password for SB20-77-01R2

Has anyone got the password for this service bulletin please, if yes can I have it please?


Many thanks


I doubt anyone on this forum has it. It is the SB to add engine monitoring to a Cirrus. You need a full kit with an Sensor Interface Unit (SIU) which have not been made for many years. What are you looking to do? If it is to add engine monitoring that might be impractical. If something else maybe we can help.

Hello Roger

It was more of information and curiosity. I came across page 1 of chap 77-10 of sr20 maintenance manual stating below:

Serials 1233 thru 1581 w/ EMax™ Engine Monitoring, 1005 thru 1232 after SB 20-77-01: Engine crank- shaft speed is indicated by an electrically operated tachometer and by the MFD. Both indications receive a speed signal from the RH magneto. Manifold…

I am curios to see what the magneto connection is (to be honest I think this is a printing error in the manual), which is why I needed the SB, but Cirrus have password protected that document!!!

Did you look in the wiring manual and IPC? According to those, all SR20s without Perspective avionics have a tach generator. Perspective aircraft get the tach signal from the magneto.

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Thanks for the info Clyde, I am only interested in the service bulletin and why it is password protected. I think I will have to write to them!

Well, if I can’t give you the SB I can give you the early and later wiring diagram. I see no difference in the tach other than a serial connection to EMax. In my experience there is no difference on the tach generator. In the 22 they do the same thing, a serial connection to the gauge that essentially tees off that data to go to the SIU for display on the Avidyne. They do have a sometimes 3 pin connector and sometimes a 4 pin one. That is independant of the EMax installation.


Very much appreciated. The first diagram is pretty much what I was also looking for. At least I can now trace the fuel flow wiring.

We do have a problem with the fuel flow indication on the analogue gauge (the one that is combined with the MAP), yesterday we lost all indication of fuel flow on both the MFD and the analogue gauge and a jumpy MAP gauge with inconsistent %power.

So today cleaned both connectors inside the cowls (on the baffle) with the aid of ACF 50, MAP is now OK on both MFD and the analogue gauge, fuel flow indicator on MFD is OK, but on the analogue gauge it only shows reading when full power is applied. So now need to find out if it is the gauge or the wiring!!!

Have you, or anyone else come across this problem before?


Come join COPA. There are over 200 posts per day discussing all things Cirrus. Lot of great information on the PAID side.

Oh yes! Join and do a search. Wiring problems, connector problems, ground integrity all have been problems along with gauge failure and SIU failure.

Hey Mo, are you still in the UK?

Hello Alex,

Yes in UK, based at Gloucestershire airport, just got our second Cirrus airworthy and waiting for a problem, spoke too early, the analogue fuel flow indication…!!!


They are password protected necause you have to buy the SB to get the parts and instructions together. If it is already installed you don’t need the installation instruction - you will find the information to diagnose and repair in one of the Cirrus manuals, like in this case from the Cirrus Wiring manual.

Thanks for confirmation Roger. Don’t need the SB, as mentioned before it was more of a curiosity!!! I found the wiring diagram quite useful.

Still we need to borrow a serviceable Map/Fuel flow gauge to identify the source of problem with Fuel flow indicator (part Number 12617-002).