Part 5: Visiting North America

Hi everyone, and for those among you who are joining us for the first time, we're flying the A330-200 aircraft (Project Open Sky model and PSS Airbus Pro 2D panel & avionics), following an easternly direction across the globe and visiting various FS2004 sceneries - mainly provided as add-ons -  as well as focusing on some technical aspects of our flight. We've already visited Europe, Middle East, Asia, Australia and Pacific and are now almost half the way of the entire trip, at the antipodes of Brussels, Belgium, where the journey began and will finish. Tahiti in French Polynesia was the last Pacific destination visited, and this is where our aircraft is awaiting its next sector. In this part, three destinations in North America will be visited, and they are all located in the United States. Further technical topics will also be introduced, mainly in the first leg of this article.

So ladies and gentlemen, fasten your virtual seatbelts once again and enjoy your virtual flights!

Leg 22: Papeete, Tahiti, French Polynesia - Los Angeles, California, United States

This route is very frequent with commercial carriers linking French Polynesia with the mother country: aircraft make a technical stop in Los Angeles before going further to Paris, with a total flight time of almost 20 hours. The Tahiti - Los Angeles route doesn't provide many diversion airports along the way : once leaving French Polynesia, no more dry land is to be seen until hitting the American coast. This is why this route will usually be operated by four-engined aircraft such as A340 or B747 in the real world, while twin-engined aircraft like the one we are flying will need a special ETOPS (Extended Twin engine Operations) approval to operate across the Pacific. This PPT-LAX flight, as well as the Anchorage-Honolulu leg that took place in Part 4, can be made with an ETOPS-180 minutes approval. We'll go deeply into the extended twin operations in the last part of Around the world 2006-2007, when we'll cross the Atlantic ocean.

Our destination, Los Angeles Intl, is one of the busiest airports in the world and the third in the United States (considering the yearly number of passengers) after Chicago-O'Hare and Atlanta. That will be a good opportunity to introduce the TCAS system and see how it overall works. But before this, we'll first focus on the altimeter instrument and altimeter setting, another important point for any flying machine. Finally, headwind conditions set above the North-eastern Pacific in the last part of the flight will give us the right time to examine the aircraft speeds and see the difference between indicated airspeed, true airspeed and ground speed, and how they are measured and calculated by the aircraft systems. In the meantime, the IRS navigation system will be introduced. A few mechanics laws and some mathematical formulas will be needed then, making this article looking more serious than it is actually.

Flight Plan

From TAHITI-FAAA (PPT/NTAA) to LOS ANGELES INTL (LAX/KLAX)  Alternate KSFO SAN FRANCISCO INTL NTAA04 EMIRI1C EMIRI ORARE G575 FICKY FICKY.LEENA3 KLAX25L

Distance 3637 nm (6728 km) Flight time 7:50

Ready for pushback on Faaa airport main apron. Another good airport scenery add-on, which made me remember the breathtaking and ahead of its time 'Tahiti Scenery' released by Wilco Publishing ten years ago, for Flight Simulator 98.

Prior to contacting the tower to obtain their IFR clearance, pilots usually listen to the ATIS provided for the departure airport. ATIS (Automatic Terminal Information Service) is a continuous broadcast of recorded information including Greenwich Mean Time (GMT, also known as 'Zulu'), weather, active runway(s), available approaches and other NOTAMs (Notices to airmen). The ATIS message is updated where any significant change occurs in the information, such as weather and active runway(s). A letter designation at the beginning of the message progresses down the alphabet each time the message is updated and starts at 'Alpha' each day.

Here's what Tahiti ATIS said:

TAHITI AIRPORT INFORMATION QUEBEC - 17:00 ZULU - WIND: 216 AT 5 - VISIBILITY: GREATER THAN 20 MILES - SKY CONDITIONS: FEW CLOUDS AT 4300' - TEMPERATURE 26 - DEW POINT 25 - ALTIMETER 29.21 - ILS RUNWAY 4 IN USE - LANDING AND DEPARTING RUNWAY 4 - VFR AIRCRAFT SAY DIRECTION OF FLIGHT - ALL AIRCRAFT READ BACK HOLD SHORT INSTRUCTIONS - INFORM CONTROL ON INITIAL CONTACT YOU HAVE QUEBEC

The interesting piece of information on which we'll focus now is the altimeter setting.

Since the birth of aviation, the altimeter principle of operation has remained the same (this is also valid for the other fundamental instruments, including the artificial horizon, anemometer, variometer and magnetic compass). Since the atmospheric pressure decreases with altitude, this physical quantity has been chosen to calculate aircraft altitude. The altimeter is then basically a barometer which measures a pressure called the static pressure. The static pressure (noted Ps) is the air pressure that is independent of aircraft airspeed and must then be measured with a nil airflow speed. This is schematically done by the following very simple device:

STATIC PRESSURE PORT

In fact, the altimeter will give the difference (or the distance) between this measured pressure (Ps) and a reference pressure (noted PO), which is chosen by the pilot using an adjustment knob. The altimeter will 'calculate' the altitude difference corresponding to the (PO - Ps) value, using the standard atmosphere laws. The standard atmosphere model provides pressure and temperature as mathematical functions of the altitude, with pressure and temperature at sea level respectively assigned to 1013.25 hPa (hecto Pascals) or 29.92 in Hg (inches of mercury) and +15°C. The classic analog altimeter, nowadays often only used as a standby instrument, has a complex mechanical system transmitting the pressure difference to the needles moving around an altitude scale graduated in feet.

The reference pressure choice is nothing else than the altimeter setting. Increasing the reference pressure will increase indicated altitude, and inversely. We do not need to be a weather expert to know that the atmospheric pressure often vary throughout the day and from one day to another. In that way, if the pilot wants to know his height above ground level, PO must be set to the current atmospheric pressure existing on the ground. This pressure is called QFE. To know his altitude above sea level, PO must be set to the atmospheric pressure existing at sea level (zero altitude). This pressure is called QNH. QNH is the reference pressure used around airports and is provided by the airport meteorological service. Pilots are informed of the current QNH by ATC as well as ATIS.

In our case, is we come back to the ATIS message, the QNH is 29.21 in Hg. This is what we set in the altimeter setting window located on the EFIS panel. In the meantime, the altimeter setting will also appear on the PFD.

As we see, the altimeter setting knob also provides the hPa unit, preferably used by the metric system. This 29.21 value (which is equivalent to 989 hPa) is actually very low and is associated with the 'Building storms' weather theme that was chosen for the first part of our flight.

If the altimeter is set to the local pressure conditions while approaching or leaving one airport, it would be hazardous for ATC and airline pilots to update the altimeter setting following the various weather conditions encountered all along the flight. This is why, above a given altitude called the transition altitude, every aircraft must use the same altimeter setting, called the standard (STD) setting with reference pressure equal to 29.92 in Hg. Above the transition altitude, which vary from one country to another, but it is most of cases far below the cruise altitude, aircraft altitudes are renamed as flight levels (FL), in hundreds of feet. Flying at FL350 will mean at 35000 feet with standard altimeter setting. ATC will distribute aircraft among various flight levels and then maintain vertical separation among them. The usual vertical separation is fixed to 2000 feet between FL290 to FL410, but can be reduced to 1000 feet in RVSM (Reduced Vertical Separation Minima) airspace, therefore increasing the number of aircraft that can fly safely in a particular volume of the sky. RVSM is currently implemented in much of Europe, North Africa, Southeast Asia and North America, as well as over the North Atlantic and Pacific oceans. Specially certified altimeters and autopilots are required to fly in RVSM airspace, this is anyway the case for most of airliners.

During climb, once leaving the transition altitude, which is 9000 feet in Tahiti controlled airspace, the QNH setting will be boxed and will flash on the PFD, advising the pilot to pull the altimeter setting knob for standard reference. 'STD' will then appear in the altimeter setting window as well as on the PFD. Once flying below the transition altitude during descent (that will be 18000 feet for the U.S.), 'STD' will flash on the PFD and pushing the knob will revert to QNH. Turning the knob will select the new QNH setting told by ATC.

Passing the transition altitude (9000') during climb: pushing the altimeter setting knob for standard reference (29.92 in Hg)

The variometer (which measures vertical speed) principle of operation is similar to the altimeter's, but without reference pressure needed. In this case, the variometer measures the static pressure variation by unit of time (PS2 - Ps1) / (t2 - t1) and converts it to vertical speed in feets per minute.

Rangiora atoll, located 192 nautical miles North of Tahiti, stretching on 70 km (43 miles) from West to East, is the biggest atoll in Polynesia, and the second by size in the world. Such islands, which were once active volcanoes, are now threatened by global sea level rise.

This outside view reveals one of the two passes of Rangiora, where the lagoon is connected to the Pacific waters.

Rangiora VOR/DME is the last ground navaid that the flight path crosses before hitting the US coast, some 3450 nautical miles away. To perform accurate navigation on such oceanic flights, aircraft can only rely on their own navigation equipment. In the meantime, the aircraft goes beyond radar coverage for Air Traffic Control and must then, like in the cross-Atlantic operations, make regular position reports to the appropriate oceanic center located on dry land. In our case, that would be Tahiti Oceanic in the first part of the flight, up to N03° 30' latitude (just above the Equator), then Oakland (San Francisco) Oceanic for the remaining leg. Flying offline with FS2004 default ATC doesn't provide any oceanic operations modeling, so we won't go further into these special procedures here.

The aircraft navigation system, for its part, is for sure modeled. Though the GPS satellite positioning system is now more and more used worldwide, the IRS is still the main navigation system used by airliners, since it is totally independent of the outside world. The IRS (Inertial Reference System) purpose is to provide the necessary information needed for navigation, including aircraft position (latitude, longitude), ground speed, true heading, ground track and drift angle. The IRS is a dead reckoning system, where estimating of current position is based upon a previously determined position and measured velocity or acceleration, time, heading and the effect of wind, as we'll see below. There are usually three IRS systems installed on airliners, so that if one of them is 'derivating', its influence on the mixed IRS position will be lowered.

In each IRS system there is an inertia station which consists of a platform and is horizontally maintained thanks to three gyroscopes Gx, Gy, Gz. Gyroscopes, which are basically made up of a high speed rotating disc, have the property to keep the 'memory' of an initial direction, whatever the external stresses to which they are subjected. This is why the artificial horizon also works with a gyroscope, the initial direction being the earth's vertical in this case. But let's close the brackets and come back to the point. To go further we have to introduce the aircraft trihedron which is a 3-D referential attached to the aircraft, with the roll axis (X), pitch axis (Y) and yaw axis (Z).

On the inertia station platform two accelerometers are installed. The first one measures the aircraft acceleration on the aircraft X axis (Ax) and the second one on the Y axis (Ay). Since the platform is horizontal, the accelerations are measured in the horizontal plane. Fundamentals of analytic mechanics tell us that

meaning that if we integrate two times the aircraft accelerations following X and Y we will calculate the aircraft's new position in the horizontal plane. Meanwhile, the aircraft is moving on the Earth's surface, which is a sphere and not a plane. The IRS' navigation calculator must then convert the measured accelerations in the aircraft's trihedron to the Earth's trihedron. The latter is defined thanks to the Earth's center, the True North, the local vertical (connecting the plane with Earth's center) and the local horizontal (which is perpendicular to the local vertical). The calculator will perform orthodromic navigation, meaning that the shortest or great circle routes will be computed, and send its signals to the Flight Management System.

The aircraft's initial position (POS init) must be known by the calculator: this is why the IRS alignment is made before the flight. Pilots will enter the aircraft's parking position on the MCDU INIT Page according to the airport diagram. As we've seen in Part 2, the initial position latitude and longitude fields are kindly automatically filled by PSS. The initial conditions needed to solve the kinematic equations also include the initial speed of the aircraft, which is of course zero.

Nowadays, IRS may also be (re-)aligned inflight, thanks to the 'GPS Align in Motion' system, using GPS real time information and providing as much accuracy as classic stationary align procedures. The IRS navigation accuracy currently provides a less than 2 nautical miles error for a one hour flight time.

Left: to align the IRS before the flight, virtual pilots just have to press LSK 3R since the parking position (LAT, LONG) of the aircraft is automatically filled.

Right: the POSITION MONITOR Page seen during flight, where the average position calculated by the 3 IRS is displayed on the MIX IRS row. In real life, pilots will refer to this page to make position reports during oceanic flights.

The IRS calculates the ground speed (GS) by integrating measured accelerations. The result is a vector (defined by a magnitude and a direction) whom magnitude will be displayed on the Nav Display (for example, 500 kts). Ground speed is the speed of the aircraft relative to the ground.

True airspeed (TAS) is the speed of the aircraft relative to the air in which it flies, the physical speed of the aircraft relative to the moving air mass. It is sometimes named aircraft velocity. In still air conditions (zero wind) and horizontal flight, it is equal to the ground speed. During windy conditions, which occur in most of times, a headwind subtracts from the ground speed (TAS > GS), while a tailwind makes ground speed greater: GS > TAS. Winds blowing from other angles to the aircraft heading will have a headwind or tailwind component, as well as a crosswind component, perpendicular to the aircraft. Headwind is favourable in takeoff and landing but occurring during cruise, it will increase flight time as well as fuel burn.

Ground speed and true airspeed vectors are linked by the following relationship:

where is the wind speed vector. Considering those vectors as forces, the ground speed is then the resultant of aircraft velocity and wind force.

In this diagram, known as the wind triangle, the wind is blowing from the sector ahead of the aircraft, there is then a headwind component that makes ground speed lower than true airspeed. The diagram considers the horizontal flight condition (parallel to the ground) and neglects updrafts and downdrafts winds, which occur perpendicular to the ground.

True airspeed direction, which is the true heading, is also calculated by the IRS thanks to the gyroscopes of the inertia station, which can detect the yaw angular variations. True airspeed magnitude computation is a direct application of aerodynamics' laws.

First, the Mach number is calculated. Mach number (M) is defined as the ratio between the true airspeed and the speed of sound.

We just have:

where 'a' is the speed of sound in the air around the aircraft.

It has been demonstrated that M is a function of the differential pressure and the static pressure:

The differential pressure (PT - PS) is the difference between the total pressure and the static pressure. We've already introduced the static pressure (PS) which is independent of aircraft speed. The total pressure (PT), also known as impact pressure, is the air pressure measured in the direction of airflow, and therefore depends on aircraft true airspeed. Total pressure is measured by the Pitot tube device, which is mounted facing forward.

If we come back to the Mach number definition, we see that the true airspeed is simply obtained following TAS = M x a, meaning that if we know the speed of sound at current altitude, the problem is solved. Mother Aerodynamics has also demonstrated that the speed of sound in the air only depends on the air static temperature following

(with a in knots and TS in Kelvins). Static air temperature (TS or SAT) is the still air temperature in the vicinity of the aircraft. Unfortunately, it is impossible to measure the static temperature of a fluid in motion. This is then the total air temperature (TT or TAT), or impact temperature that is measured thanks to a temperature probe similar to the Pitot tube. The total air temperature expresses that the air is compressed with an increase in temperature, therefore it will always be greater than static temperature during flight. Hopefully, Mother Aerodynamics (repeat) provides us with a further formula giving the static temperature as a function of the total temperature and Mach number:

That's great, guys, we should make it to L.A.!

The Air Data Computer (ADC) that inputs PT, PS and TT, will compute the true airspeed. The coupling IRS-ADC is named ADIRS (Air Data Inertial Reference System).

With the ground speed and true airspeed vectors known, the wind magnitude and direction can be directly computed, if we simply subtract the true airspeed from the ground speed, the vectorial relationship displayed above becoming

As we've seen, because of the wind force, the direction of movement of the aircraft, or ground track, is not the same as the aircraft true heading, simply defined as the direction with which the aircraft longitudinal axis is aligned and referenced to the True North direction. Therefore, the pilot must adjust heading to compensate from the wind in order to follow the desired ground track. In light private aircraft, the pilot will manually calculate the headings for each leg of the trip, using the reported wind directions and speeds supplied by the meteorological forecasts. On a modern glass cockpit airliner, the navigation calculator will do the job and compute the wind correction angle in real time.

Ground speed, true airspeed, wind magnitude and direction are displayed top-left of the Nav Display. Unless the pilot switches on 'TRUE NORTH REF' (not modeled by PSS), which may for example be needed on the high latitude polar routes, the ND will actually not show the aircraft true heading but the heading referenced to the magnetic North, which will vary from True North according to the local magnetic declination.

Finally, the indicated airspeed (IAS) is read from the airspeed indicator of the aircraft, located left of the Primary Flight Display in a glass cockpit and showing speed in knots (kts) i.e. nautical miles per hour. IAS (often noted KIAS with reference to the knots unit) is directly deduced from the differential pressure (PT - PS). It is the solution of Bernoulli's equation applicable to a perfect, compressible gas in a subsonic flow. Having the opportunity to play with my 'MathType' editor for the last time, here's the monster:

where aO and PO constants are respectively the speed of sound (around 661 kts) and static air pressure (29.92 in Hg) at sea level. This formula is though showing us that the anemometer, which measures IAS, is calibrated to the standard sea level conditions. That means that at sea level and standard pressure, the indicated airspeed will be equal to true airspeed while it will differ from it at air densities other than the standard air density (which is equal to 1). Air density decreases with altitude, temperature and is also affected by moisture content. Indicated airspeed, however, is the reference speed in aircraft operation, as we have also seen in the previous legs: the aircraft take off speeds, approach speeds, structural limiting speeds and stalling speeds, collected as V speeds, are dependent of indicated airspeed, irrespective of true airspeed. Also, speed limits, that they are imposed by ATC or appear on the approach charts, are also related to IAS.

We'll conclude this rather long theoretic presentation with an ironical, but rather sad remark: the science and equations that have been applied to aviation and made it become true were mainly established by men of genius who died tens of years, or even centuries before the first aircraft officially took the air.

Close-up to the various quantities that we've introduced, displayed on the PFD, ND and Lower ECAM (here put at the normal Upper ECAM location), as we're concluding our Pacific crossing. We simply read: Indicated airspeed: 267 kts ; Mach number: 0.82; Ground speed: 415 kts, True airspeed: 469 kts; Wind @ 53 kts blowing from the 44° sector, with a predominant headwind component which subtracts from the groundspeed; Total air temperature: -27 °C and Static air temperature: -57 °C, the ambient temperature actually at our current altitude of 38000 feet (11400 m).

Our approach to Los Angeles Intl is made via the LEENA3 standard arrival with the FICKY transition, a waypoint still located offshore some 260 nautical miles away from the airport. This is the longest standard arrival path I know up so far. The STAR is leading to the Seal Beach VOR, from which radar vectoring is expected for localizer capture. We'll land on runway 25L, one of the four parallel runways provided by the airport.

About to make our first contact with the United States @ 4500 feet

Still at 4500 feet, now approaching Seal Beach on the last leg of the standard arrival

Federal Aviation Administration approach chart (public domain)

Reduced for illustrative purposes - DO NOT USE FOR REAL WORLD NAVIGATION

ILS approach to Los Angeles, showing the four runway system with simultaneous approaches authorized on both the northern (either 24R or 24L) and southern (25L or 25R) runways. Traffic configuration during our flight was: landings on 25L and 24R, takeoffs from 25R and 24L, probably the most usual situation here considering airfield situation and runway lengths. Arriving from Seal Beach VOR, we'll intercept the localizer at HUNDA intersection, thus having a shorter final leg than other approaching aircraft arriving from the East.

This Nav Display shot taken after crossing Seal Beach VOR (SLI) during approach is a perfect opportunity to quickly introduce the TCAS equipment of our aircraft.

TCAS (Traffic Collision Avoidance System) is operating independently of ground-based equipment as well as Air Traffic Control and is conceived to enhance air safety by acting as a 'last resort' method of preventing mid-air collisions that may have escaped ATC vigilance. The TCAS-equipped aircraft monitors other aircraft in its vicinity and assesses the risk of collision by interrogating their own transponders. Therefore, non-transponding aircraft will not be detected.

With TCAS active, traffic is displayed on the ND up to 40 nm distance and within 2700 feet vertically. Other aircraft will be represented by a white diamond with relative altitude to own ship, in hundreds or feet. If contact aircraft is climbing or descending, an arrow is added beside the symbol to indicate this. For example, the contact seen in the added yellow circle is currently some 25 miles away, 2000 feet above our aircraft and is still climbing. The array of aligned aircraft seen on the right are already established on final.

Distance to an intruder aircraft associated with a collision threat is based on time-to-go, rather than distance-to-go. In that way, a 40 seconds time-to-go before a possible collision with an intruder aircraft will trigger a Traffic Advisory (TA). In this case, the TCAS is calculating a risk of collision, but the encounter could resolve itself. An aural message 'Traffic, Traffic' is enunciated, advising the pilots to closely monitor nearby traffic. If the time-to-go goes below 25 seconds, a Resolution Advisory (RA) will demand avoidance manoeuvres in the vertical plane: 'Climb, Climb' or 'Descent, Descent'. Unfortunately, traffic advisories are not modeled by the PSS software (remember the 80% of the real functions modeling...).

The TCAS switch (providing Standby, TA only or TA & RA settings) is located on the pedestal, close to the transponder panel.

Proximate intruders will be indicated by a white filled diamond, TA intruders by an amber dot and RA intruders by a red square. No intruders were reported during our approach to L.A., but perhaps it will happen in a following leg. In fact, MSFS default ATC and AI traffic engine are rather well done but their reliability is several orders of size below the real world security level, this is why TA and RA situations actually often happen: we'll see the explanation of the 'miracle' occuring while approaching LAX below...

Localizer capture

The same moment seen from the flight deck, with downtown Los Angeles straight ahead. Looking closer to the Nav Display, we see that most of approaching aircraft are actually bound on the other landing runway: they are aligned with Rwy 24R, slightly above our approach path, while ATC has cleared us to runway 25L. This explains why no conflict with another aircraft was encountered, what a chance!

Simultaneous ILS approaches are common with airports that have sufficiently spaced out parallel runways.

Together with a Northwest A320 established on 24R.

Still the rush our on Rwys 24L/24R (see the TCAS symbols still displayed on the ND), almost nobody in our approach corridor, what an easy landing!... We seem to have a preferential treatment from ATC, but I guarantee that the pope is not on board.

Finally down, this last shot concludes the most 'technical' leg of Around the world 2006-2007.

LAX air traffic controllers have to deal with one of the most busiest skies in the world. Two simultaneous aircraft are now getting airborne: a Southwest 737 from Rwy 25R and a further aircraft from Rwy 24L.

Leg 23: Los Angeles, California, United States - New York, NY, United States

This flight will leave L.A. at dawn and cross the United Sates in less than five hours. The flight will fly over Las Vegas, pass north of the Grand Canyon and south of Denver and Chicago. Our approach to John F. Kennedy airport of New York will provide us good views of Manhattan.

Flight Plan

From LOS ANGELES INTL (LAX/KLAX) to NEW YORK/JOHN F. KENNEDY INTL (JFK/KJFK) Alternate KEWR NEWARK INTL KLAX25R SEBBY1.DAG DAG J146 FJC STW LENDY LENDY5 KJFK13L

Distance 2915 nm (5392 km) Flight time 4:50

The flight path uses the J146 high altitude airway, which actually originates at Los Angeles and ends at New York. LAX-JFK is for sure one of the busiest routes in the country domestic network.

Our takeoff from runway 25R at Los Angeles, towards the sea, is to be followed by an u-turn and we will cross Seal Beach VOR again, like during our arrival procedure. From Daggett VOR, we will remain on the same airway until we reach the eastern coast.

So long L.A. Left turn abeam Santa Monica VOR, to join Seal Beach VOR as next.

City of lights... Ten minutes after engine start @ 14000 feet (4200 m)

45 seconds later, now @ 16000 ft and about to reach Seal Beach.

MegaScenery USA (see credits) is one of the very few photographic scenery add-ons that provide both day and night textures.

Flying over Las Vegas and Mc Carran Intl airport just after sunrise. Good job for the FS2004 standard scenery.

Las Vegas is behind as the Sun begins to scorch hot on the Colorado plateau, with Virgin river on the left.

Kanab Creek, just north of the Grand Canyon.

The airway is unfortunately bypassing the famous place.

Federal Aviation Administration approach chart (public domain)

Reduced for illustrative purposes - DO NOT USE FOR REAL WORLD NAVIGATION

Our approach to JFK will cross La Guardia VOR/DME, to be followed by the ILS Rwy 13L. The 1515' obstacle located right on the runway axis is the Empire State Building. Our flight path will pass a few miles north of it.

Enigma: in the LENDY5 standard arrival to Kennedy that was observed, ending at La Guardia from which radar vectors are expected to final approach course, LENDY intersection, located only 14 miles west of LGA, is to be crossed at FL190. La Guardia should then be reached at 2000 feet. Did I read well ? I'm afraid so. Well, ladies and gentlemen, please get prepared for a STEEP descent: 17000 feet within 14 nautical miles, that means 1214 feet every nm or... h'm... a 24,6% slope and a descent rate of more than 6000 ft/min if we comply with the 250 KIAS constraint of the arrival. I would suggest to add 'SPEEDBRAKE USE MANDATORY' on the STAR chart.

To comply with that steep descent profile, we hadn't much choice and had to use the autopilot selected vertical speed vertical guidance mode, as well as autothrust selected speed guidance (250 KIAS). Here, the selected 6000 ft/min vertical speed value was flashing amber/green, meaning that we were at the limit of an excessive descent rate. Indicated airspeed is slowing down to the target value, but only thanks to the speedbrakes.

Okay, we've almost made it. I don't know how is the ambiance in the cabin after the 'dive' but the passengers may now enjoy the scene.

FS2004 developers did it well also here: concluding the descent with a great view of Central ¨Park. Speedbrakes are still extended.

Another view, now revealing the typical outline of the Empire State Building, which is sadly Manhattan's tallest skyscraper again since September 11, 2001.

Houston, we've a problem. Here's a perfect example of the situation that was described in the previous leg. Left, TCAS would provide a Traffic Advisory message. Center, a collision could occur in less than 25 seconds: TCAS would enunciate a Resolution Advisory. Right, here's the 'intruder': in real life, the consequences of a collision with such a single prop light aircraft would be almost as terrible as with another airliner. In this flight, the collision would not have occurred: despite ignoring the TCAS alert since the RA messages are not modeled, the private aircraft bypassed us, more than half a mile on the left.

After a steep descent and passing close to a mid-air collision, we're trying to establish ourselves on final: too fast, too high, not aligned yet. Perhaps I should apply for another job after landing.

Leg 24: New York, NY, United States - Tampa, Florida, United States

We finally kept appearances and landed safely at New York so I'm very pleased to announce that Around the world 2006-2007 goes on.

For this article's last leg, we'll visit Florida and fly the approach that I had once the chance to experience in real life as a passenger, since a part of my family lives there. Tampa Intl airport is the third airport in Florida (after Miami Intl and Orlando Intl) and serves the Tampa Bay region. Centrally located on the west coast of the state, near the Gulf of Mexico, Tampa Bay's population, also including St Petersburg and Clearwater, is 2.5 million people. Huge residential areas, mainly made of bungalows and criss-crossed by thousands of streets, spread over the land with the only 'peaks' in the landscape being the towers of St Peterburg and Tampa's downtowns.

Flight Plan

From NEW YORK/JOHN F. KENNEDY INTL (JFK/KJFK) to TAMPA INTL (TPA/KTPA) Alternate KPIE ST PETERSBURG-CLEARWATER INTL KJFK31L SEAVW2 CRI JOANI J79 SBY J209 SAWED J121 CRG J55 INPIN LAL BRDGE BRDGE5 KTPA36L

Distance 952 nm (1760 km) Flight time 2:20

We will take off from JFK's longest runway and immediately turn left on the SEAVIEW 2 departure. The flight path will follow the east coast of the United States and hit the Florida border near Jacksonville. Towering thunderstorm clouds are expected on arrival, that will be a further opportunity to appreciate the first-rate FS2004 weather engine. 

Lining up Rwy 31L. The Empire State Building is still visible in the background but the departure sequence will - not surprisingly - avoid Manhattan island, here located straight ahead.

For this short flight, less than 1/3 of the runway length was used for takeoff!

Passing a colleague near Charleston (this was an A320 from US Airways). In such a case, the relative velocity between the two aircraft is one and a half time the speed of sound !

Already towering clouds as we're about to cross Florida's border

We're now above the Sunshine State, near Daytona Beach and starting descent.

Another encounter, though still too far to be detected by the TCAS. This B767-300 from Delta Airlines was approaching Orlando Intl.

Passing INPIN and heading towards Lakeland VOR. Below are a few of the 10,000 Florida lakes.

Proceeding to Lakeland. We're bound for runway 36L at Tampa and expect a moderate crosswind.

The other airports appearing on the Nav Display are Orlando Intl (KMCO), Sarasota-Bradenton Intl (KSRQ) and St Petersburg-Clearwater Intl (KPIE), our alternate for today. Note that I've modified the PSS airport database so that only airports that can accomodate the Airbus A330 are displayed. There are actually far more airfields in the area.

Federal Aviation Administration approach chart (public domain)

Reduced for illustrative purposes - DO NOT USE FOR REAL WORLD NAVIGATION

The topography of the Tampa Bay is clearly depicted on the IFR approach chart. Its northern part is actually split into the Old Tampa Bay (left) and Hillsborough Bay (right). We'll capture the localizer at LAGOO IAF.

Passing BRDGE at 8000 feet and starting the last leg before localizer capture.

We're now reaching the final approach altitude of 2600 feet, a few seconds before turning right to final, while the sky seems to get darker above the Tampa Bay.

The Gandy Bridge carrying the US92 road is one of the three bridges that cross the Old Tampa Bay. Now fully established for runway 36L.

Horizon 2006 heavy, cleared to land runway 36 left, wind 320 degrees, 16 knots... Autopilot is disengaged, we'll perform a manual landing.

Tampa skyline in the background

This excellent airport scenery add-on also provides 3D approach lights. I confirm that these ones are accurate!

Slightly too much to the right. Probably because of the crosswind, or concentrating on the screenshots, or both!

Nice correction as we touch down right on the runway centerline.

And Tampa here we come... you may further appreciate the perfect modeling of the airport...

Vacating the runway to taxi to the Airside F terminal. Left: the panoramic restaurant and the control tower, we can also see the (here red and blue) typical monorail shuttles that connect the airsides to the main terminal, called 'Landside'.

We also have 3D taxilights... I really love this airport. In the next leg, we will enjoy it at sunset!

This landing at Tampa concludes the 5th part - and the longest article of Around the world 2006-2007 (it was supposed to be the shortest, with only 3 destinations, but the technical stuff made up for that a little bit). In the next issue, we'll visit Mexico and a few pearls of the Caribbean. I will also introduce the Checklists and perform an external walkaround of the aircraft, just like in real life. Thank you for joining me on these three further legs in the United States and I hope you'll board the A330 again as the adventure goes on.

Cédric De Keyser
Brussels, Belgium
cdk@ngi.be