Constraints
Applying the Theory of Constraints
In your Operations Management: Processes and Supply Chains text, read the "Constraints Management at Southwest Airlines" case study on page 206. Then respond to the case study's questions 1 and 2 as your initial post for this discussion.
After reading Chapters 5 and 6 in your Operations Management: Processes and Supply Chains text, do Problem 13 on page 200. Comment on how this could help Southwest Airlines to improve gate turnaround times.
VIDEO CASE: Constraint Management at Southwest Airlines
What if you could take a commercial airline flight any time and anywhere you wanted to go? Just show up at the airport without the need to consider time schedules or layovers. Aside from the potentially cost-prohibitive nature of such travel, there are also constraints in the airline system that preclude this kind of operation. From the lobby check-in process through to boarding at the gate and processing plane turnaround, the process of operating the airline is filled with constraints that must be managed in order for them to be successful and profitable. Flight schedules are tightly orchestrated and controlled, departure and arrival gates at airports are limited, and individual aircraft have seating capacities in each section of the plane, to name a few.
Southwest Airlines is one company that has figured out how to manage its constraints and generate positive customer experiences in the process. No other airline can claim the same level of profitability and customer satisfaction Southwest regularly achieves. What is its secret?
Talk to any loyal Southwest customer and you will hear rave reviews about its low fares, great customer service, and lack of assigned seating that gives customers a chance to choose who they sit next to onboard. From an operations perspective, it is much more than what the customer sees. Behind the scenes, operations managers carefully manage and execute—3,400 times a day in over 60 cities in the United States—a process designed to manage all potential bottleneck areas.
Southwest’s famous rapid gate-turnaround of 25 minutes or less demonstrates how attention to the activities that ground operations must complete to clean, fuel, and prepare a plane for flight can become bottlenecks if not properly scheduled. In the terminal at the gate, passenger boarding also can be a bottleneck if the boarding process itself is not carefully managed. Since the individual mix of passengers presents a different set of issues with each flight that often are not evident until the passengers actually arrive at the gate, ranging from families with kids and strollers to large quantities of carry-on bags and passengers needing wheelchair assistance, operations managers must be ready for any and all situations to avoid a boarding bottleneck while also ensuring a pleasant and stress-free gate experience for all passengers.
Passengers boarding a Southwest Airlines flight.
In 2007, as part of the company’s continuous improvement activities, Southwest focused its attention on the passenger boarding process to determine whether there was a better way to board. Its existing process consisted of three groups, A, B, C, with no assigned seating. Depending on passenger check-in and arrival time, passengers were given a spot in a group. Those first to check-in received choice places in the A group. The last to check in ended up in the C group and usually had a choice of only middle seats in the back of the plane upon boarding. As passengers arrived at the gate, they queued up in their respective boarding group areas to await the boarding call.
Seven different alternate boarding scenarios were designed and tested. They included
· ■ New family pre-boarding behind the “A” group of first-to-board passengers
· ■ Family pre-boarding before anyone else, but seating choices limited on-board to behind the wing
· ■ Six boarding groups (within A-B-C groups) instead of the original three A-B-C groups
· ■ Assigned boarding gate line positions based on both boarding group and gate arrival time
· ■ Single boarding chute at the gate, but up to nine groups all in one queue
· ■ Boarding with a countdown clock to give customers an incentive to get in line and board quickly; incentives given out if everyone was on time
· ■ Educational boarding video to make the boarding process fun, inform passengers how to board efficiently, and provide the company another way to promote its brand.
QUESTIONS
· 1. Analyze Southwest’s passenger boarding process using the TOC.
· 2. Which boarding scenario among the different ones proposed would you recommend for implementation? Why?
Managing Constraints in Line Processes
· 13. Quick Stop Pharmacy is a small family-owned drug compounding business in Portland Oregon that is trying to perfect its customer service operations. John Suleiman, the owner wants to maximize the productivity of his staff as well as serve customers well. One area of concern is the drive-thru operation during the 7:30–8:30 morning rush hour. The process of fulfilling an order is as follows:
Work Element
Time (Sec.)
Immediate Predecessor(s)
(A) Greet patient and take prescription
40
—
(B) Check patient information on system
45
A
(C) Gather compounding materials
55
A
(D) Perform compounding
55
C
(E) Package and label
65
D
(F) Instruct patient on use
40
B
(G) Collect payment
25
B
· a. If all the steps are handled by one employee, how many patients could be served per hour?
· b. If James wants to process 30 patients per hour, how many employees will he need?
· c. How many stations are required using the longest work element decision rule?
· d. Using the solution developed in part c, which station is the bottleneck and how large is its capacity cushion?