1977 J POH Page 2.9 - Vacuum Gauge Markings

[autopatch]

Under the section "Other Instruments and Markings" in the original version (9/27/1976) of the manual stated "Vacuum Gage Normal Operating range (Green Arc) 4.5 to 5.0 Hg." At some point in a subsequent version, that sentence was removed from the manual in it's entirety; I checked the PDF available from the factory USB manual collection and the most current version of that page is 11/15/77 and the sentence was removed. The Table of Change on Revision G 3/7/84 lists that Page 2-9 as "Original" and unchanged.

So I have two questions. First, the practical one -- if the face of the Vacuum Gauge had to be repainted for some reason, and the most current version of the POH doesn't specify the valid values for the green arc, how will the instrument shop know what to paint?

The second question is, does anyone remember why something like this would be removed between 9/76 and 11/77 and which "original" page is the valid page. Can the values from 9/76 be used if that page has been superseded?

Thanks.

Chris

 

Edited July 12, 2017 by autopatch

[autopatch]

Well, that would make sense as an explanation. It would also lead me to believe that for the 77 year I should retain the 9/76 page 2-9.

Thank you for that bit of information.

The challenge is that the backing page 2-10 was revised with the updated placard indicating the 150 MPH gear extension speed. I'll have to check to see if there is a Service Bulletin about replacing my gauge with the light and reclaim the panel space.

Edited July 12, 2017 by autopatch

[carusoam]

This is more of an instrument question, than a Mooney airframe question.

Check on your instruments to see what their operational requirements are.

My '94 Mooney came without a vac gauge. The first owner had one temporarily installed 20 years ago.

One day it will be connected to a JPI.

PP thoughts only, not an instrument guru...

Best regards,

-a-

[autopatch]

5 hours ago, carusoam said:

This is more of an instrument question, than a Mooney airframe question.

Check on your instruments to see what their operational requirements are.

My '94 Mooney came without a vac gauge. The first owner had one temporarily installed 20 years ago.

One day it will be connected to a JPI.

PP thoughts only, not an instrument guru...

Best regards,

-a-

 

The instruments just report against the specs outlined by the manufacturer of the aircraft within the TC and POH. When setting up your JPI, the shop will refer to your POH when configuring the bottom and top of the various limits.

Today it's programming when it used to be done with a paintbrush or silkscreen.

Mine got it's certificate 12/30/76 and had the vacuum gage installed at the factory. From the above it sounds like Mooney removed the gauge in favor of a warning light from 1978 forward but my airframe never got retrofitted.

Mystery solved. I'm going to keep the original page instead of the new one.

 

Edited July 12, 2017 by autopatch

[autopatch]

Just another update. Spoke with Mooney International, and they did some research. I understand they will be re-publishing POH 1220G because they found a mistake in the art master for this page in the archives.

Stay tuned!

[carusoam]

Autopatch, you are a true MSer!

Going to the source to find the truth, then posting results here.

You are the best.

Best regards,

-a-