THE MIGHTY BOEING 747-400 – PART ONE

SOME INTERESTING “GEE-WHIZ” INFORMATION:

Over a timespan of almost forty years, South African Airways operated four different variants of the Boeing 747. Three of these types belonged to the “Classic” series. They were the 747-200, 747-300 and the smaller, extra-long range, 747-SP. The fourth type was the latest and most advanced of all the models, this being the 747-400.

I cannot even begin to describe what it was like to fly these magnificent aircraft, as there was simply nothing else like them. Suffice it to say then, that I personally consider all the 747’s, colloquially referred to as “Jumbos”, to be the most PERFECT of all the 200 or so aircraft types that I have ever flown. Therefore, all I can really do for you is jot down some “gee whiz” information associated with the operation of these aircraft.

SAA’s flagships, the Boeing 747-400s, were always readily identifiable because they were the only models that were fitted with winglets. This aircraft had a maximum ramp weight of 396 000 kilograms. Stated differently, fully laden with fuel, plus a payload of passengers, baggage, and some freight, it could weigh up to almost four hundred metric tons! 

With all eight of its fuel tanks filled, the weight of the fuel amounts to 173 000 kilograms, which, in turn, equates to about 215 558 litres. This amount of fuel would be enough to run a family car that burns about 9 litres per 100 km and that covers an average amount of mileage every month, for over one hundred years!

The cockpit is located on the aircraft’s upper deck, the roof of which is just short of nine meters above the ground. This means that when the pilots are seated, their eye levels are at about eight meters from ground level. Now, cast your minds back to what a climb it was and also to what the view was like when you got to standing on the platform of a ten-meter-high diving board! During taxi the aircraft appears to be moving slower than it is due to the flight deck’s height above the ground. Consequently, the tendency may be to taxi faster than desired. The ground speed display, as provided by the inertial reference system, is therefore continually used to determine the actual taxi speed.

The Boeing 747 has a total of eighteen wheels. There are two steerable nose wheels and they do not have any brakes fitted. The remaining sixteen wheels are located, on average, about thirty-four to thirty-five meters directly aft of the aircraft’s nose. These wheels are arranged into four bogeys of four each, all of them in the area of the fuselage and the wing roots. Each wheel is fitted with a braking system that has six brake discs and twelve sets of pads. That means that there is a total of 16×6 = ninety-six brake discs and 96 x 2 = one hundred and ninety-two sets of brake pads. The brake energy that is available to stop an aircraft needs to be enormous, as there always the possibility that a heavy-weight take-off might have to be rejected at high speed.

The crew compliment for the 747-400 model is only two pilots. Modern day technology in respect of automation, monitoring, operating systems and data presentation is such that there is no longer a need for the flight engineer that fulfilled a very vital role on the 747 “Classic”” models. On long flights, one additional pilot is carried so as to provide in-flight rest and relief. Then, on ultra-long flights of some thirteen to fourteen hours in duration, two extra pilots, one being a Captain and the other a First officer, are carried.

The cockpit area is really fantastic. Behind the Captain’s and the First Officer’s seats are two seats for any extra crew members. They are therefore able to take up a proper seating position and to strap themselves in for the take-off and landing with a full five- point waist, crotch and shoulder harness.

Just aft of the flight deck, on the right, is a toilet and washbasin for the exclusive use of the pilots on the flight deck. On the left is a bunkroom that is both sound and light proof. There is an upper bunk and a lower bunk. Each of these have subtle reading lights and air vents. On an ultra-long-distance flight, say direct Cape Town to Miami or direct New York to Johannesburg, we would divide the flight time up into four equal rest periods that were about three to three and a half hours rest long. By so doing, the relief Captain and First Officer would take the first rest period once the flight was properly under way. Just over three hours later, they would take over control of the aircraft whilst the primary Captain and First Officer went to the bunkroom for their three hour rest. This roster would be repeated for the next two rest sessions. Towards the end of the flight, the Primary Captain and First Officer, refreshed after some quality sleep, would return to the controls for the approach and landing.

At the beginning of a long-distance flight, if the aircraft was really heavy, the highest cruising level that the aircraft could usually climb to would be round about Flight level 280. At that height, the fuel flow to each engine would be high, and a poor ratio of fuel burned to distance travelled would exist. As the aircraft became lighter, so it would be “step-climbed”, increasing its altitude bit by bit so as to achieve greater economy. Towards the end of the flight the aircraft would be cruising way up high in the late thirties to the early forties. The 747 series were in fact restricted to a maximum altitude of 45 000 feet.

Four independent engine-driven hydraulic systems power the rudders, ailerons and elevators and systems such as the flaps, landing gear and brakes. There is no “manual reversion”, meaning that if, in the extremely unlikely event of all four hydraulic systems having failed, the flight controls could not be operated manually. Therefore, very cleverly, the rudder was built with an upper half and a lower half. The upper rudder is powered by hydraulic systems ONE and THREE and the lower rudder by systems TWO and FOUR. Similarly, the left elevator is powered by hydraulic systems ONE and TWO and the right elevator by THREE and FOUR.

This “gee whiz” information is enough for now. I hope that you have enjoyed what you have read so far and that this has been enlightening. Parts 2 and 3 will cover other aspects of what it was that set the Boeing “Jumbos” apart from most other airliners.