You know you’ve got a good bug when a user reports that his airplane’s wing disappears when he turns the battery switch off. It turns out that this is the same bug as the 747 rolling over to the side.
X-Plane 10.10 (beta 1 all the way through RC1) has a bug in the IO code that scrambles the electrical system of airplanes on load, sliding the electrical system selections on the “bus 2” page of Plane-Maker over by one slot (except for the last two columns, which get totally scrambled). Then, due to an accident chain that would make the NTSB blush, the results pop out in the flight model, often as an incorrect roll tendency for airliners.
This (and a number of other bugs — thanks to all of the airplane authors who tried their planes and reported bugs against rc 1) will be fixed in rc2, which will hopefully come out “real soon now™”.
If your plane is saved in X-Plane 10.05 format, this bug won’t affect you – the fix to X-Plane will cause your airplane to just work. If you have already saved your airplane with Plane-Maker 10.10, you may have to re-enter some of the amperages and bus choices for your electrical system – the amount of data scrambling depends on how you used Plane-Maker. The good news is that the damage is limited to the second electrical page so at the very worst, you’ll have to re-enter some electrical system data using rc2.
Trusting Beta Plane-Maker
This bug brings up the question: how much should you trust a beta or RC Plane-Maker? The short answer is: “not very much”. Here are my recommendations.
- Never, ever, ever release an airplane against a version of the sim that hasn’t gone final. Things do change in release candidates, sometimes major things when we find a bug like this. Wait until the version is declared “done” before you release your airplane!
- While always saving backups of your work is always a good time, it is especially important when using Plane-Maker betas. Assume a beta Plane-Maker might erase the .acf you are working on entirely; while we’ve never had it do something that bad, it has produced incorrect ACF files before due to bugs.
- Beta Plane-Makers are good for testing and trying new features and experimenting, but not for production work; wait until we go final to permanently change tool chains.
- The warnings about beta go for release candidates too!
I am working on a v9 -> v10.10 checklist for airplane authors; the actual “busy work” of editing the ACF file should be less than 30 minutes per airplane if you know what new values you need to enter for parameters that need updating, so a reasonable work-flow might be to experiment with the new features and report bugs until we go final, then make the actual update on a fresh copy of your plane from an older version.
How Did We Miss This?
The sobering thing for me is that this bug has been in our betas for four weeks and (1) we didn’t notice it and (2) no one reported it. I take a few things away from this: clearly we need to test our own planes more carefully. In 10.10 we did a lot of detailed work on our own fleet, but ironically this hid the bug from us. But I also take away from this that a lot of authors don’t even look at the build until RC.
If you make an add-on, I encourage you to at least look at a few betas before RC. Even if you don’t retest every one, taking a peak early means we can fix bugs that affect your add-on early, which is good for everyone.