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Aviation History
1994
1994 - 0081.PDF
SMART MAINTENANCE • sJa&BS Colin Murfet "The one that delivers the really hig numbers is engine monitoring." acquisition unit to a DQAR. The original ground-based data- processing system's software for the BA/ CAA automatic-landing tests was known as special-event search-and-master analy sis (SESMA) — a perfect definition of what it was designed to achieve. SESMA is no longer just a piece of software: it is now the term used to describe the whole BA programme to gather and use flight and ACMS data. Baxter, describing the SESMA system's purpose, says: "It triggers off a warning if any parameters exceed a pre-determined envelope." Usually, an operational inci dent provides the warning. The event is not necessarily one which would trigger a warning on the pilot's master-warning system; if it did, however, the pilot would file a mandatory-occurrence report (MOR). Meanwhile, it is recorded on the DQAR data analysis. A tape from a lOh flight can be searched in about lOmin. "Fundamentally, it's looking at non standard bits of flying," Baxter adds, emphasising that the non-standard han dling might have been caused by an engineering error. A classic incident would be a tailscrape, says Baxter, quoting Boeing 757s and "the long 767s" as examples. The system can enable precise determination of the inci dent's cause. Was it pure piloting error? Is it happening more often on a particular airframe than others of the same type and, if so, why? Is it happening across a type fleet — perhaps a flight-management- system software error leading to incorrect AND CURE attitude demands from the flight director? The latter, during climb rather than rotate, has been detected at Qantas with this system and a software correction has been made. The warning does no have to wait for the actua tailscrape, Baxter emphasises; it can be set to trigger if it comes within a degree. SPIN-OFF Flight-crew performance moni toring can be a spin-off from such a system. Airlines — in cluding BA — which operate it, all have specific agreements with aircrew unions about how the pilot-performance data should be analysed and even applied to continuation training if necessary. BA also has a system, called BASIS (BA systems information service), for process ing the data from MORs filed by pilots, and data from these and the SESMA are analysed together. DQAR data, explains Baxter, "...gives us the ability to look back at [the occurrences reported in] MORs and see how bad it was". Intelligently selecting the data to be recorded is essential in data management, where the quantity of data is potentially so massive. The number of parame ters monitored today, says Murfet, is around 20,000. BA defines the en velopes, outside which information is recorded, explains Baxter, by "...look ing for a deviation from the ideal, not just for near-emer gencies". The next step, he says, "...is automat ing the flow of in formation and greater intelligence in the monitoring of it". When the use of airborne datalinking becomes extensive, unless the information is filtered intel ligently, then the datalink channels would be swamped, he points out. He says that the datalinks can handle "...only 100,000th of what the QAR can record." The number of parameters monitored will increase, Baxter predicts, making intelligent filter ing even more vital. He foresees "smart skins" — the monitoring of aircraft skin stresses — but he Engine work can be planned, according to its condition emphasises that this addition depends upon success in the development of infor mation-filtering software. "Ultimately, there is a possibility that the FDR [onboard data-recording sys tems] will give data to such a resolution that you can feed it into a [flight] simulator. We are not there yet, but we have taken some steps down that road," he says. The replacement of tape DQARs with optical QARs (OQARs) in some airlines is imminent. These re cord on optical disks, giving random access which tape is unable to. Murfet also says that OQARs give "a tenfold capacity in crease", with quicker download. US airlines, even the largest, have been slow compared with Euro peans and others in electing to fit DQARs. Non-Americans say that this is because of what lawyers could make of the data, but the carriers deny this. The US Federal Avia tion Administration is working with NASA to test a system which it calls flight-operational quality assurance. This may lead it to put the FAA stamp of approval on basically a SESMA-type total information-manage ment system. USAir is working direct with partner BA on implementing it. The UK airline says that United and American are "interested". The self-propelling data revolution con tinues apace. Its promises are so great that the world's airline engineers are having trouble working out where to enter the system. Perhaps the engineers themselves need personal data-compression systems to filter the vital from the glitz. f| The aim is higher standards for lower costs FLIGHT INTERNATIONAL 12 - 18 January, 1994 3!
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