It was to thin out the schedule in DTW
on a day where there would be major delays due to the ice and freezing rain. Inbounds to DTW
would be subject to massive ground delays at the departure stations, causing most passengers to miss onward connections. It would also cause the aircraft and flight crews to be late for their next sector. End result would be that crews and aircraft would be out of position / crews would run out of duty time / the other hubs would also be affected by the knock-on effect. In other words, a large part of the hub and spoke system through all the hubs could be impacted by bad weather in one hub. It can also lead to delays the next day too as the airline scrambles to get crews and airplanes back on schedule.
One solution is to overfly the hub with the bad weather in order to keep both the aircraft and flight crew flying. Perhaps the next sector would have been GRR
, so this allows them to protect this flight and several other later flights too. Operations Planning plan ahead when weather events like this occur - they will look at ways to operate most efficiently given the known certainties of these weather events. I know it doesn't appear to make much sense to fly past DTW
either empty or with however many passengers were travelling on to GRR
, but this is far cheaper in the long term because of keeping the other hubs operating. Most of the other passengers on EWR
would have been booked on Continental to their final destinations, so the local passengers to DTW
are the only ones badly affected by the weather.
They do this quite effectively with as many flights as needed based on the anticipated conditions at DTW
. This also has the added benefit of reducing ground delays on those flights they chose to operate into DTW
. This will also allow for less deicing delays outbound from DTW
, so again, it keeps the aircraft moving rather than being snarled up. Incidentally, this all came about after the infamous DTW
snowstorm event a few years ago when people were stranded on aircraft for hours. Another thing they will do is cancel many Airlink flights into the affected hub on the premis that an A320 full of passengers landing in the hub is a better economic proposition than an RJ
with 40 passengers onboard. This also occured in MEM
with the recent icestorm.