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William A. Levinson

Quality Insider

Eliminate Muda from Aircraft Boarding

Often it takes common sense, not the theory of constraints, to stop waste

Published: Thursday, January 24, 2013 - 16:49

It is a basic principle that muda (waste) often hides in plain view, and it persists because people become used to living with it or working around it. Bricklaying, one of the world’s oldest trades, is a classic example.

Frank Gilbreth, a pioneer of motion study, developed a nonstooping scaffold, which increased productivity from 125 to 350 bricks per hour by eliminating the need for the workers to bend over to pick up each brick. In retrospect (and “in retrospect” is indeed the key phrase), the waste inherent in lowering and raising most of one’s body weight for every 5-lb. brick should have been obvious. The waste persisted for centuries, though, because people had always done the job that way, and the job eventually got done.

Similarly, it should also be obvious that a buffet table can serve twice as many people if there is room on both sides, but I have seen plenty of restaurants that put one side of the table against a wall.

Airline boarding practices are yet another example of waste that hides in plain view. The airline always did it that way in the past, and the job eventually got done. The latter observation illustrates another important concept: Inefficiency is, unlike poor quality, asymptomatic. There is no scrap, rework, or customer complaint to initiate a closed-loop corrective action process.

United Airlines recognized long ago that airplanes do not earn money when they sit on the ground, and it sent maintenance crews to a NASCAR school for racing pit crews to learn how to save time. “Our airplanes don’t earn money while they’re sitting on the ground,” said Larry DeShon, senior vice president of airport operations for United. “They need to be in the air. So, if we can shave even four or five minutes off of every aircraft turn, we can fly well over a hundred more flights a day.”

My recent airline travel experience, however, exposed considerable muda in plain view: departure delay caused by boarding airplanes from the front instead of the rear. The situation could be construed as an application of Goldratt’s theory of constraints, and also the critical path method of project management.

Suppose the aircraft has seven boarding zones, with zone No. 1 at the front of the plane. If boarding begins in zone No. 1, and passengers store their belongings before taking their seats, they block the aisle and the boarding of passengers to the subsequent zones. Zone No. 1 is therefore a constraint or, in critical path method terminology, a prerequisite activity that must be completed before the next can begin.

Project managers are quite familiar with the virtues of a parallel rather than a series structure for activities. If boarding begins in zone No. 7, it’s necessary to provide only enough time for the passengers to get to their seats, as opposed to the additional time they need to stow their luggage. Using this boarding method, people are able to store luggage and take their seats at the same time (in parallel) throughout the plane. While an improvement, a live test with a Boeing 757 showed that this procedure reduces muda by only about 10 percent.

Boarding passengers with window seats first (a procedure called the Wilma method) is more efficient even than boarding from the rear. Astrophysicist John Steffen refined this approach by not only boarding passengers from the rear, beginning with window seats first, but also by alternate rows (12, 10, 8, and so on, followed by 11, 9, 7, and so on). This keeps passengers from getting into each other’s way while they stow luggage in overhead bins. A live test of this approach, known as the Steffen method, required 3:36 min. to board a Boeing 757. Block boarding (front to back) the 757 required 6:54 min. The Steffen method reduced muda by almost 48 percent.

A video of the Steffen method in action, which includes a brief comparison to traditional front-to-back boarding, underscores the virtues of making videos of any job activity. Waste often hides in plain view because people become used to it, and they therefore take it for granted. The video makes the waste obvious, and creates an incentive to do something about it. It is then possible to compare the effectiveness of the new method to that of the old one, and cause the organization to wonder why it ever chose to live with the previous method.

Waste is all around us. We only need to open our eyes to it and recognize that just because “that’s the way it’s always been done” doesn’t make it right. Maybe by the time Boeing comes out with the next superliner, airlines will have figured out there is a better way to board a plane.


About The Author

William A. Levinson’s picture

William A. Levinson

William A. Levinson, P.E., FASQ, CQE, CMQOE is the principal of Levinson Productivity Systems P.C. and the author of the book The Expanded and Annotated My Life and Work: Henry Ford's Universal Code for World-Class Success.



"I washed my hands in muddy water - and they couldn't come clean". Thank you.

When I see some clown loading

When I see some clown loading his bag over my seat, I have yanked it out and thrown it on an empty seat and put mine in its place, after he's gone of course. When the flight attendant goes around trying to find out whose bag it is, the clown who put it up there in the first place is now the bad guy and I'm sitting there with a halo over my head. Ya' gotta fight back, people!

Another opportunity to dump on airlines?

Why is it that airlines are picked on so much?  Ever ask them why they board that way?  Maybe there is a surprisingly good answer.

actually no ...

Actually no, there is not a good reason. I have asked senior managers and executives. They have no clue. Try asking them why they price the way they do? It is all based on mistaken assumptions and broken paradigms. Okay, being a bit more charitable, my point is that there is not one best way, with every option, there is loss. But after trying many experiments, all the traditionals are going back to zone boarding and letting their premium passengers board first. Of course, that's another issue ... you can buy your way into premium now, or spend your way. On Delta, when they announce "Elite boarding" there is a veritable hoard that attacks the line. Did not used to be that way. If you were premium, you earned it by flying.

Which airline boards the best? Southwest, by a long shot. It is a fair system and everyone understands it. Line up in by number then have at it.

Elite Boarding

means you get to sit in a cramped seat on the airplane instead of a cramped seat in the waiting area (where you can stand and walk around if you want).

that would work, except for 2 reasons ...

Great piece ... I cannot tell you how many times I have gotten 5 guys together and commandeered the buffet table at a workshop and pulled it out from the wall, much to the horror of the catering staff. OMG ... the back side does not have a skirt on it!!!!!!!!!!

But there are two reasons that loading from either the back or from windows can never work, and as a guy who flies most every week, I have thought this method and many others through multiple times.

First, the airlines have made checking bags so financially punishing, that everyone tries their damnedest to carryon anything and everything. Note how few people now line up to receive checked bags at the carousel compared to 5 years ago.

Second: To point one, add the fact that there is nothing to stop those getting on from dumping their bags off anywhere in the plane ... and they do. Delta tried this, and it became extremely frustrating when you got to your seat and the overhead bins were full, and all those who got on first are lounging with their feet stretched out an nothing under their seats. The only way to manage that is to turn the flight attendents into very aggressive traffic cops, even more than they already are. I have two old high school friends who are flight attendents and this is making them crazy already.

So, combine a bad policy with bad (but rational) human behavior and you end up with a classic Design For Failure.

Healthcare also

These same ideas and principles apply to healthcare also.  Operating rooms cost $$ per minute to staff and equip.  When they're empty, they are not generating revenue.  Therefore, when one case finishes, everyone not otherwise occupied should descend on that room to prepare it for the next case.  Too often, however, that is regarded as break time for the nursing staff while they a cleaning crew from another floor to come and clean the floor.  There is also muda when the room is occupied, but nothing is happening to the patient--waiting for the surgeon or for some critical supply or equipment to arrive.  The reason such inefficiency persists in healthcare is that there is no profit motive or price competition.  Providers are paid the same whether they are efficient or not.