Which is worse, having your flight delayed two hours or having your flight cancelled and being rebooked on a flight two hours later? According to Delta Airlines, customers generally prefer a simple delay to a cancellation and rebooking. That has led to Delta working hard to minimize the number of cancelled flights. According to the Wall Street Journal’s Middle Seat column, last year Delta cancelled just 0.3% of its flights — well below the industry average of 1.7% — and at one point went 72 straight days without canceling a single flight (A World Where Flights Aren’t Canceled, Apr 2). As the graphic above and the video below demonstrate, this has taken a lot of operational refinements.
There are, not surprisingly, several things going on here that have helped Delta’s performance. Some relates to being more proactive in monitoring and performing preventive maintenance. For example, there is cooling fan for cockpit instruments. From the land of for the want of a nail, if that little fan doesn’t work, the big plane can’t fly. Delta has developed monitors to test when the fan starts vibrating too much — suggesting that bearings are wearing out. Fans can then be replaced proactively.
Another part of this is about maintaining slack and being willing to alter plans even though it might mean higher costs. This applies to both inventory (boosting spare parts inventory by a couple million dollars) and capacity (i.e., planes and people).
Typically the airline has about 20 spare airplanes of different sizes each day. About half are stationed in Atlanta and the rest spread around other domestic hubs and two in Tokyo. Delta may start the day with 10 airplanes out of service. It used to have nearly double that, but has improved its maintenance work. That means that if a remaining spare or two are pressed into service in Minneapolis and some planes with a few minor health concerns are scheduled for evening trips out of Minneapolis, a spare from Atlanta may be shifted north, an expense few airlines would take before there was an actual breakdown.
Delta’s fleet is a hodgepodge of more than a dozen different types of airplanes and some are pushing 30 years old. That makes it difficult to have the right parts available as well as mechanics trained on the right aircraft type, plus older planes tend to break down more often. …
One trick Delta began employing: adding an interim stop to change out crews and get passengers to the U.S. with just a few hours’ delay. On a recent trip, for example, one of three pilots scheduled to fly from Barcelona to New York became ill. The plane requires two pilots, each flying a maximum of eight hours, so an extra pilot is needed to cover the nine-hour trip.
Rather than wait a day for a replacement pilot to get to Barcelona, Delta had the two healthy pilots fly the passengers to Bangor, Maine, where a fresh crew was waiting to finish the trip to Atlanta.
As the article notes, international flights have been a particular point of emphasis. These generally are scheduled relatively infrequently (i.e., a delay would not be just a few hours) and involve a lot of passengers.
What I like about this example is that it shows how focusing one measure can improve others. While Delta has focused on cancellations, it has also improved its on-time performance. That just seems a natural by product of addressing maintenance issues early and making sure that planes are in their proper place.