Tuesday, February 27, 2007

GPS and Mac = Headaches!

Well, when I got my Garmin GPSMAP 96C I thought it might be interesting getting it to talk to my Mac. I wasn't wrong!!!

Firstly, I had no choice but to use a PC for updating the firmware and the Jeppesen maps on the unit. I didn't mind that so much because I don't think I will have to do that very often. I wanted to just download tracks and routes to Google Earth from it, and that proved more challenging. I purchased a copy of MacGPSPro. Then I discovered after much trying that it doesn't work with USB on my Garmin. I didn't realise I'd read the confusing website properly, and discovered it only works via Serial on this unit.

So, I purchased a Garmin serial cable off Trademe, and a USB to Serial converter. Now I find there are no maps included with the program. So once I tracked down a NZ map from linz, I found I couldn't import it into the program as it was just a scan of a paper map. So I then had to track down a calibration file, which was also interesting, and somewhere out there I found one for the exact map I had. Yippee!!

Once I had installed a driver for the serial converter and rebooted, the GPS started talking to the Mac! Woo hoo!!

I have now been able to download tracks, routes, waypoints, and it will show my current position on the map! The map is only 1:1 million, so I wouldn't mind a 1:50 thousand map, to get more detail.. We will have to keep trying. Or an aviation chart would be perfect!

But it works, and I am stoked! Will have to go for a drive and watch it on the map live...

Tauranga in Archer FWS

We decided a trip to Tauranga was in order on Saturday, so two of us hopped in FWS, one of the Archers, and I thought it might be a good opportunity to get used to the GPS. We tracked to Ruahihi and then got clearance to Tauranga. We could see White Island, or I think that is White Island, from halfway down the Kaimai ranges. The wind was blowing 15 gusting 20, and swinging through at least 30 degrees, and as usual, our landing on 07 Seal was more of an arrival than a landing!

We parked up at the Aero Club and wandered around for a while, I dropped a parcel in for a friend, and we went back after a while and got in the plane. Contacting Tauranga Ground for a clearance, we took off on the same runway, although from an intersection takeoff rather than backtracking, something I am sure some of my instructors would take issue with, although we still had about five times the runway left that we needed. On the way back, we got just on the west side of the Kaimais and the turbulence from the now strong easterly hit us, and we got thrown around and ended up gaining (according to the GPS track I downloaded) 400ft in 0.5 nm, which is about 15 seconds flight time, which was fine by me as I had just started climbing anyway. I find I enjoy most light to moderate turbulence anyway as it's like being on a rollercoaster for no extra charge.

The flight back was uneventful except for having to take a South arrival, which meant from the place I reported, I had to fly south for 5 miles before being able to track for the airfield again, and there was bugger all traffic, so I can't see why they cost me 5 miles / 2.5 minutes / 2.5 beers / $7.20 for nothing!

My landing back at Hamilton was pretty average - I slowed it down to 55 kt and it was fine until just before the fence when the stall warning went off, the tail dropped, I added power, and we 'arrived'. In hindsight I probably should added quite a bit more power, but the landing was still smooth enough.

Another good flight, 1.4 more time in the logbook, and I am a lot more familiar with the GPS to boot.

I have some concerns about those people who I have heard about who fly with only a GPS that I realised during that flight that worry me, and will definitely cause me to use GPS as a backup to my paper navigation. These issues are:

1) The GPS will lead you anywhere you tell it, and especially on a longer flight or when zoomed in, you can't readily establish where you are headed, which depends on you being awake enough to enter the right waypoint, and to keep up with any diversions due to ATC instructions.

2) Airspace may well be illustrated on the moving map, but it's not readily apparent which bit of airspace is at which level without scrolling the cursor across the map. I am sure this is why well meaning VFR pilots continue to fly into controlled airspace using GPS. A paper map is vital for seeing at a glance what the disposition of the various airspace levels is. A GPS can be used to confirm you are where you think you are on the map.

Wednesday, February 21, 2007

First flight with GPS

After getting my GPS the other day and learning how to use it, I decided to go for a fly to test it out. The plane that was free was FWS, which happens to be my favourite plane anyway.. So myself and a friend grabbed FWS, and planned to fly out to Raglan and back to test the GPS.

I attached the yoke mount, and found it fitted perfectly, and slotted the GPS in. We started up and taxiied out. Because we were flying in the evening and going west, the tower warned us about the setting sun. The aircraft has big sun visors so it turned out to be not a problem at all, as I suspected, and we took off and flew west. I checked the GPS occasionally and found it was harder than I thought to keep the CDI from drifting off.. I know it's adjustable but I don't know if that's the right thing to do or not. Anyhow, as we got closer to Raglan the VNAV indicator came alive, and I followed it down to circuit altitude, and we were right on target. A low approach and overshoot followed, after which we turned around, I punched in Reverse Route in the GPS and we followed the indications on the HSI back. Once again I had issues flying precisely enough to stop the CDI from drifting off a bit, but I guarantee after 10 hours I'll be spot on.

The map and airspace alerts proved very useful for situational awareness, but on the way back the VNAV didn't work, I figured out later you need to enable it manually for each route you fly, but that is only three button presses..

After landing, I decided to go do some circuits to practise my landings, and so we trundled to what felt like the other side of the airport, and when we finally got takeoff clearance, a large flock of magpies and plovers landed halfway down the runway in front of us, so I had to abandon the takeoff and wait for the man with the shotgun to drive past and fire blanks at them!!

The only other memorable part was when I decided to land on the seal, which is very unusual for me, my friend encouraged me to fly down the PAPIs instead of landing on the piano keys like I usually do, and we ended up landing smack bang in the middle of the rubber marks on the runway! Great fun, I must do it again!
I am off to Tauranga on Saturday so might have a crack then too..

Tuesday, February 20, 2007

Garmin GPS 96C - why I got one and first impressions

I have always suspected using a GPS for VFR flying would somehow ruin my navigation and mapreading skills, and have always resisted getting one. Had a look at a friend's Garmin colour moving map a while ago, and thought that was pretty cool, but that's as far as I got. A while ago a friend suggested even if I get a non-aviation model it would be of some use, which I had previously thought was a bad thing to do, but when the chance came to borrow a very very basic non-aviation model, I grabbed it and went flying, obviously after learning how to use it.

And I was hooked! It only had a black and white arrow to show you which way to go, but that helped a lot with situational awareness! I put in the place I was going to off the aeronautical charts, and just did a Go To..

So, I decided to buy one, but which one to buy?? I first wanted to spend no more than $200 for a eTrex, but for a little more I'd get a mapping eTrex Legend, and for a bit more I'd get a Vista, which is better, and so on, and before you know it I'm looking at a aviation model. Oh dear.

So I find out the cheapest aviation model, a grey screen Garmin GPSMAP 96 is about twice as much as I intended to spend, and then to finish me off we find out that the 96C has twice the battery life, five times the memory, plus a colour screen. And it's not a lot more than the 96. So we ordered a 96C and decided to just suck it in and get one. Hell, I'll have it for years and I'll get over the financial shock soon..

So, on to first impressions...

The box it came in is huge!! I soon find out it's got a stinking great metal yoke mount in the box, which I found out when I tested it on our aircraft, fits everything except our 1997 model C172, because that's got a stupid clipboard mount that gets in the way,

The build quailty and finish of the GPS is fantastic. All the buttons are very solid, all the connections on the rear are covered by rubber covers that fit snugly. Turning it on, and my first impression of the screen is.. Wow! The more light shining on the screen the better it looks!

I thought I had Garmin worked out when I learned how to use the eTrex, but how wrong was I !!! The 96C may be small, but I am just blown away as to how much stuff they have packed in!! It really is amazing, but power comes with complexity, and things that are easy and straightforward on the eTrex, are not easy or straightforward on the 96C. The good news is, once you read the manual and play with it in simulation mode for a few hours, the things you can do with it are astonishing for a small unit!

For my first flight, I made sure I was thoroughly familiar with it before going flying, and programmed it for a short flight from Hamilton to Raglan. I found that the screen wasn't as easy to read as I had hoped when flying towards the setting sun, but that's probably asking a lot! On the way back the screen was much easier to read. The yoke mount kept it nice and solidly attached to the yoke, and with the moving map I could easily see where I was and where I was going.

One feature of the 96C is a graphic HSI, with a programmable CDI and bug indicator, which I found quite challenging to fly precisely enough to keep the CDI from drifting off. I guess this is going to make me a more precise pilot in time, as I fly routes I have mapped out, and fly them precisely.

Another fantastic feature is programmable VNAV, which allows you to program a descent rate and distance from destination to descend to, and a VNAV indicator appears on the HSI to guide you down on your selected glideslope. You can optionally display the HSI and two data fields at the top of the moving map screen, which is potentially the best of both worlds, althought the mini HSI is a bit small.

The unit allows you to zoom in and out, and arrow around the map, and it will show you information on airspace and airfields, although that description hardly does it justice - you can get so much information it just blows me away! You can show any information in the database with a couple of button presses..

I will have to write a full review later since there isn't very much about it on the internet, but suffice it to say I am glad that it has a thick manual and a simulation mode, and bloody well don't go flying on your own until you are up to speed with it!!

Thursday, February 15, 2007

Descent Calculation

For all those flight simmers and real life pilots who are unsure when to start descending and what descent rate to use, especially if you are at a good altitude, these calculations can help.. They are simple enough you might even be able to remember them when in the plane..

The first calculation is used to determine when to begin descending, the second gives you the rate of descent to use.

For these examples, I have used 10,000 ft altitude, and 120kt groundspeed.

1) To decide when to begin descending, take the last 3 zeros off your altitude then multiply by 3, which gives you the number of nm away to begin your descent. So, take 10,000 ft, knock the zeros off becomes 10, multiply by 3 becomes 30 nm away from your destination to begin descending.

2) To decide the rate of descent to use, divide your groundspeed by 2 then multiply by 10. So 120kt / 2 = 60, times 10 = 600 ft / min to descend at. Just remember your groundspeed is used, not your airspeed.

Of course this is all going to be a little irrelevant for me shortly because I have ordered a aviation GPS with VNAV built in, which should do all this for me, and allow me to plan descents to arrive at my target alt before I bust airspace, which is a little more difficult to do with these calculations, but I still will be using them for my X-plane flights

Sunday, February 11, 2007

Pauanui for a $100 hamburger!

Finally made it to Pauanui to take my mate and his son for a $100 hamburger! After issues getting a plane - they all mysteriously became unserviceable when I went to book them, I ended up with our Archer FWS.. I flew from Hamilton to Tauranga, got there exactly the same time as my friend, and he only had to drive across town to get to the airport, and we both left the same exact time.. Anyway, I picked them up, and we flew to Pauanui..

Which is 40nm up the coast from Tauranga on a beautiful 30 degree C sunny day.. Which on the way up we did at 500 ft to get a close look at the countryside. 20 mins and we were there.. A couple of other aircraft in the circuit, then a 5 ship formation of Yaks kept us entertained when on the ground.

So we rocked on up to Pauanui, we parked up, wandered across the road to the shops, had lunch, went to the beach, watched the Yaks, then flew back to Tauranga, this time at 3000 ft. I had the Archer trimmed up, and it just purred all the way back.. We could see the Mount from Pauanui, and it couldn't have been nicer! I stuck the Archer on autopilot, trimmed it up, sat back and watched the view!

I spent a few hours with my friends in Tauranga before heading back to the airport at 6pm for a nice cruisy flight back at 2500 ft.. I always have issues coming back from Tauranga - I never quite know which way to head to get back, it just never looks quite right.. And then finding Hamilton from the east is a nightmare, so this time I took a GPS with me, and just followed the arrow back, and there we were! Couldn't have been easier!

And I got back and visited the bar on the way through, and that just capped off a fantastic day! It is the reason I got my license in the first place!! Wicked!!