Category Archives: Aviation

Writings about aviation, including chronics of my flight lessons, product reviews, and so on.

Fuel shenanigans

The saying goes that “you can never have too much fuel unless it’s on fire.” I have always been a believer in that truism, so I always fill the tanks before I go anywhere… except on a recent trip, which just confirmed the wisdom of whomever came up with the old chestnut.

I was flying DCU-IGX, which I flight planned as 394nm, just under 3:00 of flying time, and about 48 gallons of fuel. Sure enough, when I arrived, I’d drained one main tank, one tip tank, and about half of the other tip tank. The CGR-30p engine monitor, my analog gauges, and my eyeball inspection all agreed.

Fuel at IGX was $5.28/gallon. Fuel at my home airport is $4.80/gallon. “Hey,” I thought. “I have enough fuel to get home if I just fill the tip— that will give me 59gal on board, which still gives me a VFR reserve.” Visions of dollar signs dancing in my head, I filled out the fuel ticket and went into town to lift all the weights with Alex. When I returned, I verified the fill, sumped the tanks, and headed to the departure end of the runway with 59 gal on board.

Once airborne, the problems started. ATC wanted to vector me well north of where I wanted to go because of weather, and to keep me out of the RDU arrival corridor. They also gave me a higher altitude, so I burned more fuel in the climb than I’d expected. Once I got past the first waypoint, I had to divert around more weather… see where this is going? About 40 minutes into the flight it became clear that I didn’t have enough fuel to get home without a stop.

I’m not talking “had enough fuel if I ate into my reserve,” I’m talking “engine monitor shows negative fuel remaining on landing.” Noooope.

A little head scratching ensued, and I determined that I had plenty of fuel to make Winchester, where fuel is only $4.09/gallon. When I landed, I took on 71 gallons out of the 82-gallon usable capacity— within my 45-min reserve requirement, but just barely.

Lesson learned: by not filling that tank in Chapel Hill, I saved (25 gal * $0.48/gal)… a whopping $12. Then I cost myself another 30-40 minutes of diverting to Winchester, landing, fueling, and returning home. In this specific case, I was lucky because Winchester is open 24/7 and is easy to get into and out of, and their fuel is cheap. I probably netted a few dollars of savings filling up there as opposed to filling all 4 tanks in Decatur— but that unpleasant feeling of not having enough fuel aboard is one I don’t care to repeat.

Fill ‘er up!


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Flying Friday: first flights with the CGR30p

Good news: we finally got the long-awaited CGR-30P instrument installed in our plane! Back in February, I said we’d put the plane in the shop for the actual install and, rather optimistically, said that I thought we’d probably get it out within a week or two. I could write a long, sad story about the various difficulties we had, including the unexpected departure of the shop manager, his failure to tell us we needed to do a pre-install maintenance check flight, and so on, but the details are both boring and depressing. Enough to say that the install is done, there have been no major problems with it so far, and we’ll probably find another shop to use in the future.

Anyyyyyway, here’s what the finished product looks like. We had it installed in the panel in the spot formerly occupied by a defunct Stormscope, in the upper left corner of the panel. The plastic cover that Piper uses on its panels obscures the tachometer redline, which is annoying but not insurmountable.

WP_20150328_001The rest of the installation is unremarkable; the CGR unit uses a small box known as the EDC (for “engine data computer”) that’s installed in the baggage compartment. All of the temperature probes and transducers feed data to the EDC, and a simple single cable runs from the EDC to the panel. In the engine compartment, there are six probes each for cylinder head and exhaust gas temperatures, a fuel pressure transducer, a fuel flow transducer, oil pressure and temperature transducers, plus an outside air temperature (OAT) probe mounted on the pilot’s side of the fuselage. The picture above shows manifold pressure and propeller RPM at the top, an EGT/CHT bar graph in the lower left side, and fuel flow, fuel pressure, and oil pressure on the lower right.

The CGR30P is connected to the master bus, not the avionics bus, so when you power on the master switch it comes on. Although it’s possible to use it as a fuel tank gauge, that would require a bunch of additional wiring, so we kept the analog fuel tank gauges and use the CGR to monitor fuel flow. When it boots, you can specify how much fuel you’ve added and then it will track both the flow (by using the flow transducer) and your fuel remaining (by subtraction).

The control scheme is simple; the “S” pushbutton sequences between different screens on the lower half of the instrument. The rotary knob (which can be pushed to select) moves a small carat cursor around between fields. The “E” button exits what you’re currently doing. This takes a little practice, but it’s easy to learn. For example, if I want to lean the engine, I press S until I see the CHT display, then use the rotary knob to select the CHT display type, press the knob in, and dial it until it reads “CGT ROP” or “CGT LOP.” Easier said than done.

At first, it took me a minute to remember that the old analog fuel flow gauge had been disconnected while I was priming the engine. Luckily I caught on, and that gauge is now placarded as inoperative so I won’t keep looking at it. Apart from the novelty of looking at a color screen instead of a 1950s-era analog instrument, engine start, taxi, runup, and takeoff are completely unchanged. Leaning the engine for cruise will take some getting used to; because EGT6 is wrong (see below), the lean-of-peak and rich-of-peak methods are just guesswork, so I stuck with setting approximately the same fuel flow I used back when the analog gauges were connected. I was very pleased to see that setting the throttle so that the CGR read 16″ of manifold pressure gave the same steady 500fpm descent rate that 16″ of MP would on the analog gauge. In fact, the only discrepancy I noticed was that the electronic tach reads 80-100rpm faster than the mechanical tach, probably due to flex or looseness in the mechanical tach cable.

The refresh rate, quality, clarity, and lighting of the CGR30P screen are all superb; it was easy to read it in all lighting conditions, including direct sunlight (though I haven’t flown with it at night yet).

Sharp-eyed readers may notice that the cylinder head temperature bars (the green ones) don’t seem to show much of a temperature on cylinder 6. During my first test flight, I found that the EGT for that cylinder was suspiciously low, although the engine functions just fine. We think there’s a loose connection, which we’ll troubleshoot once we get the airplane back from annual. For a while, I was sure that CHTon cylinder 2 was wrong, but no, it was just that I’d chosen to display the differentials for CHT, so that the coolest cylinder reads as zero and the other cylinders show how many degrees above the coolest they’re running.

I had to fix a few other things; the CGR30P didn’t know what the analog tach’s total hour reading was, and it didn’t know that it was connected to our KLN94B GPS. The GPS feeds the distance to the current waypoint and the total flight plan to the CGR, which can use it to show how much fuel you’ll have when you get there. The CGR is also supposed to feed fuel data back to the GPS, but ours is old and doesn’t know how to use that data. Newer GPS units can display a range ring that shows graphically exactly how far you can fly– and as you change fuel burn by changing the throttle or mixture settings, the ring dynamically changes to show how far you can go. The GPS integration still isn’t working quite right, though; I need to tweak it a bit more.

By about 30 minutes into my flight to New Orleans, incorporating the CGR into my scan was second nature, and I feel comfortable operating it. I’m looking forward to downloading engine performance data and having it analyzed to see what we can learn about the health of the engine and how to operate it for the greatest efficiency and longevity– the real reason behind getting the monitor. So far, it’s a solid device and I’m happy with it.


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Flying Friday: “When Penguins Flew and Water Burned” (review)

I don’t bother to review very many books, in part because I read a lot and in part because writing reviews takes time away from reading. However, I recently received the Kindle version of When Penguins Flew and Water Burned and wanted to quickly recommend it. The book is a recap of the career of Jim Clonts, a B-52 navigator (and, later, radar navigator) during the tail end of the Cold War. Clonts writes in an engaging style, and his tales of life on a bomber crew are absolutely fascinating if you’re at all interested in military aviation. Although his crew position is navigator, he’s also a pilot and so there’s a fair bit of inside-baseball talk. The book is moderately heavy on jargon, as you might expect, but it’s still pretty approachable even if you don’t know anything about bombers or the USAF in general. Well worth a read if you’re flight-minded.


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Flying Friday: of shops and annuals

I haven’t been flying much lately, sad to say. This is mostly because of weather, but partly because I have been busy with other things. However, as spring approaches, I’ve been eager to get back in the air. A couple of weeks ago, I went flying with John, my CFII, and shot some practice instrument approaches. While I was a bit rusty, I was still able to fly a good ILS, even in the winds, but I had a little bit of trouble making the KLN94 do what I wanted to get set up for the GPS approach into Huntsville… its time is coming, though, and I hope to finally get the Avidyne IFD540 installed in early summer. That’s still some time away, though. There are two hurdles to cross first: getting our engine monitor installed and getting the plane through its required annual inspection.

First, the engine monitor. Like almost all other airplanes of this vintage, 706 has a battery of analog gauges that report on the engine health. There’s nothing wrong with this, as these instruments tend to be very reliable. The tachometer, manifold pressure gauge, and fuel flow gauge are all very important. However, the standard engine instruments have several shortcomings. First, our plane had a conventional single gauge for reporting exhaust gas temperature (EGT), and the aftermarket cylinder head temperature (CHT) gauge wasn’t working. The problem with single-channel EGT and CHT instruments is that they only tell you what one cylinder is doing, so there’s no way to see what’s going on with the other five cylinders. Second is that the gauges are scattered all around the panel; besides the EGT and CHT indicators, there’s a suction gauge (which tells you whether the engine-driven vacuum pump that drives the gyros is working), the fuel gauges, and so on. Third is that these gauges only show instantaneous data, not trends, and they don’t alert you to unusual conditions.

The solution: get an engine monitor. After much shopping and head-scratching, we settled on the CGR-30P from Electronics International. The video below will give you an idea of what this magic box does:

From my perspective, the CGR-30P does two critical things: it alerts you when an engine parameter goes out of limits (say, if the oil pressure decreases unexpectedly), and it logs data that can be used for later analysis. As a nice side benefit, it monitors CHT and EGT for all six cylinders, which has the dual benefit of giving early indication of potential misbehavior and providing the data we need to operate the engine as efficiently as possible.

(Brief digression: there is a lot of religious argument over the “correct” way to adjust the fuel/air mixture in piston engines. This article by noted mechanic Mike Busch explains the topic, and the debate, very well, along with recommending the approach that I will be using once I have accurate CHT and EGT data).

Getting the CGR-30P installed, though, requires an avionics shop. Derek and I have struggled with finding a good local shop. There’s no avionics shop at our home field, and C-Cubed, which used to be at Huntsville,  closed a few months ago. Their spot was taken over by a company called Advanced Technical Avionics (ATA). After a brief period of confusion occasioned by a management change (translation: someone got fired), we got the plane into the shop on Tuesday to start the installation. With any luck, in a week or so, the plane will be back in the air– which is good, as I have a trip planned to New Orleans next month for the New Orleans Sprint triathlon, my first of the year.

Right after I get back from New Orleans, the plane needs to go in for its annual inspection. Every general aviation aircraft is required to undergo a comprehensive airworthiness inspection each year. There are specific things that the shop will check based on the engine and airframe manufacturer’s recommendations, and there can be other things that need checking or adjustment based on how much the plane has been flown. For example, some components need to be checked every 100 or 500 hours. (This example inspection checklist gives you an idea of some of the things that must be inspected.) Then, because this is a 40-year-old airplane, there will inevitably be some things that need to be repaired or replaced because they’re worn out or broken. For example, our air conditioner doesn’t work any longer, so we’ll have the shop take a look at it as long as they’re crawling around inside the plane.

On the advice of Savvy, our maintenance management company, we’re using a Piper service center for the annual– DLK Aviation in Kennesaw, Georgia. That means that we’ll have to ferry the plane there and back again; I’ll probably rent a plane from Redstone and pick Derek up after he drops the plane off, but driving isn’t out of the question. Once the plane arrives, after one to two weeks (and some unknown amount of money, depending on whether there are any expensive surprises), we’ll have the plane back and be good for another year.

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Developing apps for the Garmin ConnectIQ SDK

Early on this triathlon season, I bought a Suunto Ambit 2s. I loved the idea of having accurate workout data for my training, plus more accurate time/distance data for my races, and the Suunto has delivered. But it’s missing a few things: its support for interval workouts is poor, and the Movescount website is less reliable than I’d like. Luckily Suunto added export to Strava, but you still have to use their computer-based app to transfer workouts from the watch to the computer to the Movescount site, so when the site’s down you can’t see your workout data. (There are also various website bugs, including one in computing swim distance that means that the results on the website don’t match the results on the watch, but I digress). Having said all that, I was planning on sticking with the Suunto because I like the industrial design; it’s comfortable to wear, looks good, and has all the basic functionality I need.

Then I read this: Garmin announces ability to develop apps on wearables, with Connect IQ.

Coupled with my native lust for all shiny gadget things, the availability of the SDK opened a whole range of possibilities, not only for apps I could get for the watch but for apps I could write. I immediately started pondering what kinds of useful apps I could build and came up with one that I thought would be very useful: a flight timer. There are at least two different flight times that I need to log for every flight: how long the propeller was turning (because that drives how much money I put into our engine reserve fund) and how long I was actually in the air (which is what I actually log as flight time).

The GPS in 706 can automatically calculate flight time from takeoff to touchdown… provided you remember to look at it after landing and before turning off the avionics master switch. We also have a Hobbs meter that measures the time when the propeller’s actually turning. However, an app that automatically records time in flight, along with the origin and destination airports, would be useful. CloudAhoy does something similar, based on ForeFlight track data (and for all I know, ForeFlight can do this already). However, a timer that’s not tied to the aircraft would have the advantage of not losing its data when you turn off the airplane, and not being tied to a phone, external GPS, or iPad greatly reduces the risk of losing data due to battery or device failures.

So, I ordered a Garmin 920XT and downloaded the Garmin SDK. On first inspection, it looks like the SDK and development model are both pretty tractable for what I want to do. I’ll be blogging about my development efforts as they progress. For now, if I can get basic logging to work in the device simulator, I’ll be happy. There are a few features I’d like to have in the app to make it useful: it should automatically log flight time from takeoff to touchdown, geocode the origin and destination points so that the log file reflects airports and not just GPS points, and provide a timer function for things such as switching fuel tanks in flight. If I can extend that to include automatically logging flights into Safelog, that’d be even better but that might be some time away.

The 920XT itself will be a nice upgrade from the Suunto, which I am going to loan to my pal Jay for use in his training, but it won’t ship until sometime in November, so I’ll be running on the simulator for a while yet (and using the Suunto to log workouts, too!)

The SDK includes a comprehensive set of API docs, the device simulator, an Eclipse plugin that runs the command-line compiler, and assorted sample apps. I’ll have ore to say about it once I get my environment set up and running and start playing with the samples. Garmin’s clearly thinking about this the right way, though; in addition to their own developer forum, they are actively encouraging the use of StackOverflow.

Stay tuned for updates!


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Disney and Universal 2014 wrapup

A few more-or-less random thoughts about our recent trip to Disney World and Universal Studios Florida:

  • Universal is a see-it-once park, I think. We enjoyed it but there was nothing so compelling that I think we’d want to go back again in five years. On the other hand, all four of us had specific things at Disney that we looked forward to doing (among them: turkey legs, the Winnie the Pooh ride, Tower of Terror, and Space Mountain).
  • Having said that, the Harry Potter attractions are superbly done: decoration, character acting, costuming, and all the little touches come together to provide a very immersive experience. Just don’t expect to be able to drink a whole mug of butterbeer. (And don’t be surprised if the Forbidden Adventure ride leaves you nauseated for a couple of hours afterwards.) Getting early access by virtue of staying in a Universal property was well worth it.
  • We didn’t buy, nor did we miss, the front-of-the-line ride access benefit that Universal sells for $60+ per person, per day.
  • Disney’s MagicBands system works extremely well and made paying for things much easier– which, I suppose, is the point.
  • The FastPass+ system takes a little getting used to because you can get multiple passes at once, but there are limits on which rides you can stack passes for. Read up on it before you go.
  • We stayed at two “value” hotels: Universal’s Cabana Bay and Disney’s All-Star Music Resort. Both had nicely equipped, clean “family suite” rooms. Both claimed to sleep six: Universal provided two double beds and a twin pull-out sofa, while Disney provided a queen, a twin sofabed, and two single fold-out sleep chairs: not ideal for six-foot teenagers, but workable.
  • Disney’s on-property wifi was great at the parks, as was Universal’s. However, the Disney in-room wifi was unusuable– worse even than the worst of the Microsoft conference hotels I’ve had to use in the past.
  • EPCOT’s International Food and Wine Festival was going on, so we got some primo foods when we ate dinner there. I’d like to do the festival again, but with more time to savor the food.
  • Tom, Matt, and I all ran into friends at the parks. It’s a small world indeed.
  • We didn’t rent a car, so we used Uber for the move from the Kissimmee airport to Universal, then a cab from Universal to Disney, then Uber again. Orlando’s taxis are about a million percent cleaner than in most other cities, but Uber was cheaper and faster.

Overall, a successful trip (good flight, too!) but boy, am I glad to be home!


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My first real IFR trip: Decatur-Manassas and back

My trip to DC to compete in the Nation’s Triathlon was my first “real” IFR flight. I say “real” because it combined flight in actual instrument conditions with busy airspace and a long cross-country—conditions I expect to encounter often as I fly around.

Earlier in the summer, I had signed up for the tri.The timing was such that I would come home from GATTS, have a couple of days to pack, and then fly up to DC, hopefully with my instrument rating. That turns out to be what happened.

Flight planning was straightforward. The DC metro area has a number of general aviation airports scattered around, but it also has significant restrictions on its airspace. Without going into all of the gory details, it’s enough to point out that the airports that are closest to central DC are heavily restricted. In order to fly to the so-called “Maryland 3”, you have to go to either Dulles or BWI, get fingerprinted, have security interviews with the FAA and TSA, and then get a PIN that you use when filing flight plans. I didn’t have time to do that, so I settled on Manassas, which is further out but would provide a reverse commute into and out of the city—it also helped that the route from Manassas to the hotel passed right by the bike shop where I’d made arrangements to rent a road bike.

I planned an early departure Saturday morning. Because I’d been out of the office for most of the week, I couldn’t leave earlier than about 5pm, and I didn’t want to fly night IFR in unfamiliar, complex airspace after a full, and tiring, day at work—that’s how accidents happen. My original plan was to fly from Decatur to KGEV, fuel up with avgas and diet Coke, and then continue on to Manassas. The weather at Decatur at departure time was OK, with an overcast layer about 2000’, and Huntsville Approach quickly cleared me to my target altitude. The first hour or so of the flight was smooth on top, then things got a bit bouncy because there were clouds at my filed altitude—with some light rain and a fair bit of chop. Once past that, though, things were looking good until I looked at the weather at my destination airport and alternate . Both were below minimums, so instead I flew a bit further east and landed at Winston-Salem, which was nicely VFR. It turns out that the airport there has self-service or full-service fuel, with a whopping $1.69/gal price difference—but getting to the self-service pump from the FBO is an adventure that involves runway crossings and, in my case, aggravating the pilot of a Malibu who had to hold short while I taxied. Such is life.

The flight into Manassas was perfectly uneventful, just the way I like. I had filed direct from Winston-Salem to Manassas, but I didn’t expect to get that routing, and sure enough, I didn’t; Potomac Approach sent me direct to the Casanova VOR, then direct Manassas. It was fun watching the Foreflight traffic display en route, since I could see a ton of traffic into Reagan.

Watch out for the big iron!

Watch out for the big iron!

Going to CSN first wasn’t much of a diversion, so it was no big deal. Manassas was VFR, but storms were expected later, so after I landed, the fine folks at Dulles Aviation hangared the plane. (I also want to point out that they provided stellar service: the rental car was ready when I got there, saving me a commute to the nearest Avis office some 12 miles away, and they treated me like I had just flown in on a Gulfstream.)

The return trip looked simple enough too. I filed direct Manassas to Greenbriar, WV. The race was on Sunday, and I needed to be at work Monday morning, so I had to leave late in the afternoon, meaning that several of the airports I would normally have considered as fuel stops were either closed, or would be. Greenbriar was reporting 900’ overcast, which was fine with me, so I filed, preflighted, and started up, then called Manassas Ground to get my clearance.

Here’s what I was naively expecting: “N32706, Manassas Ground, cleared as filed to LWB, climb and maintain 9000’, departure frequency…”

Here’s what I got instead: “N32706, Manassas Ground, cleared to LWB via the ARSENAL FOUR departure, thence the Montebello transition, then direct NATTS, then direct LWB; departure frequency…” Thus we see how ATC deals with the expectations of a novice IFR pilot. This set off a frantic burst of knob-twiddling as I tried to set up the KLN94 for that departure (which it didn’t have, since its onboard database was too old). I eventually got it set up, was cleared for takeoff, and then got a series of ridiculous vectors from Potomac Approach that sent me well north of where I wanted to be. However, the flight to Greenbriar was nice and smooth between layers, and, as advertised, the weather on arrival necessitated shooting the ILS, which I did smoothly. After taking on fuel, it was off to Decatur; the rest of the flight was unremarkably smooth except for a great sunset and some tasty snacks (yay vanilla wafers!) I considered it a very successful trip!

A great sunset to cap off a great trip

A great sunset to cap off a great trip. Not shown: vanilla wafers.

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