No, it wasn't a "schedule change", it was a re-quoted ETD. The flight still showed 11:40 as the scheduled departure time but 12:50 as the ETD.

A re-quoted ETD does not change anything in the PNR so there was nothing to see there. Within a certain point before departure, the display of a PNR also displays ETD and ETA information for the flight but it may have been too far in the future for that to happen. So it may have been that the reservations representative who did see it took the extra step of manually looking up the ETD/ETA information.

i know this is hurting when you have all set to go then there is something that stops you but you need not worry. you may receive another message regarding all set for the flight. The all that is happening is for your good... :)
Have a safe journey and hope you will be on the right time where you want to be...

Always the ultimate goal! Welcome to FlyerTalk! :-::-:

Better proactive than not!

That's the strange thing - the first rep (who was very nice and sympathetic, but just could not see the delay in her system) saw this email in her system and that it went out, but could not see the actual delay posted for the flight (although the website did) nor a delay warning on my PNR.

UA Providing Advance Notice (multiple days) of Delays/Cancellations
 

This is new to me--flying SEA-SFO on 6/24, yesterday I was rebooked on a flight several hours later, and just now received this notification from UA "Your flight on Jun. 24 (UA1531) from Seattle to San Francisco has been canceled due to operational difficulties."

Does that mean a light load? Just wondering.....

UA knows that something will break somewhere, so they rolled the dice and your flight was the winner !

Possible aircraft and crew allocation issues?

Unfortunately your logic is convincing :)

Does UA do any schedule mapping 4 days out?

From the fact that you can only search for a tail number 3 days out you *might* think that they don't assign one until then but we know this to be false.

Is there some operational handoff at that point? Or do they redo the schedule at that point to account for unanticipated maintenance?

Or are these processes continuous and occur as far out as necessary when a frame needs to be taken out of service for unscheduled maintenance?

Communication?
 

Maybe somebody looked at the schedule for four days out and realized they were in trouble.

So they communicated the problem as soon as they realized it so passengers had time to deal with it.

Ok, this post is overly optimistic for this board ...

Yes and yes.

All it takes is negative availability for an aircraft on one flight somewhere 4 days from now and something has to give. This is likely the flight selected for the hit.

This thread ought to be merged with the one with people claiming that UA loused up by telling them at the last second when it had to have known ages ago....

That was my thought, also.

I wouldn't be one bit surprised if they look at loads when deciding which flights (it's unlikely to be just one) get the axe in a situation like this--thus making people think they cancel flights for too light a load.

Could also be they had a plane they needed to take out for major unscheduled MX repair and had to shift schedules to accommodate.