On 5 Apr, 16:32, T8 wrote:
On Apr 5, 11:22*am, JS wrote:



You're right, it's about 100 hours.
* It's just another thing to deal with at Annual time. For many people
using "clear log" at Annual is sufficient to keep the gremlins away.
But if you fly a lot, that isn't enough. Perhaps stick a post-it note
in the logbook to remind you of when the next "clear log" is due...
* SPOT batteries should get changed at each Annual too. I put 200
hours on the 2 Lithium AAs (version 1) with no problem, but doubt I'd
push it another year.
* At the bottom is a way to make and test a log without flying, to
check 302 security.
Jim

Clearing the flight log memory in a 302 or 302A
This may help reduce flight log security issues on future flights.
Important Note: This will erase all flight logs in memory!
1. * * *Connect the 302 or 302A to a PC using the RS-232 serial cable that
was supplied with the 302.
2. * * *Power the 302 or 302A with 12 volts and make sure the unit is
turned-on. *The GPS antenna does not need to be connected.
3. * * *Run a terminal emulator program on the PC. *A good one to use is
HyperTerminal. *It is included with most versions of Windows. *To
access it go to:
o * * * Start Menu / All Programs / Accessories / Communications /
HyperTerminal
4. * * *In the "New Connections" window enter "302" for the Connection Name
and then click the OK button.
5. * * *In the "Connect To" window, set the "Connect using" parameter to
match the desired communications port. *This is the port which the
RS-232 serial cable is connecting with. *It is usually COM1, COM2,
etc. and will vary from PC to PC. *Then click the OK button.
6. * * *In the "COMx Properties" window set the parameters as specified
below and then click the OK button:
o * * * Baud Rate: 4800
o * * * Data Bits: 8
o * * * Parity: None
o * * * Stop Bits: 1
o * * * Flow Control: None
7. * * *You should now see GPS data sentences appearing in the
HyperTerminal window.
8. * * *Hold the "Ctrl" button on your computer's keyboard and hit the "c"
button (Ctrl-c). *The flow of GPS data should stop.
9. * * *At the "cmd" prompt type: "clear log" and hit the Enter key. *I
don't think there is any acknowledgement from the 302 other than that
the "cmd" prompt reappears.

Checking the 302 logger with HyperTerminal:

* Connect as above
Ctrl C
Type START
Allow it to log 10 minutes.
Type STOP
* Then download the log with the CAI 302 utility and check security.

Thanks JS. *Somehow, I though the point of the memory upgrade was to
avoid having to do this...

-T8


Some time ago I had security fail with a 302ACFR that hadn't been
prevented by prior regular clearing of the flight log but did go away
when I sent the unit back to Cambridge for the Flash upgrade and re-
sealing.

However another possible cause is a flat security memory backup
battery. That's what caused my most recent security fail - this time
with a 302 DDV - and when I took advice (identity withheld for obvious
reasons) about having the flash upgrade done to the unit at the same
time as the battery replacement/re-seal I was told that:

"the original chips used became obsolete so an almost direct
equivalent has been cobbled onto the original board in the last 2
years production. There were then some timing issues, but Phil
Schlosser did some consultation and sorted out the problem. It turned
out that the timing had always been marginal, so there was a software
update that makes both old and new memory chips more reliable. The
original ones do not need the odd hard-wired jumpers to make them work
on the pcb. There is no difference in functionality between the
original and replacement memories, and it is believed by the design
team that the ones the unit was designed around are more reliable.
(The new ones have in principle more memory, but there is not the
control available to use it)."

I can't vouch this but I didn't get the flash changed on the second
unit.

John Galloway