HOW SAFE IS THE AIRPLANE YOU DRIVE?
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HOW SAFE IS THE AIRPLANE YOU DRIVE?
The writer was working as an Engineering Consultant at a German firm that designed large equipments and systems for commercial and military aircraft and helicopters. The writers’ responsibilities included the establishment and subsequent management of the Reliability, Maintainability and Systems Safety department, which operated as a part of the Product Support organization.
This was the writer’s second tour in Germany. He had previously worked as a contract manager on a major European fighter aircraft program. In the performance of his duties on his second tour the writer functioned as department manager and the writer was required to interface with other European companies that were involved on the same aircraft design and development program. In certain cases the writer would direct or advise individuals working within those companies.
In total, there were six companies, including the firm the writer was on contract to. The companies and their responsibilities are shown below.
Company “A”: This firm was the primary design authority and the primary integrator. They developed all primary design specifications, manufactured some major structural elements and assembled the aircraft. They also had the primary certification responsibility for the entire aircraft with the exception of the wings.
Company “B”: This firm designed the wing structure and had design authority over all of the various companies that supplied elements of the wing to include flaps, slats, flap and slat drive systems, fuel systems and interface with engine and landing gear suppliers. This firm also was responsible for the certification of the wings.
Company “C”: The responsibility of company “C” was that of wing integrator. There was minimal design responsibility and minimal certification sign-off. The primary function of company “C” was to take the wing structure which was built by company “B” and install the systems that were built by other firms to include companies “D” and “E” (see below). The completed wing was sent to company “A”, who installed it on the completed airframe.
Company “D”: Companies “D” and “E” shared component design and manufacturing responsibilities. In some cases, one company would design a component and the other company would manufacture that component and that part would then be used in the systems designed by either company. Company “D” had design responsibility for the slat drive system. This included the preparation of Reliability and Safety documents as well as after market product support. This is the firm where the writer was employed. The writer was also the lead engineer with overall responsibility for Reliability, Maintainability and Systems Safety documentation created by companies “D”, “E” and “F”.
Company “E” was responsible for the design of the flap drive system. The flap drive mechanism was designed and built by company “D” and the actuation system was designed and built by company “E”. Interconnecting shafting was designed and built by company “E” which also designed and built the tracks or rails that supported the flaps during their transition from the closed to open and back to the closed position.
Company “F”: Company “F” worked under the design control of company “D” which prepared the design specification for the computer which controlled the operation of the flap and slat drive systems. Company “F” built the flap and slat computer. The computer was designed and built with a great deal of system redundancy to include a self-diagnostic capability. The high degree of redundancy was necessary to minimize the possibility of placing the aircraft in jeopardy due to a system malfunction. Any computer-detected malfunction would cause the respective system to shut down. Additional responsibilities included all related Reliability, Maintainability and Systems Safety documentation.
To avoid any confusion by the reader in his or her attempt to digest the alphabet soup created when inter relating the misdeeds of companies A, B, C, D,E and, F, the writer will attempt to break them down into more easily absorbed components.
Both firms “D” and “E” constructed an “Iron Bird” of their respective systems. An “Iron Bird” is a functional mock-up that allows the system designers to simulate the operation of their systems. The systems comprise all of the dynamic elements of the system to include drive elements, gearboxes, shafting, position indicating units and dynamic braking elements. The “Iron Bird” actuating elements are connected directly to controllable load cells, which simulate the air, loads that the slats or flaps would react during flight. A separate computer and not the flap/slat computer control the load cells. Since the two “Iron Birds” were about 900 miles from each other it required that each “Bird” have its own flap/slat computer. Such was not the case.
Company “F” furnished company “D” with a fully functional “brass board” flap/slat computer. A “brass board” computer had all of the capabilities of a flight worthy computer but it was not built to a full production standard. What company “F” furnished company “E” was equivalent to one eighth of the “brass board” computer being used by company “D”. As previously stated, the flap/slat computer had a very high level of redundancy. The computer is broken into two major elements and each major element was broken down into four sub-elements. What company “E” received was one of the sub-elements.
The reason given by company “F” for refusing to provide a “brass board” to company “E” was that they suspected company “E” of luring away key employees of company “F” and stealing trade secrets. The writer’s company (“D”
tried to intercede but company “F” steadfastly refused to cooperate. The writer made companies “B” and “C” aware of the problem and they took no action. Although the contract specifically stated, that any situation that impacted the Reliability Maintainability and Systems Safety of the aircraft must be brought to the attention of company “A”, it never was.
The small portion of the flap/slat computer would allow commands to be sent to the flap drive unit on the “iron bird”, extending and retracting the flaps, but there was absolutely no diagnostic capability. The non-redundant element was “dumb” and if any malfunctions were to arise on the flap “iron bird” the problems would have to be solved using troubleshooting techniques initiated by technicians. One of the main purposes of the flap/slat computer was to diagnose problems and provide the technician with a real time indication as to which element of the system was at fault. The other purpose was to protect the aircraft from being damaged or being placed in aerodynamic jeopardy.
The prime purpose of the “iron bird” was to verify not only the flap system but the computer as well. This would be accomplished via insertion of known faults to determine if the computer was capable of detecting those faults.
Upon completion of all the testing, the documentation would be submitted to company “B” who would draft the request for certification for the flap system. Since only 5-10% of the overall test program was accomplished, the flap system was incapable of being certified. Company “A” was unaware of this situation and it can be logically assumed that the certification authorities were also unaware. The aircraft was eventually certified and has been in series production since that time
On the very first revenue flight, for a launch customer airline, one of these “certified” aircraft landed in Egypt and during taxi in, the pilot was unable to retract the flaps. Technicians checked the indicators on the flight deck and on the computer to no avail. The computer did not recognize the fault. As a result, the aircraft was flown back to Northern Europe in non-revenue status with the flaps fully extended. Upon reaching the home base, the technicians and engineers were unable to determine the cause of the lock-up. They eventually disconnected the drive system and hand cranked the flaps to the retracted position. Upon reconnecting the system, the flaps were cycled in and out several times and the aircraft was placed back in revenue service.
During the cycling of a sub-scale “iron bird/ where only a single slat actuator was being tested against a simulated air load, the test department at company “D” decided to disassemble the actuator to check it for wear. It was after the disassembly and cleaning of the parts that the writer was called in to checkout one of the parts. Examining the part under high power magnification, the writer observed what looked like a spider web pattern that had been etched into the flat surface of the part. Further inspection under a microscope showed tiny indentations or pits that were extremely small. The indentations were so close together that the pattern looked like fine lines etched in the surface. Inspection of the mating surface showed a mirror image of the same etched pattern.
The writer had seen this phenomenon before. Stray or ungrounded electrical currents that caused sparking between mating parts caused it. The writer discussed the problem with the stress engineer who stated that he too had seen the part but he insisted that it wasn’t spark erosion. He said it was stress corrosion. The writer knew that it was a no win situation to argue a point with a German engineer.
When the sub-scale “iron bird” was put back in service, the writer had a technician in the product support group perform a test. The test was to determine if there was electrical continuity between the actuator and the sub-scale “bird”. He reported that there was no continuity.
This indicated that the electrical currents, generated by internal friction of the actuator parts, could not flow to the ground potential of the “iron bird”. The writer was satisfied that his conclusion was in fact correct. Spark erosion could destroy the bearings and the highly polished surfaces of the actuator, running up the maintenance costs and possibly cause operational problems.
Armed with this knowledge, the writer spoke with a senior design engineer who was English not German. He authorized a check of the “iron bird” to see if the same problem could be detected. It could, and it was. The iron bird installation was in accordance with the same drawings that were used to install the system on the aircraft. If no continuity existed on one, it would not exist on the other, and this was a major violation of the certification requirements. The writer made a trip to England to talk to his counterpart at company “E”. He ran a continuity check of the flap drive installation on his “iron bird” and verified that his system was also ungrounded This further compounded the problem of not being able to properly certify the wing flap system due to inadequate testing. Now, not only were the flaps not properly tested, but also both the flap and slat systems were not properly grounded. If both of these situations had been made known to either company “A” or the certification authorities, the systems would have to be redesigned, the wing would have to be modified and a new stress analysis performed. Also, the flap system would have to be re-tested using a full-up computer. Yet company “A” and the certification authorities were unaware of the problem even though the writer made a noble attempt to make the proper notification via the so-called chain of command. In this case the chain was made up of non connected individual links. As previously indicated the contract specifically stated that company “A” is made aware of such problems.
The writer prepared a technical report outlining the problems with accompanying suggested fixes. The report was sent to the department director for his review and approval. He sent the report to his bosses, the program manager and the vice president of the company.
Outlined in the report were the ramifications of the problems describing the end effects on the aircraft. Those end effects were from the lowest to the highest end effect were:
1. The arcing (sparking) could effect the proper operation of the flap/slat computer, the inertial navigation computer, the fuel control computer and, other electronic systems.
2. Each time the flaps were retracted, the static charge on the flap surface would arc to the upper skin of the wing or to the rear spar. This charge could be as high as 400-1400 volts. The constant arcing could etch away material, weakening the skin or the spar and open the base metal to corrosion, which would further weaken the structure.
3. The built-up charge on the flaps could result in electrical shock to maintenance personnel.
4. The ungrounded static charge could cause internal arcing in power transmission elements seriously effecting gears and bearings. This would result in higher than normal maintenance, higher parts consumption and, higher operating costs for the operator.
5. The proper grounding is required to eliminate the above problems but the primary requirement for proper grounding or bonding is to protect the aircraft and passengers in the event of a lightning strike. If elements are not properly grounded a lighting strike could result in a localized explosion caused by the expansion of the surrounding air resulting from the induced arcing. The writer referenced a document prepared by company, “A” which specifically stated the design requirements to protect the aircraft from lightning strikes.
6.
The document described the two areas most likely to be hit by lightning. One was the nose radome, which had built in bonding straps, and the other was a partially extended slat. If lightning would attach itself to the partially extended ungrounded slat it could at least cause a total disconnection of the slat drive shaft system. At worst, the lightening arc across to the nearest slat jack and then arc across to the wing structure causing an explosion in the wing fuel tank resulting in the loss of the wing. The lightning strike document also defined the final test of the completed aircraft to verify that all systems and major flight control elements were properly grounded. This test would be performed by company, “A” which also wrote the document.
The response to the writers’ report was not what was expected. The vice president and the program manager stated that they would take no action and they would not comply with the contract, which required our company to notify company “A”. It was their contention that if our company identified a problem of any kind our company would be required to absorb all incurred costs of the redesign.
They further indicated that if company “C” were to identify the defect in the design they would give our company direction to change the design and we would be paid for our efforts
With that, the writer took a trip to Northern Germany to confer with his counterparts in company “C”. They read the writer’s report and their response was “déjà vu - all over again”. They stated that they couldn’t notify the writer’s company of a defect in our design without admitting that their design would have to be altered and, a new stress analysis performed. They too didn’t wish to absorb the cost incurred in the redesign, modification and stress analysis.
This problem was enriching the coffers of the European Airlines, as the writer was now off to England, to visit company “B”. The writer expected a great deal of support from company “B” especially since they were the wing designer and had the overall responsibility of gaining certification. After reading the report, they stated that they were sympathetic to the writer’s plight but they were not in any position to force companies “C”, “D” and,”E” to make the necessary changes. Later, with full knowledge of the design deficiencies and the fact that the flap system was inadequately tested, company “B” obtained certification on the wing.
Now, the writers only hope, was that the lack of electrical bonding of the flaps and slats would be discovered by company “A” when they performed the lightning bonding check, after the aircraft was fully assembled. The writer does not know if the test was never performed or if the test was unable to detect the lack of bonding between the flaps and slats and the wing structure. In either case, every plane that was rolled off the production line was an accident waiting to happen.
The writer could not notify company “A” of the problem because to do so would result in his termination. What the writer did do, was to create a CYA (cover your ass) file. This was necessary, to protect the writer from involvement, in any future litigation that might arise if one of the aircraft crashed. Legal culpability wasn’t a real problem if the aircraft was registered in any country other than the United States. But, if that model aircraft were registered in the United States, the writer would turn over a copy of the CYA file to the FAA Large Aircraft Certification Branch in Seattle, to absolve himself of legal culpability.
The writer returned to his duties as department manager and shortly thereafter the department director, an American was discharged. A German who didn’t understand the organization function replaced him. One of the first actions taken by the new director was to restrict the access of the writer to the test labs. Shortly thereafter, the writer and his staff were placed under the control of the engineering manager.
Since the writer was persona non grata in the test labs, there really wasn’t too much to do other than to concentrate on the training of the German staff members. It was during this lull in the writers’ activities that something happened in the “iron bird” test lab. It was so serious that only a few people knew about it and those, few who knew, were told to keep quiet, and above all, this information was to be withheld from our associate contractors and especially from company “A”.
The writer only learned about the situation after he finished his contract and had been working in Italy for almost six months. The writer’s new position was as a consultant to the director of an Italian helicopter manufacturer. His duties were similar to those in his previous position in Germany. Set up the program and train and supervise the staff.
The writer made frequent trips back to Germany, to visit friends. It was on one such trip that the writer had an opportunity to chat with the previously mentioned English design engineer.
He told me that they had been pressure cycling two hydraulic control modules when one of them developed a hairline crack and began spraying hydraulic fluid all over the lab. The two modules were part of a power control unit, which comprises the two modules, two hydraulic motors and a gearbox. With the exception of the gear box
internal design, the power controls units for the flap and slat drive systems are the same.
The control modules, as the name implies, control the speed and direction of the flaps and the slats. By pressure cycling the modules, the engineers could duplicate the stresses and strains that the module would see during each flight cycle. The pressure would cycle from zero to 3000 pounds per square inch and back to zero. The leak developed at about the 1800th cycle, which was equivalent to 1800 flight hours. The module was disassembled and examined, to determine the cause of the internal crack. A new module was built up and used as a replacement for the defective module. When the replacement module had been cycled 1800 times, the second non-leaking module was connected into the test stand and the test continued until several thousand more cycles were run.
Upon the completion of the tests, the modules, the gearbox and the hydraulic motors were assembled to form a slat power control unit. This unit was then installed on the “iron bird”. As soon as the hydraulic pressure of 3000 pounds per square inch was applied to the module, one of the hydraulic motors began driving the gearbox and the slats started to extend. The engineers were amazed, because the computer and the command sensor unit were both in off or retracted position. The computer was aware that the slats were moving but it couldn’t tell them to stop, because, it had not commanded the slats to start.
The slats moved to the full out position and mechanically locked-up. The problem was traced to an internal hairline crack that allowed the fluid to bypass a control valve and flow directly to the motor. The engineers had no idea how many pressure cycles had been applied before the crack developed. They also determined that the cracks (external and internal) had propagated from the same general area inside the module. The root cause was a faulty manufacturing process.
Had the cracking occurred early on in the “iron bird” development program there would not be much of a problem, but when it did happen, there were about seventeen aircraft in revenue service. This was a major problem that impacted the flight safety of those aircraft as well as the aircraft in flight test and in the production cycle.
If it occurred on the slat system during cruise flight, nothing would happen, because the air loads on the slats were greater that the power developed by the slowly turning hydraulic motor. When the aircraft slowed down to low speed cruise the air loads would decrease and the slats would slowly extend. This too was not much of a problem because the pilot could still control the aircraft. Besides, the pilot would be extending the slats anyway, in preparation for landing.
If an external leak developed, it would result in the loss of a hydraulic system. This would not constitute a problem because the aircraft has three hydraulic systems, and the aircraft could be successfully operated on two hydraulic systems. In a pinch, it could be operated on only one system.
However, if the internal crack developed in the flap power control unit during high-speed flight, the flaps would slowly extend. In the case of the flaps, the air loads assist the flaps in extending. When they extend to a critical point the flaps could be torn away from the wings causing loss of control or the wings could be torn away from the aircraft. Either way the airplane would crash and everyone aboard would perish.
Because of the magnitude of the problem, company “A” and the certification authorities should have been notified and the seventeen operational aircraft should have been grounded until a certifiable fix was implemented. Such was not the case. What company “D” did, was to take seventeen ship-sets of power control units and they incorporated what they felt was an acceptable fix. They then contacted the operators, telling them that they had improved the design of the power control units and they would provide two “improved” units along with a technician to exchange the “improved” units for the installed units. The airlines thought that it was a good deal, so they accepted their offer.
It was never determined if the fix solved the cracking problem. It is the writer’s opinion that the fix will only delay the onset of the crack development.
This information was added to the writer’s CYA file and promptly forgotten. Several months later while perusing an American aviation journal, the writer came across an article stating that the aircraft under discussion was about to receive FAA certification. This caused the writer to take action. He promptly made a photocopy of the CYA file, added a cover letter and fired it off via international airmail to the FAA office in Seattle.
Two months later, the writer received a short letter from the FAA thanking him for his comments. Two months after the first letter a second letter arrived. This letter stated that the FAA had brought the matter to the attention of their French counterparts and the French stated that they were aware of the problems and that the systems were modified to certification standards.
With that news in hand, the writer contacted his English friend who was still working at company “D”. The writer inquired about the status of the system design in light of the French reply to the FAA. The writer was told that the design had not been changed. This prompted a second letter to the FAA, in which the writer absolved himself of any culpability in the event of a crash. The writer further stated in the letter that the FAA would have full responsibility, if they didn’t take action. The writer also requested that his name not be used if the FAA confronted any of the involved companies, as Europe was a fertile ground for a consulting engineer. Since there was a strong interrelationship between European aerospace firms, being blackballed by one firm was to be blackballed by all of them. To further protect himself the writer would inform future clients of his actions before negotiating a contract. The writer was to work on two more contracts in Europe. One in Italy and another in Holland.
While still employed by the Italian Helicopter Company, the writer took his final trip back to Germany. While walking down the main street, the writer observed a BMW pull up to the curb. The door opened and out stepped one of the writers former staff subordinates. He asked the writer if he had written a letter to the FAA. The writer replied that he actually wrote two letters. The writer asked the reason for the question. He was told that there was a major investigation headed by the FAA and that the vice president and the program manager were fired. He also stated that the FAA had shown my letter to everyone involved. So much for future work in the European aircraft industry.
While still working in Europe, the writer made frequent trips to England and Northern Europe. On several of those trips the writer found himself flying on one of those infamous aircraft. It was white knuckles all the way. The writer was constantly observing the wings waiting for something to happen. In Europe, passengers can request to go forward to the flight deck. On those trips, the writer would query the pilots as to how they would counter a flap runaway or non-commanded flap operation. They would always state that it would never happen, because the computer would stop it. Upon hearing their answer, the writer told them the story. When the writer finished, the pilots would stare blankly out the window. The writer then told them how to counter such a condition by shutting down two of the three hydraulic systems. This would stop the movement. The writer went on to say that they could then turn on one of the two systems. If the flaps started to move, that switch would be placed in the off position and the other switch turned on. If the flaps didn’t move, when the first switch was turned on, then the second switch would be left in the off position. The writer further stated that they had only a few seconds to take their initial action of turning both systems off. The writer further suggested that the pilots inform their training departments, so that this condition could be incorporated into the simulator-training syllabus.
Upon returning to the United States, the writer would on occasion contact any new operators of the company “A” aircraft, telling their training department of the problem and suggesting that they incorporate the flap runaway condition into their simulator program. Once, when the writer was on a well-deserved vacation, visiting his oldest son in Montana, he contacted another operator to explain the problem and the suggested counter action. They expressed some degree of surprise at his calling and thanked him. Several days later the writer received a call. The woman on the other end of the line identified herself as a member of the legal staff of the American subsidiary of company “A”. She stated that the operator who wondered why they had not been informed of such a serious problem had contacted her office.
The lawyer asked the writer why he was badmouthing their product, which had been certified by the European and American authorities. The writer explained that the problem was kept secret from her company and that he made those calls in the interest of safety and not to defame her company and its products. The writer told the lawyer that he would gladly stop making the calls, if the lawyer could arrange a telephone conference between himself and an engineer, who could explain exactly how company “A” solved all the problems. She agreed to set up such a teleconference but needless to say, the call never came. The writer did stop making his calls, but he didn’t lose interest.
FOLLOW ON INFORMATION: The nature of the program was that companies “D” and “E’ would alternate in the lead rolls in the design of the flap and slat drive systems. On the follow on aircraft, company “E” would direct the efforts of company “F” the builders of the flap slat computer. Company “F” openly stated that if company “E” were lead contractor, company “F” would break from the consortia and bid on the contract as an independent firm. I do not know if this came to pass as by that time I left the program. In any case, I firmly believe that company “F” was intransigent in their way of doing things and did not adequately perform a proper Failure Mode Effects Analysis on the Flap Slat computer so the problem goes on. As an added note an Air Canada A-320 had the flaps retract during takeoff and the computer did not stop this action and the pilots had to power their way out of the situation.
If you fly an Airbus and your Flaps or Slats have uncommanded movement you can do one of two things. Shut off both hydraulic systems powering the effected system. Turn one system on. If the system moves then shut that system off and turn the other system on. If the system does not move, leave the other system off. You can also take your chances by turning one system off and leaving the other system on. If the movement stops then leave the other system on. You have to be fast for the second option because if you guessed wrong the following air loads will pull the flaps out and then there is a third thing to do and that is to pray.
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The Cat
This was the writer’s second tour in Germany. He had previously worked as a contract manager on a major European fighter aircraft program. In the performance of his duties on his second tour the writer functioned as department manager and the writer was required to interface with other European companies that were involved on the same aircraft design and development program. In certain cases the writer would direct or advise individuals working within those companies.
In total, there were six companies, including the firm the writer was on contract to. The companies and their responsibilities are shown below.
Company “A”: This firm was the primary design authority and the primary integrator. They developed all primary design specifications, manufactured some major structural elements and assembled the aircraft. They also had the primary certification responsibility for the entire aircraft with the exception of the wings.
Company “B”: This firm designed the wing structure and had design authority over all of the various companies that supplied elements of the wing to include flaps, slats, flap and slat drive systems, fuel systems and interface with engine and landing gear suppliers. This firm also was responsible for the certification of the wings.
Company “C”: The responsibility of company “C” was that of wing integrator. There was minimal design responsibility and minimal certification sign-off. The primary function of company “C” was to take the wing structure which was built by company “B” and install the systems that were built by other firms to include companies “D” and “E” (see below). The completed wing was sent to company “A”, who installed it on the completed airframe.
Company “D”: Companies “D” and “E” shared component design and manufacturing responsibilities. In some cases, one company would design a component and the other company would manufacture that component and that part would then be used in the systems designed by either company. Company “D” had design responsibility for the slat drive system. This included the preparation of Reliability and Safety documents as well as after market product support. This is the firm where the writer was employed. The writer was also the lead engineer with overall responsibility for Reliability, Maintainability and Systems Safety documentation created by companies “D”, “E” and “F”.
Company “E” was responsible for the design of the flap drive system. The flap drive mechanism was designed and built by company “D” and the actuation system was designed and built by company “E”. Interconnecting shafting was designed and built by company “E” which also designed and built the tracks or rails that supported the flaps during their transition from the closed to open and back to the closed position.
Company “F”: Company “F” worked under the design control of company “D” which prepared the design specification for the computer which controlled the operation of the flap and slat drive systems. Company “F” built the flap and slat computer. The computer was designed and built with a great deal of system redundancy to include a self-diagnostic capability. The high degree of redundancy was necessary to minimize the possibility of placing the aircraft in jeopardy due to a system malfunction. Any computer-detected malfunction would cause the respective system to shut down. Additional responsibilities included all related Reliability, Maintainability and Systems Safety documentation.
To avoid any confusion by the reader in his or her attempt to digest the alphabet soup created when inter relating the misdeeds of companies A, B, C, D,E and, F, the writer will attempt to break them down into more easily absorbed components.
Both firms “D” and “E” constructed an “Iron Bird” of their respective systems. An “Iron Bird” is a functional mock-up that allows the system designers to simulate the operation of their systems. The systems comprise all of the dynamic elements of the system to include drive elements, gearboxes, shafting, position indicating units and dynamic braking elements. The “Iron Bird” actuating elements are connected directly to controllable load cells, which simulate the air, loads that the slats or flaps would react during flight. A separate computer and not the flap/slat computer control the load cells. Since the two “Iron Birds” were about 900 miles from each other it required that each “Bird” have its own flap/slat computer. Such was not the case.
Company “F” furnished company “D” with a fully functional “brass board” flap/slat computer. A “brass board” computer had all of the capabilities of a flight worthy computer but it was not built to a full production standard. What company “F” furnished company “E” was equivalent to one eighth of the “brass board” computer being used by company “D”. As previously stated, the flap/slat computer had a very high level of redundancy. The computer is broken into two major elements and each major element was broken down into four sub-elements. What company “E” received was one of the sub-elements.
The reason given by company “F” for refusing to provide a “brass board” to company “E” was that they suspected company “E” of luring away key employees of company “F” and stealing trade secrets. The writer’s company (“D”
tried to intercede but company “F” steadfastly refused to cooperate. The writer made companies “B” and “C” aware of the problem and they took no action. Although the contract specifically stated, that any situation that impacted the Reliability Maintainability and Systems Safety of the aircraft must be brought to the attention of company “A”, it never was.The small portion of the flap/slat computer would allow commands to be sent to the flap drive unit on the “iron bird”, extending and retracting the flaps, but there was absolutely no diagnostic capability. The non-redundant element was “dumb” and if any malfunctions were to arise on the flap “iron bird” the problems would have to be solved using troubleshooting techniques initiated by technicians. One of the main purposes of the flap/slat computer was to diagnose problems and provide the technician with a real time indication as to which element of the system was at fault. The other purpose was to protect the aircraft from being damaged or being placed in aerodynamic jeopardy.
The prime purpose of the “iron bird” was to verify not only the flap system but the computer as well. This would be accomplished via insertion of known faults to determine if the computer was capable of detecting those faults.
Upon completion of all the testing, the documentation would be submitted to company “B” who would draft the request for certification for the flap system. Since only 5-10% of the overall test program was accomplished, the flap system was incapable of being certified. Company “A” was unaware of this situation and it can be logically assumed that the certification authorities were also unaware. The aircraft was eventually certified and has been in series production since that time
On the very first revenue flight, for a launch customer airline, one of these “certified” aircraft landed in Egypt and during taxi in, the pilot was unable to retract the flaps. Technicians checked the indicators on the flight deck and on the computer to no avail. The computer did not recognize the fault. As a result, the aircraft was flown back to Northern Europe in non-revenue status with the flaps fully extended. Upon reaching the home base, the technicians and engineers were unable to determine the cause of the lock-up. They eventually disconnected the drive system and hand cranked the flaps to the retracted position. Upon reconnecting the system, the flaps were cycled in and out several times and the aircraft was placed back in revenue service.
During the cycling of a sub-scale “iron bird/ where only a single slat actuator was being tested against a simulated air load, the test department at company “D” decided to disassemble the actuator to check it for wear. It was after the disassembly and cleaning of the parts that the writer was called in to checkout one of the parts. Examining the part under high power magnification, the writer observed what looked like a spider web pattern that had been etched into the flat surface of the part. Further inspection under a microscope showed tiny indentations or pits that were extremely small. The indentations were so close together that the pattern looked like fine lines etched in the surface. Inspection of the mating surface showed a mirror image of the same etched pattern.
The writer had seen this phenomenon before. Stray or ungrounded electrical currents that caused sparking between mating parts caused it. The writer discussed the problem with the stress engineer who stated that he too had seen the part but he insisted that it wasn’t spark erosion. He said it was stress corrosion. The writer knew that it was a no win situation to argue a point with a German engineer.
When the sub-scale “iron bird” was put back in service, the writer had a technician in the product support group perform a test. The test was to determine if there was electrical continuity between the actuator and the sub-scale “bird”. He reported that there was no continuity.
This indicated that the electrical currents, generated by internal friction of the actuator parts, could not flow to the ground potential of the “iron bird”. The writer was satisfied that his conclusion was in fact correct. Spark erosion could destroy the bearings and the highly polished surfaces of the actuator, running up the maintenance costs and possibly cause operational problems.
Armed with this knowledge, the writer spoke with a senior design engineer who was English not German. He authorized a check of the “iron bird” to see if the same problem could be detected. It could, and it was. The iron bird installation was in accordance with the same drawings that were used to install the system on the aircraft. If no continuity existed on one, it would not exist on the other, and this was a major violation of the certification requirements. The writer made a trip to England to talk to his counterpart at company “E”. He ran a continuity check of the flap drive installation on his “iron bird” and verified that his system was also ungrounded This further compounded the problem of not being able to properly certify the wing flap system due to inadequate testing. Now, not only were the flaps not properly tested, but also both the flap and slat systems were not properly grounded. If both of these situations had been made known to either company “A” or the certification authorities, the systems would have to be redesigned, the wing would have to be modified and a new stress analysis performed. Also, the flap system would have to be re-tested using a full-up computer. Yet company “A” and the certification authorities were unaware of the problem even though the writer made a noble attempt to make the proper notification via the so-called chain of command. In this case the chain was made up of non connected individual links. As previously indicated the contract specifically stated that company “A” is made aware of such problems.
The writer prepared a technical report outlining the problems with accompanying suggested fixes. The report was sent to the department director for his review and approval. He sent the report to his bosses, the program manager and the vice president of the company.
Outlined in the report were the ramifications of the problems describing the end effects on the aircraft. Those end effects were from the lowest to the highest end effect were:
1. The arcing (sparking) could effect the proper operation of the flap/slat computer, the inertial navigation computer, the fuel control computer and, other electronic systems.
2. Each time the flaps were retracted, the static charge on the flap surface would arc to the upper skin of the wing or to the rear spar. This charge could be as high as 400-1400 volts. The constant arcing could etch away material, weakening the skin or the spar and open the base metal to corrosion, which would further weaken the structure.
3. The built-up charge on the flaps could result in electrical shock to maintenance personnel.
4. The ungrounded static charge could cause internal arcing in power transmission elements seriously effecting gears and bearings. This would result in higher than normal maintenance, higher parts consumption and, higher operating costs for the operator.
5. The proper grounding is required to eliminate the above problems but the primary requirement for proper grounding or bonding is to protect the aircraft and passengers in the event of a lightning strike. If elements are not properly grounded a lighting strike could result in a localized explosion caused by the expansion of the surrounding air resulting from the induced arcing. The writer referenced a document prepared by company, “A” which specifically stated the design requirements to protect the aircraft from lightning strikes.
6.
The document described the two areas most likely to be hit by lightning. One was the nose radome, which had built in bonding straps, and the other was a partially extended slat. If lightning would attach itself to the partially extended ungrounded slat it could at least cause a total disconnection of the slat drive shaft system. At worst, the lightening arc across to the nearest slat jack and then arc across to the wing structure causing an explosion in the wing fuel tank resulting in the loss of the wing. The lightning strike document also defined the final test of the completed aircraft to verify that all systems and major flight control elements were properly grounded. This test would be performed by company, “A” which also wrote the document.
The response to the writers’ report was not what was expected. The vice president and the program manager stated that they would take no action and they would not comply with the contract, which required our company to notify company “A”. It was their contention that if our company identified a problem of any kind our company would be required to absorb all incurred costs of the redesign.
They further indicated that if company “C” were to identify the defect in the design they would give our company direction to change the design and we would be paid for our efforts
With that, the writer took a trip to Northern Germany to confer with his counterparts in company “C”. They read the writer’s report and their response was “déjà vu - all over again”. They stated that they couldn’t notify the writer’s company of a defect in our design without admitting that their design would have to be altered and, a new stress analysis performed. They too didn’t wish to absorb the cost incurred in the redesign, modification and stress analysis.
This problem was enriching the coffers of the European Airlines, as the writer was now off to England, to visit company “B”. The writer expected a great deal of support from company “B” especially since they were the wing designer and had the overall responsibility of gaining certification. After reading the report, they stated that they were sympathetic to the writer’s plight but they were not in any position to force companies “C”, “D” and,”E” to make the necessary changes. Later, with full knowledge of the design deficiencies and the fact that the flap system was inadequately tested, company “B” obtained certification on the wing.
Now, the writers only hope, was that the lack of electrical bonding of the flaps and slats would be discovered by company “A” when they performed the lightning bonding check, after the aircraft was fully assembled. The writer does not know if the test was never performed or if the test was unable to detect the lack of bonding between the flaps and slats and the wing structure. In either case, every plane that was rolled off the production line was an accident waiting to happen.
The writer could not notify company “A” of the problem because to do so would result in his termination. What the writer did do, was to create a CYA (cover your ass) file. This was necessary, to protect the writer from involvement, in any future litigation that might arise if one of the aircraft crashed. Legal culpability wasn’t a real problem if the aircraft was registered in any country other than the United States. But, if that model aircraft were registered in the United States, the writer would turn over a copy of the CYA file to the FAA Large Aircraft Certification Branch in Seattle, to absolve himself of legal culpability.
The writer returned to his duties as department manager and shortly thereafter the department director, an American was discharged. A German who didn’t understand the organization function replaced him. One of the first actions taken by the new director was to restrict the access of the writer to the test labs. Shortly thereafter, the writer and his staff were placed under the control of the engineering manager.
Since the writer was persona non grata in the test labs, there really wasn’t too much to do other than to concentrate on the training of the German staff members. It was during this lull in the writers’ activities that something happened in the “iron bird” test lab. It was so serious that only a few people knew about it and those, few who knew, were told to keep quiet, and above all, this information was to be withheld from our associate contractors and especially from company “A”.
The writer only learned about the situation after he finished his contract and had been working in Italy for almost six months. The writer’s new position was as a consultant to the director of an Italian helicopter manufacturer. His duties were similar to those in his previous position in Germany. Set up the program and train and supervise the staff.
The writer made frequent trips back to Germany, to visit friends. It was on one such trip that the writer had an opportunity to chat with the previously mentioned English design engineer.
He told me that they had been pressure cycling two hydraulic control modules when one of them developed a hairline crack and began spraying hydraulic fluid all over the lab. The two modules were part of a power control unit, which comprises the two modules, two hydraulic motors and a gearbox. With the exception of the gear box
internal design, the power controls units for the flap and slat drive systems are the same.
The control modules, as the name implies, control the speed and direction of the flaps and the slats. By pressure cycling the modules, the engineers could duplicate the stresses and strains that the module would see during each flight cycle. The pressure would cycle from zero to 3000 pounds per square inch and back to zero. The leak developed at about the 1800th cycle, which was equivalent to 1800 flight hours. The module was disassembled and examined, to determine the cause of the internal crack. A new module was built up and used as a replacement for the defective module. When the replacement module had been cycled 1800 times, the second non-leaking module was connected into the test stand and the test continued until several thousand more cycles were run.
Upon the completion of the tests, the modules, the gearbox and the hydraulic motors were assembled to form a slat power control unit. This unit was then installed on the “iron bird”. As soon as the hydraulic pressure of 3000 pounds per square inch was applied to the module, one of the hydraulic motors began driving the gearbox and the slats started to extend. The engineers were amazed, because the computer and the command sensor unit were both in off or retracted position. The computer was aware that the slats were moving but it couldn’t tell them to stop, because, it had not commanded the slats to start.
The slats moved to the full out position and mechanically locked-up. The problem was traced to an internal hairline crack that allowed the fluid to bypass a control valve and flow directly to the motor. The engineers had no idea how many pressure cycles had been applied before the crack developed. They also determined that the cracks (external and internal) had propagated from the same general area inside the module. The root cause was a faulty manufacturing process.
Had the cracking occurred early on in the “iron bird” development program there would not be much of a problem, but when it did happen, there were about seventeen aircraft in revenue service. This was a major problem that impacted the flight safety of those aircraft as well as the aircraft in flight test and in the production cycle.
If it occurred on the slat system during cruise flight, nothing would happen, because the air loads on the slats were greater that the power developed by the slowly turning hydraulic motor. When the aircraft slowed down to low speed cruise the air loads would decrease and the slats would slowly extend. This too was not much of a problem because the pilot could still control the aircraft. Besides, the pilot would be extending the slats anyway, in preparation for landing.
If an external leak developed, it would result in the loss of a hydraulic system. This would not constitute a problem because the aircraft has three hydraulic systems, and the aircraft could be successfully operated on two hydraulic systems. In a pinch, it could be operated on only one system.
However, if the internal crack developed in the flap power control unit during high-speed flight, the flaps would slowly extend. In the case of the flaps, the air loads assist the flaps in extending. When they extend to a critical point the flaps could be torn away from the wings causing loss of control or the wings could be torn away from the aircraft. Either way the airplane would crash and everyone aboard would perish.
Because of the magnitude of the problem, company “A” and the certification authorities should have been notified and the seventeen operational aircraft should have been grounded until a certifiable fix was implemented. Such was not the case. What company “D” did, was to take seventeen ship-sets of power control units and they incorporated what they felt was an acceptable fix. They then contacted the operators, telling them that they had improved the design of the power control units and they would provide two “improved” units along with a technician to exchange the “improved” units for the installed units. The airlines thought that it was a good deal, so they accepted their offer.
It was never determined if the fix solved the cracking problem. It is the writer’s opinion that the fix will only delay the onset of the crack development.
This information was added to the writer’s CYA file and promptly forgotten. Several months later while perusing an American aviation journal, the writer came across an article stating that the aircraft under discussion was about to receive FAA certification. This caused the writer to take action. He promptly made a photocopy of the CYA file, added a cover letter and fired it off via international airmail to the FAA office in Seattle.
Two months later, the writer received a short letter from the FAA thanking him for his comments. Two months after the first letter a second letter arrived. This letter stated that the FAA had brought the matter to the attention of their French counterparts and the French stated that they were aware of the problems and that the systems were modified to certification standards.
With that news in hand, the writer contacted his English friend who was still working at company “D”. The writer inquired about the status of the system design in light of the French reply to the FAA. The writer was told that the design had not been changed. This prompted a second letter to the FAA, in which the writer absolved himself of any culpability in the event of a crash. The writer further stated in the letter that the FAA would have full responsibility, if they didn’t take action. The writer also requested that his name not be used if the FAA confronted any of the involved companies, as Europe was a fertile ground for a consulting engineer. Since there was a strong interrelationship between European aerospace firms, being blackballed by one firm was to be blackballed by all of them. To further protect himself the writer would inform future clients of his actions before negotiating a contract. The writer was to work on two more contracts in Europe. One in Italy and another in Holland.
While still employed by the Italian Helicopter Company, the writer took his final trip back to Germany. While walking down the main street, the writer observed a BMW pull up to the curb. The door opened and out stepped one of the writers former staff subordinates. He asked the writer if he had written a letter to the FAA. The writer replied that he actually wrote two letters. The writer asked the reason for the question. He was told that there was a major investigation headed by the FAA and that the vice president and the program manager were fired. He also stated that the FAA had shown my letter to everyone involved. So much for future work in the European aircraft industry.
While still working in Europe, the writer made frequent trips to England and Northern Europe. On several of those trips the writer found himself flying on one of those infamous aircraft. It was white knuckles all the way. The writer was constantly observing the wings waiting for something to happen. In Europe, passengers can request to go forward to the flight deck. On those trips, the writer would query the pilots as to how they would counter a flap runaway or non-commanded flap operation. They would always state that it would never happen, because the computer would stop it. Upon hearing their answer, the writer told them the story. When the writer finished, the pilots would stare blankly out the window. The writer then told them how to counter such a condition by shutting down two of the three hydraulic systems. This would stop the movement. The writer went on to say that they could then turn on one of the two systems. If the flaps started to move, that switch would be placed in the off position and the other switch turned on. If the flaps didn’t move, when the first switch was turned on, then the second switch would be left in the off position. The writer further stated that they had only a few seconds to take their initial action of turning both systems off. The writer further suggested that the pilots inform their training departments, so that this condition could be incorporated into the simulator-training syllabus.
Upon returning to the United States, the writer would on occasion contact any new operators of the company “A” aircraft, telling their training department of the problem and suggesting that they incorporate the flap runaway condition into their simulator program. Once, when the writer was on a well-deserved vacation, visiting his oldest son in Montana, he contacted another operator to explain the problem and the suggested counter action. They expressed some degree of surprise at his calling and thanked him. Several days later the writer received a call. The woman on the other end of the line identified herself as a member of the legal staff of the American subsidiary of company “A”. She stated that the operator who wondered why they had not been informed of such a serious problem had contacted her office.
The lawyer asked the writer why he was badmouthing their product, which had been certified by the European and American authorities. The writer explained that the problem was kept secret from her company and that he made those calls in the interest of safety and not to defame her company and its products. The writer told the lawyer that he would gladly stop making the calls, if the lawyer could arrange a telephone conference between himself and an engineer, who could explain exactly how company “A” solved all the problems. She agreed to set up such a teleconference but needless to say, the call never came. The writer did stop making his calls, but he didn’t lose interest.
FOLLOW ON INFORMATION: The nature of the program was that companies “D” and “E’ would alternate in the lead rolls in the design of the flap and slat drive systems. On the follow on aircraft, company “E” would direct the efforts of company “F” the builders of the flap slat computer. Company “F” openly stated that if company “E” were lead contractor, company “F” would break from the consortia and bid on the contract as an independent firm. I do not know if this came to pass as by that time I left the program. In any case, I firmly believe that company “F” was intransigent in their way of doing things and did not adequately perform a proper Failure Mode Effects Analysis on the Flap Slat computer so the problem goes on. As an added note an Air Canada A-320 had the flaps retract during takeoff and the computer did not stop this action and the pilots had to power their way out of the situation.
If you fly an Airbus and your Flaps or Slats have uncommanded movement you can do one of two things. Shut off both hydraulic systems powering the effected system. Turn one system on. If the system moves then shut that system off and turn the other system on. If the system does not move, leave the other system off. You can also take your chances by turning one system off and leaving the other system on. If the movement stops then leave the other system on. You have to be fast for the second option because if you guessed wrong the following air loads will pull the flaps out and then there is a third thing to do and that is to pray.
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The Cat
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Just in case you didn't see this on the A-320 thread below I am adding it in for your further information.
In a previous post someone made the comment about mismatched wires and indexed connector plugs and how could this lead to the problem discussed in this thread. Here is how it could happen. A major German supplier of power drive systems for the secondary flight control systems on Airbus Aircraft did not incorporate indexed electrical connectors on any of the components they supplied on the A-310. It was their contention that they would impact the delivery schedule of their systems to the wing integrator and besides, it would have a severe impact on the cost of their equipment.
With this in mind consider the following. The only means incorporated in the wiring system to combat misconnection of connectors onto an appliance was tiebacks on the wire looms. The first time the appliances required maintenance or were removed for cause thew tiebacks were cut. After the maintenance the tiebacks were either not replaced or, they were not in the same condition as before the maintenance. This would allow for cross connecting. If the wires were cross-connected on the PPUs the first time power was applied the flap or slat system would shut down and the computer could not diagnose the problem. If the wires on the command sensor unit were cross connected there would be no indication as to the problem but it would seriously impact the problem of trouble shooting if a defect were to occur.
If a connector were mis connected on the power control unit the system would not operate correctly and the effected system would most likely lock up and to top it off the computer may not be able to diagnose the problem.
I can’t say if this problem was rectified on later models but it still exists on the A-310.
If you want to hear more about this and other problems go to my posting entitled “How safe is your aircraft”?, on these threads.
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The Cat
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The Cat
In a previous post someone made the comment about mismatched wires and indexed connector plugs and how could this lead to the problem discussed in this thread. Here is how it could happen. A major German supplier of power drive systems for the secondary flight control systems on Airbus Aircraft did not incorporate indexed electrical connectors on any of the components they supplied on the A-310. It was their contention that they would impact the delivery schedule of their systems to the wing integrator and besides, it would have a severe impact on the cost of their equipment.
With this in mind consider the following. The only means incorporated in the wiring system to combat misconnection of connectors onto an appliance was tiebacks on the wire looms. The first time the appliances required maintenance or were removed for cause thew tiebacks were cut. After the maintenance the tiebacks were either not replaced or, they were not in the same condition as before the maintenance. This would allow for cross connecting. If the wires were cross-connected on the PPUs the first time power was applied the flap or slat system would shut down and the computer could not diagnose the problem. If the wires on the command sensor unit were cross connected there would be no indication as to the problem but it would seriously impact the problem of trouble shooting if a defect were to occur.
If a connector were mis connected on the power control unit the system would not operate correctly and the effected system would most likely lock up and to top it off the computer may not be able to diagnose the problem.
I can’t say if this problem was rectified on later models but it still exists on the A-310.
If you want to hear more about this and other problems go to my posting entitled “How safe is your aircraft”?, on these threads.
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The Cat
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The Cat
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Why is everybody complaining about the way the airbus is built? Boeing also assembles the planes in the Seattle area form components gathered all over the globe. Everybody that has ever had to deal with maintenance knows that almost every plane is different. serial# ... has this ,but from serial#.... this system is installed, modified after serial#.... Sounds familiar? Fun to do maintenance with all this fine print
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To: Streamline:
As indicated in the posting I worked on the program as manager of RMS on the wing secondary flight control system. Everything in the post is true. I have been in the industry since 1955 and I started in RMS in 1968. I have found problems on every program that I worked on and 90% of the things that were wrong were never corrected because of many reasons including cost and pride of the designer. I swear that I will never do this work again for the above reasons but I can't do anything else unless it is teaching which I do on occasion. I am now working on the newest Jet to come onto the market and when I finish that job I'll be working on the A380. I'm 70 years old and I'm still slogging my way through life.
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The Cat
As indicated in the posting I worked on the program as manager of RMS on the wing secondary flight control system. Everything in the post is true. I have been in the industry since 1955 and I started in RMS in 1968. I have found problems on every program that I worked on and 90% of the things that were wrong were never corrected because of many reasons including cost and pride of the designer. I swear that I will never do this work again for the above reasons but I can't do anything else unless it is teaching which I do on occasion. I am now working on the newest Jet to come onto the market and when I finish that job I'll be working on the A380. I'm 70 years old and I'm still slogging my way through life.
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The Cat
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Sure know now why many companies' travel departments avoid travel on AirBus aircraft if at all possible.
To be fair, the Boeing Company has not been all that straightforward with regard to the rudder hardover incidents, which date all the way back to the 707.
And Douglas....well the DC10 after inital problems has turned out ok, only now to be retired by many airlines (except as freighters). The MD-11 seems to turn turtle on landing from time to time,.....so that leaves....the Lockheed L1011 as the best?
To those that have flown this wonderful aircraft, nothing is better.
To be fair, the Boeing Company has not been all that straightforward with regard to the rudder hardover incidents, which date all the way back to the 707.
And Douglas....well the DC10 after inital problems has turned out ok, only now to be retired by many airlines (except as freighters). The MD-11 seems to turn turtle on landing from time to time,.....so that leaves....the Lockheed L1011 as the best?
To those that have flown this wonderful aircraft, nothing is better.
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LU Z.
I have read your posting and I understand fully that you were wondering why there were no comments/reactions.
An eye opener it is, your article and the way it is written makes it understandable for all in this industry. Companies A through
F.are easely identified.
Now, with your experience and insight, would you agree with me that at the U.S side of the ocean there are also companies A to Z in the same industry and having the same ethics.
(Now Tower D. is gonna read your article in full )
I also took the effort to look up several of your previous postings and I am with Straemline here, you are an "asset" worth to have in house.
And as for company "D", we where not impressed from were I came from.
I will read your future postings anytime.
Best regards
AV
I have read your posting and I understand fully that you were wondering why there were no comments/reactions.
An eye opener it is, your article and the way it is written makes it understandable for all in this industry. Companies A through
F.are easely identified.
Now, with your experience and insight, would you agree with me that at the U.S side of the ocean there are also companies A to Z in the same industry and having the same ethics.
(Now Tower D. is gonna read your article in full )
I also took the effort to look up several of your previous postings and I am with Straemline here, you are an "asset" worth to have in house.
And as for company "D", we where not impressed from were I came from.
I will read your future postings anytime.
Best regards
AV
Guest
Posts: n/a
Yes, the whole saga made me think about the 737 hardover issue (although there it is only Boeing primarily involved on that one)
The advice to pilots regarding shutting down the hydraulics reminded me of the DC-10 which lost control to the elevators in-flight. The pilot had previously considered this possibility and (independantly) practiced landing on differential flaps (or was it slats? long time ago) on the sim, and as result got the 'plane down safely.
The modern transport aircraft is a wonder of self-diagnosing and redundant systems so it's not surprising that accident rates are low; but there's always been the "if this happens, and if then that happens" possibilities. Irresponsible of manufacturers (whether East or West of the Atlantic) to sweep safety under the carpet, or "cost evaluate" pax lives.
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What goes around . . .
. . often lands better!
The advice to pilots regarding shutting down the hydraulics reminded me of the DC-10 which lost control to the elevators in-flight. The pilot had previously considered this possibility and (independantly) practiced landing on differential flaps (or was it slats? long time ago) on the sim, and as result got the 'plane down safely.
The modern transport aircraft is a wonder of self-diagnosing and redundant systems so it's not surprising that accident rates are low; but there's always been the "if this happens, and if then that happens" possibilities. Irresponsible of manufacturers (whether East or West of the Atlantic) to sweep safety under the carpet, or "cost evaluate" pax lives.
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What goes around . . .
. . often lands better!
Guest
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It is an amazing account. Sadly it is all too common in todays litigious world. I have never had a problem with the flaps on the A320 but I do know of a nasty incident when negative g activated the wing tip brake with the flaps at full. The ECAM said place the flap lever to 3 (it assumed asymmetry) and the crew then had the wrong flight control bias for the existing flap position. That was a computer software problem, but it was swept under the carpet in a similar manner.
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FL390
Part of the problem is that people are not prepared to listen to or read such accounts. I did read it through, it took all of 5 minutes. Furthermore there is nothing in the least amusing about it. It is potentially a nightmare situation for you guys out there who have to fly the aircraft. I do not fly it anymore, although I had a very high regard for it when I did.
Part of the problem is that people are not prepared to listen to or read such accounts. I did read it through, it took all of 5 minutes. Furthermore there is nothing in the least amusing about it. It is potentially a nightmare situation for you guys out there who have to fly the aircraft. I do not fly it anymore, although I had a very high regard for it when I did.
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Very interesting reading to say the least. I would suggest that people print this out and take time to read it. You'll have no problems identifying the companies involved. And this shouldn't just interest Airbus fliers, but all pilots, because you can be damn sure that ths kind of thing happens at all Airplane Manufacturers, whether they sub-contract or not.
Thank's LU, it's having people like you posting on PPRuNe that make it worthwhile logging on. Scary to think that selecting a flap setting (or activating your rudder) could trigger off a disaster, all because the maufacturers want to save money or even save face.
Thank's LU, it's having people like you posting on PPRuNe that make it worthwhile logging on. Scary to think that selecting a flap setting (or activating your rudder) could trigger off a disaster, all because the maufacturers want to save money or even save face.
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I'm not a pilot, just another sort of techie, but I read it all the way through. Twice.
Deja vu all over again.
The saga of the booster joints on the Challenger shuttle is eerily similar, with tenders, competing companies, CYA files, warning events, "lost" reports etc.
There are plenty of similar stories in my field. Try building a hospital.
Is this sort of "company/project culture" an unchangeable, inevitable part of human nature?
Will we EVER learn? I dunno.
Courageous post. Pity that there aren't more people like Lu around.
Deja vu all over again.
The saga of the booster joints on the Challenger shuttle is eerily similar, with tenders, competing companies, CYA files, warning events, "lost" reports etc.
There are plenty of similar stories in my field. Try building a hospital.
Is this sort of "company/project culture" an unchangeable, inevitable part of human nature?
Will we EVER learn? I dunno.
Courageous post. Pity that there aren't more people like Lu around.
Guest
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Many of the younger guys have been mesmerized by the AirBus FBW system, and how it can "protect" the pilot from a problem. The older guys certainly know better, Murphy's law is there to catch the unwary. In addition, it has created a group of young guys who have VERY poor airmanship, and a lack of understanding of the required aeronautical skills. The type is best be avoided, crew or pax.
Guest
Posts: n/a
My intuition tells me that in order to increase their share of the market Airbus was forced to explore new areas, hence new and greather risk.
In stead of using the FBW to improve on performance they concentrated on the flight control laws, affecting the pilots more than payload.
Once they found the money to finance it there was no way back.
We will see how big a gamble the A 380 will turn out to be.
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Smooth Trimmer
[This message has been edited by Streamline (edited 06 June 2001).]
In stead of using the FBW to improve on performance they concentrated on the flight control laws, affecting the pilots more than payload.
Once they found the money to finance it there was no way back.
We will see how big a gamble the A 380 will turn out to be.
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Smooth Trimmer
[This message has been edited by Streamline (edited 06 June 2001).]