Nexus - 1702 - New Times Magazine-pages

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But in the early 1960s, the accountants looked for But not surprisingly, Boeing is dismissive of this cheaper, simpler ways to provide that air. It was realised "insignificant" fact, which should now be understood as hat all jet engines have vast amounts of compressed air an obvious "about-face" innovation. Boeing prefers to available from the forward section of the engine, before publicise the fuel economy, which many members of the he fuel is added and burned. public can readily relate to, and to invent likely reasons It wasn't long before they were taking this hot, high- ‘o deny any truth for the real reason... pressure air and piping it into the cabin. They would Unsurprisingly, there was no public reference to the call it "bleed air", as it was "bled off" the jet engine real reason for dumping bleed air on the occasion of the compressor section. B 787's inaugural flight on 15 December 2009. At the time, many engineers warned that if the bleed air should become contaminated with oil from within _ Bleed air and fume events he engine or hydraulic fluid, then everybody in the je So what exactly would Boeing prefer the public not to aeroplane would not be breathing pure air but a now about? Since 1963, there has been an ongoing contaminated mixture of air and...oil. debate as to how clean the bleed air is. Boeing itsel However, the risk was thought negligible, such tha admits that in abnormal situations, mainly when oi bleed air quickly became the only way to ge seals "rarely" fail, the engine oil can contaminate the air. compressed air into the cabin of each and every aircraft. This leads it to claim that the air is "generally safe in since that period, including turboprop aircraft where a normal operations". But what about abnorma jet engine drives a propeller. operations—the every-other-day The first bleed-air jets were occasions? What Boeing does he Boeing 727 and the . not acknowledge readily is tha McDonnell Douglas DC-9, but it What Boeing does not oil seals oo not always fai d be 36 bef De t oft i Boeing would Sudldenly decide, acknowledge readily IS that over ‘many hours, “leaking ‘Sil in 1999, not to use bleed air in oil seals do not always fail into the ait shat bleed si uture designs. It would build a 9 e fact is that bleed air and Piet: suddenly but often fail il are allowed to mix due to. new type of jet: the Boeing 787 oil are allowed to due to Dreamliner. This jet would also slowly over many hours, * a basic design feature which be made from composite : ) . deliberately allows smal materials and have a relatively leaking oil into the air. amounts of oil to pass through igher cabin pressure. oil seals to provide lubrication; But Boeing would never be e the fact that jet engine oi able to admit that it had ditched seals prefer a constant- bleed air, as it continued to build bleed-air aircraft. | temperature environment to perform "normally" and Obviously it would take many, many years for a tend to leak when warming up or cooling down; complete change of technology. This was a double bind ¢ the fact that when power changes are made, such as for Boeing. Meanwhile, Airbus denies any problem and __ on take-off or at the top of descent when an incredible continues, some say foolishly, down the bleed-air route. number of revolutions are suddenly increased or One fact of airline flying is that while you are sitting | decreased, there are differing tolerances within the jet comfortably at 35,000 feet, the actual cabin pressure is and the potential for oil to leak. at about 8,000 feet—or as if you are sitting on the top of There are a number of basic facts which now must be a small mountain. Most people will know that this "lack presented. There will always be a few minor differences, of air", although bearable, is a compromise and that, _ but the following facts are known: ideally, the cabin air pressure should be at or near sea ¢ aircrew and passengers generally breathe the same evel. air; if the pilot is sick, so will the passengers be sick; If this were so, it would take a massively strong ¢ all jet aircraft use bleed air: turboprops, Air Force aeroplane hull to contain the sea level pressure at high — One, corporate jets; altitude and this would be "uneconomic". However, the ¢ the chemicals in the jet engine oil are extremely Boeing 787 has a more comfortable cabin pressure of _ toxic, especially since an organophosphate (OP) is only 6,000 feet—a definite selling point, but only for added to make the engines last longer and provide fire- hose "in the know". retardant properties. A little-mentioned but fundamental fact that Boeing So what are organophosphate chemicals? They were prefers to keep quiet about is that the bleed airina 787 developed during World War II by the Germans, will only be used for melting ice on the wings. The — specifically to do harm to human nervous systems. actual cabin air will be provided by an old style of air | They have since been used in pesticides, e.g., in sheep pump, driven not by mechanical pumps but by modern —_ dip—hence the dreadful neurological illnesses affecting electric air pumps. many sheep farmers in the UK during the 1980s and But not surprisingly, Boeing is dismissive of this “insignificant” fact, which should now be understood as an obvious “about-face” innovation. Boeing prefers to publicise the fuel economy, which many members of the public can readily relate to, and to invent likely reasons to deny any truth for the real reason... Unsurprisingly, there was no public reference to the real reason for dumping bleed air on the occasion of the B 787's inaugural flight on 15 December 2009. acknowledge readily is that oil seals do not always fail suddenly but often fail slowly over many hours, leaking oil into the air. 18 * NEXUS What Boeing does not FEBRUARY - MARCH 2010 www.nexusmagazine.com