Technology in Aircraft Maintenance - Essay Example

Technology in Aircraft Maintenance The avionic industry as a whole and especially, technology in aircraft maintenance has also grown significantly since the last few decades. It has developed from a push-button, light-up test for deciding the health of single avionic equipment to a centralized airplane integrated health management system. This advanced system intervenes and collect data from all assemblies of aircraft equipment to make sure that all systems of aircraft are functioning properly, and if in case any fault that will be indicated at the front panel in the cockpit. It has further developed to become a valuable analysis tool for aircraft maintenance people. This has helped to save the time for fault location and in turn reduced the effective time aircraft is on ground for maintenance (aviationtoday.com, N.D.). The assessment of long-term aging responses of materials and structures using testing and analytical techniques is very difficult, particularly for the complex environment met in aircraft maintenance. It is difficult to get satisfactory calculation of materials performance even with the best techniques. It is significant to build up testing and analysis methods which provide the best possible knowledge of materials and structures performance to help materials selection to design new aircraft and evaluate their whole life cycle. Aging of commercial aircraft has become a most important issue since a lot of older aircraft attain their design life. Aircraft industry world wide and specially NASA and Federal Aviation Administration have already succeeded important methods to appraise and monitor the aging aircraft, giving importance to corrosion of material, fatigue damage and non-destructive testing methods. This will help to build up enough and correct scientific knowledge such as the aging issues, and can be considered in the future design process. The capability to know and foresee aging processes can have immediate implications for dealing with existing aircrafts. (Starke, et al, 1996). Since the factors like fatigue and corrosion of the airframe structure, the effects of aircraft aging increased the likelihood of crash and damages. To manage safe operations of the commercial aircraft, depend on the ability to predict necessary changes in the inspection and maintenance measures to compensate for the aging process. The FAA formed the National Aging Aircraft Research Program (NAARP) to deal with the problems relating to the ability to perfectly maintain the older aircraft. The aim of the plan is to ensure persistent airworthiness of the commercial aircraft through upgrading in equipment, techniques, practices, and procedures in aircraft and engine design, repair, maintenance, and inspection (DTIC, 1991). The Boeing’s ongoing research objective is to know how operating aircraft beyond their design service life will have an effect on maintenance (Boeing, 2004). For this reason they split up an aircraft’s life into three stages: the ‘newness’ period, the ‘mature’ period, and the ‘aging’ period. The newness period typically is the first five to seven years of an aircraft’s life or till up to its first D check (an entire structural evaluation and restoration). The second stage (mature) ends at the second D check and the aging period start after the second D check and continue till the aircraft’s designed life. From these three stages a ‘maturity carves’ is formed by which Boeing standardize the costs of aircrafts of various ages so that the values can be correctly compared. These maturity features are used to adjust expected maintenance costs of different-age aircraft (Dixon, 2006). Due to aging of aircraft, structural weakness and the start and growth of cracks develop on the main load carrying members, like fuselages and wings. So it is not guaranteed such aircraft continue to be safe if they are certified to operate more than their designed life. Scientist at the Computational Materials Institute (CMI) at the Cornell Theory Centre combine the subjects Materials Science, Computer Science, and Physics to develop a system that can foretell when and where cracks will occur and how that can affect aircraft safety. The answer to these problems can involve huge number of unknowns and need large numbers of parallel computers interconnecting the solutions between the subjects and requires inventive computational science approaches to information creation, averaging, and transfer (CTC, N.D.). Since last few years, the aircraft wiring safety has acquired significant attention because of the ill-fated TWA 800 in 1996 and Swissair 111 in 1998 disasters. Because of these accidents and other safety aspect, the issue of wiring safety has been taken up and is being addressed as part of the Aging Transport Systems Rulemaking Advisory Committee (ATSRAC). As per the information’s available, there are occurrences of smokes inside the cockpit of commercial aircraft. These can compromise aircraft safety. The use of Built-In-Test (BIT) by the aircraft maintenance technician’s have delayed or even misled technicians if the error turns out to be in the system wiring. Although thermal circuit breakers were basically included to protect the electrical wire insulation damage due to overheating situation caused by uneven current flow, there are other factors such as chemical contact, location of wiring bundles, and maintenance events that can damage aircraft wiring. These conditions can cause themselves in arcing incidents which cannot be safe guarded only by thermal devices. These situations needs extra safety means to improve the level of aircraft wiring protection. Because of these causes, a number of proposals have been offered to improve aircraft wiring safety which include the development of arc fault circuit breakers (AFCB) for better wiring system safety. This equipment monitor the electrical wiring for arcing which indicates the unsafe wiring conditions that could result in fires or loss of the electrical circuit performance. Arc fault circuit breakers (AFCB) would change conventional thermal circuit breakers, providing a dual-function mechanism that supplement the traditional over-current protection with electronic arc fault protection packaged in one circuit breaker device. This technology along with other interruption mechanism can enhance aircraft wiring safety. (Pellon, et al 2006). Over and above, Airbus called for an electrical installation re-evaluation program on old A320s, called Electrical Installation Maturity Review (EIMR). This program includes the wiring inspections of a sample of in-service aircraft to decide the condition of the complete wiring system, and to collect and use data for the purpose off: to confirm the wiring system design principle and advance the present electrical design; to verify the material selection; to confirm the performance of the total electrical wiring installation and to renew if required the inspection and repair processes. These inspections gave precious information in respect of technology with regards to certain electrical parts, wiring installation and operators’ maintenance practices and also pointed out the need for increased knowledge, among electrical maintenance personnel, of the importance of electrical wiring system. (Chevant, N.D.). The rise of maintenance costs of commercial aircrafts due to the increased frequency of scheduled servicing caused the airlines industry to look at the idea of preventive maintenance approach. Hence the Reliability-Centred Maintenance (RCM) has surfaced and can be seen as of reactive, time-based, condition-based, and proactive maintenance practices. The maintenance technicians should know system limitations and facility coverage’s, equipment tasks, functional failures, and failure modes, all of which are crucial parts of the RCM program (Pride, 2007). Different monitoring and controlling systems have been devised for fixed-wing aircraft. But the Health and Usage Monitoring Systems (HUMS) was devised for the rotorcraft, which enables the systems capacity to record engine and gearbox performance and offer rotor track and balance. The prime role of HUMS is to monitor vibration of rotor and give useful caution of possible failure of very important parts within the rotorcraft system. It can also monitor back up power unit usage and contain built-in test and flight data recording (FDR) functions. A HUMS is designed to retrieve, examine, communicate and store data collected from various sensors that observe the important mechanism for safe flight (HUMS, 2006). Automated Test Equipment (ATE) offers consistent testing and fault finding facility for all levels of avionics systems. ATE is used to monitor and control test and measurement devices, keeping human interaction at a minimum (IAI, 2002). In the beginning of 1980s, commercial aircraft started the use digital systems. ARINC and aircraft industry jointly developed the first standard for health management ARINC-604 ‘Guidance for Design and Use of Built-In Test Equipment.’ This paradigm represents the start of vehicle health management, where one or more line replaceable units (LRUs) equipped with front panels offered maintenance technicians the facility to test the health of various systems. In1988, Airbus introduced the centralized Fault Display System (CFDS) on the A320 aircraft. This improved the maintenance procedure by offering the technician with the potential fault on the display panel. Another major development was the introduction of Centralized Maintenance Computers in late 1988s and early 1990s made major difference in the maintenance field. The CMC collect health status data’s from various airplane systems, merge these data’s to decide the source of fault, and connect the source or fault to the technician for appropriate maintenance procedure. The CMC can display these results on the Multifunction Control Display Unit (MCDU) or link these results to ground stations while in flight to support maintenance management. Further as an enhancement to CMC design, Boeing and Honeywell jointly introduced the next generation CMC, as a part of integrated avionic suite on the 777 aircraft in 1995. Different from the earlier CMC design Boeing 777 CMC adopted a model based method, in which cause-effect interface and fault distribution paths were captured in a loadable database, using ground based tools. This procedure lessened the effort needed to modify the CMC for the specific aircraft (Bird, et al, 2005). In the field of commercial aviation the future tendency moves ahead with new technologies go on to be added and explored. Numerous innovations are based on the present day technologies, for example wireless and internet convenience, pooled together in new ways to provide value added service to customers. Technologies in aircraft maintenance systems for commercial aviation have significant progress since the beginning of simple BIT tests in the early 1980s. These developments continue as the technology progresses in Integrated Vehicle Health Management (IVHM) and process advancement such as Sense & Respond. It must be remembered that most of these technologies are not only useful to commercial aviation but also acknowledged its usefulness in the field of space vehicle. In conclusion, IVHM technologies are going to have a major role to play in the next generation spacecraft vehicle in support of the vehicle automation, mission planning and execution (Bird, et al, 2005). References aviationtoday.com, (N.D.) 727 to 787: Evolution of Aircraft Maintenance Systems, Avionics magazine, Special Report. Retrieved on 02 May 2007 from http://www.aviationtoday.com/Assets/Honeywellsmall.pdf Bird, G., Christensen, M., Lutz, D. and Scandura, P.A. (2005) Use of Integrated Vehicle Health Management in the Field of Commercial Aviation Management. First International Forum on Integrated System Health Engineering and Management in Aerospace, November 2005. Retrieved on 02 May 2007 from http://ase.arc.nasa.gov/projects/ishem/Papers/Scandura_Aviation.pdf Boeing, (2004) Airframe Maintenance Cost Analysis Methodology, briefing presented to RAND Corporation, September 2, 2004. Chevant, D. (N.D.) Aging aircraft electrical systems investigation. Retrieved on 02 May 2007 from http://www.content.airbusworld.com/SITES/Customer_services/html/acrobat/fast_34_p2_10_aging.pdf Cornell Theory Center (CTC), (N.D.). Aging Aircraft, Retrieved on 02 May 2007 from http://www.tc.cornell.edu/ctc-main/research/case_studies/CS2002-12-05_AgingAircraft.pdf Dixon, M. (2006) The Maintenance Costs of Aging Aircraft: Insights from Commercial Aviation, Prepared for the United States Air Force, RAND Corporation, Retrieved on 02 May 2007 from http://www.rand.org/pubs/monographs/2006/RAND_MG486.pdf DTIC, (1991) Program Plan - National Aging Aircraft Research Program, Retrieved on 25 March 2007 from http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA242891 HUMS, (2006 ) HUMS: Health And Usage Monitoring Systems, Aviation Maintanence. Retrieved on 02 May 2007 from http://www.aviationtoday.com/am/categories/bga/76.html Israel Aerospace Industries Ltd. (IAI), (2002) Automatic Test Equipment (ATE) Retrieved on 02 May 2007 from http://www.iai.co.il/ELTA.aspx?FolderID=33799&lang=en Pellon, C.V., Potter, T.E., Sekar, S.C., Parker, M.T., and Smith, P. (2006) Aircraft Electrical System Monitoring with Arc Fault Circuit Protection and Automatic Fault Location, SAE International, Retrieved on 02 May 2007 from http://www.sensata.com/files/Arc-Location_060906.pdf Pride, A. (2007). Reliability-Centered Maintenance (RCM) National Institute of Building Sciences. Retrieved on 02 May 2007 from http://www.wbdg.org/design/rcm.php Starke, E.A. et al, (1996) Accelerated Aging of Materials and Structures: The Effects of Long-Term Elevated-Temperature Exposure, National Materials Advisory Board, National Academy Press, Washington, D.C. Read More