Re-Engineering USAF Avionics Maintenance: Lean Challenges

The U.S. Air Force has publicized its new approach to heavy maintenance through the High Velocity Maintenance (HVM) program. Experts at Warner Robins Air Logistics Center (ALC) aim to apply Lean principles such as waste reduction, standard work and continuous process improvement to radically improve heavy maintenance efficiency and throughput, starting with a prototype project based on the C-130.

Less is known of the ALC’s new take on avionics maintenance. The fact is, avionics maintenance isn’t standing still. Depot officials want to apply the same Lean principles across avionics maintenance activities at the ALC. Instead of applying the philosophy in avionics on a piecemeal basis, officials want to use it across the board.

Thus, Warner Robins’ Electronic Enterprise was born. Just as aircraft structures differ from aircraft electronics systems, so the approach to improving avionics maintenance has to be tailored to that environment. Although avionics work is more challenging to rationalize along Lean principles, Warner Robins engineers have been given the rare opportunity to exploit infrastructure renewal and reorganization efforts that have already been launched. Although officials expect some additional costs, the Electronic Enterprise isn’t a high-dollar program because it will extract benefits from ongoing projects to modernize facilities, update automatic test equipment (ATE) and consolidate the maintenance organization.

Holding the new initiative together is a shift from the "test-fix-test" and "fly to failure" mentality to an approach centered on equipment overhaul and predictability. However, the success of the idea remains to be seen. The Electronic Enterprise initiative is still in the planning stages and experts are developing its business case. It will probably start as a prototype and expand as it proves its worth. Like HVM, the Electronic Enterprise will be "another big muscle movement," says Ken Percell. He is the director of engineering and Air Force Smart Operations for the 21st Century program adviser for the ALC.

The idea of the Electronic Enterprise is to improve depot-level avionics maintenance by "using some of the same principles [as the HVM program], such as continuous process improvement," he says.

A big shift at Robins would mean a lot in military avionics ciricles, given that the ALC is the Air Force center of excellence for avionics repair. Percell sees it as an "opportunity to literally take the bricks and mortar, test equipment, personnel and requirements for avionics repair, throw them up in the air and put them all back together again in a new form."

This attempt to re-engineer avionics maintenance has been driven, in part, by the service’s gradual movement from a three-level to a two-level maintenance infrastructure. This evolution grew out of the recognition that support needs to mirror the way the service is fighting wars. As the focus has shifted to smaller forces that move more rapidly into and out of conflict zones, it made sense to consolidate maintenance, as well. So, where weapons systems were reliable enough to do without extensive, "intermediate-shop" support, maintenance has been reorganized into two levels: flight line and depot. As a result, there has been more pressure on depot maintainers to fill the gap.

Standardization Challenge

It is more difficult to standardize avionics repair processes than heavy maintenance processes since the time required to complete an avionics repair has been highly variable. The time it takes to repair an item depends on what the fault is and how long the ATE program runs before it finds the fault. This variability was exacerbated by the decades-long philosophy of "test, fix, test," as opposed to a preventive maintenance approach. Avionics boxes were flown until they failed, and then repaired and sent back to the fleet.

"Every unit that walks in the door is a different beast," Percell says. The time required to test a line-replaceable item (LRU) might be one hour or eight hours, depending on how far the test procedure goes before it hits the failure. Military depot officials are "embracing" the idea of the Electronic Enterprise because is promises to address some of the "weird dynamics" of avionics repair, he says.

The element of unpredictability only worsens over time. "As the avionics inventory of the Air Force has aged, it’s become more obvious that every box is making more and more trips to the depot because all the parts that haven’t failed yet are much older than they were before," Percell says. So, at some time, a decision has to be made to "bring [the boxes] in, tear them down, overhaul them, test them and put them back in the inventory."

Under the overhaul approach, when a box comes into the depot, mechanics will immediately open the unit, take out and replace the life-limiting parts, clean out the chassis and "bring [the box] a lot closer to the way it was when it left the factory," he says. This approach, the thinking goes, will increase material costs for a certain period of time, but will improve equipment reliability in the fleet and efficiency on the shop floor. It will also allow maintenance tasks to be standardized and Lean principles such as standard work and continuous process improvement to hone the operation.

Changing from a test-fix-test to an overhaul methodology would eliminate the first test to find out what’s wrong, Percell says. Instead, the mechanic opens the box and removes and replaces the known, routine failure items and life-limiting items. Thus, at one stroke, you get more stability on the maintenance production floor and on the flight line.

Percell hopes that the reliability data the ALC has been collecting for years for predicting supply demands in ordering parts will help identify and eliminate the weak links in the system.

This will help in the application of engineering dollars to either redesign a box or to overhaul it, extending the time between depot visits. He hopes to extend the time between visits by "close to, if not more than, an order of magnitude."

ATE Factor

Another factor which will influence the program’s success is the new, general-purpose test equipment coming into the ALC’s inventory.

Known as VDATS, for Versatile Depot Automatic Test System, the new testers are expected eventually to replace many platform-specific ATE systems in the depot. The introduction of ATE that can test a broad range of digital, analog and radio frequency (RF) components will provide the opportunity to further reorganize the avionics shops along product categories, as opposed to specific weapons platforms.

Reorganizing the shops and adopting an overhaul methodology will make it easier to implement Lean principles in avionics repair, Percell predicts. Take "standard work," for example, a key Lean theme.

Under the test-fix-test methodology, the only work that could be standardized was the process of taking a component out of a box and the process of putting the component back in the box, he says. Everything in between differed from unit to unit. But under the overhaul paradigm, and with more homogeneous shops, the workload would be more consistent and "you’d get the ability to flow standard work throughout the process" and also get more consistent quality, Percell says.

Under the overhaul paradigm, aging avionics units would gradually move toward a more predictable status, so that the mechanics’ approach could be more uniform, with less of a requirement for specialized knowledge of the quirks of problem avionics units. Under the new approach maintenance experts will analyze commonalities to improve the repair and maintenance process. If mechanics are working on similar equipment, for example, there may be common test procedures, configuration for installation of parts on circuit boards,, and checkout steps after work has been done. These commonalities would be grist for the Lean standard work and continuous improvement process mill.

Like the HVM program, the Electronic Enterprise will also adopt a mechanic-centric focus, where avionics technicians’ test adaptors, for example, will be right at hand, when needed. Multiple copies of the new test system will also cut down the waiting time that now occurs with the depot’s current, aging one-of-a-kind testers. And the new testers will also alleviate the problem of ATE downtime.