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Stargazing Over The Atlantic

"See? What did I tell you? Piece of old tackie. All they do is sit there and watch the
auto-pilot do the flying." This was the comment by a passenger to his friend visiting
the flightdeck on one of my 747 flights from Cape Town to Miami some years before
9/11.
The passenger incidentally, was a commercial pilot with some two thousand hours of
flying experience on light aircraft. I knew the non-flying public were ignorant but a
statement like that coming from a fellow aviator? Maybe that old saying 'a little bit of
knowledge is a dangerous thing' was true after all

Actually, 'driving' this thing is really easy," I replied sarcastically. "All we do is push
the 'fly' button to take off and the 'land' button to tell the autopilot to put us safely
back on the ground again. Simple isn't it?"

The passenger caught my drift immediately. "Okay, maybe not," he apologized. "But
what is it you guys actually do up here for fifteen hours?"

That question made me realise that in spite of the fact that aeroplanes have been
around for over a century, the public are still completely ignorant of aviation. Ask
anybody what a tonsillectomy or an appendectomy is and I'll bet most people have
some idea. Ask them what a fuselage or empanage is and watch the look on their
faces. To some people flying is an ordinary as climbing on a bus - to others, it's a
terrifying ordeal. Neither perception is accurate in the objective sense. Considering
that you're strapped into a metal tube moving at nearly a thousand kilometers per
hour through an environment that - merely inches away - would not sustain your life
for more that a few seconds, this is hardly a bus trip!

But then, given the incredible technology used in designing, building and flying
theses machines, and the corresponding reduction in risks; flying should no longer
be a terrifying ordeal either. And on a higher level, even professional pilots outside
an airline environment don't suspect how involved a transoceanic flight can be. How
come? Maybe the difference between a doctor and a specialist is a fair comparison
So, getting back to my passenger's question. What is so different about flying a wide
body jet over the ocean at night compared to any other flight? What do we really do
on a 747-400 flightdeck for fifteen hours? Stare at the stars? Well, in reply I'd have
to point out that it all starts with the planning - much of which is done by a very
capable dispatch and scheduling office. For one thing, on those long haul flights we
carry a double crew, the captain and three first officers. This is so the flight can be
divided up into acceptable duty periods. One crew sleeps in the bunk directly behind
the flightdeck, then rotate halfway through the flight when the operating pilots
become tired. This is especially important as the last situation you need is to have a
fatigued crew perform a Cat 3 approach onto a fogbound runway at the end of a
fifteen hour flight when you're low on fuel. People have died because of that!
The pre-flight briefing is extremely thorough and carried out by professional
dispatchers. Their job is to inform us on the status of the aircraft, that is, any
technical snags that may be relevant to our flight. Then the regional and long range
weather forecast is reviewed along with the Sita flight plan which general aviation
pilots will know as the 'nav log.' Next, the expected zero fuel weight (ZFW) is given
to us. This will influence some of our decisions, as will the nature of the cargo on
board. (Dangerous goods for instance could affect a decision in an emergency.)
And then of course there is the fuel planning. Now this is a particularly interesting
aspect. Unlike a light aircraft where you generally top up the tanks regardless of how
much you need, we have to be particularly careful with this decision. You cannot
simply fill the tanks! This is because on a jet, the more fuel you carry, the more fuel
you burn to keep it aloft and correspondingly the less the payload you can carry. And
payload after all, is what makes a flight economically viable in the first place.
Above the legal requirements, if you still have space, you can load extra fuel or
payload - but not both. An increase in one is a sacrifice to the other, so it is a
delicate balancing act. Also, the heavier the aircraft, the lower will be the cruise
altitude, the more fuel you burn. Sort of a catch 22, robbing Peter to pay Paul.
In the case of the old Miami flight the problem was somewhat different. Fifteen hours
of flying while burning ten tons of fuel per hour means we needed 150 thousand kilos
of fuel to complete the flight. Then there is the added fuel for the diversion if we
can't land, that's about another eight tons. Then the thirty minutes of' holding' fuel in
case we end up having to enter a holding pattern. Chalk up another couple of tons.
What about contingency fuel is case of diverting around weather? Better add a few
more tons. Oh, and don't forget, just to taxi this beast to the runway will require at
least one ton of fuel.

By the time you add it up, a typical American flight (if you can call any flight 'typical')
will need between 164 and 174 thousand kilograms of fuel, the difference being the
forecast winds and routing on the particular day. (The upper winds are mostly from
the west so you can bargain on a headwind for most of the way, only the velocity
varies.)

So, there we have it. A fuel decision! But wait! The 747-400 can carry 175 thousand
kilos of fuel, but that is only if the specific gravity of the fuel is dense enough. What
if it isn't? What if it's a warm day? What if the SG is not dense enough and the tanks
are volumetrically full, but the weight of the fuel is not sufficient for the flight? What
do we do now?

WARM FUEL: The way this problem is solved is quite ingenious. The schedule was
designed in such a way that the aircraft began its trip in Johannesburg with a flight
down to Cape Town before its trans-Atlantic marathon. This short sector only
requires thirty odd tons of fuel, but in fact is loaded with at least sixty tons of
'tankering' fuel. Two hours cruising at high altitude in ambient temperatures of
minus 50 degrees Celsius was enough to change the density of the tankering fuel to
a SG high enough to leave sufficient space in the tanks for the balance of the Miami
fuel to be loaded in Cape Town.

Problem solved - for the moment. Now let's say it’s a warm evening. Hold that
takeoff! The air’s not dense enough to support all that weight within the length of the
runway. Eventually after a delay we start the takeoff roll at max gross weight, which
typically is close to 400 thousand kilograms, and head out northwest over the ocean.
The takeoffs are always manually performed; the autopilot only has the capability of
performing autolands.

This is the last time we will see land for eight hours until we cross Recife on the horn
of South America. Now's a good time to establish communications on the long range
HF radios. Initially we speak to CPT on the HF, then Johannesburg and also ZUR,
SAA's monitoring station. If anything goes wrong at this stage, search and rescue
will be South Africa's responsibility. Later on it will be transferred to Brazil and then
to a myriad of other countries before ending up with the USA. For this reason
communication is absolutely vital.

SPACE JUNK: As we continue out over the dark void the night becomes incredibly
black and yes, the stars (when you have time to study them) are absolutely
magnificent! You may even be lucky enough to glimpse the dramatic sight of space
junk re-entering the atmosphere or, as I watched in awe one night, the comet
Shoemaker-Levy 9 on its orbit around the sun. And you will not believe how may
meteorites you can count in a minute. But I digress. The relief crew have dinner and
then hit the bunk for a few hours rest. They'll be woken later over Brazil.
As we burn fuel the aircraft becomes lighter and we begin a series of step climbs that
will continue throughout the flight, keeping the aircraft at optimum altitude. The
fuel-flows start coming down nicely as we climb higher, but all the while we must
watch the wind. Generally the wind speed increases the higher we fly so we better
make sure that the reduced fuel-flow isn't compromised by the increased headwind.
The forecast wind has a direct bearing on the track planned before the flight. A bit
like ocean-going yachts adjusting their course to take advantage of, or negating the
effect of, the wind.

Forecasts on the Sita flight plan are uncannily accurate but you can never be too
sure, weather still remains an inexact science. On such a long flight it is normal to
pass several weather fronts, both warm and cold, along with all the associated
thunderstorms and clear air turbulence. Weather radar makes dodging the active
cells relatively simple but you must be careful how you do it. If you pass them on the
leeward side be prepared for a rough ride.

Navigation itself is done using two GPS's and three Inertial Reference Systems (IRS)
which are highly accurate laser gyroscopes. Reporting points are termed ‘waypoints’
and are simply latitudes and longitudes or prime meridians where radio calls are
made on HF and 126.9 in case of other traffic in the area.

The first half of the flight feels incredibly lonely as there are no other aircraft
operating on that sector of the route and if an emergency occurs midway over the
Atlantic the only alternative is Ascension Island, and even that is a good few hours
away. It is only approaching Recife that you start hearing the familiar VHF chatter
and pick up the occasional TCAS (traffic collision avoidance system) symbol on the
CRT. Talking of CRT's, the 400 has a six-tube EFIS system and is ergonomically
designed making the fuel, hydraulic and other systems extremely efficient for the
pilots to manage. On the older 747 classic's that was the Flight Engineer's job.
The three autopilots can be disconnected at any time but with the management
duties taking up so much time, why fly manually except to check the trim? Besides,
at high altitudes the air is very thin and the effort required to fly accurately would
distract you from your other duties. But what the heck if you really want to, go
ahead, fly the aircraft. Just don't overload the other pilot with your duties because
remember, when you are flying manually he has to monitor you!

By now we have comms with Braza and then with Recife, time to check out that fuel.
On the northbound sector it should not be a problem as at this stage we have burned
almost half our load and if we're running short we can always divert into San Juan or
one of the other islands for more. But on the southbound flight you need to be wide
awake as it is the last half of the flight that is over the ocean and if you run short
there is nowhere to go!

Crossing Recife you're tired - time to wake the relief crew. You change seats, brief
the fresh pilots on your progress, then head for the bunk. The bunk beds are really
great. Completely enclosed in a tiny cabin, it is a little quieter that the flight deck
although most of us still sleep with earplugs.

While we are resting the other crew is speaking to Cayenne in French Guiana and
Paramaribo in Surinam, then Puerto Rica, radioing ahead for destination and
alternate weather. By now the white TCAS targets are becoming more frequent on
the screen, which is fine as long as they do not change to amber and then red. If
they do, be prepared to take evasive action immediately - there is another aircraft in
you flight path! Unlike over Africa, ATC and radar control are generally very good,
but don't bet your life on them. If something happens the ATC will be the one
walking away from the accident, not you.

BREAKFAST: The primary crew are woken about thirty minutes before descent and
briefed on the expected landing conditions and the fuel situation. Just enough time
for a quick breakfast, then a review of the Jepp approach and landing charts before
starting the descent. Some airports have complicated arrival and departure
procedures, which can be programmed into the Flight Management Computer (FMC),
but as with the autopilot, and indeed any computer, it is only as good as the human
punching the information into it. The descent is not the 'hit or miss' affair it can be
on light aircraft either. It would be foolish to start the descent too early, correcting
the error with thrust and high fuel flows when you haven't much more than reserve
fuel left. If weather permits, the landings are performed manually, which ironically is
far less stressful than setting up for an autoland. This is because autolands are done
in really bad visibility and although the autopilot flies the aircraft more accurately
than a human, any failure in the systems will require a split-second decision to
continue the landing or go-around. Either decision will have serious implications. If
you go around you can bargain on burning at least two tons of that precious fuel
before you start your next approach. (Better check that you still have enough to get
to that alternate airport if you need to). And if you choose to land, make sure you
can see the runway, otherwise you are about to make the newspaper headlines!
Computers on a modern flight deck are not there to take the responsibility away
from the crew. Rather, they make far more information available to them, enabling
the crew to make more rational and objective decisions. And these days, that is what
this job is all about.

These are just some of the factors that occupy our thoughts before and during a
flight. Obviously there are many more, but if you ever visit the flight deck and see
the crew staring at the stars, rest assured, they are contemplating far more that just
the universe.

(The author flew the Boeing 747-400 before being appointed as a Training Captain
on the Airbus A340 with SAA.)

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