Monday, September 29, 2008

Marking Time

For pilots who fly frequently and need to log their time accurately, keeping a paper logbook can be a real pain in the fundament. Even if you only fly occasionally and always in the same aircraft, logging time can be important. Especially when you need to generate a Form 8710 for an FAA check ride. I've used an electronic logbook for several years in addition to my hardcopy logbook. I recently found that I'd let my electronic version fall behind by several months. The further it fell behind, the more I dreaded the inevitable hours of drudgery that would be required to bring it up to date. Add to that the fact that there always seem to be arithmetic errors in my paper logbook, no matter how careful I am.

My electronic logbook had fallen behind on previous occasions, which got me to analyzing just why this was the case. I'm a tech-savvy sort of pilot and I use my laptop for a variety of aviation-related tasks, so it wasn't technophobia. Then it hit me. The reason was so obvious: The electronic logbook I was using is a Windows-based application and I'm primarily a Mac user. This meant that I had to first launch my virtual Windows environment on my Macbook before I could enter my times. After getting the application going, I had to deal with Windows-style user interface conventions, which is one of the main reasons I don't use Windows.

I had investigated Mac-based logbook programs in the past. Since I wasn't sure I'd like a new logbook program and I had thousands of hours to enter, I was hesitant to migrate. Two things pushed me over the threshold. One was the realization that my DPE application had expired and I was going to need to tabulate some weird statistics to re-apply. The other was my recent acquisition of an iPhone.

The iPhone has help simplify my life as a flight instructor, especially for the two or three times a week when I commute to the airport on my bicycle. The iPhone lets me access the Mac calendar that I use for my teaching schedule, it provides an email interface as well as a web browser that I can use to access aircraft scheduling sites. And of course I can use it to call Walmart ... er ... I mean Lockheed-Martin Flight Service. And it all syncs up automatically with my Macbook at home, allowing me to leave my Macbook behind and carry a lot less weight on my bike.

I've installed a few apps from the iTunes store and this got me to thinking that someone must have created an aviation logbook app that would sync with a Mac-based application. It didn't take long to discover that such a combination of products already exists in the form of LogTen Pro and LogTen Mobile. But before I committed to the whole shooting match, I wanted to be sure my investment in hours of data entry for my old electronic logbook would not be lost.

I was able to export my old electronic logbook as a comma-separated value (CSV) file. Next I downloaded a trial version of LogTen Pro and began The Great Import Experiment. It took a bit of massaging of the CSV file to get things right (just a few mass search/replace commands in TextEdit) and then I was ready to import. LogTen Pro makes importing data easy by providing a field-driven selection process that allows you to map fields from your CSV file to the LogTen Pro fields. After about 25 minutes of experimenting, it was clear that importing all my old electronic data into LogTen Pro on my MacBook would be successful. So I purchased a license on-line, entered the key I received by email, and I was ready to import my old data.

I spent about 4 hours over the next three or four days entering the data from my paper logbook and correcting some errors I found in the data I had imported. While this sounds like a lot of work, it actually took far less time than entering the information in the old PC-based logbook I had been using. In the process, I became very familiar with LogTen Pro's user interface. Most of what I saw I liked, though I do have a few minor complaints.

One issue was that I specified "Instructor" as my user profile and LogTen made the inconvenient assumption that all my flight time was dual instruction given. That was easy enough to get around as was adding some custom fields that I need to track (hours of instrument and multi-engine instruction given, for example).

There are several features that make LogTen Pro powerful and easy to use. You can configure all the aircraft types that you fly and as an instructor, I fly a bunch. LogTen Pro also remembers each aircraft and has an auto-complete feature that makes it easy to enter registration numbers. Once you've told it what aircraft type is associated with a particular registration number, the aircraft class, category, and type are automatically filled in when you enter a flight. While this might not be as important to folks who fly just one type of aircraft, it's a huge time-saver for me.

You can also print out your logbook in a variety of popular formats, such as the one used by the venerable Jeppesen Professional Pilot Logbook.

If you are a professional pilot, you can enter the time you reported for duty so that LogTen Pro and LogTen Mobile can track your duty limits for the day, week, month, and year. There are too many features to describe here and while you might not need all of them, I've found that LogTen Pro contains all the bells and whistles I need.

After getting my LogTen Pro logbook in order, I was ready to commit to LogTen Mobile on my iPhone. I'll write about my impressions of LogTen Mobile in a separate post. Suffice to say that I've used both products for several weeks with favorable results. I'm able to use those few minutes of idle time throughout the day to enter my flight times and that sure beats forgetting to enter my times electronic form and having to spend hours to get up to date. In fact, I've yet to enter any new flights in my paper logbook. Right now, all my new flights are logged in electronic format. And of course I do back-ups on a regular basis.

If LogTen Pro interests you, just click here to download a trial version or to purchase LogTen Pro.

Sunday, September 21, 2008

No Free Lunch

I'd been wrestling with this post for several weeks, never quite satisfied with the results. Then I happened to read this post. I guess great minds travel in the same rut, but here are my thoughts on the topic.

There's a classic argument that pilots, instructors and examiners engage in about the relationship between pitch, power, airspeed, and altitude when flying a fixed-wing, powered aircraft. There are basically two camps: One says that power always determines altitude and pitch always determines airspeed. The other camp counters that power always determines airspeed and pitch determines altitude. Many pilots, instructors, and examiners tend to be very attached to their pitch/power argument, some to the point of religious fervor. A few months ago I read an article by a respected instructor that again made the claim that one, and only one, explanation was correct. If only life were so simple.

Aircraft pitch (and the resultant angle of attack) plus power equals performance is often all that can be agreed upon. I tread lightly when entering this debate by emphasizing something very uncontroversial.

Pitch and power are intertwined: If you change pitch you'll likely have to adjust power and vice versa.

The reason we can't come up with a universal answer is because a lot depends on the details: Your aircraft's weight, power loading, wing loading, configuration, and phase of flight. Given that most aircraft designs are inherently stable, most of the work that a pilot or flight crew does is manage the aircraft through transistions and changes in equilibrium between the four forces of lift, weight, thrust and drag.

With enough money you can make anything fly, or so the old saw goes. Substitute energy for the word money and the saying is still true. For fixed-wing aircraft, energy is usually (but not always) a combination of chemical energy from an engine generating thrust with a propeller, the potential energy of altitude as well as the aircraft's velocity (airspeed).

Engine power can be increased or decreased within operating limits and the amount of thrust generated will vary with environmental factors.

Lift can be increased by increasing airspeed, but the speed is limited by the amount of power available and the structural limits of the aircraft.

Pitch can be adjusted up or down to control lift, but too much pitch will result in a stall and in some situations may overstress the aircraft.

When deciding whether to adjust power or pitch, I encourage pilots to consider their aircraft's current, total energy picture as well as the safe operating envelope for the airframe and the engine.

There is no free lunch in aviation - except for ground effect, when you buy your flight instructor a burger on a long cross-country flight, and the free cookies and popcorn served at your local FBO. A wing generating lift is also producing drag. Engineers like to describe different two different types of drag - induced and parasite. Induced drag results from the production of lift. Parasite drag is ... well ... a drag - something we have to tolerate. Induced drag is simply the cost of doing business if you want to generate lift.

Flying an approach to landing is a complex energy management task and this is where the pitch-for-airspeed camp and the power-for-airspeed camp tend join the battle with great zeal. Most of the folks who say power-for-airspeed, in my experience, either used to fly pretty large aircraft, are currently flying pretty large aircraft, or are hoping to fly pretty large aircraft in the future. On the other end of the spectrum are pilots who were taught by their primary instructor that the best way to slow a light aircraft during an approach to landing is to increase the aircraft's pitch attitude. While this technique does indeed work (and sometimes is the best way), it's seldom a successful strategy for tracking a glide slope.

I say both camps are right, in a way. Here's why.

When teaching approach to landing in heavier, propeller-driven aircraft (with greater wing and power loading), I encourage pilots to first reduce power and trim to get the aircraft to a speed where landing gear and flaps can be safely extended. If your aircraft has a retractable gear, just extending the gear will create enough drag to start a descent. Adding flaps in some aircraft designs (Cessna singles) causes the aircraft to pitch up while in others (Beechcraft) it causes a pitch down moment, but this effect is usually momentary. In this first phase of the approach to landing, some might say I'm squarely in the "power for airspeed" camp.

Continuing an approach to landing once the gear and some flaps are configured, the goal is to "go down and slow down." Losing altitude and slowing the aircraft's speed are at cross purposes from a total energy standpoint, so what's a pilot to do? This is where some might say I switch sides and encourage pilots to think "configuration, trim, power:" Continue to configure additional flaps for landing, adjust pitch for the desired approach speed, and then adjust power if you need to increase or decrease the rate of descent.

The reason I switch camps is that after you have configured the landing gear and flaps, further power reductions can result in spectacular descent rates in heavier aircraft. This where turbo-prop aircraft can do some amazing approach antics, especially if there are no passengers on board to worry about. With piston engines, making a habit of drastic power adjustments is generally considered to be a bad practice and can reduce the longevity of those engines (something many air traffic controllers don't seem to understand or care about when they vector you to a slam dunk approach). The good news is that once you've done an initial power reduction and landing configuration in a heavier aircraft, you probably won't need reduce the power much to continue to the descent at a manageable airspeed.

The situation is different in most light, fixed-gear, single-engine training aircraft. The wing loading is so low in these aircraft that you may find yourself in a situation where you've configured all the flaps, removed all or most of the power, and you still can't get the desired rate of vertical descent without gaining air speed. This is where increasing the aircraft's pitch to a slower speed or entering a forward slip to landing are the only ways to effect a higher sink rate and control airspeed. These two techniques are the last resort after you have reduced power and configured the aircraft: They should not be the first tools out of the box.

The last thing to keep in mind that it takes time for control inputs, power changes, and configurations to have an effect on an aircraft. Flying an aircraft through a sea of air is different than having tires in contact with the ground where you get prompt changes in speed in response to throttle and brake inputs, so flying an aircraft takes more planning and imagination.

When you reduce an aircraft's pitch to level off from a climb, for example, the aircraft won't accelerate immediately, so the reduction in pitch and power usually can't be immediate. Yet I often see pilots climb to their target altitude and then abruptly pitch the aircraft to a level attitude and reduce power without considering their complete energy picture. The aircraft must first accelerate before the angle of attack can be reduced and it takes power to accelerate. A smooth level-off from a climb requires finesse, attention, patience, and above all, the ability to visualize the equilibrium change the aircraft is undergoing.

Leveling off from a descent with pitch alone will not work if you want to maintain the same air speed you had in the descent, yet I frequently see pilots reach their level off altitude in a descent who simply pitch up without considering the need for power. These pilots pitch up to arrest the descent, airspeed decays, and then they seem baffled a few seconds later when they are having trouble maintaining altitude. Again, the key is energy management, a concept of the aircraft's total energy picture. Finesse, anticipation, and patience are helpful, too.

Airspeed changes in level flight are another problem area and this is one of the few times where judicious use of trim can help maintain altitude while increasing or reducing power. What I often see is pilots whose trim inputs are more appropriate for spinning a roulette wheel or "Wheel of Fortune" than flying an aircraft smoothly. Airspeed won't change immediately, so changing power and then gradually trimming the aircraft is the more efficient technique.

The truth is there is no simple answer to the pitch/power/airspeed/altitude debate. I encourage pilots to be skeptical of simple answers. Rather than basing your flying on simplistic platitudes, why not develop a concept of total energy that will enable you to fly smoothly and to anticipate the need for changes is pitch and power? In the air, anticipation is a more successful strategy than simply reacting with brute force and understanding your total energy picture is far better than any simple rule of thumb.

Tuesday, September 09, 2008

New Jersey Left

My teaching schedule has been a bit hectic lately, hence little time to blog. With two days off in a row, I've found a spare moment to regroup and talk about a topic that recently came up - RNAV direct, off-airway routings when flying under IFR.

A manager I had years ago in the software world introduced me to the concept of the New Jersey Left. Some folks also know this as a Boston Left, too. The concept is basically this: You are on a crowded, two-lane city street, waiting at a red light. The on-coming traffic is being led by one car that needs to make a left turn. There is no room for the cars behind the left-turner to pass on the right. The light turns green and the left-turner, paying attention and gifted with fast reflexes, turns left in front of you and, this is the important part, you let them do so out of consideration to the folks behind the left turner who otherwise would have to wait until the next green light. You are delayed a second or so and that allows several other people to get on with their busy lives. Ah, cooperation! It's a sweet thing when it happens.

The FAA recently announced that pilots who want to be assigned RNAV standard departure procedures (SIDs) or RNAV Standard Terminal Arrivals (STARs) need to file an ICAO flight plan. You see, the current FAA Form 7233-1 flight plan uses a single-letter equipment suffix to describe the type of navigational equipment onboard the aircraft. This overly simplistic simplistic system worked fine back in the 1960's when most aircraft either had a couple of VOR receivers and maybe an Automatic Direction Finder. It still worked in the 70's when distance measuring equipment (DME) became popular as pilots began to realize that being able to immediately discern their distance from a VOR station without doing mental math or using a second VOR was a pretty good thing. The simple equipment suffix continued to work into the 1980's as flight management systems (FMS) became more prevalent. And it still worked in the 1990's as IFR GPS receivers with moving maps became commonplace, even as many old school pilots where complaining "Pshaw, that's just cheating."

In the last few years, the combination of FMS and various flavors of WAAS and non-WAAS GPS has resulted in numerous levels of navigation performance and the matrix became too complicated to develop a kludge for the equipment suffix. Enter the Form 7233-4 ICAO-style flight plan for certain RNAV flights - you can read more here and here.

Now virtually every other country has been using ICAO flight plans for quite some time, which allows the pilot using said form to describe in fairly complete detail just what sorts of knobs, dials, and screens they have on board. In the FAA's defense, they tried to switch everyone to the ICAO flight plan format several years ago. AOPA lobbied strongly against the proposal, saying it was too complicated to get every U.S. pilot to switch. I remember reading that argument and thinking at the time that my BS meter was reading firmly in the yellow, if not in the red.

The good news for many of you out there is that most GA aircraft still won't need to file an ICAO flight plan unless they are equipped to fly (and want to fly) RNAV SIDs or STARs. ATC's computerized system for assigning clearances has been programmed based on well-established operational reasoning and that isn't going to change anytime soon, near as I can tell.

I recently tried experimenting with an ICAO IFR flight plan to see if using it would result in a more direct routing to a nearby airport. After much research on how to get the flight plan filled out correctly, I filed an ICAO flight plane using DUAT. And when my student called clearance delivery, we got exactly the same clearance we always get. And the additional detail supplied in the ICAO flight plan didn't seem to make any difference to the approach controller once we were airborne. Given a vector to join an airway, we had to specifically request to proceed direct to a fix on the airway, thereby reminding (or perhaps informing) the controller that we had en route RNAV capabilities.

Most pilots who fly RNAV-equipped aircraft regularly will learn to request direct-to shortcuts, and you can too. Here are some basic scenarios for requesting direct-to navigation, but remember that the controller may say "unable direct" for a variety of reasons. It still doesn't hurt to ask.

If a controller tells you "fly heading 120, vectors Red Bluff" and you notice that the 120 heading is virtually direct Red Bluff, you can respond with "heading 120 and we can proceed direct Red Bluff now if that's okay." In these situations, I've found controllers are usually quite happy to give you direct-to the fix.

When you are being vectored to join an airway and you want a shortcut that you believe will not pose a traffic problem or a obstacle clearance problem, request direct-to the fix to which you want to proceed. A little caution is in order here. If you specify a fix that is outside the controller's sector, they may say "unable" simply because they don't know where that fix is located. You can sometimes help the controller out by specifying what the on-course heading would be to your desired fix.

If the shortcut you want will take you through busy airspace at an inconvenient altitude when the controller is busy, the answer will most certainly be "unable" and you may as well not ask. My experience has shown me that flying at a higher altitude and in a faster aircraft is more conducive to getting a shortcut than flying at a lower altitude in a slower aircraft.

If you fly the same route frequently, asking for a shortcut will help you learn the controller's constraints. Some controllers will take the time to explain when a shortcut will work and when it won't. Other controllers will just bark at you, so be prepared. But by asking for direct, you remind the controller that you are RNAV capable.

And the next time you read about how NexGen will allow aircraft of the future to route themselves, how VORs are going to be phased out, and how everyone will be able to fly direct to their destination, you can take that with the appropriate amount of sodium chloride. Until then, you can ask for your own shortcuts from ATC and, with a little knowledge and cooperation, you might just get to your destination a bit faster and burn less fuel in the process.