Tag: design capacity

OM in the News: Redesigning the Overhead Baggage Bin

baggage bins

Frustrated at having his own carry-on bag taken from him when overhead bins filled, Boeing engineer Brent Walton asked the question many travelers ask: “Why don’t planes have enough bin space for all passengers?” Then he figured out a solution—make bins tall enough so you can turn bags on their side, like standing up books on a shelf rather than laying them flat.

Boeing’s new Space Bin increases the number of bags a typical plane can carry by nearly 50%, reports The Wall Street Journal (Oct.15, 2015). A single-aisle Boeing 737-900 with 181 seats has room for 57 more bags, or a total of 174 rollaboard bags. That’s enough to accommodate a planeload of passengers with room for their coats. The space bins are big enough so you can actually stack two bags on top of each other or push two in sideways together. Alaska Airlines took delivery of the first Space Bin 737 on Friday and will put it into service this week. The new design can be retrofitted into most 737s, the most common plane in airline fleets, and it doesn’t add any weight to the airplane. Alaska has decided to retrofit its 737s and install big bins on new planes.

Passenger surveys show the lack of overhead space is one of the biggest gripes about airline travel today. Boarding a plane has dramatically changed because of the carry-on crunch. Gate agents wrest bags from passengers in late boarding groups to tag them for checking. Some airlines have baggage tag printers at gates for all the bags that don’t fit in overhead bins. And flights get delayed when too many passengers can’t find room for their bags.

Classroom discussion questions:

  1. Why is this new product design (or redesign) so important to airline operations managers?
  2. How will the new layout impact the boarding process/time?

Teaching Tip: Using Prisons to Teach Design Capacity

The Wall Street Journal (June 18-19,2011), of all places, provides a great classroom example on the subject of capacity ( Supp. 7). The context is the California prison system, which was just ordered by the Supreme Court to reduce its prison population to 137% of capacity, citing unsafe overcrowding. Since capacity usually refers to the maximum number of units that can be produced or contained in a specific time (see our definition in Supp.7), it’s hard to comprehend filling a space beyond 100% of that limit.

 But the Journal writes that “the numbers on California’s prison overcrowding were based on its penal system’s design capacity“. The state traditionally planned for prisons to hold one inmate per cell. But most facilities doubled their population almost immediately after opening because of a glut of inmates. The state claims that it has recently reduced its prison population to 179% of capacity.

California also measures its prison system by operational capacity, or the number of prisoners who can be housed given actual conditions at prisons. Because of double-bunking, the operational capacity is almost twice the design capacity, meaning the system was able to claim to be only 9% above operational capacity in 2009. (The courts rarely recognize this measure). Adding to the confusion, a 3rd measure, rated capacity, based on fire marshals’ assessments of how many prisoners can be housed safely, is also used in some states.

The prison example provides an interesting contrast to our more traditional discussion of bakery capacity in Example S1.