The Day-Year Switcheroo
Remember that beautiful flight you did last Tuesday? The one where you thermalled up to cloudbase and managed a personal best? Yeah, well according to your logger, that happened in the year 0024. On the 25th of January, sure. But in the year 0024.
Welcome to the DDMMYY vs YYMMDD problem - a date encoding mess that has been quietly haunting IGC files since certain manufacturers decided the IGC specification was more of a suggestion than a rule.
What's Actually Happening
The IGC standard is pretty clear: dates should be encoded as DDMMYY (day-month-year). So January 25th, 2025 gets written as 250125.
But some instruments - and we won't name names here because we're all trying to get along - decided to write dates as YYMMDD instead. Same flight becomes 250125 which, when parsed correctly, means "the 25th day of January in the year 2025" but when read by software expecting DDMMYY format, gets interpreted as "January 1st in the year 2025."
Wait, no. It gets interpreted as "the 1st of some month in the year 25" because the day field now contains 25 (which was supposed to be the year).
It's a mess. Your entire timeline gets scrambled. Flights show up in the wrong order. That XC you're proud of? The app thinks it happened decades ago or decades in the future depending on which way the encoding went.
How Bad Is It Really?
If your instrument writes dates wrong, every single flight you upload will have a broken date. This means:
- Your timeline shows flights completely out of order
- Season statistics become meaningless
- You can't reliably filter by date range
- The "same day flights" feature shows the wrong day's worth of activity
- Your annual progression graph looks like abstract art
But here's the thing: we can fix it. Because the pattern is predictable. If we know a date got swapped, we can swap it back. 25/01/25 becomes 25/01/25 in the correct format when we reverse the operation.
The Fix: Two Ways to Tackle It
We added two features to handle this without making you re-upload everything or manually edit IGC files:
1. Fix Date Encoding (Bulk Operation)
Select multiple flights with broken dates (or all of them if your logger consistently produces bad dates), open the actions menu, and hit Fix Date Encoding.
This swaps the day and year values for every selected flight in one go. The operation shows you a before/after preview so you can verify it's doing the right thing. If your flights have been showing up as happening in the year 0024 or 0026, this fixes them all at once.
When to use it: Your instrument consistently writes wrong date formats, and you've got dozens (or hundreds) of flights to correct.
2. Use Suggested Date (Single Flight)
Sometimes you just need to fix one flight. Open the flight details, click the action menu (three dots), select Change Date, and you'll see a card showing the Suggested Fix if we detect a potential date swap issue.
One click and the date gets corrected. You don't have to manually enter anything.
When to use it: Spot-checking individual flights or handling one-off date issues.
A Warning, Because We Care
Both features come with big red warning dialogs because this operation swaps day and year values. If you run it on flights that already have correct dates, you'll break them.
Only use these tools if:
- Your flight dates look obviously wrong
- You know your instrument produces YYMMDD format instead of DDMMYY
- The suggested date looks more correct than the current date
If you're unsure, check one flight first. Look at the preview. Make sure the "fixed" date is actually when you flew.
Why This Matters
Flight data should be reliable. Your timeline should make sense. When you look back at a season's worth of flying, the dates should match reality - not some scrambled alternate-timeline version where you were apparently flying paragliders in the year 25 AD.
This fix restores order. It makes your logbook usable. And it means you can trust the statistics, filters, and analytics We-Fly provides because the underlying date data is finally correct.
The Bigger Picture
This is one of those issues that seems small until you hit it. Then it's maddening. You upload flights. The dates are wrong. You try to fix them manually. You realize you have 200+ flights to correct. You give up.
We built these tools because date encoding problems shouldn't require a computer science degree to fix. Click a button. Review the preview. Apply the fix. Move on with your life.
The sky is complicated enough. Your logbook shouldn't be.
Get Your Dates Straight
If your flights are showing up in the wrong year, head to your flights page, select the affected flights, and run Fix Date Encoding. The whole operation takes seconds.
Got questions? Found a weird edge case? Let us know. We're always listening.
Good air ahead.