The International Cessna^® 170 Association

Can a panel mounted IFR ceritfied Garmin 530(which has the ability to display the equivalent of a heading indicator), be used in place of the Gyro heading indicator? 91.203 requires a Gyroscopic Heading Indicator "or equivalent". The question assumes the gyro heading indicator has become inoperative for one reason or another.

In most cases the answer is yes as long as you have a mag compass. Every FSDO will have a different opinion but the general consenses is that the Garmin 530 will be secondary or supporting.If you have a Mag compass then you are ok. My FSDO also made me put an additional placard on my installation. "Not For Stand Alone Nav Use." Have a look. V/R Doug

Thanks for the response Canav8. Looks like you have a great co-pilot. My co-pilot is now flying SH60's for the Navy - I miss him every day.

This is an interesting question that could get into splitting hairs and arguing over punctuation and websters dictionary definitions. Does anyone remember someone saying that it depends on what the definition of "is" is?
The suggestion that different FSDOs will have different readings on this question is only relevant if the subject aircraft is being subjected to FAA scrutiny such as an application to be added to a 135 certificate. In such a case the FAA is mandated to ensure the aircraft and its equipment conform to regulatory requirements and as we all know, FSDO inspectors do not always have the same opinions. Otherwise, it is unlikely that the FAA would be aware of a particular aircraft's configuration unless it becomes involved in an incident or accident. And oh by the way, the insurance company that covers the owner of that aircraft will also be interested in its configuration especially if it does not conform to regulatory requirements which would then give the insurance company cause to deny coverage.
Please do not take this the wrong way, but the only intelligent way to answer your question is to contact the manufacturer of this equipment and ask them if they will certify that it meets the requirements of 14 CFR 91.205(d) (8)(9) as an attitude or a direction indicator and, if so to provide documentation in writing.
This is a fairly serious subject with some pretty obvious safety implications. The ability of an aircraft to be controlled under instrument flight rules with sufficient accuracy to comply with a radar vector given by ATC is fundamental to IFR separation. The ability of an aircraft to be controled under IMC by use of certified instruments is fundamental to survival. I have always advised pilots to read the FLIGHT MANUAL SUPPLEMENT (emphasis intended) to determine the allowable operations and operating limitations of a particular instrument or system. If that document does not specify the use that is suggested in this question, then it probably is not intended or authorized by the manufacturer. Be safe.

After reading the question again, It appears that the issue involves using the GPS equipment in lieu of the gyroscopic equipment in the event of failure. Answer: in an inflight emergency following failure of a gyroscopic instrument, YES use all available resources to safely control the aircraft and advise ATC of the problem. But to continue operation after the failure ie. initiate other flights using the GPS as the instrument required by 91.205 in lieu of the gyroscopic device, refer to my prior post. My advice is not intended to put anyone down or discourage good questions. I am just trying to help.

Robert Eilers wrote:Can a panel mounted IFR ceritfied Garmin 530(which has the ability to display the equivalent of a heading indicator), be used in place of the Gyro heading indicator? 91.203 requires a Gyroscopic Heading Indicator "or equivalent". The question assumes the gyro heading indicator has become inoperative for one reason or another.

Robert,
The Garmin 530 only knows and displays "Track" it has no way determining what is the compass heading of the aircraft.

Robert Eilers wrote:Can a panel mounted IFR ceritfied Garmin 530(which has the ability to display the equivalent of a heading indicator), be used in place of the Gyro heading indicator? 91.203 requires a Gyroscopic Heading Indicator "or equivalent". ...

In my opinion...NO!

Firstly, the applicable FAR is not 91.203.

It's 91.205 (d) which describes required equipment for Instument Flight rules. Item (9), Gyroscopic direction indicator (directional gyro or equivalent)... refers to a REQUIRED DIRECTIONAL GYRO (or equivalent such as a LASER-RING-GYRO, etc.) In other words, for the average C-170 to fly IFR you MUST have a Dirctional Gyro. A GPS does not provide that guidance. It only reports historical track.

Robert Eilers wrote:... The question assumes the gyro heading indicator has become inoperative for one reason or another.

If your D.G. fails in flight, you may continue flight as necessary to effect a safe landing. However, FAR 91.213 (b) (3) requires that before making another takeoff, the D.G. must be operable.

I don't think any FSDO anywhere,...not even Alaska...will differ in opinion on this subject.

Folks, please allow me to stop you all from barking up the wrong tree. Most of you have jumped at this topic without having all the facts. The original poster said gyro heading indicator. Some of you started to quote regs. please be careful. First off FAR 91.205 is the song we are singing out of our hymnals. 91.205 does not make reference to a gyro heading indicator. It can be easily confused withother instruments, a magnetic compass, a magnetic compass card, and a directional gyro. The original poster asked if a Garmin 530 could be used in place of a gyro heading indicator. My understanding was "Can it be used in place of a magnetic compass card?" Now I am guilty of not clarifying this from the beginning and also responding without asking more questions but I would like to reiterate what I said based on what he asked. The 530 is certified IFR.It cannot be used as a source of primary flight instrument display under FAA certification rules. It can be used as a secondary or supplimentary flight instrument indicator. If the poster intended to say that the 530 was a direct replacement so as for him to remove an instrument and replace it with the 530 then the answer is NO! his last statement eg. was in case the other one quit. Well that means that it can be used as a backup as Voreesh commented on. Thanks for allowing me to clarify my answer and sorry for the confusion.Very Respectfully(V/R) Doug

canav8 wrote:Folks, please allow me to stop you all from barking up the wrong tree. Most of you have jumped at this topic without having all the facts. The original poster said gyro heading indicator. Some of you started to quote regs. please be careful. First off FAR 91.205 is the song we are singing out of our hymnals. 91.205 does not make reference to a gyro heading indicator. It can be easily confused withother instruments, a magnetic compass, a magnetic compass card, and a directional gyro. The original poster asked if a Garmin 530 could be used in place of a gyro heading indicator. My understanding was "Can it be used in place of a magnetic compass card?" Now I am guilty of not clarifying this from the beginning and also responding without asking more questions but I would like to reiterate what I said based on what he asked. The 530 is certified IFR.It cannot be used as a source of primary flight instrument display under FAA certification rules. It can be used as a secondary or supplimentary flight instrument indicator. If the poster intended to say that the 530 was a direct replacement so as for him to remove an instrument and replace it with the 530 then the answer is NO! his last statement eg. was in case the other one quit. Well that means that it can be used as a backup as Voreesh commented on. Thanks for allowing me to clarify my answer and sorry for the confusion.Very Respectfully(V/R) Doug

Doug,...Respectfully.... I think you've confused the matter even more.

FAR 91.205 does indeed require a gyro heading indicator (DG), under subparagraphs (d) (9) it specifies a required a "gyroscopic direction indicator." (D.G.)

The question initially posed was,

Robert Eilers wrote:Can a panel mounted IFR ceritfied Garmin 530(which has the ability to display the equivalent of a heading indicator), be used in place of the Gyro heading indicator? 91.203 requires a Gyroscopic Heading Indicator "or equivalent". The question assumes the gyro heading indicator has become inoperative for one reason or another.

This question implies that if the DG has failed, can the Garmin 530 be used in lieu of the DG, and the Answer is contained (as I previously posted) in 91.213 (b) (3).
Answer: NO further flights may be undertaken. (NO TAKEOFFS)

Did anyone else notice that this flight crew has turned the airplane UPSIDE DOWN?

The quick-thinking co-pilot has evidently grabbed the controls to correct the yoke-position and is attempting to roll it back right-side-up.

GOOD BOY! Now get that brain-dead guy on the left OUT OF YOUR SEAT!

voorheesh wrote: Answer: in an inflight emergency following failure of a gyroscopic instrument, YES use all available resources to safely control the aircraft and advise ATC of the problem. But to continue operation after the failure ie. initiate other flights using the GPS as the instrument required by 91.205 in lieu of the gyroscopic device, refer to my prior post. My advice is not intended to put anyone down or discourage good questions. I am just trying to help.

canav8 wrote:The 530 is certified IFR.It cannot be used as a source of primary flight instrument display under FAA certification rules. It can be used as a secondary or supplimentary flight instrument indicator. If the poster intended to say that the 530 was a direct replacement so as for him to remove an instrument and replace it with the 530 then the answer is NO! his last statement eg. was in case the other one quit. Well that means that it can be used as a backup as Voreesh commented on.

gahorn wrote:This question implies that if the DG has failed, can the Garmin 530 be used in lieu of the DG, and the Answer is contained (as I previously posted) in 91.213 (b) (3). Answer: NO further flights may be undertaken. (NO TAKEOFFS)

No confusion here, it sounds to me you are all saying the same thing.

Great discussion on the intent of 91.205 - I really knew the answer - I was just hoping maybe the FAA had finally recognized the progress made in state of the art GPS equipment. The reality is that a IFR certified GPS heading direction display, backing up a wet compass is just as effective and accurate and safe as a Gyro heading direction indicator, backing up a wet compass. In practical application we set the DG to the wet compass, and likewise can compare the GPS heading direction indicator to the wet compass. I am thinking about the situation where-in I find myself on the ground in some place like ELY, NV, on a long cross country, with a failed Gyro heading indicator or HSI and no help in sight for miles. Rather than park the airplane in ELY, shipping the Gyro off for repair and taking the bus home - filing IFR and punching through a shallow overcast using the GPS Gyro heading indicator seems practical and safe. I'm not suggesting anyone violate FARs unnecessarily. I just think the FAA needs to get their head out of the sand and genuinely recognize the progress made in GPS technology.

Robert, I am trying figure out how you are getting a "heading" from a GPS unit unless it has some sort of gyro input? A straight GPS will give "track" but not heading.

lowNslow - you are correct the GPS heading indicator depicts track. However, as you bank and change heading so does your track. The track change is reflected on a GPS heading indicator display as a change in heading - similar to that depictd by a Gyro heading indicator. The more sophisticated GPS's allow the selection of a display that depicts essentially a heading indicator, as the heading/track of the aircraft changes the heading indicator on the displayed page also changes similarly to what you would see on a Gyro heading indicator. Admittedly, there is a small lag (as the GPS updates the track info.) but fractions of a second and easily anticipated.

Robert Eilers wrote:The track change is reflected on a GPS heading indicator display as a change in heading - similar to that depictd by a Gyro heading indicator.

Yes, "similar," yet very, very different. The fundamental differnece between what the 530-derived "heading" indicator and that of the FAR-required "Gyroscopic Direction Indicator" is that the 530 is providing satellite-based direction only. The satellites--and thus the 530--have no idea what effect the ambient wind is having on the aircraft in flight. Unless you have magnetic heading input into the 530, it has no way to compare actual magnetic heading to ground track information. Here in Kansas, it is very common to have a pretty strong crosswind component, thus creating a significant difference between ground track and aircraft heading. Under VFR, sure...substitute the GPS indication. Under IFR, no way!

As posted earlier, refer to your flight manual supplement...it is the gospel regarding what you can and cannot legally do with your equipment. I do not have one handy, but I suspect somewhere in the owner's manual for the 530 is a very big disclaimer stating that those depictions are for reference only.