DHC-3T Altimeter K-window InHg error

[ChuckOman]

Hi Oisin -

Thanks for the new DHC-3T SP1 v1.180724 and all the improvements.

Noticed however that at least in P3D4.1, the Inches of Hg displayed in the altimeter's Kollsman window is off.
Happens in all versions (turbine, float, etc) and liveries.
Unique to the MilViz DHC-3T. Not present in my other P3D4 aircraft - I've checked.
Independent of weather source (ASP4 vs pressure set directly in P3D4 weather)
Not influenced by nav installation used (default vs GTN)
The altimeter altitude - thousands and hundreds needles- is always correct if you push the B key.
When the B key is pushed, th KAP-140 autopilot baro does set to the correct value, which also suggests the local baro is getting to DHC-3T correctly, and the problem is specific to the Kollsman window display scaling.

Here is some data on the error:
29.40 In Hg actual => 29.37 In Hg displayed
29.45 => 29.45
29.52 => 29.52
29.92 =>30.22
30.16 =>30.58
30.22 =>30.70
Note that error isn't simply an offset - the sign and magnitude depends on baro pressure.
K Window displayed value is correct only at 29.52
Perhaps an error in the Kollsman window scaling factor within the altimeter gauge.

The error is operationally significant - if you follow RW procedures and set your altimeter using Kollsman window to destination ATIS (rather than the B key shortcut) your displayed altitude can be hundreds of feet off.

I don't recall noticing this problem in v1/80706, but I'd only been flying the DHC-3T a few days, so it may also have been in original release. Nothing on the new DHC-3T forum about it. However I noticed one report from the DHC-3 radial about a altitmeter in Hg error that could well be same problem - guessing it is same gauge.

Until this is fixed, the only workaround is to ignore the K window and always use the B key to set the altimeter. At least the KAP-140 baro will then be correct.

Chuck O

[Chuck Jodry]

Chuck, Thank You for the report , your having taken the time to to quantify the discrepancies was appreciated and invaluable in resolving the issue ..
It will make it into an update with any other completed fixes in the least possible delay .

Best Regards
Chuck Jodry

[ChuckOman]

I see the Kollsman window problem is all fixed in v1.180807. Many thanks.

[obie311]

Is yours fixed? I downloaded and installed the new file. My Kollsman window is still wacky in 4.3.29.25520