I saw that when I looked through Part 25 but I thought there was an actual time limit for the descent somewhere. I know that's why there is a limit to the maximum altitude that you can fly with a pack deferred, for instance, so that you can make the descent if you lose the other pack or decompress. It just states that the cabin altitude can't be above 15,000 feet or 25,000 feet for 2 minutes. I fly the Airbus and it has a cabin pressure limiter restricting the cabin altitudes to 14,500 +/-. I suppose that's all the guidance there could be and I was imagining a time limit. Part 25 gives the manufactures the out by saying those design ciriteria only apply to situations "not shown to be extremeley improbable".

We fly with the TCAS in below at cruise altitude so I'd do what I had to do to avoid traffic but I think I'm still not waiting the entire 20 km to descend.