Rick6a

Rick6a

Well Known Member
Question: For purposes of acquiring an airworthiness certificate, does the compass tape depicted on many modern EFIS's qualify as a compass required by FAR? I know DAR's have to attend periodic seminars. Has the issue ever been discussed or ruled upon? Are all DAR's on the same page as far as interpretation goes or is this a gray area best dealt with by conforming to the wishes of a given FSDO?
 
Amateur-builts fall under part 91 for night and/or IFR operations. Part 91.205 states that you must have a "magnetic direction indicator". The compass tape on EFIS does satisfy this rule.
Yes it has been discussed at the annual seminars, however there are still a few DARs that won't accept this. Remember DARs can add any restriction they feel is necessary.
972-784-7544
 
Hi Mel,

My reading of the NZ rules are the same "magnetic direction indicator", do you have any reference / documentation from your FAA / DARs that details the above interpretation.

Carl
 
Compass

Autozone has a nice magnetic compass that you can get for about five bucks and stick on your panel with a suction cup,My DARdid not require one though and the dynon compass tape was fine with him.
 
zkvii said:
Hi Mel,

My reading of the NZ rules are the same "magnetic direction indicator", do you have any reference / documentation from your FAA / DARs that details the above interpretation.

Carl
Click to expand...
Carl,

As I understand it, the AirBus does not have a wet compass of any kind installed. Good enough for an RV, then good enough for an AirBus.
 
refocus / more background.....

Hi,

I'll rephrase - what I'm looking for is an FAA or EAA or "DAR" document that Mel or other 'signing' authorities reference / use on this subject. (not what Airbus may or may not do....)

I have put a TSOd vertical card compass in our electrically dependant aircraft (ie. if my EFIS mag go away, I'm a glider, at which point navigating by wet compass is not my #1 concern ;) ) to go with the flow, but the adjustment is pretty useless, I'm bang on North, West and East, but currently nearly 40 degrees out at south.... it is just $$$ dead weight.

The GRT EFIS, TruTrak, 430 and GRT GPS all have magnetic heading - and line up within 1 degree, so I have indication (and backups).....

Thanks for the Dynon link - that is good background / working through the process.

Carl
 
Ref. FAR part 91.205

Required instruments are listed under part 91.205.
91.205 starts out saying that it applies to "Standard Certificated Aircraft". This in itself excludes experimental amateur-built aircraft. Current operating limitations for experimental amateur-built aircraft state that to be flown at night and/or IFR conditions the aircraft must comply with 91.205. 91.205 states that the aircraft must have a "magnetic indicating device."
Therefore; daytime VFR, 91.205 does not apply.
 
Interesting Mel,

So are you saying 'mag indicating device' vs wet compass debate depends on if you are Day VFR only vs IFR / Night VFR?

[It is a shame that I can't get South to read something sensible!]

Carl
 
That's correct.

zkvii said:
Interesting Mel,

So are you saying 'mag indicating device' vs wet compass debate depends on if you are Day VFR only vs IFR / Night VFR?

[It is a shame that I can't get South to read something sensible!]

Carl
Click to expand...
Daytime VFR you don't need either.
972-784-7544
 
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Washington FSDO

The Washington DC FSDO approved my Dynon D10 for the magnetic indicator. It is magnetic based. You may want to call Dynon or the instrument manufacturer and they may wish to add their support. Dynon sent me an email that was more than enough for FAA. By the way, the internal sensor and calibration process resulted in a compass correction card with all zeros.
 
zkvii said:
I have put a TSOd vertical card compass in our electrically dependant aircraft (ie. if my EFIS mag go away, I'm a glider, at which point navigating by wet compass is not my #1 concern ;) )
Click to expand...

Don't quite get how losing your efis makes your plane a glider.

Regardless, it may be a good idea for you to carry either a handheld GPS or a handheld nav/com with VOR to find your way.

Relying on a whiskey compass would be my last resort.
 
Explaination...

jmartinez443 said:
Don't quite get how losing your efis makes your plane a glider.
Click to expand...

The GRT power is dual fed from two seperate batteries / alternators / buses. I also have TruTrak heading and GPS headings. The 'only' practical way I'm going to loose power to all of these is a dual battery / dual alt failure - at which point I have no spark and therefore no engine power. As a glider I'm not worried about VORs, Compasses etc - just what is visible in front of me....

Carl
 
Whiskey compass

Thanks Mel,
That is how I read them also. It's to bad that the EAA judges don't see it this way. When I had them judge my 9A a few years ago, they called my plane unairworthy for not having a whiskey compass, I have a GRT EFIS. So I guess "we" are not all on the same page.

Frank
 
Mel said:
Daytime VFR you don't need either.
972-784-7544
Click to expand...

Mel, I might be misunderstanding what you are saying but I thought that such a device **was** needed from an FAA perspective (magnetic indication device).

Am I wrong or mis-understanding something here??

James
 
Not for daytime VFR!

Only for night or IFR.
91.205 is for "Standard Certificated Aircraft".
"Operating limitations" state that 91.205 applies for night and/or IFR.
 
judging

Frank N821BF said:
Thanks Mel,
That is how I read them also. It's to bad that the EAA judges don't see it this way. When I had them judge my 9A a few years ago, they called my plane unairworthy for not having a whiskey compass, I have a GRT EFIS. So I guess "we" are not all on the same page.

Frank
Click to expand...

Frank, Not sure how this helps you but I have spoken at length about this with two judges that are in my chapter. Appearantly they dont look for a "wet" compass but if you have one then they have to have the correction card. Many do not so they give the gig.
 
A wet compass is about the only instument that will never fail you. For 100 bucks, I'm going to put one in my 9, regardless of what Airbus is doing! If you were to have a Dynon failure at night, I'll bet you will think it is the best
1oo bucks you ever spent.
 
Mel said:
Only for night or IFR.
91.205 is for "Standard Certificated Aircraft".
"Operating limitations" state that 91.205 applies for night and/or IFR.
Click to expand...
This thread made me remember a factory aircraft I owned that had two pieces of required equipment. The only required instrumentation was an airspeed indicator. The other item was a piece of equipment quite surprising to find on a required list.
 
What was the other item?

Larry,

Don't keep us in suspense. Please tell us the other item and what airplane it is.
 
A Wheel

n2prise said:
Larry,

Don't keep us in suspense. Please tell us the other item and what airplane it is.
Click to expand...
Please note I said aircraft not airplane.

The aircraft is a Schweizer 1-26 glider. Look at the W&B on page 4. http://www.126association.org/docs/wb.pdf

A knowledgable friend and I were talking about this yesterday. I can't find any minimum equipment list in the FARs for gliders but the glider has flight limitations based on airspeed so logically there would need to be some way to determine airspeed. Later I realized the logical fallacy in this as there are also G loading limits (approximately what would be aerobatic limits today) and no accelerometer is required on this or many other aircraft with G limits.

As to the wheel, I have no idea why a wheel would be on a required equipment list. My friend thought it might have something to do with the allegation that it is a wheelbarrow wheel.

It is also interesting that the manual calls this aircraft "high performance" in light of the fact that it has almost exactly the same measured best glide (at a bit different speed) as a Boeing 707, although the claimed glide is a bit better.

All this sounds king of funny, but in reality I have a great deal of respect for the 1-26 which is regularly flown many hundreds of miles and is capable of operating at well over 37,000 feet.
 
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