Tuesday, July 04, 2006

Vectored DPs & the G1000

First I'd like to wish all my U.S. readers a happy and safe Fourth of July.

It's often said that flying single-pilot IFR is like playing a game of chess: You want to be at least two moves ahead of your current position, as illustrated by vectored departure procedures like the Anaheim Three Departure out of Fullerton, California. How the G1000 handles this procedure is quite interesting.

Let's say you're departing runway 24 at Fullerton for a flight to Paso Robles. In a piston engine aircraft, it's likely you'll be assigned the Anaheim Three. After entering KFUL->LHS->AVE->PRB->KPRB as your flight plan in the G1000, press the PROC button and load the Anaheim Three departure, specifying runway 24 and the Lake Hughes (LHS) transition.

When you look at the moving map after loading the procedure, you'll be surprised to see that no part of the departure procedure is depicted. The first course line indicated is from Lake Hughes to Avenal. One assumes the folks at Garmin decided that since you will be vectored, it is premature to display any of the route, even though the departure procedure tells you the route to expect. The software engineer in me wonders if this is a bug, but I digress.

To make the departure route appear, enter the flight plan, highlight the first waypoint in the procedure, SLI, press Direct, and then press Enter twice.

Now the entire route is depicted, but you may as well leave the flight plan display active with the cursor positioned over the next waypoint to which you think you'll be vectored. While you are at it, get the VOR receiver tuned to the appropriate VOR and the bearing pointer enabled on the Primary Flight Display so you will be ready to intercept a particular radial should SoCal ask you to do so.

After takeoff, fly the runway heading to at least 400' AGL, but highlight the next waypoint so you'll be one step ahead of the game. I've shown this on the PFD, but the flight plan display on the PFD disappears each time you proceed direct to a waypoint so I recommend using the flight plan display on the MFD, which is more well-behaved.

Let's say SoCal gives you a left turn to 120˚, just like the procedure says. You are certainly no longer headed to the Seal Beach VOR. In case you're wondering that yellow circle displayed on the moving map is the temporary flight restriction around the Disneyland theme park.

If SoCal tells you to fly your present heading and intercept the Seal Beach 058˚ radial, you can activate the leg between SLI and POXKU or you can ask for direct to the next waypoint. If ATC can accommodate a direct to request, they usually will because it's often less workload for them.

Unfortunately, the G1000 waypoint sequencing behavior I described for approach procedures does not occur with this departure. You'd think that the default behavior would be for the G1000 to figure out which leg of the departure you are closest to and activate that leg, but that's not how it works.

Interestingly, the waypoint sequencing behavior does appear work with the older Garmin 530 (at least on their PC simulator). With the Garmin 530, activating the leg between SLI and POXKU will result in intelligent waypoint sequencing and the leg of the departure that you are closest to will automatically become the active leg.


Ron said...

The behavior of the FP screen on the PFD and the autosequencing idiosyncrasies don't bother me nearly as much as the fact that 3 of the 4 G1000 equipped aircraft I fly don't even have a bearing pointer. All they have is the HSI.

In other words, from a needle standpoint, they're as well equipped as a C152.

I don't understand why Garmin would allow anything of the G1000's caliber to go out the door with just a single CDI. I suspect that they just assume with all the moving maps, you won't need to display information from two nav sources at the same time. But as a pilot, the G1000 limitation is baffling.

I understand a bearing pointer upgrade is available, and that the current systems are being built with that capability. But for those of us flying the older models, we literally can't teach a student how to do an intersection hold using two VORs.... unless we want the student switching back and forth using the CDI key. Again, a ridiculous thing to have to do when flying behind a $40,000 panel.


John said...


My understanding is that the addition of one or two bearing pointers is a software or firmware upgrade for the G1000. It is a drag not having them. A G1000-equipped DiamondStar I occasionally fly has the same issue.

Another drag is when you have a brand new 182 with a G1000, with XM weather capability, but the subscription for the XM service has not be purchased.

Talk about all dressed up and no where to go ...