January 21, 2013
Credit: Credit: MTU Maintenance Zhuhai
Bradley Perrett Zhuhai, China
Sometimes, when an airline calls, it wants an overhaul shop to receive its turbofan in three months. Getting that much notice is good, because anyone running an engine overhaul plant likes to know just what the technicians and equipment will be doing at least four weeks ahead. A long, dependable schedule is an efficient schedule.
But sometimes the customer wants its engine in the shop in two weeks. Or next week. Or even tomorrow. “And sometimes they want tomorrow but the engine turns up a week later,” says Frank Bodenhage, chief executive of MTU Maintenance Zhuhai. While commercial aviation does not always work the way engine overhaul managers would like, the challenge is particularly great in Asia, where many airlines seem to forget that pulling apart and reconditioning a commercial turbofan takes a bit more planning than, say, servicing the chairman's Mercedes-Benz.
MTU Maintenance Zhuhai, which overhauls CFM and IAE engines for narrowbody airliners, has accepted that it cannot change Asian airline habits. While expanding its plant by 50%, the company has also reorganized its work practices to increase flexibility.
Most of the work at the company, owned equally by MTU Maintenance and China Southern Airlines, is now performed by multi-skilled teams who can be quickly switched between disparate engines. So the people who disassemble newly arrived engines normally know how to pull apart two different types. Those who assemble the cores of one type can also work on the cores of another, and so on.
In each area of activity—say, assembly or turbine blade inspection—a single manager has the authority to switch teams from one job to another. Bodenhage says the company has eliminated a layer of supervisors that would have resulted in meetings being held to discuss which teams could be moved to where.
MTU Maintenance Zhuhai has targeted a particular market segment that is a boon to flexibility: CFM56-3s, the engines used by Boeing 737-300s and 737-400s. Since such engines are no longer very valuable, their owners are happy to accept longer turnaround times as part of a job that usually will not be very expensive. By having such non-urgent engines on the floor, the process managers at Zhuhai can switch teams to and from them according to the demands of engines under shorter contracts.
The work is organized mainly with simple paper and magnetic-whiteboard processes that the company has found to be robust and easy to use. Simplicity helps flexibility.
Another old-fashioned point of simplicity is that MTU Maintenance Zhuhai uses traditional docks—fixed spaces in which an engine is worked on. In doing so, it has rejected the flow-line production process, in which engines and parts would move one after another from station to station. The flow-line helps efficiency in part by keeping everyone aware that if a job is not done on time then other jobs are held up, but Bodenhage says it demands the careful scheduling that is hardly possible when too many customers want work done at short notice. With docks, a team can just walk away from one engine and begin work on another without affecting anyone else.
If there is a loss of efficiency there, another process makes up for at least some of it. Traditionally, mechanics pulling apart an engine would take off each piece, set it aside, take off the next and so on. Then, at the end of the day, they would take all the parts to the various places in the plant where each would be worked on next. At a cost of just €60,000 ($80,100), the plant has introduced a new system in which, during the course of the workday, mechanics periodically signal that certain parts have been removed. Forklift drivers, directed through the plant by software, presently turn up, collect the parts and take them immediately to their destination. Parts flow continuously in small batches.
This has three advantages: turnaround time is saved, because work can begin on a part within an hour or so of its removal, rather than the next day; costly and scarce mechanics do not spend their valuable time in transporting parts; and work on assemblies is not hampered by the accumulation of parts around them. The process works in reverse, too. As mechanics build an engine assembly, the forklift drivers arrive every hour or so with parts that will shortly be needed.
The staff developed these new practices, says Bodenhage. In looking for ways to increase flexibility and cut costs, the company decided not to pay for consultants and relied instead on its staff for ideas, partially because workers would be more committed to a system they helped to craft.
The facility also overhauls CFM56-5s, CFM56-7s, and V2500-A5s, the latter two accounting for 80% of its work.
The Zhuhai plant was always designed for expansion. It went into operation in 2003 with three structural bays, each 24 meters (79 ft.) wide. The first, with spare room, housed equipment for all types of engines, such as machines for cleaning, non-destructive testing and plasma spraying. The rest of the work was completed in the other two bays, with a total capacity of 200 engine shop visits a year. With about 600 people, the plant is now running at that rate, up from about 140 in 2007.
The plant's designers left space on site for two more bays, one of which has now been built, providing enough area for 300 shop visits a year, although the company does not have that much work yet and therefore has not hired all the people nor installed all the machines it would need for that capacity. Bodenhage says that the new limit should be reached in about five years. Presumably the plant will eventually be widened with a fifth bay. Beyond that, the site is big enough to double the length of the plant. At some point, if business warrants it, four times the original capacity could be built. The plant is taller than needed for CFM56s and V2500s. China Southern has ordered Boeing 787s with General Electric GEnx engines, so that type is a likely candidate as the first widebody engine at the site.
MTU Maintenance Zhuhai has an assured base load of work from China Southern, but the company has been growing faster than the demand for overhauls for that shareholder, because it has been receiving strong orders from unaffiliated customers. China Southern now accounts for about half of the plant's work, other Chinese airlines for about a quarter, and airlines from elsewhere, mostly Asia, for the rest. Bodenhage expects the outside work will continue to grow faster than demand from China Southern.
Chinese commercial traffic development suggests that China Southern's requirement for CFM56 and V2500 overhauls should grow at something like 10% or more a year. Even if, as seems likely, the carrier's demand slows with a general moderation in the industry and a switch in emphasis to long-haul international business, it is not hard to see the overhaul shop needing that fifth bay later this decade.
The perennial problem in Chinese airframe and engine maintenance is attracting and retaining technicians. Bodenhage says the company has effective methods of finding people, but notes that an expansion in aviation activity in the area—for example, at Zhuhai-based general aviation manufacturer Caiga—could make things tougher. Competition for staff comes from non-aviation industries, too, such as automotives.
Keeping employees turns out not to be a problem, however. Bodenhage says annual turnover is significantly less than 5%. Wages across the industry are rising at about 10% a year.
Because of the rapid growth, the average worker at the site is still younger than 30. Experience takes time to accumulate, and so the company probably must always trail other MTU Maintenance narrowbody engine shops at Hanover, Germany, and Vancouver, British Columbia. It sends people to the other plants to help with work surges, and they pick up ideas there. In one case, still most unusual for a Chinese aviation operation, the skills flowed the other way: once, when the Vancouver facility had to quickly gear up its CFM56 work, experienced hands from Zhuhai were sent to help refresh the Canadian plant's skills.