Relocating the compass as a safety measure

jliltd

jliltd

Active Member
In further review of the STC Installation instructions for the G5 with GMU 11 remote magnetometer, there is a sentence explicitly forbidding removal of the whiskey compass after installing the GMU 11 in concert with the G5.

Section 2.1 reads, "As installed by this STC, the G5: cannot replace the non-stabilized magnetic compass (Whiskey Compass must be retained in the
aircraft)."

So that trumps all FARs, Advisory Circulars and Definitions. So no, you cannot replace your existing compass with a G5 with GMU 11 as primary magnetic direction indicator source.

This is also true when installing the GMU 11 in concert with the G3X Touch for Certified Aircraft for Part 23 installation. In that particular set of instructions you are required to re-calibrate the whiskey compass after installing the G3X Touch.

So no bye, bye compass. You might be able to re-mount the compass somewhere like a panel hole.

Jim
 
Kent Wien

Kent Wien

Well-Known Member
jliltd said:
In further review of the STC Installation instructions for the G5 with GMU 11 remote magnetometer, there is a sentence explicitly forbidding removal of the whiskey compass after installing the GMU 11 in concert with the G5.

Section 2.1 reads, "As installed by this STC, the G5: cannot replace the non-stabilized magnetic compass (Whiskey Compass must be retained in the
aircraft)."

So that trumps all FARs, Advisory Circulars and Definitions. So no, you cannot replace your existing compass with a G5 with GMU 11 as primary magnetic direction indicator source.

This is also true when installing the GMU 11 in concert with the G3X Touch for Certified Aircraft for Part 23 installation. In that particular set of instructions you are required to re-calibrate the whiskey compass after installing the G3X Touch.

So no bye, bye compass. You might be able to re-mount the compass somewhere like a panel hole.

Jim
Click to expand...
Thanks Jim,

I tried a SIRS compass on the panel. There wasn’t a place where it wasn’t getting interference. I’ll stick with the stock compass location.

Just read one of the first reviews of a Husky (the first?) that questioned the logic of the compass location back then.

Kent
 
B

bcone1381

New Member
My iPhone has an app called Smart Tools Pro. It has 20 different tools for measuring “Stuff. Length, angles, distance, vibration, audio to measure noise levels, a “bubble” level, etc. One tool of interest to us is called Mag Flux. It’s reading 32 as it sits on my desk. As I move it around my iPad I can get it to read over 1200.

I took this “tool” and moved it around my experimental kit’s tube fuselage to help locate what I think will be a good spot for the Sirs compass. Some times magnetism in different places will cancel each other out.

As I choose fasteners, I’m trying to use SS and avoid cadmium plated steel near the compass. I keep magnets away from my fuselage too.

I’ve found small areas where the magnetism rises sharply and they are pretty small and things fall off quickly.

I guess what I’m saying is you don’t have to guess where a good spot is for a compass. I made my choice using real measurable data.
 
lowlevelops

lowlevelops

Member
I don’t know that I have ever looked at a whiskey compass in an airplane in the first 36 years of my flying career... I have never looked at the one in the husky, I don’t think I would miss it.
 
jliltd

jliltd

Active Member
lowlevelops said:
I don’t know that I have ever looked at a whiskey compass in an airplane in the first 36 years of my flying career... I have never looked at the one in the husky, I don’t think I would miss it.
Click to expand...

Trace,

I get you. I didn't even realize the Husky had a compass until it sprung a leak on a hot Summer day over Kansas and made me look like I wet my pants. Thankfully, it went unmentioned. I wet my pants often enough that my friends tend to ignore it. ;)
 
M

Meadowlark

Well-Known Member
I have decades of experience with GPS systems..... Pretty much since their inception. The systems I have owned and operated include almost all of the manufacturers of GPS. I have had nearly every type of GPS failure that can possibly happen. As such, I have learned to not trust my GPS equipment! I certainly will not put my life on the line with (especially) Garmin equipment. How often does the government decide to turn off the satellites?

If your vacuum system fails..... That never happens, does it? You will lose your heading indicator! Oh, I see that you have modern, electric heading and guidance equipment..... How often do electrical systems fail? Far too many times.

Twice while flying, GPS has failed me. Leaving me to fly by dead reckoning and referring to a compass heading...... Simplicity is king!

J/C GTF & P48
 
D

dogday

Active Member
Meadowlark, a week after I got my pilot's licence, I took my Cessna for a long VFR cross country (Big Lake, Alaska to Mexico City) using dead reckoning. On my way back to Big Lake, I stopped in McAllen, TX and had what I considered the leading edge of electronic navigation for GA aircraft installed (Loran C) to lessen my navigation work load. With Loran C, you quickly learn not to blindly trust electronic navigation.

Typically before off airport departures, I ensure that my directional gyro heading matches the compass and adjust as necessary. At airports, I just use the runway heading to check my directional gyro. During long flights, I occasionally ensure that my DG matches my compass heading. I can't imagine flying MVFR depending using electronic navigation data alone.
 
Brad20j

Brad20j

Active Member
Has anyone put a rubber edge guard/protector on the bottom edge of the compass bracket to protect your head? Perhaps a commercial one or a small, slit, rubber hose?
 
Matt Russell

Matt Russell

Member
Kent Wien said:
Thanks Jim,

Just read one of the first reviews of a Husky (the first?) that questioned the logic of the compass location back then.

Kent
Click to expand...
A review would be right to be critical. It's a garbage location for a hard metal box. And it's not there on the ACA aircraft. Thank you for this thread; I came here to start it if I couldn't find it.
Edit: I'm starting to think a 3D printed breakaway mount for the compass could be the safest, easiest solution that doesn't require relocation, kind of like the steering column stalks on a car are all designed to break away. Good luck getting that one approved, I suppose.
 
Flying Dave

Flying Dave

Active Member
They make what are basically sweat bands for motorcycle brake fluid reservoirs. I have ours covered with one. If you need the compass it can be removed in a second.

 
Ak Kurt

Ak Kurt

Well-Known Member
Mike, I think we tried the Sirs unit on brother Kent’s airplane and we could not find an acceptable place to mount it. I will let Kent comment further.

Kurt
 
Kent Wien

Kent Wien

Well-Known Member
Yep. I was excited to try the SIRS. Sadly it had way too much interference everywhere we tried. I’m just living with the stock location. I store a Rosen visor over the compass to protect my head a bit.
 
belloypilot

belloypilot

Active Member
Thanks for the report. We have a SIRS in the Grumman and like it. I‘m sure I’m more vertically challenged that most Husky drivers that are concerned about the hazard of the stock compass location because I’m no too concerned about it, but thought the SIRS might be an option.
 
Matt Russell

Matt Russell

Member
Thinking about this a little more, I'm nearly convinced the factory steel mount for the original wet compass might be replaced with a well-designed ABS plastic mount that would breakaway with impact forces. Certainly any energy absorbed by breaking the mount is less energy transmitted to a pilot's skull. This method is quite common for automobile interior parts like steering column stalks, shifters, etc.
I wonder what it would take to get such a part approved as a replacement for the factory mount, either on a case-by-case basis or by STC. The part could be 3D printed in ABS.
 
belloypilot

belloypilot

Active Member
Matt Russell said:
Thinking about this a little more, I'm nearly convinced the factory steel mount for the original wet compass might be replaced with a well-designed ABS plastic mount that would breakaway with impact forces. Certainly any energy absorbed by breaking the mount is less energy transmitted to a pilot's skull. This method is quite common for automobile interior parts like steering column stalks, shifters, etc.
I wonder what it would take to get such a part approved as a replacement for the factory mount, either on a case-by-case basis or by STC. The part could be 3D printed in ABS.
Click to expand...
Do you think that level of approval would be necessary or would it just be considered a minor modification?
 
Matt Russell

Matt Russell

Member
belloypilot said:
Do you think that level of approval would be necessary or would it just be considered a minor modification?
Click to expand...
It's certainly minor in my mind, but I'm certain the US regs would require steps and documentation for compliance. My understanding is you generally can't swap-out a part with a change of material on a Part 23 certified aircraft without an STC or field approval.
 
You must log in or register to reply here.
Top