Spare parts and repair-planning systems also act as systems of record for sourcing and tracking the parts required for a maintenance event. “In the MRO world, buying a part is the last resort,” says Wodarski. “The first logistics challenge is always whether I can move parts I already have in my network from one location to another where they're needed. If so, how do I get it there? If I can't satisfy the demand with parts that are already in my network, do I have something on order? If not, do I go to a parts broker or to the OEM?”
For any given part number, Wodarski adds, an airline or an MRO provider may have several parts in motion, such as one that is out for repair or in transit from a supplier. “The coordination and control of those simultaneously moving inventory positions is critical,” says Wodarski.
A planning application aggregates data from the disparate sources related to those parts and suggests the most effective way to meet the parts demand. “We have criteria to figure out how to best move the inventory within your network and then make a recommendation,” says Wodarski. Once a planner accepts that recommendation, the system sends the information to the appropriate warehouse and transportation management systems that will fill the orders.
Systems of record such as ERP, inventory optimization and parts planning are known as supply chain management systems. They help organizations decide how much inventory to carry and what modes of transportation to use to ship products. Then they create a plan.
Supply chain execution systems act on those plans. They make things happen in the supply chain. Warehouse management systems (WMS) and transportation management systems (TMS) keep track of the amount and location of inventory in storage (stock-picking activities when parts are pulled to fill an order or for a maintenance event), create replenishment orders when stock falls below minimum levels and manage transportation activities.
In industries such as retail, wholesale grocery and beverage, it is common to use a best-of-breed, or standalone, WMS or TMS system. Due to commercial aviation industry compliance requirements, warehousing and transportation software systems are more commonly integrated components of a broader MRO software package. “In most supply chains, you buy a part, you get it shipped where it's needed, and you're done,” says Chris Reed, managing director of Trax, an MRO software provider. “In our industry, you have rotables that are moving back and forth between locations. You have parts that require special containers, special transportation and even specialist companies to move the parts.”
In addition, conventional WMS and TMS systems are not designed to manage the compliance requirements associated with a repair, monitor inventory levels to minimize obsolete stock and understand how many repairable parts could become serviceable and go back onto the shelves. Those benefits are the result of integrating supply chain execution into MRO programs. “When logistics applications are integrated into an MRO application, you know what parts are needed to perform the task, the configuration of those parts and when they're needed,” says Mxi's Elliott. “You also have visibility into the parts you have in stock. That allows you to avoid ordering parts that you already have or ordering non-compliant parts.”
When a maintenance plan is generated, it builds a bill of materials that will be required for that event. When the bill is sent to the warehouse management application, the WMS reserves parts that are in stock for that event, automates the steps to pick, kit, pack and deliver them on time to a technician, and automatically creates a requisition of parts that must be purchased.
The systems also can automate the replenishment of regularly used parts. “If you understand your demand and monitor your stock levels, you can manage the replenishment so you don't have to expedite a shipment,” says Elliott. “That reduces your transportation costs.”