Paul's Down-Home Page

Earlier this week I suffered an indignity common to all VFR pilots who fly cross-country: I got stuck someplace by weather.

I’d flown into Houston on Saturday evening, planning to hop down to Corpus Christi the next day and then back to Alexandria Sunday night. The weather Saturday night when I arrived (after a loooong flight featuring a steady 40kt headwind) was marginal VFR, with ceilings of just under 3000’, but the weather cleared a good bit Sunday afternoon to the west. I wasn’t able to get to Corpus, but I had hopes that the weather would clean up Monday morning so I could make it to Alex to surprise Julie before she arrived.

Long story short: not only did the weather not improve, it got quite a bit worse and stayed that way until midmorning Wednesday.

This picture from Tuesday morning sums it up nicely. In the foreground on the left, you see N1298M, my trusty steed. Pretty much everywhere else, you see clouds. The weather at the time I took this was 600’ ceilings with visibility of 3/4 statute miles. Needless to say, that is not legal weather for flying under visual flight rules. Later that day, it started to rain, and rain, and RAIN. I wasn’t the only plane stuck on the ground, but at least the FBO operated by Gill Aviation had a good restaurant (try the pecan-crusted catfish!) and free cookies.

Wednesday morning the weather cleared a bit; it was 2800’ broken and 7SM visibility when I took off. I had to pick my way around a bit; instead of going direct I first went north to Conroe/Lone Star Executive, thence more or less direct to Bastrop (which has an almost deserted airport with a super helpful attendant), thence direct to Redstone. The flight home was perfectly uneventful, with weather steadily clearing as I got further to the east. But being pinned on the ground was aggravating, and it’s clear that I need to work on getting my instrument rating sooner rather than later. Luckily I have a plan…

BLUF: this was one of the most difficult written exams I’ve ever taken, far harder than any IT certification exam I’ve done,

Back in December I wrote about the instrument written, widely alleged to be the most difficult of the FAA’s written exams.

There’s a lot of disagreement over the “right” way to earn a new rating or pilot certificate. What works for me is to study the knowledge base that I have to demonstrate mastery of while I’m working on the airmanship portion. Some folks advocate completing the written before any flight training starts, while others prefer to put the written off until right before the check ride. I guess my approach is somewhere in between. At the time of my December post, I had envisioned taking the test sometime in the first quarter; right after Christmas, I had the opportunity to sign up at a reduced rate for the Aviation Ground Schools program, so I signed up and set a goal of taking the exam on 10 February, the day after the school ended.

My path to the exam involved several different sources of information. The FAA doesn’t publicly post its pool of test questions, but the exam has been around long enough, and the knowledge areas are well-enough known, that all of the major test prep products have more or less the same questions. Each provider has a different approach to how they teach the material; some prefer Gleim, some swear by ASA, and so on. I spent a lot of time with Sporty’s Study Buddy app, which is a pretty faithful simulation of the test, and I read everything about IFR I could get my hands on, including the excellent AskACFI web site and the forums at the Cessna Pilots’ Association web site. Caroline, one of my two flight instructors, gave me a list of stuff to read that was very helpful, and I started working my way through both the FAA Instrument Procedures Handbook and the FAA Instrument Flying Handbook. It’s fair to say that I was stuffing my head with a lot of somewhat disconnected facts and factoids, so I was a little concerned when I headed off for my test prep seminar last weekend.

The seminar I chose is run by Don Berman, who started flying the year I was born and started instructing before I was housebroken.  Online registration was simple and quick, and I got ample preflight notification of everything I needed: what to bring, where the class would be held, what the cancellation policy was, and so on. The seminar I attended was held at the Comfort Inn near Houston Hobby: not a fancy hotel, but adequate for what we needed. When I arrived, Don introduced himself, gave me a fat stack of material, and got us started right on time. He’s an extremely lively presenter and his long experience as a pilot, flight instructor, and classroom teacher shines through, both in his delivery and in the quality of his presentation and visual aids. He’s also clearly got a lot of experience with classroom management; he started and ended on time, gave us adequate breaks, and kept everyone on task. He handed out optional quizzes at lunch both days and Saturday at the end of class, along with a final exam (again optional) on Sunday. The questions were hand-selected by him from the pool of questions in the ASA book; he said that if we could handle them, we should have no trouble with the actual exam.

In fairness, I should point out that Don bills his seminars as test preparation seminars— that’s exactly what they deliver. There were a few areas (like how to interpret an HSI, a navigation instrument that I’ve never flown with) where I came into the seminar with weak skills. Don taught me what I needed to know to dissect and answer test questions about HSIs, but I’m still not ready to jump in an HSI-equipped airplane and use it for a cross-country flight. Which is fine— the test covers all sorts of other things that I will probably never use, including automatic direction finding (ADF) equipment. With the test out of the way, I can now focus on building skills with the equipment I do fly with.

One of my biggest customers asked that I be in Raleigh on the 10th, so I flew there straightaway and stayed there Monday and Tuesday (escaping just in time to avoid their snowmageddon). Today was my first window of time to schedule the test. I was a little concerned that I would forget some of the more esoteric material, and I did. However, my basic knowledge was pretty solid, and I think the random selection of test questions was feeling friendly since I only got a handful of questions on my weaker topics. One interesting aspect of the test is that a new set of questions, with associated diagrams, was just added to the test pool on Monday, so there were some question types that were new to me.

I passed the exam with an 87%, a score I am delighted with. That said, I have a few problems areas that I need to work on as I continue my training, and I realize that passing the written doesn’t mean that I know anywhere close to all that I need to pass my check ride… but I’m getting there!

A couple of weeks ago, I wrote a post about piston aircraft engines (tl;dr: ancient and expensive technology but generally very reliable). The fact that the general aviation fleet is still powered almost exclusively by these engines may have surprised you, and I wish I could say that it’s getting better right away.. but it’s not. There are some encouraging signs on the horizon, though.

One alternative is to just replace the engine (or its components). This can be done through a process known as supplemental type certification (STC), an existing airframe/engine combination can be changed, often in significant ways, provided you can prove to the FAA’s satisfaction that the changes are not unsafe. For example, there is a well-known STC for many models of Cessna 182 that allows you to run plain auto gas in the engine. There are others covering all sorts of engine upgrades and replacements: Electroair makes an electronic ignition system, Peterson, Texas Skyways, and P.Ponk make kits to replace the 182’s engine with larger and more powerful versions, and there’s even an STC to put an SMA diesel engine up front. At the high end, O & N Aircraft will happily sell you a turbine engine that will turn your Cessna 210 into a real beast (and set you back several hundred thousand dollars, too.)

The problem with STCs is that they tend to be expensive (since the manufacturer has to run the entire FAA approval gauntlet) and very specific (the STC allows you to make the specified changes only to the exact make and model specified in the STC). The expense of STC engine swaps raises the question of how much sense it makes to put an expensive engine into an inexpensive airframe, e.g. Peterson quoted me more than $80,000 to put a new engine into a 1969 182 with a market value of just under $50,000. That didn’t seem to make a lot of sense to me. Less expensive STCs, such as the Electroair electronic ignition, may have reliability or efficiency benefits that make sense, but it’s hard to see that happening for an entire engine.

A few manufacturers have made other attempts to give us better engines. One that I remember well was the Mooney PFM, a collaboration between Porsche and Mooney that put an air-cooled Porsche flat-six into the Mooney M20. The PFM had a single-lever throttle (with no manual mixture or prop adjustment), was fuel-injected, and could optionally be turbocharged. However, it wasn’t very successful in the marketplace despite its advantages.

My longtime friend Phil asked a great question in a comment to the previous post: what about turbine and diesel engines? Why don’t manufacturers just use them instead? Well, they do in new aircraft. For example, Piper will happily sell you a Meridian (with a Pratt and Whitney PT6 turbine, the gold standard in turboprop engines) starting at about $2.2 million dollars or a Mirage, which is about 40 knots slower, uses a piston engine, and costs roughly half as much. Turbine engines, of course, are mechanically and operationally simple and very robust, but they are expensive to acquire and maintain, which pretty much rules them out for the class of airplanes that most GA pilots have access to. Diesels are starting to make inroads too; the only model of Cessna 182 you can now buy is the Cessna 182 JT-A, which replaces the old-school piston engine with a 227-hp SR305 diesel (the same as the one available via STC for older 182s). The history of diesel engines for general aviation is long and complicated; suffice to say that Cessna and Diamond are the only two manufacturers I can think of who are currently selling diesel-powered aircraft despite their efficiency advantages. However, the idea of a drop-in diesel STC replacement for the O-470, IO-540, and other popular engines is gaining traction in the market, with both Continental and Lycoming developing products.

More interestingly, Redbird’s RedHawk project is converting Cessna 172s by putting diesel engines and improved avionics in them; I suspect that Redbird will be very successful in selling these refurbished aircraft as primary trainers, and that may serve as an effective tipping point both for generating demand and demonstrating the potential market for diesel STCs for other lower-cost/older aircraft. We can only hope…

I had originally planned to write more about engines this week, but reality— or simulated reality— has intruded, and this week I’m going to talk about flight simulators.

For your convenience, I’ll skip the part of this post where I would wax lyrical about how cool it was the first time I played Sublogic’s old Flight Simulator on an Apple II. It was cool but it wasn’t much of a simulator experience. Fast forward from the mid-80s to today and the state of the art in PC-based simulators is X-Plane, an almost infinitely customizable simulator that can handle aircraft from gliders up to the Space Shuttle. (The demo video on their web site is well worth a look to see some of what can be done with suitable hardware). There are hundreds of different airplane types available, including military, general aviation, biz jets, and big iron such as the Boeing 7×7 line. Each aircraft has its own customized flight model and appearance, so what you see can be as realistic as the designer of that model feels like building in (and as realistic as your graphics hardware can support). Here’s a fair example of what the sim looks like on my setup:

Daylight approach to runway 32 at Alexandria International Airport

This is a daylight approach (created by checking the box that says “use the current date, time, and weather”) to runway 32 at Alexandria International. You can see the runways, taxiways, other airport stuff, ground features, and the Red River. The more powerful your computer, the more graphical features you can turn on. Since I am running on a 3-year-old MacBook Pro, I have the detail level set to “medium” but perhaps one day I’ll have enough hardware to turn up some of the visual fidelity knobs.

However, visual fidelity isn’t why I wanted a simulator. There are people, including many non-pilots, who like to hop in the sim and pretend that they are airline pilots, fighter pilots, or whatever. I wanted one as a means to practice instrument flying, which often involves being in conditions where you can’t see a darn thing outside. For example, right now the weather at KMGY (Dayton-Wright Brothers) is 1.5 miles visibility, an overcast layer at 300 feet, and light snow. Here’s what the approach to runway 2 there looks like right now; It doesn’t take much GPU horsepower to draw solid gray, as you can see:

Same daylight, different weather, this time at KMGY

So why bother? If you take a look at the approach plate for the GPS approach to runway 18R at Huntsville, you’ll see that there are specific lateral and vertical points to hit: inbound on the approach, you fly to the JASEX intersection, and you cannot arrive there below 3000’. From there, you fly a course of 182° to GETEC, where you arrive at 2500’, and so on. Understanding where you need to be during the approach, and then putting the airplane in that position, is the key to a safe arrival. Practicing the skill of mentally visualizing your aircraft position and orientation relative to the approach layout, then controlling the aircraft as needed, is really valuable, and in a simulator you can repeat it as often as necessary without delay, even pausing it when needed. For that reason, the FAA has allowed you to log up to 20 hours of simulator time as part of the requirements for an instrument rating, provided you spend that time with an instructor and are using an approved simulator. (They recently announced that they will only allow 10 hours of time to count, effective February 3, but the AOPA and other groups are fighting that proposed rule change.)

Without going into all the boring details, suffice it to say that there are many different gadgets to practice your flying with, from the massive, super-high-fidelity simulators used by airlines to the home-brew rig I’m using, with a $50 piece of software and another $200 in controllers, all running on a commodity laptop. This article from IFR Refresher explains the difference nicely: a simulator is a full-size replica of a specific type of aircraft cockpit, with motion and high visual fidelity. Training devices (TDs) don’t have to have motion, and there are several subtypes, including PC-based devices (PCATDs) and basic and advanced training devices (BATDs and AATDs, respectively).

For your simulator practice time to be loggable, you need a PCATD, BATD (such as this Redbird TD or FlyThisSim TouchTrainer), or AATD. My slapped-together rig is not FAA-certified as any of these, so I can’t log the practice time, and therefore it doesn’t count towards the requirements for my rating. However, being able to practice approaches before I fly them is invaluable, and I plan to make heavy use of the ability to do so. To help with that, I’ll probably spring for the FlyThisSim analog Cessna pack, which includes higher-fidelity models for several of the aircraft I normally fly. In particular, the pack includes the Garmin G430 and G530 GPS systems, which are very useful when flying approaches since they give you a moving-map rendition of your location and position and they can be coupled to the autopilot so that the GPS provides lateral guidance (though the airplanes I fly don’t have vertical coupling so the pilot still has to control altitude). Coupled with judicious use of the expensive and fancy Redbird FMX AATD at Wings of Eagles, this should help me (eventually) master the complex process of safely flying an IFR approach.

If you’ve noticed, car manufacturers often brag on the technology or fuel efficiency of their engines. If you recognize phrases like “fuel-injected,” “variable valve timing,”  “double overhead cam,” or “turbocharged,” then the automotive industry’s marketing has succeeded— even if you don’t know what those things are you probably think of them as desirable.

Now forget most of that. The basic design of most aircraft piston engines are stuck solidly in the 1930s.

Take, for example, the 1975 Cessna 182P I often fly, N1298M. Its engine is a Continental O-470-U variant. No electronic ignition. No fuel injection. It weighs 390 pounds, makes 230 horsepower, and costs about $21,000 to overhaul (more if you replace your timed-out engine with a remanufactured or factory-new one).

Yep, that’s right. The engine in that airplane costs as much as many cars do, and yet from an efficiency perspective it’s terrible— 470 cubic inches to make only 230 horsepower! (In fairness, the O-470 is capable of more; in the 182 it’s derated to 230hp). By comparison, the Nissan Altima— hardly a supercar— has a 213 cubic-inch engine (well, 3.5L, really) that makes 270hp and can be completely replaced for about five grand. Now, in fairness, the Nissan engine is a much newer design. Maybe a better comparison is the engine from a 1975 Corvette, which made 205hp from 350 cubic inches and weighed about 325lbs. I won’t hazard a guess at the original cost, but overhauling a small-block 350 would cost maybe $1500 in parts today.

Behold the mighty O-470

Newer aircraft of course have somewhat more modern engines. For example, a 2012 Cessna 182 (identical in performance to the 1975 model I normally fly) uses a Lycoming IO-540-AB1A5 engine that still makes 230hp, but features fuel injection and a somewhat more modern design than the O-470. An overhaul for this engine will run you about $24K, while a brand-new one lists for just under $77K. (In 2013, Cessna stopped selling the piston 182 and moved to a new diesel engine, a topic I’ll have more to say about in part 2.) Another example: the Cirrus SR22G5, the latest version of the best-selling piston single, runs a fuel-injected Continental IO-550N that, apart from being fuel-injected, is still just as noisy, heavy, inefficient, and expensive as its predecessors.

Besides the expense, these engines require much more management than you might think. In flight, whether your engine is fuel-injected or carburated, you have to adjust the fuel-air mixture as you change altitude. You must also monitor the cylinder head temperatures (CHTs), and in some aircraft you have to adjust cowl flaps or other cooling devices. When was the last time you had to do that in your car? You don’t; in pretty much every car built since the late 1970s, a computer takes care of adjusting spark timing, mixture, and a number of other parameters to get the best performance or economy from the engine. All you do is press the accelerator. In a piston airplane, that’s a different story (something I’ll also talk more about in part 2).

The reasons for this sad state are many and complex, but the biggest two are easy to describe succinctly: reliability and cost.

Despite the fact that these engines use ancient technology, they are superbly reliable because their basic design is so mature. Engine and airframe manufacturers have 50+ years of data about their behavior, and when the possible consequences of an engine failure escalate from “pull over and call a tow truck” to “fall screaming out of the sky and die in a fireball,” you can see why that reliability is so desirable.

Cost is a multifaceted factor. First, it is exceptionally expensive to certify anything for aviation use. The FAA has a demanding and complex set of rules (known as “part 23”), backed by a fairly arbitrary process, for certifying things such as engines, propellers, and avionics. It’s prohibitively expensive for most new entrants to get a new engine and airframe combination certified. Manufacturers such as Cessna and Piper have little incentive to spend millions of dollars certifying new engine designs for their 50+-year-old airframe designs. Second, these engines are produced in very low volumes by modern manufacturing standards. In a really, really good year, Lycoming or Continental might sell a number of new engines measured in the low thousands (perhaps more, but it’s certainly fewer than 10K units/year). In that volume, it’s hard to see much improvement from scale, and given that these engines are largely hand-built, this is unlikely to change.

I haven’t touched on another drawback, one which really requires its own post: piston engines normally run on leaded fuel. This has several related consequences: economic (it’s more expensive because it’s a lower-volume product), environmental (duh), political (various satraps in California have tried several times to ban or legislate leaded aviation fuel out of existence), and technical. Some engines, such as the ones for the 182, can be made to run on ordinary auto gas (known as mogas), but higher-compression engines in larger airplanes need the lead to prevent pre-detonation, so we’re stuck with it for now.

Like the weather, the state of engine tech in general aviation is often discussed but there is little individual pilots and owners can do about it. Manufacturers, though, have a variety of tricks up their sleeve, which I’ll discuss in part 2.