D
Dan(Guest)
Guest
Will the magnetic heading on the EFIS meet the requirement for vfr in an experimental?
Cliff
New Member
It did not qualify for my inspector (DAR). I have a real magnetic compas to make the
FAA happy. I use the D10 all the time. (external magnometer).
Cliff
FAA happy. I use the D10 all the time. (external magnometer).
Cliff
- Joined
- Mar 23, 2005
- Messages
- 13,226
As far as we have heard, per FAA regs, all aircraft (VFR or IFR) require a compass that requires no power (electric / vacuum / whatever). It's the ultimate backup instrument, at least until the earth's magnetic field fails.
gmcjetpilot
New Member
- Joined
- May 21, 2005
- Messages
- 20
Where does the FAR's say that. Part 91 not part 121 air transport.
Look I have read a case where a DAR inspecting a homebuilt said you must have it (wet compass) and another 3 where there was no comment made regarding the Dynon or other electronic magnetometer device as the prime and solo mag heading ref. It sounds like another very inconsistent DAR/FAA issue. :-/
Where does it say that in the regs? It does not say in any Reg that I have read in part 91 that requires a "whisky compass." Could you verify ref? It must be written down somewhere. If it is not black & white than it is an interpretation.
One DAR or FAA inspector’s answer is not a sure thing. I have no plan on backing up my wet compass for now. If it is true that it can’t use electrical power for a compass, than I guess I should back-up my altimeter, airspeed and attitude indicators, since it does not recommend they be independent of electrical power either? These items are more critical. I know part 121 air transport aircraft require back-up, but not GA planes, especially VFR. The need for redundant systems or independance of power is not defined in the Regs as far as I know. VFR or IFR there is no diff, but if you are flying IFR you should ahve back-up to all critical instruments, but I would not consider it a major priority to back-up the compass as much as the attitude indicator.
The "jelly jar" compass full of alcohol, sometimes leaking will not add much safety VFR or IFR. If you have complete electrical failure (zero electrical power) in with an all-electrical panel in IMC conditions, I am sure the "ultimate back-up" passive compass will not save you. Since GPS I never really look at the compass much anymore since I am trying to track not dead reckon.
Thanks George
Look I have read a case where a DAR inspecting a homebuilt said you must have it (wet compass) and another 3 where there was no comment made regarding the Dynon or other electronic magnetometer device as the prime and solo mag heading ref. It sounds like another very inconsistent DAR/FAA issue. :-/
Where does it say that in the regs? It does not say in any Reg that I have read in part 91 that requires a "whisky compass." Could you verify ref? It must be written down somewhere. If it is not black & white than it is an interpretation.
One DAR or FAA inspector’s answer is not a sure thing. I have no plan on backing up my wet compass for now. If it is true that it can’t use electrical power for a compass, than I guess I should back-up my altimeter, airspeed and attitude indicators, since it does not recommend they be independent of electrical power either? These items are more critical. I know part 121 air transport aircraft require back-up, but not GA planes, especially VFR. The need for redundant systems or independance of power is not defined in the Regs as far as I know. VFR or IFR there is no diff, but if you are flying IFR you should ahve back-up to all critical instruments, but I would not consider it a major priority to back-up the compass as much as the attitude indicator.
The "jelly jar" compass full of alcohol, sometimes leaking will not add much safety VFR or IFR. If you have complete electrical failure (zero electrical power) in with an all-electrical panel in IMC conditions, I am sure the "ultimate back-up" passive compass will not save you. Since GPS I never really look at the compass much anymore since I am trying to track not dead reckon.
Thanks George
- Joined
- Mar 23, 2005
- Messages
- 13,226
George,
FAR 23.1303 says:
The following are [the minimum] required flight and navigational instruments:
(a) An airspeed indicator.
(b) An altimeter.
(c) A direction indicator nonstabilized magnetic compass.
We are obvioulsy interested in (c). The compass in the EFIS is gyro stabilized. Thus it does not offically meet the requirments of this regulation. The "non-powered" requirement that we had heard about before must have come from this requirement, since anything that stabilizes a compass will automatically require external power (electric or vacuum)
We're not experts on the FAA's requirements, but we do believe that this regulation is what ends up requiring a standard "whiskey" compass in an aircraft.
Link to 23.1303:
http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/BB1326A92FACEFC7852566870070C319?OpenDocument&Highlight=magnetic%20compass
FAR 23.1303 says:
The following are [the minimum] required flight and navigational instruments:
(a) An airspeed indicator.
(b) An altimeter.
(c) A direction indicator nonstabilized magnetic compass.
We are obvioulsy interested in (c). The compass in the EFIS is gyro stabilized. Thus it does not offically meet the requirments of this regulation. The "non-powered" requirement that we had heard about before must have come from this requirement, since anything that stabilizes a compass will automatically require external power (electric or vacuum)
We're not experts on the FAA's requirements, but we do believe that this regulation is what ends up requiring a standard "whiskey" compass in an aircraft.
Link to 23.1303:
http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/BB1326A92FACEFC7852566870070C319?OpenDocument&Highlight=magnetic%20compass
gmcjetpilot
New Member
- Joined
- May 21, 2005
- Messages
- 20
Thanks I missed the stabilized part, clearly a wet compass is not stabilized.
In fact it is so un stabilized, it is even useless in many flight conditions. Why would you want something you can actually use and is more accurate.
Oh, well, I think Wal-mart has some for $1.99 with a sticky back might work in my RV.
I'll even "swing it" and write a deviation card.
Thanks Again George
In fact it is so un stabilized, it is even useless in many flight conditions. Why would you want something you can actually use and is more accurate.
Oh, well, I think Wal-mart has some for $1.99 with a sticky back might work in my RV.
I'll even "swing it" and write a deviation card.
Thanks Again George
gmcjetpilot
New Member
- Joined
- May 21, 2005
- Messages
- 20
You are right Mr. Dan the man. Part 91.205(b)(3) just says: Magnetic direction indicator.
FAR part 23 does not apply, since it is not referenced in experimental aircraft op limits but part 91 is.
I agree we should use the FAR's as a guide and not stray "far from the FAR". :
Great, if the jiggle compass is not needed, I will save the $1.99 and a trip to Wal-mart and leave it off. Really I look at GPS track 99% if the time. The only time I really check the Mag compass is taking the runway to check it.
GPS give ground speed which you can estimate winds aloft from. Usually I don't care about resolving the exact wind component/direction, except when taking off or landing which provided by ATIS. ;D
Cheers George
FAR part 23 does not apply, since it is not referenced in experimental aircraft op limits but part 91 is.
I agree we should use the FAR's as a guide and not stray "far from the FAR". :
Great, if the jiggle compass is not needed, I will save the $1.99 and a trip to Wal-mart and leave it off. Really I look at GPS track 99% if the time. The only time I really check the Mag compass is taking the runway to check it.
GPS give ground speed which you can estimate winds aloft from. Usually I don't care about resolving the exact wind component/direction, except when taking off or landing which provided by ATIS. ;D
Cheers George
D
Dave Lively(Guest)
Guest
Yes, I believe Dan is correct. I went through this with my DAR and FAA inspector (I was one of the lucky ones to have a FAA inspector looking over my DAR's shoulder). I had done a computer search of the FAR/AIM and believed that only a magnetic indicator was required for experimentals. Both the DAR and FAA came back with the same conclusion after a few days of research on their own. I had shown them a TSO'd vertical card compass that I had intended to put in my plane for backup but that there was no place where the pilot could see it that it didn't throw off the D-10 compass by 10-20 deg and therefore had decided to eliminate it. Would rather have both but happy they agreed that a "Whiskey Compass" is not actually required for experimentals even though they both said they had never seen an aircraft without one.
J
John Clark(Guest)
Guest
The FAA inspector asked about the part 91 rules. He agreed that a magnetic heading device (D10) was ok. I would suggest that a backup is your GPS. If you are given a vector, add the east variation and fly that GPS track.
ghostriver
New Member
Hi,
As far as I know, all airliners have a magnetic compass. I know that the Airbus aircraft have the alcohol compass as does the B-2 (as seen in an "Aviation Week" awhile back).
Also, for IFR I believe, one still needs a needle and ball even if you have several separate attitude indicators. (This does not apply to airliners.)
As far as I know, all airliners have a magnetic compass. I know that the Airbus aircraft have the alcohol compass as does the B-2 (as seen in an "Aviation Week" awhile back).
Also, for IFR I believe, one still needs a needle and ball even if you have several separate attitude indicators. (This does not apply to airliners.)
Yes they do, and boy am I glad that I'm not building an airliner (which falls under Part 135). Actually what I am building is an experimental aircraft which falls under part 91.205. That means I must have a "Magnetic Direction Indicator".
The Dynon EFIS with EDC qualifies as a megnetic heading indicator. Now just make sure that your DAR or FAA inspector agrees with that (some do and some don't). If not, you will have to decide whether or not you would rather fight it (i.e.call in the EAA) or just put in a whiskey compass to make them happy.
Eric Newton - Long Beach, MS
Bearhawk #682
The Dynon EFIS with EDC qualifies as a megnetic heading indicator. Now just make sure that your DAR or FAA inspector agrees with that (some do and some don't). If not, you will have to decide whether or not you would rather fight it (i.e.call in the EAA) or just put in a whiskey compass to make them happy.
Eric Newton - Long Beach, MS
Bearhawk #682
Part 91 applies to "Standard Certificated Aircraft." The operating limitations for amateur-builts state that part 91.205 applies for night and/or IFR. Even then the requirement (91.205(b)(3))is for a "magnetic direction indicator." The Dynon meets this requirement. Part 23 does not apply to experimental amateur-built aircraft.