On the evening of April 14, I boarded a plane to London, where I was scheduled to teach a series of continuous improvement classes. The following morning, as my flight neared the United Kingdom, the pilot announced that our flight was being diverted to Brussels due to a cloud of volcanic ash blowing in from Iceland. Thus began my unplanned, four-day stay in Belgium.

Don’t get me wrong; I greatly prefer landing safely anywhere to crashing at my intended destination. However, my four-day experience in overcrowded Belgian airports, hotels, and train stations made me start thinking about the trade off between the efficiency benefits of being lean vs. the risk of not having enough reserve capacity to handle unplanned events. Granted, this was an extreme example. I really wouldn’t expect the European rail system to have the capacity to handle its normal load plus that of the entire air transportation system that was shut down for nearly a week. However, this experience highlighted the fact that having some reserve capacity comes in handy during a disruption of the status quo.

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