BK ADF KR87 - Flight and Elapsed Timers

[Costa Leite]

Dear All

Our legacy BK ADF KR87 (yes, in europe we mandatory still use ADF) has a problem with the Flight Timer / Engine Timer.

Right now, after power up, the KR87 starts counting Flight Time, but it should start counting on Engine Time only.

Before this happens, right after power up the unit started counting Engine time and only after departure the KR automatically started counting Flight Time.

I think this unit has somekind of a switch connect to the Landing Gear Indication. But we never touched that gear connection, and this is not the first time we have this problem. But before, this problem just disapeared and the KR87 started counting correctly by it self.

So, I guess this can be a faulty wire contact or a wrong wire connection?? Does anyone knows where to look or how can this be solved?

Thanks in advance for your shared knowlodge!!

Cheers

Fredi

 

 

[PT20J]

You’ll have to figure out how the flight timer is activated. There might be an air switch (look for something protruding from an inspection panel underneath the wing). The airspeed safety switch might have a second microswitch used for a flight timer.

Skip

[carusoam]

Interesting….

My ‘94 Mooney shares some genes with Fredi’s…..

My ADF did not get connected to an airspeed switch…

So… it starts counting when the power is supplied…getting manually reset prior to lift off if using this timer…

Other things to check… the engine hour meter on the back wall of the baggage area…. Is probably connected to an oilP switch….

Whatever is supplying the engine hour meter with power, may be connected to the BK ADF…(?)

Connecting it to the airspeed switch… is an interesting idea… the AS switch is only inches away from the ADF…

Sounds like a loose wire might be occurring between the AS switch and the ADF… (?)

Does ET on the ADF button actually stand for engine time…? 

The ADF became less useful by the day after my M20R came home…

PP thoughts only, not an instrument guru…

Best regards,

-a-

 

[Costa Leite]

Actually I was wrong and forgot that ET is for Elapsed Time  I already reviewed this topic name.

Just found an interesting installation manual for KR87.... On pages 25 - 27 it is clearly explained the possible wire connection to a gear retract switch or squat switch, which would be to the AS switch in our Late J Mooneys, for the Flight Timer reset:

https://dokumen.tips/reader/f/kr87-install
 

I am just wondering if someone solved this problem before and knows exactly where the wiring is going to from the ADF??

[PT20J]

My 1978 M20J had an air switch connected to the Davtron flight timer. It was located in an inspection panel under the left wing near the inboard leading edge. I think it was a factory installation, but I'm not sure.

[carusoam]

Fredi,

What year is your Mooney?

My 94 M20R didn’t get a few wires connected that would have made things really top notch…

The GPS didn’t get connected to the engine monitor… neither did the FF data… (fuel to destination)

My ADF didn’t get connected to the AS switch… (flight timer)

 

GPS and engine monitoring were so new at the time… 

Best regards,

-a-

[carusoam]

If you take the wiring diagrams on the last pages to your favorite avionics guy…

And the details of the airspeed switch…. (May be found at KNR-inc’s website…  he has a write-up on the OH of this switch…)

That would probably complete/minimize his research and homework to enable connecting the switch to the ADF…

There are two choices of output on the switch, and two for the ADF… depending on status of the switch, mate it to the proper choice on the ADF…

 

PP thoughts only, not an avionics guru…

Best regards,

-a-

[Aerodon]

In Canada, flight time is defined as 'when aircraft starts to move under its one power' or something similar.  So having the ADF (or hobbs) start counting when the engine starts is a good approximation, connected to an oil pressure switch.  (I've seen these fail, and the hobbs just carries on counting).  This is 'flight time' for my personal logbook.  So I prefer this method of activating the ADF, especially if no hobbs is installed.  But activating on 'master on' or 'avionics bus on' is close enough.

Most GPS's do a good job of counting 'airtime' from takeoff to touch down, this is engine time for the logbook.  Or the simple flight schools way of doing this is Hobbs - 0.2 hours, or tacho time.

Rather than spending money on getting the ADF 'airspeed' trigger, put that money towards a GPS that counts proper flush time (Area 660 does a good job of keeping track of flights).

 

Aerodon

 

 

 

 

 

[Costa Leite]

Thanks all for your comments.

Our Mooney is a 1998 M20J Allegro SN 24-3429 (third last built). The original panel is shown on picture in attach. The factory installed Mini-Flo was correctly wired to the KLN-89b GPS for Fuel to Destination information. The factory installed EDM 700 never had the FuelFlow function and so it never been wired to GPS... I believe that this wasn´t anymore an option since Mooney started instaling the Mini-Flo instead..

Since factory the Flight Timer of the ADF worked perfectly, counting from wheels up moment (or similar). Both on factory KLN-89b and also on current GTN750 GPS, we have the flight time information. I am only trying to have also this information correctly shown right where it has been displayed before. I guess I must have a disconected wire somewere, or a broken switch.

Hoping that someone had this issue before and could share his findings here to give me a shortcut on the troubleshooting 

But you are right Anthony, with all the above information, our avionics guy should easily sort this out.

Cheers,

Fredi

 

 

 

 

 

[carusoam]

From the KNR-inc website…

Kerry has a pic and details regarding the air speed switch…

https://www.knr-inc.com/shop-talk-articles.html?id=93:201901-electric-gear-safety-system&catid=25
 

This will at least help find the device, and see if a wire is hanging off of it…

Best regards,

-a-

[Costa Leite]

I just asked Mooney if they know where the ADF KR87 is wired to in order to get “airborn” information for the FlightTimer, and here is the answer:

“Good Afternoon Frederico,

Thank you for the inquiry - I have attached the Aircrafts Master Schematic and I also found the Installation of the KR87 ADF interconnect page for your reference.

I hope this answers your question”

I confess I got a bit lost after checking both diagrams :/

Does anyone can understand if the KR87 is connected to the Gear lights of the Anunciatir Panel, or if is wired to the Airspeed Safety Switch?

800383_RH_J2.pdf KR87 ADF.PDF

[PT20J]

1 hour ago, Costa Leite said:

I just asked Mooney if they know where the ADF KR87 is wired to in order to get “airborn” information for the FlightTimer, and here is the answer:

“Good Afternoon Frederico,

Thank you for the inquiry - I have attached the Aircrafts Master Schematic and I also found the Installation of the KR87 ADF interconnect page for your reference.

I hope this answers your question”

I confess I got a bit lost after checking both diagrams :/

Does anyone can understand if the KR87 is connected to the Gear lights of the Anunciatir Panel, or if is wired to the Airspeed Safety Switch?

800383_RH_J2.pdf 1.82 MB · 0 downloads KR87 ADF.PDF 140.08 kB · 0 downloads

The KR87 drawing shows the flight timer input connected to pin 4 of receptacle RC104A. Find connector RC104A on the main schematic to see what it connects to on the airframe.

Skip

[carusoam]

Highlights for adults, hidden picture game…

I tried a short cut… go to the obvious switches, and see if I could find anything related to Skip’s RC104A hint….

First, I found the Kulite OilP sensor… nothing hinted towards RC104A…

Then I found the airspeed switch… something very similar… EG104A

 

See if the two drawings can be melded together to show the whole answer…

See if Skip’s RC104A is actually and EG104A… or maybe RC becomes EG as it crosses a line somehow… (?)

There are two AMP connectors for the airspeed switch… named RC04A….  See the red dots added (Closer?)

 

See how I got this far…

Best regards,

-a-

 

[PT20J]

10 minutes ago, carusoam said:

Highlights for adults, hidden picture game…

I tried a short cut… go to the obvious switches, and see if I could find anything related to Skip’s RC104A hint….

First, I found the Kulite OilP sensor… nothing hinted towards RC104A…

Then I found the airspeed switch… something very similar… RG104A

 

See if the two drawings can be melded together to show the whole answer…

See if Skip’s RC104A is actually and RG104A…

 

See where I got this far…

Best regards,

-a-

 

Good sleuthing, Anthony. The airspeed switch second set of contacts go to connector RC04A. My guess is that that's actually the  RC104A on the KR87 dwg. The pinout seems right.

 

[carusoam]

Add this one to the mystery files….

I highlighted a few things related to the ADF…

One of them mentions a relay box….  That may be of interest if the ship has this particular installation…

Best regards,

-a-

[Costa Leite]

Many thanks to bought of you!!

I will forward this info to my mechanic right away!