I used to think, perhaps like most people, that most commercial flights are flown to get from point A to point B. Sometimes, it might be a milk run, but that just means that it goes from point A to B to C to D. To that point, I’ve had the admittedly curious experience of flying a Southwest Airlines flight from Burbank (BUR) to El Paso (ELP) via Las Vegas (LAS) and Albuquerque (ABQ). It was a long day and a lot of take-offs and landings. (and I also got to see what I think was a Super Guppy at ELP!)

Obviously, more or less straight-line routes are predominant, following the invisible but well-marked flightways across the US, North America, and the rest of the globe. Just as obviously, I’ve been on a/c flights which had to make significant course adjustments due to weather, whether it was hurricanes, mesoscale thunderstorms, or extremely fast jet streams. These are all reasonable things to do.

In my rabidness with this new ADS-B monitoring, I discovered last week a route I’d never seen a commercial a/c take. A major US freight carrier’s flight entered my ADS-B monitoring space about 150 miles NNE of me, then executed a dogleg around the west side of the greater Phoenix area, then departed my coverage headed to the ESE toward El Paso. The only reason I even noticed it was that it suddenly popped up on my Virtual Radar Server (VRS) display and it was fascinating in the grand arc it traced around Arizona, yet never touching the ground.

This carrier apparently does this regularly, and someone on-line called it a “sweeper” route. The flight is scheduled to depart Denver (KDEN) and arrive Memphis (KMEM), a straight-line distance of only 872 miles. However, it generally takes a circuitous route, which on the day I saw it, was 2108 miles. Here’s a graphic of the same flight, even more extreme, with the route distance well over 2450 miles. The bit that’s in red is the portion that I can hear with my ADS-B receiver.

The purpose for the flight becomes apparent when it was called a sweeper. Just in case extra packages show up at the last minute at PHX, ELP, DFW or somewhere else along the route I suppose this flight can divert and grab those. If another plane has mechanical problems at one of the airports along this route, this flight can stop and grab the freight. If your mission is to guarantee delivery next day of someone’s letter or package, it costs you a lot in money and reputation to blame it on mechanical problems or a bin being already full.

Pretty interesting things to be learned with this ADS-B tracking. In the meantime, I’ve set up an alert at FlightAware for when this flight gets scheduled and I received my first alert just a little while ago.