the corresponding line select keys.

Now with the take off speeds filled (note that V2 is equal to VR with 161 kts or 186 mph or 298 km/h). Take off speeds will usually be  announced by the First Officer (pilot non-flying) during take off: 'V One' ... 'VR' or 'Rotate' ...'V Two'. For those like me who don't really remember what V1, VR and V2 speeds precisely mean, here are the definitions compiled after a quick internet search: V1 is then the Takeoff decision speed, the minimum speed where it will be possible to continue the takeoff after an engine failure. This is also the maximum speed at which it will be possible to bring the aircraft to a complete stop within the remaining runway length if takeoff is abandoned. Therefore, if one engine fails after V1, takeoff must be carried on and the problem treated once airborne as an inflight emergency.

VR is the Rotation speed where the pilot in command initiates rotation to lift off aircraft attitude and climb away with the scheduled takeoff performance.

VR must be greater of equal to V1.

V2 is the Takeoff safety and Initial climb speed, the minimum speed at which climb can be continued safely. With Airbus, V2 is also called the Take off target speed. An engine failure happening between V1 and V2 is then critical, but this is an extremely rare event, because of engine reliability and seeing that V1 and V2 are in most cases close to each other (for our current flight, V2 is even equal to VR). Anyway, aircraft crew are trained to face such extreme situations, easily modeled in (real) flight simulators.

The transition altitude is also automatically set according to the PSS database (we'll focus on transition altitudes and altimeters in a following article). The default values for thrust reduction, engine out acceleration altitudes and FLEX take off temperature are kept. The flaps setting defaults to position 1, and we'll also keep that setting. Airbus also takes off with flaps at position 2, when less runway length is available for example. Note that the Airbus flaps lever is not marked in degrees like on other airliners but with very simple numbered positions. Lever positions are UP, 1, 2, 3 or FULL. Position 1 will only command the slats extension in flight with indicated airspeed above 215 kts (CONF 1). On the ground (before take off), and in flight below 215 kts, slats and flaps will be extended at position 1 (CONF 1+F).

Flaps lever on the Pedestal (shown in position UP)

On the TAKE OFF page, the FMS also displays the computed minimum flap retraction speed (F), minimum slat retraction speed (S), and green dot speed (O), which is the maneuvering speed in clean configuration (with flaps and slats retracted). These speeds also appear on the PFD speed scale and will vary throughout the flight, since the aircraft weight and balance vary also.

Hmmm... interesting AI traffic miracle: the very high approaching 747 did succeed on its landing runway 16R a few seconds later!

... while this one left just before us as flight QF64. Note the CONFIG 1+F for flaps setting on upper ECAM.

The PFD shown during take off roll and approaching V1, as shown by the speed tape. The magenta triangle shows the managed reference target speed of V2 + 10, which is commanded by the Speed Reference System (SRS), a vertical guidance mode automatically engaged at take off ensuring optimum climb performance.The RWY lateral guidance mode is also automatically engaged, it keeps ground track equal to the departure runway heading.

After take off, approaching the green dot speed. Slats and flaps are retracted (flap lever in position UP). The new managed target speed is now 250 kts, we're already in the CLIMB phase.

Left, the PFD shown when reaching the cruise altitude of FL360. The target airspeed is then the managed cruise speed of Mach 0.82 displayed on the MCDU CRZ performance page. The red speed tape lower limit (called VMAX) is the aircraft maximum operating speed in clean configuration at this altitude.

Above Papua New Guinea jungle with Port Moresby behind us.

The MCDU Progress (PROG) page shown here allows selecting a new cruise altitude, monitors optimum and maximum cruise flight levels and checks navigation accuracy. We can see that the current optimum cruise flight level (FL402) is now 4000 feet or so higher than our current level. At this optimum altitude, aircraft performance will be better and fuel burn lower. Pilots may then ask ATC to obtain a higher level clearance in such case. This Progress page is then strictly different from Boeing and other airliners FMC's 'Progress' page.

The PFD and MCDU performance page shown during descent. Current managed target airspeed is 267 kts.

The APPROACH phase is activated by pressing LSK 6L. A confirmation will be asked by the MCDU that will then display the APPR performance page. Approach phase activation is made following the pilot's valuation, but will usually occur between 20 and 30 miles from the destination airport.

The APPR page is similar to the TAKE OFF page with the minimum flap retraction, slat retraction and green dot speeds displayed in the center column. Note that they are all different compared with the take off phase. A further speed, the minimum selectable speed (VLS), is displayed. A bit greater, the computed approach speed (VAPP) will be 146 knots for this landing. This is the speed that should be reached before touchdown. Destination airfield QNH, temperature, wind as well as Minimum Descent Altitude (or Decision Height) for the landing runway can be entered also, but I confess that I often leave these fields blank. Finally, the flaps setting for landing is also chosen here: Airbus A330 may land with flaps at CONFIG 3 of FULL. I usually leave the default FULL setting here also.

Flying with autothrust managed speed engaged, the APPROACH phase is a very 'smart' feature provided by Airbus. When APPR phase becomes active, the managed speed guidance will automatically decelerate the aircraft to maneuvering speed in current configuration until 10 feet above the ground. In that way, if APPR phase is activated in clean configuration, speed will decelerate to the green dot speed and managed target speed will continue decreasing once flaps are extended. When flaps are set to CONFIG 1, speed will slow to S speed ; once in CONFIG 2 speed will then slow to F speed. When the landing flap configuration is reached (CONFIG 3 or FULL), the speed will finally slow to the approach speed VAPP.

Since the autothrust and autopilot systems work indenpendently (we will focus on the autopilot system in the following leg), autothrust can then be used when manually flying, and, in particular, flying an approach. Keeping the managed speed active on the approach is up to my mind the easiest and safest way to fly, unless ATC demands lower or higher speeds (which never occurs though with FS2004's default ATC). In real life, however, Airbus pilots seem to prefer to de-activate the autothrust system if flying manually.

Guam approach to runway 06L begins at the ZEEKE IAF (last waypoint of the flight plan), from which a 7 DME arc from the Nimitz VOR/DME (located on runway axis some 3 miles from the airport) is followed at 2600 feet. The 7 DME arc was a bit 'skipped' on its end as I concluded with a visual approach.

The PFD captured during approach. We're flying with managed speed guidance, selected vertical and lateral guidance (ALT and HDG).

Flaps have just been set to CONF 2, speed is then decreasing to F speed. Still on the speed tape, the double orange stroke represents the maxiumum speed for the next (greater) flaps position (CONF 3 in this case). Above, the red tape now shows the forbidden speed range for current flap position.

Localizer capture – now flying manually, flaps FULL, autothrust still engaged and already at VAPP (146 kts or or 169 mph or 270 km/h).

The Pacific atmosphere is perfectly rendered by the add-on scenery...

... also with this second shot taken in the evening of our arrival, with an approaching thunderstorm.

Leg 19: Agana, Guam (USA) – Anchorage, Alaska, United States

Prior to visiting further Pacific islands, connecting two extreme locations is proposed on this 19th leg. Since it took place in February, the weather contrast will be even better, with bad winter conditions at the destination, requiring full autopilot approach capabilities. In the meantime, we'll go deeply into the Airbus autopilot main features here, making up the last technical matter that will be tackled in this fourth part.

The route is not a straight line across the Pacific, but it will first head towards Japan, then right to the Bering Sea, the flight path passing south of the Kamtchatka peninsula and north of the Aleutian Islands. Finally, the Alaska chain of mountains peaks will be seen emerging from the clouds during descent. Another thing to say, the international date line is crossed in this flight. Flying eastbound, the arrival date is the preceding day of the departure one!

Flight Plan

From GUAM INTL (GUM/PGUM) to ANCHORAGE INTL (ANC/PANC) Alternate PAFA FAIRBANKS INTL PGUM HAMAL B586 OTTER KAGIS A590 AMOTT AMOTT5 PANC

Distance 4369 nm (8082 km) Cruise alt. FL 340 Cruise spd. Mach 0.82 Flight time 9:20

The Airbus Autoflight system is a part of the Flight Management System (FMS) and controls Autopilot (AP), Flight Director (FD) and Autothrust (A/THR) systems. The Autothrust system was introduced in Leg 17 and we'll not go deeply into the Flight Director here, let's just say that the pilot can manually fly the aircraft following the Flight Director commands, which tell through the PFD what the Autopilot would do if it was controlling. As said above, Autopilot and Autothrust systems work independently and A/THR can then be used when manually flying. On Airbus aircraft, Autopilot can be engaged immediately after take off.

The Autoflight system operation modes are selected using the Flight Control Unit (FCU), centrally located on the glareshield. As we'll see it is very different from the Boeing Mode Control Panel (MCP) and provides the typical and unique Airbus autoflight controls. The autoflight operation modes are displayed as Flight Mode Annunciations (FMA) on the PFD.

The FCU seen before startup, with the first altitude cleared by ATC selected.

The FCU provides four knobs that can be rotated, pushed and pulled (in this PC flight simulation, these functions are available through the mouse buttons).

Left is the knob which controls airspeed (SPD) through the A/THR system. Second to the left (above the 'LOC' button) is the heading (HDG) knob which controls lateral guidance. The two knobs on the right provide vertical guidance, with the altitude (ALT) sand vertical speed (V/S) knob.

If a knob is pulled, the pilot takes direct control of this function, and the selected value in corresponding FCU window becomes a target. This is called the selected guidance. Turning the knob will modify the target value. In that way, pulling the airspeed knob in flight will capture aircraft current airspeed, and selecting another speed by turning the knob will make A/THR reach that speed. Regardless of selected speed, A/THR will however not exceed minimum or maximum aircraft speed limit for current configuration. With selected speed guidance, the target speed will be represented by a cyan triangle on the PFD speed tape. This is selected speed guidance.

In the same way, pulling the lateral guidance knob will engage HDG mode and capture aircraft current heading, and turning the knob will select a new heading, the aircraft will turn towards the new target in the direction of knob turn. This is selected lateral guidance.

If altitude selected in ALT window is above current aircraft altitude, pulling the altitude knob will engage the Open Climb (OP CLB) selected vertical guidance. In this mode, the aircraft will climb directly to selected altitude, and no flight plan constraints will be honored. The target airspeed will be maintained by controlling aircraft pitch and autothrust will maintain climb thrust (THR CLB mode). Now, if altitude selected in ALT window is below current altitude, pulling the altitude knob will engage Open Descent (OP DES) mode, in which the aircraft will descent directly to selected altitude. The target airspeed will also be maintained by controlling aircraft pitch, while idle thrust (THR IDLE mode) will be commanded. When approaching selected altitude, the aircraft will level off and autopilot vertical guidance will switch to ALT mode.

If a knob is pushed, the control is given to the Flight Management System which can guide the aircraft according to all its computations and the information provided by the pilots through the MCDU, including the route, aircraft Zero Fuel Weight and performance options, as we've seen in the previous legs and articles. This is the managed guidance. If a function is in managed guidance, a white dot appears in the corresponding window on the FCU, and the window becomes dashed. The altitude window, however, is never dashed, and the vertical speed knob (see below) doesn't provide a managed guidance function.

Pushing the SPD knob will activate managed speed guidance. Managed speed guidance will make autothrust control the FMS computed speed following current flight phase, and will comply with speed constraints and limits if the flight plan constraints are honored. The managed target airspeed will be represented by a magenta triangle on the PFD, if the target is inside the displayed scale. Otherwise, the triangle is replaced by a magenta numeric readout above or below the scale.

Pushing the HDG knob will provide managed lateral guidance (NAV mode). With this mode engaged, the aircraft will follow the flight plan entered in the MCDU. This is then analog to Boeing's 'LNAV' function. NAV mode will be automatically armed on the ground after a route is entered in the MCDU, and will then automatically engage after take off once autopilot is engaged. The NAV mode is then the default lateral guidance mode once airborne if a flightplan is entered in the MCDU.

The managed vertical guidance, engaged by pushing the ALT selector knob, will provide automatic vertical control of the aircraft, following the vertical profile associated with the flight plan. CLB and DES managed vertical guidance modes will be used during climb and descent, with flightplan constraints observed. If the aircraft levels off at an altitude constraint, the ALT CST mode will engage. When reaching the cruise altitude, the ALT CRZ mode engages.

Airbus managed vertical guidance can be compared to Boeing's autopilot 'VNAV' function. The 'VNAV' function, however, handles both FMC vertical and speed guidance on a Boeing airliner, when, as we've seen, speed and vertical guidances work independently with Airbus.

Lateral and vertical guidances, though being engaged by distinct knobs, are not strictly independent. In that way, managed vertical guidance requires also managed lateral guidance to be engaged. Wishing a managed descent will then not work if flying with the HDG lateral  guidance mode, but with the NAV mode well.

The vertical speed knob, for its part, works a bit differently. Though being also pushed or pulled, it doesn't provide any managed guidance. The V/S selected vertical guidance mode can be engaged in two ways, with autothrust maintaining target airspeed. Pulling the V/S knob will capture and maintain aircraft current vertical speed, while pushing the knob will engage V/S mode with zero vertical speed, which results in aircraft levelling off (see the 'PUSH TO LEVEL OFF' notice close to the knob). The selected vertical speed can be changed by turning the selector knob, and the V/S window remains dashed unless V/S mode is engaged.

The Airbus has actually two identical autopilots (AP1 and AP2), which are engaged or disengaged by pressing the corresponding button on the FCU. The two autopilots cannot be engaged simultaneously: selecting AP2 will automatically disengage AP1, and vice versa. During ILS approaches, however, both autopilots can be engaged for enhanced accuracy, as we'll see and the end of this flight.

The following flight will then illustrate most of the autopilot functions that were introduced here. Most of flight phases will be flown with managed lateral and vertical guidance, while selected lateral and vertical guidance will be used for the initial approach. With bad weather conditions and poor visibility at the destination, both autopilots will be engaged on the ILS final approach. Managed speed guidance will be used throughout the whole flight.

FCU and PFD Flight Mode Annunciations seen after takeoff. AP1 has just been engaged, and Open Climb selected vertical guidance mode has been engaged by pulling the ALT selector knob.The NAV managed lateral guidance mode, which was automatically armed before takeoff, is now automatically engaged. On the PFD, active vertical and lateral guidance modes are shown in green, while armed modes are displayed in blue. This is now the case of the ALT mode, to which the OP CLB mode will switch when reaching selected altitude. With FLEX power set, the autothrust system is armed and will become active once we reach the thrust reduction altitude and retard the thrust levers to the CL gate, as we've explained in Leg 17.

Levelling off at cruise altitude of 34000 feet, with the FMA showing MACH │ ALT CRZ │ NAV modes.

The Nav Display shown when approaching the Top of Descent point. The magenta dot close to AMOTT represents a speed change. In this case, this is the point in the computed descent profile associated with the flight plan, where the altitude will go below 10 000 feet and speed will then be restricted to 250 kts IAS.

Contrary in the Boeing's VNAV vertical guidance, the descent will not start automatically from cruise altitude when reaching the Top of descent (T/D) point computed by the FMS. Airbus pilots must then, once reaching T/D, select a lower altitude in the FCU altitude window and push the altitude selector knob if wishing a managed descent. This is what we'll do here.

Left, the PFD shown just when the managed DES mode is engaged (when a new mode is engaged, it is boxed in white for a few seconds). The 'MORE DRAG' message means that managed guidance is currently unable to keep target speed. Partially extending the speedbrakes would solve the problem, but the autopilot will usually do it well on its own: right, the airspeed is now just in the middle of the managed descent speed range represented by the two brackets. Close to the altitude tape is the Descent Path Indicator that shows the aircraft's vertical deviation to the computed descent path and is working just like a glideslope: we were too high on the left shot, just on the descent path on the right one.

At FL250 (descending to FL180), 113 miles from destination, with northern lights in the sky!

At 56 miles from destination, 11 000 feet, still descending and about to penetrate the cloud layer

The autopilot LOC (for Localizer) and G/S (for Glideslope) modes can be used during ILS approaches and will allow the aircraft to carry on the approach in poor visibility conditions. Pressing the LOC button on the FCU will arm the LOC mode and track the localizer signal. Pressing the APPR button will arm both LOC and G/S modes. LOC and G/S modes can only be armed when an ILS frequency is tuned. After localizer and glideslope interception, LOC and G/S modes become active. As a quick reminder, the ILS (Instrument Landing System) is made up of two signals, the Localizer and the Glideslope (or Glider Path), whom imaginary planes intersection provides the ideal descent path towards the landing runway. ILS deviation (and possible additional distance information provided by a Distance Measuring Equipment or DME) are precisely displayed on the Nav Display with ROSE ILS mode set. Localizer and glideslope deviations are also available on the PFD.

LOC and G/S modes can then be armed before ILS interception, but ILS capture will be made with autopilot selected vertical (V/S) and lateral (HDG) guidance here. Once the localizer is intercepted, LOC mode will be engaged ; and once the glideslope is intercepted, APPR button will finally be pressed, engaging both LOC and G/S modes.

Initial approach, descending to the beginning of final approach altitude of 1600 feet using the V/S selected vertical guidance mode (selected vertical speed is 1000 feet/min). We're turning left, trying to capture the localizer with current selected heading of 10°, symbolized by a blue triangle on the ND's horizontal situation indicator. The blue and green arrows added on the ND respectively show the localizer and glideslope deviations, the ND being set to the ILS mode selected on the EFIS panel.

Beginning of final approach: the glideslope is intercepted and APPR button is pressed, automatically turning off the previously pressed LOC one (not shown here). Both LOC and G/S modes are now active, and the second autopilot can be and is then engaged. 'AP1+2' appears on the PFD Flight ModeAnnunciations fifth column showing autoflight status. The fourth column shows the approach capabilities: we're tuned to an ILS which supports up to the CAT IIIC instrument approach that has no decision height and no runway visual range limitations. We are however flying a common ILS approach now (ILS Rwy 06R) with a 200 feet decision height, set through the MCDU and also displayed on the PFD. The Decision Height (DH) is the height (above ground level or AGL and measured by the radar altimeter) at which, during an ILS approach, decision must be made to continue the approach or execute a missed approach. If the required visual reference is not established at the decision height, a missed approach must be initiated. When reaching the decision height, the cockpit synthesized voice will announce 'MINIMUM' in addition to the altitude callouts made below 400 feet.

The Airbus A330 autopilot is capable of performing a full automatic landing if LOC and G/S modes are still engaged at 400 feet above the ground. These modes would then switch to the LAND mode which provides both lateral and vertical guidance, maintaining localizer and glideslope. The FLARE (reducing vertical speed prior to touchdown) and ROLLOUT (at touchdown) modes would follow, and the 'only' thing that the pilots would have to do is to retard the thrust levers 10 feet above the runway and execute braking action once on the ground. In real life, full automatic landings in very low visibility conditions require specially equipped aircraft and appropriately qualified crew.

I've tried to simulate such automatic landings several times, but the result was each time a rather 'heavy' touchdown, meaning that all the passengers were brought home safe and sound but also that the undercarriage would have sent an incicive complaint letter to Horizon Dreams Airlines later if it had been able to.

This is why a manual landing is performed here. With the poor, but not dreadful visibility conditions on arrival, the automatic approach will lead us to short final. At about 350 feet QNH or a bit more than 200 feet AGL – which is the Decision Height – both autopilots are disengaged, but autothrust managed speed remains active as usual.

At 500 feet, approach lights in sight, both autopilots still engaged. The poor visibility is mainly due to heavy snowfall.

Short final, close to the decision height. Autopilot LAND mode engaged, but both autopilots were disengaged less than one second later to conclude with a manual landing.

On the PFD, the red tape against the altitude scale represents the ground, with ground level based on radar altimeter, while the upper limit of the orange tape against the speed scale is the speed at which Alpha floor flight envelope protection mode would become active, just below the minimum selectable speed (VLS).

Safely down. Hope that the passengers have brought something warm to put on in their suitcases.

Anchorage is a frequent technical stop for Asian carriers operating intercontinental routes across the Pacific.

These two 747-400 are taxiing out for departure. The newest generation ultra-long range aircraft such as the

Airbus A340-500 or Boeing 777-200LR do not need to refuel here any more.

Leg 20: Anchorage, Alaska, United States – Honolulu, Hawaii, United States

Back to the Pacific islands now, the two remaining legs of this 4th part will visit the 'hot spot' volcanic archipelagos of Hawaii and French Polynesia.

The route between Anchorage and Honolulu will not be a straight line across the Pacific, but a path first huging the Canadian and American western coasts, some 160 nautical miles away (B453 airway), then finally heading towards Hawaii (A332 airway) after a 90 degrees right turn abeam of the state of Oregon. A twin-engined flight from North America to Hawaii needs an ETOPS–180 minutes approval, meaning that the diversion time is extended to 3 hours in case one engine fails during flight. We will go deeply into the ETOPS (Extended Twin Engine Operations) in the last part of Around the world 2006-2007.

Flight Plan

From ANCHORAGE INTL (ANC/PANC) to HONOLULU INTL (HNL/PHNL) Alternate PHTO HILO INTL PANC ANC3 NOWEL J805 MDO B453 KYLLE HEMLO A332 ABSOL R463 MAGGI CHAIN SAKKI PHNL

Distance 3465 nm (6410 km) Cruise alt. FL 390 Cruise spd. Mach 0.82 Flight time 7:45

As number one for takeoff, a classic Boeing 737-200 powered by first generation twin spool turbojets - a rather rare sight today.

Horizon 2006 heavy, taxi into position and hold. Lining up runway 06L.

Airborne in a nice winter morning, with Asian MD-11 and 747-400 in the background.

Right turn on the ANC3 departure, which occurs once being 9 miles away from Anchorage VOR.

Deep blue...

Honolulu approach will be the LDA/DME Rwy 26L, a 45° offset approach procedure beginning at SAKKI IAF and concluding with a visual landing. The localizer path comes rather close to the Honolulu skyline, just before the final left turn.

Federal Aviation Administration approach chart (public domain). Reduced for illustrative purposes – DO NOT USE FOR REAL WORLD NAVIGATION

On the localizer track, some 10 miles away (left) and beginning the final turn (right).

Final turn almost completed: note the ND course, still set to the localizer course, making almost a 45° angle with current heading.

Leg 21: Honolulu, Hawaii, United States – Papeete, Tahiti, French Polynesia

Further palm trees for this last leg, Tahiti is the biggest island of French Polynesia, as well as the 'youngest' one in the Society Islands archipelago, stretching from West to East in the very middle of the South Pacific. The flight path look is this time nothing else than a straight line, crossing the Equator for the third time in our trip. The main special feature of this flight is the distance of the alternate airport, Rarotonga Intl in the Cook islands, located 617 nautical miles (1140 km) from the destination. Almost each populated island in the Pacific has its own airfield, but very few of them can actually accomodate widebody airliners. The alternate distance, which is filled in the fuel planner as we've seen in Leg 17, will then mean a great additional fuel load.

Flight Plan

From HONOLULU INTL (HNL/PHNL) to TAHITI–FAAA (PPT/NTAA) Alternate NCRG RAROTONGA INTL PHNL PALAY2 PALAY V7 MOANA V1-7 IAI B595 TIAMA ARONA ARONA1M NTAA

Distance 2430 nm (4495 km) Flight time 5:30

Taxiing to runway 26R holding point while a colourful MD-82 is waiting for its takeoff clearance.

Nice CB cloud formation seen during descent

Short final, flying the VOR Rwy 22 approach.

Landing runway 22 at Faaa airport doesn't provide any ILS but has one advantage: the available length between runway treshold and the only taxiway connecting to the terminal is longer, then backtracking the runway is not necessary after a reasonable landing run. Still interesting clouds effects in the sky...

We've now reached the end of Part 4 and are already almost half the way of our trip around the world. Part 5, which should be shorter than this one, will visit North America with three selected destinations in the United States.

Cédric De Keyser
Brussels, Belgium
cdk@ngi.be