Tuesday, August 30, 2011

Direct, But Not From Here

I mentioned taking deserved flack on my PPC ride for not using the GPS (it had an expired database and thus was not approved for IFR operations) to improve my situational awareness. While approach procedures change, and airway radials get renumbered, it's very rare that an airport or navaid is actually moved and pilots are encouraged to use situational awareness tools that are available to them, whether $15,000 installations or reused pieces of cereal box. (You can make a hold entry cheat sheet that way, if you have the normal problems with holds and not the crazy, make up a new way to screw up a hold everytime ones that I devise. Hint: do not track inbound on your EFC). The GPS avaialble to me here is a Garmin 530W.

It is familiar. There's a large rectangular screen with buttons and knobs all around it. It's a navcom unit, meaning that you use it to talk on the radio as well as tell where you're going, but the radio transmission readibility is poor, so we only use it for monitoring frequencies. I suspect an antenna connection, just because that was the cause of a simiar problem in a C172 years ago, and the maintenance manager said they hadn't investigated that yet. On the left side are knobs to adjust com volume and squelch and nav radio volume, plus there are flip flops switches to exchange active and standby frequencies. That means you never adjust the frequency you are actually using, but select the new frequency on standby and then switch them. That way it doesn't sound like you're in scan mode on your car stereo.

The exact tuning procedure is easy, with one little trick. The bottom left knob tunes either comm or nav frequencies, and by default it's the commuications frequency. You push it to toggle between control of each and it will time out and go back to comm. It's a double knob, with MHz on the outside knob, and kHz, in 25 kHz steps on the inner one. I'm not someone who walks around with a perfect picture of the wavelengths and frequencies of all her devices in her head, so I'm grateful to a pilot who years ago must have forgotten the English word frequency, because while he was in the run up area he asked the ground controller to repeat it with "Vat is ze megahertz?" That simple call forever reminds me that com and VOR frequencies are in MHz and I can place the others in relation, thanks to having learned my metric prefixes in grade three.

The bottom row is buttons: CDI, OBS, MSG, FPL, VNAV and PROC, are also familiar from other modern Garmins like the GNS430, and the right side has a range rocker, the lovely Direct-to button (looks kind of like D> except that the line carries right through the letter and ends in a rightward-pointing arrow), and MENU, CLR and ENTER buttons. On the bottom left is a double knob that cycles between page groups on the outside and individual pages on the inside. Yes, this is pretty much like the GNS430. Not that that means I'm awesome with it. I have a resistance to being really good with GPS units because I fear the loss of the navigation skills I developed before they were so ubiquitous. But really I am already losing those skills, but using GPS badly. In fact, if I learn to use this so well that it needs only the least amount of my attention, and I know its limitations well, that leaves more attention over to do real navigation.

A quick example of something I've already learned and used is how to use the direct to funtion to select a track not direct from my present position, but along a particular track to a facility. It's so obvious, once you know how: select the fix you want, hit the direct-to key, and then on the screen that comes up verifying the fix you asked for, cursor through the fields to the one that shows the direct track and change it to the desired track. Hit enter twice and there is the radial/track displayed on the moving map. This can be used to intercept final approach, a VOR radial or a track to an NDB. It's great when doing the last in wind, because it provides great confirmation that I am really on track, and improves my ability to intercept a track that is a moving and very unsteady target in a turn. (Banking affects the direction an ADF needle points, so you can never be sure you're on track until you're wings level again, making it hard to know if you have to increase or decrease bank to have the turn work out).


Rob said...

I have been using Garmins for over 18 months now and never knew of this ability! It will definitely help with situational awareness as you say.

(P.S. post cards etc. are on their way, life is just getting in the way!)

jwenting said...

My guess is that had you used the unit despite the database being outdated you'd have got flak from the examinator because of that.
Had you told him/her that it was outdated and therefore would not be used, that might have been fine but of course you could have taken flak for that as well.

Sometimes people are just out to get you, and there's no way to prevent it.

Tim said...

For an even easier way of setting the course, rather than scrolling through all of the fields, if the Garmin is slaved to an HSI or OBS just hit the OBS button, twist in the course and hit the OBS button again.

Sarah said...

It's my "job" to refresh the club's 430w every 28days, so I know what a pain it is keeping the database current. In the US, the FAA allows you to use said GPS even with an expired DB if you check that the info (approach or enroute data) has not changed since the cycle date. So you can at least theoretically use an expired GPS database for an actual IFR approach. ( Enroute too, but it's much harder to verify nothing has been changed. )

This does not apply to a GPS like the one I took my CPL ride in. It was an ancient KLN-84 last updated in the 20th century. Maybe that was more like your situation in the PPC.

As far as situational awareness... do Canadian NDB approaches exist in the Garmin? If so, ( again, in the US, I don't know TC rules ) you could use an IFR GPS instead of the ADF entirely, not just for SA. That would make it too easy for a traditionalist like Aviatrix I suppose...

Chris said...

That is an awesome tip. Thank you.

nicnacjak said...

Great tip. I've only been abale play with the 430 in The Redbird. Have you played with the VNAV functuionaliy yet?