J3 Instrument Panel

I have asked this question on another forum. I have a 46 J3 and want to relocate my TAC to a different location. My A&P/IA is concerned that changing up the order would violate some regulation. I don't know of anything that prohibits me from changing the location of my instruments: TAC, Airspeed, Compass, Altimeter, Oil Pressure/Temperature. Considering I want to move some stuff to go back to the original config I think it's ok. Any help is much appreciated.

Thanks,

Bruce Summers
Collierville, TN

As long as the cable for the tach isn't kinked and can still operate properly ... do it. Ask your A&P/IA to show you the regulation which is in question.

Bruce, the requirements that he is concerned about are intended to be associated with aircraft that are tandem, in that the instruments should be placed in such a way to not be difficult to see. There are some requirements that require the primary flight instruments be positioned in a standard location/pattern but the tachometer is not one of these instruments. I would not squawk this change on a J3 if I were inspecting it. However, I think you’ll find moving it may be more trouble than it’s worth.

Can you cite those requirements? I do not recall any regulation pertaining to arrangement.

Log entry only. In a nutshell, all required instruments are still installed, so not prohibited and not even a major modification.

As asked above, exactly what reg is he citing for this claim?

Web

Thanks. That's what I figured.

No reg being cited. I'm looking through Part 43 and I don't see anything.

Bruce

bob turner said:

Can you cite those requirements? I do not recall any regulation pertaining to arrangement.

Click to expand...

Here we go....

Gladly - Keep in mind that the OP's mechanic is inccorect using this refrence.... and I am only assuming this is what his concern is....

23.1321 - Amendment Number: 23-49, Effective Date: 03/11/1996

Again, not applicable in this situation.

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The only reference that applies in this case is;

CAR4
Specifically, 04.510 & 04.650, which do not suggest/require a standard location (only a duplication of instruments if necessary), unlike the above, later regulation, that I assume the mechanic is referring to.

If you have trouble finding these regulations let me know...

You mean this?

Sec. 23.1321 — Arrangement and visibility. (a) Each flight, navigation, and powerplant instrument for use by any required pilot during takeoff, initial climb, final approach, and landing must be located so that any pilot seated at the controls can monitor the airplane's flight path and these instruments with minimum head and eye movement.

As Grant says, does not apply to CAR 4a or CAR 3 aircraft. Good thing; with a passenger I can ot easily see the compass.

I would edit that to change the type or make it italic, but the editor is no longer willing to cooperate.

bob turner said:

You mean this?

Sec. 23.1321 — Arrangement and visibility. (a) Each flight, navigation, and powerplant instrument for use by any required pilot during takeoff, initial climb, final approach, and landing must be located so that any pilot seated at the controls can monitor the airplane's flight path and these instruments with minimum head and eye movement.

As Grant says, does not apply to CAR 4a or CAR 3 aircraft. Good thing; with a passenger I can ot easily see the compass.

I would edit that to change the type or make it italic, but the editor is no longer willing to cooperate.

Click to expand...

Yes but keep reading.....

....In addition:
(1) The instrument that most effectively indicates the attitude must be on the panel in the top center position;
(2) The instrument that most effectively indicates airspeed must be adjacent to and directly to the left of the instrument in the top center position;
(3) The instrument that most effectively indicates altitude must be adjacent to and directly to the right of the instrument in the top center position;
(4) The instrument that most effectively indicates direction of flight, other than the magnetic direction indicator required by §23.1303(c), must be adjacent to and directly below the instrument in the top center position; and....


yada,yada,yada....


Again, this is likely the regulation the mechanic believes he would be violating. However, since the J3 certification basis is CAR4 then this does not apply... The regulation above does have some teeth for FAR Part 23 aircraft so be careful....

I think my Decathlon is part 23. The instruments are arranged that way, but only because I re-designed the panel.

Edit - photos of stock Decathlon panels do not really track that regulation. Maybe the type certificate overrides it.

bob turner said:

I think my Decathlon is part 23. The instruments are arranged that way, but only because I re-designed the panel.

Edit - photos of stock Decathlon panels do not really track that regulation. Maybe the type certificate overrides it.

Click to expand...

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bob turner said:

Edit - photos of stock Decathlon panels do not really track that regulation. Maybe the type certificate overrides it.

Click to expand...

Sure they do if you read the correct Part 23 ammendment based on the Certification Basis, which is found in the TCDS. The TCDS does not "Override" the regulations....It doesn't work that way....

bob turner said:

I think my Decathlon is part 23. The instruments are arranged that way, but only because I re-designed the panel.

Click to expand...

You are correct the 8 series are Part 23, but from a very early ammendment of that part. (23-1 & 23-6) Early on, the Part 23 Regulations were almost identical to CAR3 & 4. Your decathalon, and all decathalons were certified under Part 23, dated Feb 1,1965 as ammended by 23-1 & 23-6. If you read 23.1321 from those ammendments you will find there was no "instrument specific" arrangement requirement.

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I think we have answered the OP original question... If you have more questions understanding the regulations feel free to reach out to me via PM. ;-)