Business & GA, Commercial

Pulling Aircraft Diagnostics Together Digitally

By James W. Ramsey | April 1, 2001
Send Feedback

The longstanding war against flight cancellations and delays is being waged on many fronts. One battle being fought by aircraft operators is against maintenance-related delays. Their weapons are better diagnostic techniques, which allow them to identify and fix airplane problems faster. And many operators are arming themselves with paperless, all digital systems.

Not all aircraft operators seek the same digital diagnostics, however. Larger carriers want systems on site and prefer to restrict data bases to their own Web sites, while smaller airlines and business-jet operators look to an Internet-based system to provide the same savings and efficiency enjoyed by their larger counterparts.

Honeywell’s Aircraft Maintenance and Operations Support System (AMOSS) was designed to satisfy both user types. AMOSS is a PC-based software system that delivers diagnostic information to aircraft technicians. It consists of software applications that are interconnected by local or wide area networks at the airline’s maintenance center, and it integrates aircraft and ground support systems, including maintenance "library" tools, often located separately. AMOSS also provides downlinked aircraft data, currently via the Airborne Communications Addressing and Reporting System (ACARS).

Into ‘Tomorrow’s World’

America West is the first U.S. carrier to adopt AMOSS "to take us from today’s world to a vision of tomorrow’s world," says Jeff McClelland, the airline’s senior vice president-operations. Phoenix-based America West–the ninth largest U.S. airline, with a fleet of 140 aircraft–is combining its use of AMOSS for diagnostic troubleshooting with its conversion to a paperless maintenance operation by early 2002.

"The biggest reason for choosing the system, as we looked at it and others, is that it makes it easier for technicians to isolate problems by having a single source of information," says McClelland. "[AMOSS takes] us from a paper and microfilm world to consolidated documents and an integrated AI- [artificial intelligence-] type troubleshooting capability.

"We expect AMOSS to increase dispatch reliability, shorten the time for maintenance delays, and reduce the number of maintenance cancellations, along with decreasing the number of our no-fault-found component removals," he adds.

Clifford Tanner, director of America West’s maintenance operations and control center, is equally enthusiastic about the Honeywell system. He envisions AMOSS will "simplify the process for the line technician and avionics technician in troubleshooting [and] simplify the process as we integrate all our digital data into the system."

America West had been eyeing the AMOSS system since 1995 and decided to invest in it last summer. The airline currently is training some 1,100 technicians and support personnel in the system. It expects AMOSS to be operational at its three major hubs–in Phoenix, Las Vegas, Nev., and Columbus, Ohio–by October. America West plans to deploy the system to its other manned maintenance stations and to its heavy check vendors early next year.

The airline will employ the AirGTI system, designed by Honeywell subcontractor Jouve Data Management, to convert its maintenance documents records to a digital format. Meanwhile, Honeywell is tailoring AMOSS to link with the airline’s Septre mainframe computer used for maintenance tracking and parts routing, according to Bruce Cronin, America West AMOSS manager.

AMOSS in Australia

Before America West made its decision to buy the system, Ansett Australia Airlines pioneered AMOSS, signing a six-year contract in September 1998 and implementing it last August. Ansett is installing the system in six maintenance locations, including Melbourne and Sydney. It expects AMOSS to reduce maintenance-caused delays and cancellations by 10% and reduce no-fault-founds by 25%. (The latter are suspected faulty components that, upon being removed and shipped to a repair station, are found to be serviceable). Ansett currently transfers maintenance data via wireless local area networks (LANs) at its airports and hangars where AMOSS is installed.

America West, like Ansett, is in the process of installing ACARS on its fleet. Its Boeing 757 fleet is fitted with the data link, and its Airbus 319/320 and B737 fleets will follow. When fully installed, the entire fleet will be tied into AMOSS.

AMOSS streamlines the line maintenance process by providing a "single view" of all necessary maintenance information. It integrates a host of diagnostic tools and displays all necessary information on a single screen on the maintenance technician’s desk or on a portable laptop. As well, AMOSS covers all facets of the aircraft, nose to tail, including engines, avionics, hydraulics, even cabin equipment such as in-flight entertainment (IFE).

Two Ways to Go

A customer can purchase AMOSS in two ways, explains Gautham Ramohalli, product line manager for integrated maintenance systems at Honeywell’s Aerospace Electronics Systems. First is the one for major airlines, in which AMOSS is located at the carrier’s facility, specifically and exclusively for that airline’s use.

Or, a smaller operator can subscribe to the service provided by Honeywell in Phoenix, forgoing the expense of on-site hardware. Rather, the customer accesses the system’s data through the Internet.

"If [maintenance crewmen] have a problem with an airplane coming in, they would log onto AMOSS over the Internet and then say, ‘Here are the symptoms I am seeing on the airplane. Help me’," Ramohalli explains. "A screen will come up that says ‘airline XYZ, you are now logged in and authenticated. You can now use AMOSS.’

"When you log in, you get access to your airline fleet only," he adds. "Honeywell will maintain a generic data base of the different aircraft types you fly. Using an aircraft pin number, you will list symptoms of the problem, and a dropdown list is offered of items to pick from. You enter all available information, and we come back with ‘Here’s what you need to fix the problem’."

The company still is working out the logistics and legal issues of the Honeywell database. Ideally, Ramohalli would like to see one big database shared by aircraft operators, so they can learn from each other’s problems. But he recognizes that this probably will not happen because of sensitivity of maintenance records and dispatch reliability figures.

The Internet version of AMOSS has yet to be sold, but Honeywell projects its availability in six to eight months. The company says operators of bizjets, especially those fractionally owned, and commuter airlines have shown interest in AMOSS. Honeywell claims it is close to landing a contract from a prominent fractional operator, but it is not signed yet.

AMOSS comes in two packages: a message management unit – called "message view"–for controlling ACARS messages, and a diagnostic model. Austria’s Lauda Air was Honeywell’s first message view customer–but has yet to opt for the diagnostic system. Ansett Australia and America West chose to purchase the full system.

The ACARS message management processing module receives ACARS messages from the aircraft in flight, decodes them into readable form, and determines which airline department–engine analysis, maintenance department, avionics, cabin services, for example–should receive them.

The AMOSS diagnostic function is designed to work with other airline maintenance equipment. "The basic AMOSS will tell you whether and when an engine has been replaced, but it will not tell how long it has operated," says Ramohalli. "For that, we rely on systems like Sabre or Septre, which specifically focus on maintenance tracking and engine reliability and parts tracking. We have links to those systems."

A business case for investing in AMOSS focuses on the economics of line maintenance, according to Charles Hearne, business development manager for Honeywell’s Avient Technologies. He claims that a recent study, which used Air Transport Association and International Air Transport Association estimates, puts maintenance costs at $200,000 per year per aircraft due to unnecessary delays, cancellations, unnecessary repairs and excessive spares.

While 80% of line maintenance problems are simple to troubleshoot, the other 20% create the problem, Hearne says. "And it is AMOSS’s job to help solve those." The short timeframe–less than 25 minutes on short-stop (through) flights–exacerbates the line maintenance process to resolve a problem.

Normally, maintenance technicians learn of a maintenance problem from ACARS messages, voice messages, the aircraft crew logbook, and/or conversation with the flight crew. But until now, the troubleshooting information needed to combat the problem has not been centralized. Typically, it has resided in maintenance control, in the original equipment manufacturer’s (OEM’s) aircraft maintenance manual, the illustrated parts catalog (IPC), the structural repair manual, and in wiring diagrams.

Other factors entering into the line maintenance equation are parts location and availability, aircraft configuration and routing, and repair history. Then there is the question, can the repair be delayed and performed at the next station, or be handled at the aircraft’s overnight location?

AMOSS helps resolve all of this by providing a single view of all necessary maintenance information pertinent to the problem. It uses model-based diagnostics and troubleshooting that evolved from the software for the central maintenance computer (CMC) Honeywell developed for the Boeing 777.

This experience, along with subsequent development, led to a cost-minimizing algorithm for troubleshooting. AMOSS is designed to provide explicit directions for the optimal sequence of maintenance activities. All interactions and outcomes are recorded, so the system can actually "learn" from its experience.

"Not all airlines can afford to equip their [older] aircraft with a CMC," says Hearne, "so we’re making the technology available through a ground-based activity, for quicker fault diagnosis.

"We learn through experience. Much of this ‘tribal knowledge�’ comes out of the senior staff in maintenance control," he adds. "We’re passing the knowledge of that person on to the [airline’s maintenance] organization. It is up to the airline to make the decision." Hearne emphasizes. "We [Honeywell] don’t presume to make the [maintenance] decision."

AMOSS provides line maintenance with "distributed troubleshooting," something the airlines don’t have now, Hearne says. This allows some maintenance to be done where the aircraft is located and more done at another station–and steps don’t have to be repeated.

"We can set up AMOSS to route information the way the airline wants it," Hearne adds. "We can make the process meet their process. We can look at repair history, legacy parts data–all that in other data repositories. However, we don’t store data in AMOSS. Rather, pointers show where the info resides."

Money-Back Guarantee

Hearne claims AMOSS comes with "performance guarantees." Both Ansett Australia and America West have agreements with Honeywell that the system will improve the airline’s delay rate. "If we don’t deliver on this, after people are trained and it has been in service for a period of time, we provide almost a money-back guarantee," he maintains.

And AMOSS’s future? Honeywell says it seeks a launch customer for its Future Air Navigation System (FANS) ground support system, with AMOSS serving as the backbone. Such a system will provide ACARS message processing and allow the addition of new modules in the future to integrate with communication, navigation, surveillance/air traffic management (CNS/ATM) functions.

Meanwhile at Collins and ARINC

Rockwell Collins and ARINC also use Internet technology to enhance reliability and maintainability for their air transport and business aviation customers.

At Collins, e-commerce is employed as well, to expedite product and parts ordering and various other on-line customer services. Collins Aviation Services Unit provides information via the Web to all service centers and other maintenance locations. Customers use the Web to access a database inside Collins, which is restricted to customers.

Use of the "secure extra-net" allows access to specific customer data, says John Fischer, Collins’ director of customer services programs, Air Transport Systems. The system allows customers to track a component’s repair status on-line, including shipping information.

Collins has made available its on-line Repair Status application since 1999, beginning with one service center and evolving to service 50 air transport and business and regional jet customers, according to David Unkrich, lead business administrations group, Collins Aviation Services. The service covers Collins components only.

Collins’ "Recap" feature focuses on helping customers improve reliability through an evaluation and corrective action program. It, too, is limited to Collins components and also is offered on the Internet, but requires a user password.

Recap offers historical repair information to the airline. It tracks reliability–mean time between unscheduled removal (MTBUR) and mean time between failure (MTBF)–and provides reports for customers.

"We look at [a part’s] reliability, identify areas that are deficient, and recommend corrective action," Fischer says. The system accommodates airlines that do their own maintenance and those who send all or part of their components back to Collins. All data is available to the customers.

"We are focused on reducing cancellation rates by improving reliability," Fischer adds. "It is key to our customer services and product support organizations for addressing product deficiencies."

Some 30 airlines, comprising half of the world’s air transport fleet, now subscribe to the Recap program, Fischer claims. All Collins products and services can be accessed at on the Web. Features accessible include service department, technical publications, training, service parts, catalog and products, and e-Store.

Rockwell Collins’ Integrated Information System (I2S)–an integrated communications network that manages information for an airliner’s flight crew, cabin crew, passengers and maintenance staff–also is used to improve dispatch reliability (December 1999, page 26). The system, undergoing operational trials aboard three Condor Flugdienst GmbH Airbus 320 aircraft, allows operational data to be relayed to the ground for analysis by maintenance specialists. American Airlines also uses I2S to uplink graphical weather data on two Boeing 777s.

The Condor Airborne Information Network (CAIN) was certified in late 1999 and is in revenue service. It takes in-flight information such as engine and aircraft systems performance supplied to the on-board aircraft condition monitoring system (ACMS), stores the data, and then sends it to maintenance personnel via an airport gate link. The system cuts down on expense required for ACARS messaging, which is in real- time.

The Condor trials also have demonstrated use of crew e-mail, which involves having a laptop in the cockpit, hooked to an I2S server. The e-mail messaging uses the Transport Control Protocol/Internet Protocol (TCP/IP) and the airline in-house system. It does not produce an ACARS-like text message.

Last January, the National Aeronautics and Space Administration (NASA) selected Rockwell Collins to lead a team to develop a satellite-based graphical weather information service. Now, two American Airlines Boeing 777s traveling between the United States and Asia receive graphical weather updates in the cockpit via the I2S system. The weather data is being transmitted via WorldSpace Corp.’s Asiastar satellite.

ARINC uses the Internet to relay operational and maintenance information between the aircraft and ground technicians. It offers a new product called OpCenter, tailored for small airlines or corporate operators who can’t afford more expensive systems.

OpCenter is a message management system–similar to AMOSS–which enables air-to-ground communications to supply engine or other aircraft systems data to the ground crew. ACARS would be the data link if available, but ARINC says information can also be relayed via satcom, HF or VHF data link–and it can be sent in real-time or stored. Chicago Express is the first OpCenter customer, followed by Gemini Air Cargo based at Washington’s Dulles International Airport.

Receive the latest avionics news right to your inbox