Help Requested- Clearnav 1

[Hank Nixon]

Does anyone know the procedure for clearing flight logs form aa Clearnav 1?. CN2 has a feature that does this.

At a contest and the latest flight log does not show. More than 100 logs in the stack.

Thanks

UH

[Ryszard Krolikowski]

To access all the files in CN1, plug in USB splitter with USB mouse and CN1 USB stick.

Before CN1 application on internal micro SD gets activated, use mouse to pull up cumulus background screen and click on windows ce start icon, bottom left.

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[Hank Nixon]

Thanks for the help

UH

[Mark Zivley]

Greetings,

I have a CN2 that's occasionally had an issue logging a flight.   What is the procedure for clearing all the logs on a CN2?   Having read the post above about the splitter and the mouse I started down that path, but didn't ever get to a point where I was able to see a window ce start icon.   Perhaps I missed a step.

Thanks in advance.

Mark

[Hank Nixon]

For the CN2 the procedure is:

Insert your start up stick

When the menu of options is displayed, look for the button at the bottom of the screen that allows erasing files.

Unfortunately the CN1 is quite a bit harder, but it can be done. Bad news is that it did not solve my problem of today's flight not being listed to download. Sigh 

[Mark Zivley]

Thanks!

[David Cleveland]

Hank - Did you solve the lack of flight logging issue? After reading your request I looked at my Clearnav 1 flight log listing and noticed it stopped logging last June. I usually don't look at the Clearnav flight log because I use a different method for file download, so this was a bit of a suprise.

Thanks for the heads up. Any resolution?

David

[Hank Nixon]

What I have learned.

I was able to access the Windows CE operating program using the guidance provided by Ryzard.

After noodling around I found the folder that has flight logs.

I was assuming that memory was full.

I deleted about 100 logs.

I expected to see my next flight.

But no.

Further learning and digging led me to look at the bottom of the list.

The files were there but with 06 dates, and sort of random.

It seems that for some reason the files are not properly identified.

The files are good and have all correct attributes, including the correct date.

I have no explanation but suspect it is related to old GPS engines.

Other brands are starting to see something similar.

That is what I have learned. 

UH

[Lynn Alley]

The GPS epoch is a bit more than 19 years, so dates of 2006 do indeed look like they may have been recorded with the epoch off by one.  But the current epoch started in 2019, so if you have anything after that, it means your GPS engine is capable of working in the current epoch.  Modern engines are supposed to learn the number and handle rollover automatically, but older ones require setting the epoch number.  This is often done by setting the date, which causes the GPS to remember the epoch number in the config.

The best explanation is that the GPS engine somehow lost its config, and with it the current epoch number.  I'm not a ClearNav guy, so I can't offer help on how it might be reset.  Maybe there is a way to force a date change on the whole unit, which could maybe set the date and reprogram the epoch number in the GPS?

Lynn Alley

"2KA"

[Ryszard Krolikowski]

While we have the attention of ClearNav 1 and ClearNav 2 users, I would like to address an issue unrelated to the current flight and error log cleaning discussion.

I have noticed that many pilots maintain waypoint and SUA files on their devices that are not necessary for their current flying location. I recommend keeping only the relevant site information on the device and storing other sites data on a  USB stick.

Removing unnecessary files from the CN1 and CN2 prevents the system from freezing and significantly improves responsiveness, particularly when using the thermal helper mode.

Best regards,

Ryszard Krolikowski

To view this discussion visit https://groups.google.com/d/msgid/rasprime/9bf4852a-1218-4e62-97f1-ae50713c16can%40googlegroups.com.

[Moshe Braner]

Some old GPSs "know" when they were made, so they adjust the epoch across the rollover in 2019.  But when reaching 19 years since they were made, they assume they're back in 2006.  This happened late last year to an LX7007 we have.  The Neo 4 GPS in it cannot have the epoch reset, so we're stuck with that.  That's a shame, since it works fine otherwise, and was an IGC certified flight recorder.  WeGlide automatically adjusts the epoch for you if you post the flight within 2 days of it happening.  I guess they assume you didn't decide to post a flight from 2007 exactly one epoch late.  (The date discrepancy is exactly 1024 *weeks.*)  Any chance the appropriate SSA committee would approve the use of such a device for badges and state records?  You need an Official Observer anyway, have the OO sign off saying they observed this flight happened in 2026 not 2007?

[David Cleveland]

We have a glider that has an LX Navigation 7007. Yes, last year the date started reading incorrectly. All of the data in the .igc files are correct, except for the date. The igc file can be modified manually to read the correct date, but then it doesn't pass verification (of course).

I have a different glider with a Clearnav 1 flight computer. My recent flights are not showing on the flight log list, incorrect date or not. I have not cleared the older log files yet. The same glider has an older round Clearnav vario. The flights on the flight log are showing with proper dates and data.

Reading the input from Moshe and Lynn it looks like this is a hardware issue, not easily solved. It seems a shame to throw out perfectly good equipment.

Lynn, you have an older SN10. Any issues?

DC

[Dave Nadler]

On Thursday, April 23, 2026 at 2:12:00 PM UTC-4 David Cleveland wrote:

... Lynn, you have an older SN10. Any issues?

SN10 gets data from an external GPS. If it sees an earlier epoch (from an old GPS),
it corrects the GPS date time (and SN10's flight log) to the current epoch.
So, no problems for the SN10 with current firmware...

Enjoy,
Best Regards, Dave

[Lynn Alley]

Yeah, what Dave Nadler said.  My SN10 uses an external GPS that has the correct current epoch.

I have been thinking about it a bit more, and the fact that the epoch got messed up on Dave Cleveland's and Hank Nixon's systems in the middle of the epoch makes me think the likely cause is failure of the GPS engine's internal battery.  The battery is soldered on to the board of the GPS engine, and likely would require professional help to replace it.  Some engines have replacement firmware that defaults to the current epoch if the battery fails, instead of the previous epoch that covered about 2000-2019.  I would suggest contacting the manufacturer's support.

If no manufacturer's support is available, a DIY replacement might be possible.  But beware, many  IGC approved loggers have anti-tamper mechanisms that could make the approved logging function stop working if the case is opened.  (Sigh).

L.

[Mark Zivley]

I successfully cleared the flight logs and it copy a good number of files over to my thumb drive.   the files end in .LOG   Is there a way to convert them to igc or another file type if I wanted to determine flight times?   Maybe I need some CN software?

On Saturday, April 18, 2026 at 8:03:39 PM UTC-5 Hank Nixon wrote:

[Charles Mampe]

I would save a copy of your flights, then take one and change from ".log" to ".igc" and see if it opens in a viewer (actually try your usual viewer and see if it opens now). The file extension change may fail as a record for badge/record flights, but work fine in a viewer (WeGlide, Skylines, etc.).

[Moshe Braner]

Open the files in a text editor and see if it looks like an IGC file, which would start with something like:

AXSPBVNFLIGHT:1
HFDTE270611
HFFXA050
HFPLTPILOT: ...

and later continue with a bunch of "B-records" such as:

B1806454431077N07236914WA005040050401609
B1806514430974N07236990WA005440054401609
B1806574430880N07237090WA005840058401509
B1807034430801N07237206WA006150061501509
B1807094430727N07237329WA006420064201509

If it really is an IGC file with the wrong file name suffix, changing the suffix will not void the file "security".  OTOH if it is not an IGC file, changing the suffix will not make it one.  SeeYou may be able to convert it to an IGC file.