Safety is of primary importance in civil aviation. The regulatory authorities require every maintenance measure, every repair, and every unusual event relating to an aircraft to be documented in the log book. The log book has always been an important paper document in the life cycle of an aircraft. If, for example, the pilot notices that the engine is too loud, he or she can make a note of this in the aircraft’s log book. As soon as the necessary maintenance work has been carried out, this information is also recorded. In addition, the log book contains a list of all the parts that have ever been replaced in an aircraft.
Information on safety and comfort
Lufthansa Technik now has a global exception management system that enables log book information to be viewed across the whole company. The IT service provider Lufthansa Systems has successfully implemented the new application on the basis of SAP R/3 Enterprise. The MARIS (Maintenance Record Information System) solution is Lufthansa Technik’s central application for documenting log book information relating to the aircraft. In future, the results of structure defect repair reports will also be recorded in MARIS. These reports are carried out at regular intervals to check for hairline cracks in the tail of an aircraft, for example. All these entries are available online to the pilots, operational headquarters, engineers, and technicians with the help of the MARIS system. As a result, it is possible to guarantee that all measures ensuring passenger safety and comfort have been completed on time and in full, for the whole Lufthansa fleet.
“With MARIS, the teams from Lufthansa Technik and Lufthansa Systems have been able to replace the host-based legacy system,” explains Dr. Zhangzheng Yu, IT director for aircraft maintenance at Lufthansa Technik. “Among other things, the new solution is very easy to learn as the screens are laid out in a similar way to the aircraft log book pages,” says Dr. Yu. A total of 4,000 users now access the content stored in MARIS from the Intranet and Internet via a Web connection alone. The high-availability solution is based on SAP R/3 Enterprise and enables worldwide access around the clock.
Development with SAP modules
MARIS is a technical innovation. For example, Lufthansa Systems developed the interfaces for maintaining the data with the help of SAP Business Server Pages. This programming procedure, which was introduced with SAP Web Application Server (SAP Web AS), makes it possible to define the applications with the associated user interfaces. The interfaces are designed on the basis of the log book pages that employees are familiar with from flight operations. A new users simply needs the Internet address in order to dial in to the system from any PC with a conventional browser. Thus practically no costs are incurred for the connection of new users worldwide. The data is stored in SAP standard objects such as maintenance notifications and orders. During development, the experts used the SAP update modules to store data. These ensure that access to the servers is error-free. Access calls are not triggered individually but are first temporarily stored in function groups and then processed together.
Extremely high system availability of this central application is of the utmost importance for Lufthansa. For this reason, the production system consists of two linked computers that are supplied with data in parallel. If one of the computers goes down unexpectedly, the second computer is still available for the application. If the downtime of the main computer has been scheduled, it is possible to switch to a third computer as well. Fully automated monitoring of the system and the application ensures that faults are noticed immediately, and if they do occur, for example during access via the Web or to interfaces, the people responsible are notified directly by email or SMS. The faults are then recorded in a Web-based reporting tool and the reports plus the applied solution are stored. In this way, all information relating to system operation is transparent, and it is possible to ensure that the same fault does not occur twice.
High availability ensured
A “replication procedure” ensures the high availability of the SAP application even during maintenance activities, such as a release upgrade. All updates in the system are carried out using the Application Link Enabling (ALE) technology provided by SAP. If an update is made in Exception Management while the maintenance work is taking place, ALE makes that that the update procedure switches to a second SAP application. Once the maintenance work has been completed, the data changes that were made in this period are updated a second time to the original SAP application. As a result, the solution and all its key functionalities are available even during maintenance work.
Lufthansa Systems also uses ALE technology for interface connection. This is combined with a DBCON connection, which defines the interfaces to non-SAP systems. The advantage of this is that the interfaces can be reactivated at any time if a connected system fails, and no data is lost.
A customer-specific locking concept was developed so that maintenance of data in the SAP landscape is possible quickly and smoothly over the Internet. This concept locks the data in the SAP application during actual updating for just a few seconds, and then releases it again for other users. Web access to MARIS is protected by special HTTP encryption and authentication with changing passwords. In addition, it is possible to log in to the Web application using read devices with chip cards.
Reports in PDF format
The reports are created as PDF documents which can be printed out directly from MARIS via Web access on any printer. It is also possible to order the reports using an email or telex request. The application then sends the report as a PDF document directly as an email or alternatively as a telex. This traditional technology was important for Lufthansa as there are still individual locations across the world that have a telex connection but no Internet connection. The emails are also sent in encrypted form, so that only authorized requesters are able to read the data.
The solution developed by Lufthansa Systems was quality-checked by SAP using a safeguarding process specially developed for the project. At the start of development, SAP experts took a close look at the replication procedure and the locking concept described above. The experts also carried out fine tuning of the SAP solution during the mass tests in which the actual system load was simulated using automatic test tools and “live” users. During implementation, this procedure meant that MARIS was stable and had good performance from the very first day of productive operation, November 1, 2004. Thanks to the system’s user friendliness and technical stability, it was immediately well-received by users, and acceptance is still high four months into day-to-day operation.