Today was supposed to be a tough day to begin with; it ended up being nearly three hours longer than scheduled.
The airplane we started with this morning had its antiskid braking system deferred. It's really not a big deal, because the anti-skid only comes into play when heavy braking is used, and that's pretty rare for the airports we fly into. Inoperative antiskid, however, does affect takeoff and landing performance tables rather significantly.
Early in the day, I mentioned to the captain that this could potentially cause a problem on our fifth leg, when we'd be landing in Great Falls. That airport is undergoing a huge construction project; the 10,500 foot Runway 3/21 is completely torn up, so we've been using Runway 34/16 - 6300 feet long. With the right combination of temperature, winds, and aircraft weight, I realized that we might not be able to land in Great Falls. However, I had done this trip a number of times the last month, and we always had an airplane swap after leg four. I assumed this would be the case again, particularly since the short runway would prompt the router to send an airplane with operative antiskid.
Inbound to Seattle on leg four, we got a message from dispatch. My earlier fears turned out to be well-founded: the temperature and winds at Great Falls were such that our antiskid-less Megawhacker would be extremely weight limited for landing - and we had a full passenger load. Despite this, we were slated to keep the same airplane. Once we got on the ground, the captain called dispatch and sorted through our options. Maintenance could attempt to fix the antiskid system; minimum wait time, three hours. We could accept the weight penalty, and leave 30 passengers behind. We could just fly into Helena, our final destination for the day - but a bus for the Great Falls passengers couldn't be arranged soon enough. Or, we could wait for the next Megawhacker inbound to Seattle, and swap planes then. This was what we ended up doing, and it cost us about 2.5 hours.
Now, the antiskid system had been deferred for five days. One of the infuriating things about this situation is that you'd think someone would've seen it coming down the pike. I considered it obvious enough that I didn't think to alert anybody. Yet, the problem was not discovered until one hour before our scheduled departure, when the dispatcher tried to work up landing performance for Great Falls. Now granted, until she actually inputed the temperature and winds, nobody knew just what the performance restriction would be. But even the most favorable scenario would've made us leave passengers behind. You don't need exact numbers to realize that inop antiskid + short runway = weight restricted performance. It just seems that nobody outside of our crew realized that an airplane with inop antiskid was scheduled to fly to a short runway today.
When flight crews question puzzling decisions made by crew scheduling, dispatchers, and aircraft routers, we often hear the admonishment, "You just don't have the big picture." Okay, fair enough, we usually don't. But if you're going to tell us that we don't have the big picture and should therefore mind our own business, it'd be comforting to know that someone has the big picture!