G1000 Approaches

[CoffeeIcePapers]

We're talking missed approaches here, not enroute.

Enroute, using GPS, the G1000 will set the CDI for you. On a missed approach, the moving map will get you to the holding fix, depict the hold, and even tell you what kind of entry to make. The G1000 will also set the CDI for you on the missed approach if that's necessary.

Again, it isn't giving you course guidance. You could be 10 miles off course and it can appear that you are on course if the map is zoomed out. When flying low to the ground, you want to know exactly where the airplane is relative to the course.

 

[Goonie]

We're talking missed approaches here, not enroute.

Enroute, using GPS, the G1000 will set the CDI for you. On a missed approach, the moving map will get you to the holding fix, depict the hold, and even tell you what kind of entry to make. The G1000 will also set the CDI for you on the missed approach if that's necessary.

It is necessary. Thats is what he is trying to tell you.

You have to have course guidance and a moving map is not a legal form of it.

 

[Mike H]

Mojo, in the procedure you link to, the holding fix is a vortac, not an NDB. In fact, you don't need ADF at all to identify the IAF because it's a DME fix off of the vortac. You don't need to switch your nav source at all and you can still use the moving map to fly the missed.

IFR Refresher is generally a pretty good read. They know more than I'll probably ever know about round dial IFR flying, but sometimes they're completely flummoxed by glass cockpits, and especially the by the G1000.

 

[Douglas]

I think there may be a miscommunication of definitions here.

 

[CoffeeIcePapers]

Mojo, in the procedure you link to, the holding fix is a vortac, not an NDB. In fact, you don't need ADF at all to identify the IAF because it's a DME fix off of the vortac. You don't need to switch your nav source at all and you can still use the moving map to fly the missed.

I realize that, but it is demonstrating the procedure I am talking about. Switching to GPS mode after the MAP. In the OP's example, we are using an NDB as the holding point, so we need the GPS in order to get there.


Basically, what I am getting at is this:


If you are using a LOC orVOR for course guidance, you should be using Nav 1/Nav 2 as your CDI source.

If you are using your GPS for course guidance, you should have GPS selected as the CDI source.

 

[Aviator_Bakeek]

There have been some very interesting points made, I would say that I am still not convinced from a FAA standpoint that switching to GPS/FMS upon the MAP would comply with a non GPS approved overlay approach.

The G1000 POH also verifies what my instructor had said, however, Garmin is not the higher authority to the FAR's/AIM.

The ADF can be substituted for GPS. If you remain in NAV with the ILS and have a pointer with the GPS fix for the LOM selected, I believe this would be an acceptable and legal means of navigation. Any disagreements?

Also, from what I have been taught and teach, the moving map IS NOT an acceptable means of navigation. You must have the CDI active to be truly legal. From my limited experience, I have seen this mistake and I believe it makes a pilot lazy. The map is excellent for SA, but I frequently see a dependence on it which I feel is a significant disadvantage of the G1000 which in turn yields poor pilotage and dead reckoning skills. Just my $.02

 

[JLF]

You don't need to switch your nav source at all and you can still use the moving map to fly the missed.QUOTE]

What chain of system failures would require using the moving map to fly a course IFR? Like Mojo elaborated to that is nothing close to positive course guidance. Not that the moving map isn't handy and all.


I believe GPS in lieu has changed, or been elaborated in subsequent AIM revisions to either substitute means or alternate means of navigation. The AIM does refer users to refer to the AFM or AFM supplements as well. If you go to the FAA website and do an Advisory Circular search on RNAV, GPS, and WAAS you piece a lot of info together.

 

[NJA_Capt]

I would say that I am still not convinced from a FAA standpoint that switching to GPS/FMS upon the MAP would comply with a non GPS approved overlay approach. They must then pass those appovals to users and/or placard them against certain uses.

The G1000 POH also verifies what my instructor had said, however, Garmin is not the higher authority to the FAR's/AIM.

Actually, Garmin IS the authority, or any other avionics manufacturer. They must prove to the FAA that their equipment meets/exceeds the requirements placed on them by the FAA. Certification regs (FARs) determine which criteria the OEMs must meet. There are many other regs besides 61,91,121. These regs determine whether GPS/FMSs can be used for approaches and how.

Take a look at this:
http://fsims.faa.gov/PICDetail.aspx?docId=B556E1FC7C41EF8B8525734F0076660E

There is a chart half way down that may be helpful.I also think you may be confusing switching to GPS at the MAP as an overlay. It is not an overlay (bad term) when using a GPS past the MAP.

 

[Aviator_Bakeek]

Actually, Garmin IS the authority, or any other avionics manufacturer. They must prove to the FAA that their equipment meets/exceeds the requirements placed on them by the FAA. Certification regs (FARs) determine which criteria the OEMs must meet. There are many other regs besides 61,91,121. These regs determine whether GPS/FMSs can be used for approaches and how.

Take a look at this:
http://fsims.faa.gov/PICDetail.aspx?docId=B556E1FC7C41EF8B8525734F0076660E

There is a chart half way down that may be helpful.I also think you may be confusing switching to GPS at the MAP as an overlay. It is not an overlay (bad term) when using a GPS past the MAP.

I disagree that Garmin is the authority on how the approach procedure should be conducted. Just because the FAA specifies certain expectations for the manufacturer, does not mean full usage through the system (ADS-B/Mode S for example). Garmin is the authority regarding proper operating technique and service requirements.

I checked out that link and while it was very interesting, I believe it was intended for a 135/121 operation (the beginning talks about OpSpecs). Either way, there was nothing approving certification for missed approach procedures or precision ILS approaches. Very interesting however.

I agree that switching to GPS at the MAP is not technically an overlay, which is why it also is technically not approved to use sole reference to anytime you are on the KTKI ILS RWY 17 approach from the IAF to the MAP and then for the entire missed procedure if you must use a GPS fix in lieu of a LOM/NDB.

 

[Mike H]

I realize that, but it is demonstrating the procedure I am talking about. Switching to GPS mode after the MAP. In the OP's example, we are using an NDB as the holding point, so we need the GPS in order to get there..

It might have been a little less confusing if you hadn't linked to an irrelevant approach to what the OP was talking about. My point is the same, however. You can certainly use the moving map to get to and fly the hold at the NDB. Just how accurately do you think NDB holds are flown without a moving map?

What chain of system failures would require using the moving map to fly a course IFR?

Doesn't have to be a chain of failures. Any single failure that would require you to fly using the back-up instruments and/or magnetic compass would make it entirely prudent to use the moving map for course guidance- because that's all you'd have. You wouldn't be able to fly an ILS, though.

 

[Aviator_Bakeek]

I used the simulator this afternoon to test some of my theories and found that my technique worked very well. I was in GPS until before the IAF and then switched to NAV (and I loved how the course and frequency was already there). I used the PFD softkey and select bearing pointer 1 to the GPS, and then I had the FLUET LOM (ILS LOM for 17 at KTKI) and had reference to it the entire approach.

I shot another ILS approach with a different missed procedure and as long as you verify the missed procedure on the flight plan it practically holds your hand the entire way while watching the bearing pointer. I really like it because it helps so greatly with your situational awareness and the features make single pilot IFR much more manageable.

 

[NJA_Capt]

I disagree that Garmin is the authority on how the approach procedure should be conducted. Just because the FAA specifies certain expectations for the manufacturer, does not mean full usage through the system (ADS-B/Mode S for example). Garmin is the authority regarding proper operating technique and service requirements.

Manufacturers are held to a certain standard for their equipment. They do not just make a pretty screen and tell you how to use it. Before a device is certified (or not) it must meet certain criteria set forth by the FAA (TSO). When the FAA signs off (certifies) a new package, the manufacturer has demostrated that the avionics are approved for certain operations, ie...terminal, approach and enroute. If they meet the criteria of the TSO, it is approved for such operations.....in the avionics manual.

A missed approach is still in the terminal area and is non-precision, therefore it can be used for the segment following an approach.

If all else fails: Read the Manual.

http://www8.garmin.com/manuals/G100...SA01595WI-DAirplaneFlightManualSupplement.pdf

The Garmin G1000 Integrated Avionics GNSS navigation system
as installed in this aircraft complies with the equipment requirements of AC 90-100A for RNAV 2 and RNAV 1 operations. In accordance with AC 90-100A, Part 91 operators following the aircraft and training guidance in AC 90-100A are authorized to fly RNAV 2 and RNAV 1 procedures.​

When using the G1000 VOR/LOC/GS receivers to fly the final approach segment, VOR/LOC/GS navigation data is must be selected and presented on the CDI of the pilot flying.​

Use of the GARMIN G1000 GPS/SBAS receivers to provide navigation guidance during the final approach segment of an ILS, LOC, LOC-BC, LDA, SDF, MLS or any other
type of approach not approved for “or GPS” navigation is prohibited.​

[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]http://rgl.faa.gov/regulatory_and_guidance_library/rgadvisorycircular.nsf/0/5c94e4f44ba319a98625729c00612f37/$FILE/AC%2090-100A.pdf
[/FONT]
l. AC 90-94, [FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Guidelines for Using Global Positioning System Equipment for IFR En Route and Terminal Operations and for Non-Precision Instrument Approaches in the U.S. National Airspace System. [/FONT]

d. Aircraft with a statement from the manufacturer [FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]documenting compliance with the criteria in this AC (appendix 1 or 2, as applicable, and appendix 3) meet the performance and functional requirements of this AC. These statements should include the airworthiness basis for compliance. Compliance with the sensor requirements in paragraph 8 will have to be determined by the equipment or aircraft manufacturer, while compliance with the functional requirements in Appendix 3 may be determined by the manufacturer or by inspection by the operator. [/FONT]

[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Pilots and operators can confirm the capability of their equipment on this list, or obtain equipment performance information from the relevant aircraft and avionics manufacturer. [/FONT][/FONT]

[FONT=Times New Roman,Times New Roman]http://rgl.faa.gov/Regulatory_and_G...ircular.nsf/list/AC 90-105/$FILE/AC90-105.pdf[/FONT]
[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman](4) M[/FONT]aintaining LNAV in missed approach. If abandoning a procedure while on an RF Leg or initiating a go-around or missed approach (through activation of TOGA or other means), the flight guidance mode should remain in LNAV to enable display of deviation and display of positive course guidance during an RF leg. If the aircraft does not provide this capability, crew procedures must be used that assure the aircraft will adhere to the specified flight path during the RF Leg segment.[/FONT]​

[/FONT]

[/FONT][/FONT]

 

[CoffeeIcePapers]

The moving map shows the missed approach procedure on the map. It IS course guidance. That's why it's there

Sorry to bump this, but I did some research and found some more info.

http://www.aopa.org/whatsnew/air_traffic/gps_in_lieu.html

When using GPS course guidance; i.e., navigating to/from an NDB or locator outer marker (LOM), the course deviation indicator (CDI) must be set to 1 nm or terminal sensitivity.

Still trying to figure out where they got that from.

 

[adam25560]

Quick G1000 question, When flying some approaches why does the inbound course shown on the G1000 differ from what is published on the approach chart? Magnetic variation over time? I've been looking through all the Garmin literature, FAA docs, internet, and haven't been able to find a credible sourced answer in them. Thanks much-

 

[CoffeeIcePapers]

Quick G1000 question, When flying some approaches why does the inbound course shown on the G1000 differ from what is published on the approach chart? Magnetic variation over time? I've been looking through all the Garmin literature, FAA docs, internet, and haven't been able to find a credible sourced answer in them. Thanks much-

AIM Chapter 1:

l. Conventional Versus GPS Navigation Data
There may be slight differences between the course information portrayed on navigational charts and a GPS navigation display when flying authorized GPS instrument procedures or along an airway. All magnetic tracks defined by any conventional navigation aids are determined by the application of the station magnetic variation. In contrast, GPS RNAV systems may use an algorithm, which applies the local magnetic variation and may produce small differences in the displayed course. However, both methods of navigation should produce the same desired ground track when using approved, IFR navigation system. Should significant differences between the approach chart and the GPS avionics' application of the navigation database arise, the published approach chart, supplemented by NOTAMs, holds precedence.
Due to the GPS avionics' computation of great circle courses, and the variations in magnetic variation, the bearing to the next waypoint and the course from the last waypoint (if available) may not be exactly 180° apart when long distances are involved. Variations in distances will occur since GPS distance-to-waypoint values are along-track distances (ATD) computed to the next waypoint and the DME values published on underlying procedures are slant-range distances measured to the station. This difference increases with aircraft altitude and proximity to the NAVAID.