Faulty Altimeter in J430

Australian designed and manufactured Jabiru Aircraft/

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Neels22
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Faulty Altimeter in J430

Unread post by Neels22 » Sat Aug 01, 2020 3:41 pm

Good day fellow avcommers I don’t know if this is the right place to ask but here goes. I recently bought a J 430 with very low hours but there is a glitch in the altimeter at ground level it shows an altitude of over 10000 ft adjusting the QNH is not helping And I have tried turning the knob both ways but can’t get it back to 5300 that is my true ground altitude any tips or hints is there a self fix or only back to an AMO? Picture attached
Thankyou in advance
Oh And how do I join the jabbi club??
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Chalkie
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Re: Faulty Altimeter in J430

Unread post by Chalkie » Sun Aug 02, 2020 8:44 am

Neels, you have a Three Pointer Altimeter, go to Kiki and read up... https://en.wikipedia.org/wiki/Altimeter

Your altimeter seems to have the baro sub-scale at 1022 mb / hP. Correct, the indicated altitude is almost 10 100 ft.

To correct the altimeter to your field elevation of 5300 ft:

1. Set baro sub-scale to local QNH

2. Loosen the screw next to the altimeter setting knob. DO NOT try to remove the screw, just loosen it enough so that you can pull the knob out and disengage the baro sub-scale.

3. With knob pulled out you will be able to set the pointers back to 5300 ft by turning setting knob counter-clock-wise. You should end up with the outer triangular pointer about halfway between the 0 and 1. The short pointer at 5 and the long pointer at 3.

4. Carefully re-engage setting knob to sub-scale gears and tighten setting screw.

Your altimeter should be fixed.
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Re: Faulty Altimeter in J430

Unread post by Neels22 » Sun Aug 02, 2020 1:58 pm

Thank you Chalkie I will go and try it this afternoon!!
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Re: Faulty Altimeter in J430

Unread post by Neels22 » Mon Aug 03, 2020 7:27 pm

Chalkie I tried what you told me but I cant get the baro subscale to disconnect the knob don’t pull to disconnect from the gears anymore advice
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Re: Faulty Altimeter in J430

Unread post by Chalkie » Tue Aug 04, 2020 12:30 pm

Neels22 wrote:
Mon Aug 03, 2020 7:27 pm
Chalkie I tried what you told me but I cant get the baro subscale to disconnect the knob don’t pull to disconnect from the gears anymore advice
It is a bit of a fiddle, but can be done as long as the locking screw has been released enough. I guess 3 or 4 turns out. Sometimes it takes a firm pull, and a wiggle. If you not able to disengage the baro sub-scale gears, then a visit to the instrument shop is called for.

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