TechOps’ line maintenance operation, which engaged Realization in 2010-2011, also improved performance. In the summer of 2010, when Delta was dealing with the Northwest merger, the maintenance completion factor was “less than stellar,” said John Laughter, senior vice president for maintenance operations, at a recent Realization conference. There were 29.3 cancellations/day in the summer of 2010. But by the following summer these were down to 11.2 a day, a more than 60 percent improvement. Maintenance-related cancellations typically occur when deferred minimum equipment list (MEL) and time-controlled maintenance items expire before completion and no substitute airplanes are available for a flight. Expirations, in turn, can be traced back to problems such as parts shortages and misalignment of people, parts and aircraft. To address this problem Delta decided to cut work in process (WIP) and focus on throughput, Laughter said. Before the changes were adopted, each of the 350 aircraft that came into one of the maintenance stations every night—about half the fleet—received a kind of “customized” treatment, Laughter said. The workers did as much as they could for each one, but resources were spread thin. Part of the new plan was to “clean up” expiring items for 15 days rather than the previous 2.5-day period. When the new implementation began,
TechOps still did lower-order checks on all 350 airplanes every night, but focused more on MELs—on 200 rather than 350 aircraft. This reduced the work of the materials team almost in half and sharpened the focus on aligning people, airplanes and parts. Eventually WIP was reduced to the point where a substantial time buffer was available to deal with the unexpected.
Delta TechOps also revamped base maintenance. C-check throughput for MRO customers increased by 35 percent from the summer of 2010 to summer of 2011. The launch phase, which begins seven days before the aircraft arrives, includes “full kit 1” on the dock before work begins. This is all the material that maintainers anticipate will be required to complete a normal C-check. Inspectors are then “poured” onto the airplane to complete that task in a “couple days,” said Gary Taylor, a TechOps manager. Then comes the assessment phase, when mechanics evaluate non- routine needs for “full kit 2.” This customer inventory has to be received quickly because there is only a short time from identification to use. The attack phase also pours on maximum manpower. Delta TechOps found that, when working on an aircraft while other planes are in the hangar, it’s important to stagger the planes, so than no more than one aircraft is going through a critical function at the same time. The base operation has implemented Concerto and is using it to measure not only progress on the critical chain, but also buffer consumption, Taylor said. “It’s key that customers understand buffer consumption and how they affect that.” If customers fail to provide parts quickly it means we’re consuming buffer, he said.
LTMI
Lufthansa Technik Maintenance International (LTMI) has been implementing Concerto since August 2011, said Thomas Muetzel, LTMI team manager for Lean production and quality. LTMI has started applying CCPM concepts to C-checks and A-checks for non-Lufthansa customers.
26 Aviation Maintenance |
avm-mag.com | February / March 2012
LTMI adopted CCPM to increase
productivity and revenues after the loss of a large integrated customer. The unit realized that too many projects were in progress at the same time, so that mechanics were not being efficiently used—only 30 percent of their time was being applied to production. Greater efficiency would increase throughput and allow LTMI to price its services more competitively and win more business. LTMI followed “CCPM rule 1”—targeting WIP and focusing resources within checks and across the hanger, Muetzel said. The unit decided, for example, to do no more than one C-Check at a time and to limit the number of active workgroups within a check to five. By reducing WIP, CCPM also helps LTMI identify real constraints, such as management capacity and qualified mechanics, so as not to overload them, Muetzel said.
The unit also focused on clear, global priorities, issue resolution and buffer management. This allows, not only mechanics, but also their management and support staff, to concentrate on the same work and get it done quickly, he said. One high-level priority was that A-checks should take precedence over C-checks, Muetzel explained. If an A-check comes in while a C-check is in progress, resources are shifted to the A-check until it is completed and then returned to the C-check. Both checks get finished faster since workers are not multitasking between the two projects. LTMI uses buffer management to adjust priorities dynamically, based on actual execution, and to pinpoint areas where issue resolution is required. The unit also adopted full kitting.
As of early November 2011, LTMI had completed two C-checks under CCPM.
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