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The mountain was simply too high... - or was the airplane flying too low? by Tim van Beveren (from the book "THEY ALWAYS COME DOWN") Again a story of the miracle-plane with which also the stupidest pilot do nothing wrong that even, - like Mr. Mehdorn, the former chairman of Airbus Germany liked to emphasize -, could be piloted by his secretary or an average schoolboy. So why then invest much money into the pilots training, yes maybe in the end even into current training-programs if that is in reality completely excessive? The invention of Airbus had succeeded even better than the squaring of a circle: "From now on flying becomes completely safe, and even cheaper then before." - Beating arguments of Airbus- salespersons, back in those days. "Yes that is what we have always wished for!", - not the real experts, but the self- appointed aviation experts applauded within the airlines. So they went dynamically to work, to help such a melodious, bold promise to the breakthrough. All long year experiences were laid aside, even those gathered by painful realizations and lessons. Flying had been newly invented again, and who really wanted to stay grumbling aside? But as an old German saying says: "arrogance often comes before the fall". This time, it was one of these falls, where a completely intact airplane became destroyed, because the mountain, which happened to be, where the airplane flew, was simply too high... It is Monday evening, 20. January 1992. The Airbus A 320 of the French airline Air Inter, registration F-GGED approaches the airport Strassburg- Entzheim, coming from Lyon. At the end of this event we count 87 killed and five seriously injured people; minor injured only four passengers survived the crash. The 4l year old captain, with a total flight-experience of 8.806 hours has flown the A- 320 to that date exactly for 126 hours. The copilot, 37 years old, adds 3.615 flight-hours into the event, but only 61 hours on A 320. Would it not have been reasonable to have a third pilot in the cockpit to support the others? But where would we get to if we involve ourselves in some thoughts like this? Both pilots had completed their training with the Airbus affiliated training facility of Aeroformation. By kind of the house's "short and dryly" philosophy. Please no "unnecessary gimmicks" or the disclosure of too much insights into the technology they have to master. - And by all means trying to avoid to explain to them all of the small and big corners and crusts, where one must be very careful and attentive. Generously after the motto: "Man can do nothing wrong, and that is what everybody should stick to." However: one can. The experience is missing, one doesn't cope with the ergonomics of the airplane, and under the multiplicity of displayed information the attention to one value gets lost, just for a short period of time. But it is quite an important one: the vertical speed. Therefore, the airplane flies into the mountain. "Pilot error", - this is quite instantly recognizable.
The handling of the autopilot by the so-called "flight control unit" (FCU) can lead to mix-ups. With the same knob, according to the pre-selected mode, you dial in either the vertical speed or the angle. Through pressing another small black button you may switch between the angle and the speed, - back and forth. In closest neighborhood to this switch is a second, identical push button, with the same "press-sensitivity". But this one is responsible for the display of the pre-dialed altitude in meters or feet respectively. Wasn't the right button pressed sufficiently solid? Was maybe the wrong button pressed instead? Advantages and disadvantages of "push button flying"! The indication (feet or meters) however is displayed in digital LCD and only differs in one comma-position. For example: if a descent angle of 3,3 degrees was chosen (that corresponds to approximately 800-900 feet per minute) the display reads: "-3.3". If a descent is selected with 3.300 feet per minute, the display will read "-33". The chances for errors are so high that Airbus after this accident has modified the display. The Air Inter pilots thought, they have selected a descent angle as of 3,3 degrees, - but obviously they were descending with 3,300 feet per minute. Therefore their flight ended at the Mont Saint Odile, only some few miles ahead the airport of Entzheim. The communication between the machine and the human being in the A 320 virtually and exclusively works on the optical level. If it was missed to teach the pilot in his training certain patterns, by means that he can separate the especially important displays of the not quite so important once at each and every flight-phase, then he is forced to have all possible displays in his scan. Since this is not feasible simply because of the amount of information displayed simultaneously, he inevitably has to rely on the aircraft performing the value he had previously selected. The actual vertical speed is imposed at the primary flight display and has to be read off in a digital value indication. That is roughly, as if one asking: "What time is it?", would be replied: "19 divided through 34, divided through 16, 17, 18....!" As significant as the digital time may also be the digital vertical-speed readout. But it is just considerably more dangerous, as both is not ascertainable in the glance of an eyesight. The numeric value first must be read off, then consciously be processed, "angle" or "speed"?, before it finally makes a sense. Air Inter had admittedly saved the expenses for a Ground Proximity Warning System (GPWS) as it has not been mandatory in those days to have it on board, but however showed a quite generously mood in affording a so called Head Up Display (HUD) for their A 320 captains; - enormously modern, the "top latest state of the art gimmick" in civil aviation. To check the instrument indication inside the cockpit is totally unessential; the view of the captain can wander through the windshield unhindered, even if it is hazily or it becomes dark. Nevertheless, he sees everything: flight-attitude, altitude, course, speed. However, he will not see in which operating mode the autopilot is currently working. That can only be seen inside the cockpit, on the display screen. But if one must look inside anyway, for what in Christ's name then the imposed piece of information on the windshield? Should the pilots maybe only use this data in the last part of their approaches, after the last checklist has been read, prior to the landing? Was that taught in this way to these Air Inter-pilots? A GPWS has become equipment-standard since it was recognized that unintentional ground-contacts may be avoided with its help. A prominent computer-voice and a red light warn the pilots of a dangerous approach at the ground. May it be too quickly, the aircraft approaching too flat, to steep or that the airplane is not accordingly prepared (flaps and gear extended). These pieces of equipment are developed continually and have adapted the latest technology. Their benefit is proven. Unfortunately just the installation of such an appliance was not mandatory according to the French certification regulations and therefore it was not installed. According to rumors among the French pilots community, Air Inter did not install the system because they were operating in a stiff competition with the French express train TGV. For this reason within Air Inter the approaches should have been made always quick and also steep, thereby avoiding delays. In regard to such maneuvers it is said that the GPWS was often triggered and consequently causing bewilderment among the crews. The pilots of the accident flight anyway joked during their approach about the absence of an ice detection sensor at their modern new airplane. Would they only have complained earlier about the absence of a GPWS... The rescue-operation was considerably delayed because the ELT (Emergency Locator Transmitter) installed in the tail of the plane was destroyed at impact. Normally this device is supposed to encounter tremendous impact forces and fire. It activates itself at an impact and starts transmitting an emergency signal that can be tracked by satellite - and good old normal radio bearing. The events after the crash and during the large-scale search and rescue are quite scandalous. When only minor injured passengers after several hours of useless waiting set out on foot to get help, the first rescue units whom they meet did not believe them at all. Somewhat later, a special unit of the military hits the crash site just to block it off entirely and start their search for the black boxes. Nobody helped the injured survivors, who could not get out the mangled debris mass and the military even did not allow the medical teams to come close to the crash site. The area is completely cordoned off. First look for the Flight-Data- and the Cockpit-Voice-Recorder. The emergency doctors, who had to watch this in anguish, are sure that this action had lead to the death of further passengers trapped in the wreckage as consequence. These people are frostbitten, because the data-recorders were more important. The rescue operation can in general only be called chaotic. Strangely enough, in this case as well some seconds are missing from the voice-recorder shortly before the impact. Further the tape of the flight-data-recorder was useless because it had been destroyed at impact, - another normally considered "indestructible" component to be installed in every aircraft. Therefore the data retrieved from the maintenance recorder (quick access recorder - QAR) was used in the later evaluation. In the aftermath of this accident, the French accident- investigation-commission recommended: - a mandatory installation of a GPWS, - to improve the ergonomics of the A 320 cockpit, - and over all consider ergonomic aspects during the development of new aircrafts. Furthermore a study is to be conducted how the modes of autopilot operation can be represented better ascertainable. Chief A 320 designer Bernard Ziegler, five years after the accident was indicted and facing a criminal court proceeding. In January 1997 shortly after retiring from Airbus Industrie the former vice-president of the engineering department was accused by the competent jurisdiction of the court in Strasbourg, as a representative for the manufacturer. He was accused that already in an early planning stage he was aware of the potential dangers implemented in the design and the consequent lack of information on behalf of the pilots. He thereby should be held jointly responsible for the death of 87 people. The French accident report however also illustrates that insufficient training has been one of the causes of the accident. In view of this accident it appears once again that rather more intensive training is required for the safe operation of this modern aircraft than for a conventional airplane. However, there is still hope. Let's hope that the urge to introduce improvements, is not only sensed when the row of the tombstones has become longer. When again the mountain was not too high, but rather the airplane actually was flying too low...
(1995) |
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But let's look into this issue a bit more thoroughly and put some light to the question how such a mistake can develop. This is the only reasonable consideration if something went wrong, - not only in aviation. |
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