Big Turn, Little Turns, Big Turn

DME arcs can be problematic for infrequent IFR flyers because, like holding patterns, arcs are not that common. A DME arc simply involves flying a circular course around a VOR/DME or VORTAC station (aka the station) at a specified distance, as if the aircraft were attached to the station on a string. Distance Measuring Equipment (DME) onboard the aircraft displays the distance from the station, though an certified GPS receiver can substitute for DME. It's easy to visualize a DME arc if you have a moving map and many late-model GA aircraft with fancy GPS units will fly a DME arc on autopilot while you sit back and watch. Without a moving map, joining an arc and tracking it accurately is more challenging, but it can be an enjoyable challenge. To that end, here are well-tested techniques for flying DME arcs, with or without GPS.

Anatomy of an Arc

The primary protected area around an arc is quite large (4 miles either side), but during a check ride or proficiency check pilots are expected to remain within one mile of the specified arc distance. Approaches incorporating a DME arc will have at least one minimum altitude to maintain, but altitude step-down fixes may be defined at particular radials along the arc.

DME arc Required Obstruction Clearance

Instructors and examiners often use the term right arc for an arc that keeps the station on the right wingtip of the aircraft, or left arc where the station stays on the left. Air traffic controllers usually refer to the general direction from the station where you will fly the arc, such as "arc Southeast." I've see at least one approach chart use the phrase arc clockwise. With calm winds, the station should remain directly off the wingtip. 

Remote, non-radar environments tend to have instrument approaches that use DME arcs because they help air traffic controllers who lack radar to maintain separation between aircraft. I saw a lot of approaches with DME arcs flying in the Caribbean for that very reason. Arcs also allow pilots to fly on their own navigation and get established on an approach course from en route environment. Consider the KLOL VOR/DME-A approach where you could be arriving via the Lovelock 219˚ or 054˚ radial, which happens to correspond to Victor 6.

Get Ready, Get Set ...

From a proficiency standpoint, flying a DME arc demonstrates your ability to plan and maintain orientation. Here are the basic steps.

1. Get established on the correct radial leading to the arc
2. Fly toward the arc
3. Turn approximately 90 degrees onto the arc
4. Maintain orientation as you track the arc
5. Depart the arc on the appropriate radial

More simply, flying a DME arc consists of:

• Big turn
• Several small turns
• One last, big turn

Consider the three basic navigation equipment set-ups found in most GA aircraft:

• Two CDIs (Course Deviation Indicators)
• One HSI (Horizontal Situation Indicator) and one CDI
• One HSI and one RMI (Radio Magnetic Indicator, G1000's call it a bearing pointer)

If you have two separate VOR receivers, set one to navigate to the arc and the other to the fly the radial or course you'll use to exit the arc. Early editions of the FAA's Instrument Flying Handbook cautioned the reader that DME arcs should not be attempted without an RMI/bearing pointer. That wording was removed several years ago.

Tune your DME to the correct station and identify the Morse code id, remembering that these identifiers are broadcast just twice a minute. Beware of DME units that automatically use a frequency tuned on one of your VOR receivers, sometimes called remote channelling, because it's easy to inadvertently get distance information from the wrong station. When possible, consider manually tuning and identify the DME frequency. If you're using an IFR-approved GPS receiver to fly an arc, you have several options covered later.

Fly to the Arc

In the example shown, the aircraft is Southbound, tracking inbound on the CEC 343 radial toward the 11 DME arc. You could set HSI course pointer is set to exit the arc on the I-CEC localizer with the course needle set to 114 degrees and set the #2 CDI is set to fly to navigate around the arc. In this example the aircraft is headed TO the station to join the arc, but other approaches may have you headed FROM the station to join an arc. The first common mistake pilots make is they lose track of the station's position relative to their aircraft. Don't let this happen.

Some folks get all wound up about whether the radial should be at the top or bottom of the CDI. Keep it simple: Set the top of the OBS so it matches the general direction you need to fly to join the arc, in this case 163 degrees. For an HSI, set the course pointer so the arrow generally points in the direction you need to fly.

The Big Turn


Do yourself a big favor and get established accurately on the arc from the get-go. If you blow through the arc by turning early or late, you've made a lot of work for yourself and you're more likely to bust the 1 mile tolerance. It may sound simple, but you need to clearly understand which way you'll be turning initially to join the arc.

Approach charts are oriented North-up and if you're a Track-up person, the chart representation can seem upside-down: There's no shame in rotating your approach chart to a track-up orientation to help you visualize your situation.

With the chart oriented Track-up, it's obvious you want to turn right and keep the station off the left wing. If you're flustered or task-saturated and you simply guess, you have a 50-50 chance of getting it right. You certainly want better odds than 50-50 when flying in the clouds, right?

Many pilots recall a DME arc as being a series of small turns, forgetting that the initial turn onto the arc requires a big turn - roughly a 90 degree turn. You need to turn right, so look at the heading at the three o'clock position of the HSI or CDI. In this case, you'll be turning to a rough heading of 253 degrees. If you have a heading bug, bug that heading.

A 90 degree change in heading at 3 degrees-per-second takes time so you must to lead the arc to account for the distance covered during the big turn. A rule of thumb is to use 5% of your groundspeed as the lead distance. Assuming your ground speed is 120 knots, start turning onto the arc about 0.6 miles before the arc or when the DME reads 11.6 miles. Depending on winds aloft, your groundspeed may differ significantly from your indicated airspeed, so select the groundspeed readout on your DME and pay attention to it. When your DME reads 11.6, make the big turn.

After the big turn, the course pointer points to station

Turn Ten, Twist Ten

Regardless of which way you turn to get on the arc, stay on the arc by making a series of small, strategic changes in heading while adjusting your OBS or HSI to track your progress. Let's say you are using an HSI to fly the arc, twist the OBS so that you just barely have a full-scale needle deflection in the direction you are flying. Not sure which way to twist the course pointer? It's really simple, same side safe:

1. Determine your current heading
2. Locate that heading on the OBS or HSI
3. Twist the OBS or HSI course pointer so the needle deflects on the same side of the CDI as where you found your current heading

Current heading on same side as course deviation bar = Same side safe

Using an RMI/bearing pointer is much simpler: Just adjust your heading to keep the arrow head of the pointer generally aimed at the station.

While you fly the arc, consult your DME to determine your distance and speed relative to the VOR/DME station. By setting the DME unit to ground speed/time-to-station mode, you can strive to see a ground speed (relative to the station) that is below 20 knots or so. That's taxiing speed and you won't get too far off the arc at those speeds.

If you have a heading bug, use it to track your chosen heading and adjust the bug each time you change heading to remain on the arc.

Let's say after joining the arc the DME indicates 11.2 miles. You're outside the arc and need to turn at least 20 degrees toward the station. Don't be afraid to make an aggressive heading change if you are outside the arc. On the other hand, if you joined the arc and the DME indicated 10.5 miles you are slightly inside the arc and that's not a bad place to be. Maintaining the current heading which should eventually take you back onto arc or turn away from the station by just 10 degrees. Wait 5 or 10 seconds and you should see the DME distance increase.

If the DME distance is within 0.1 or 0.2 miles, fly your present heading and wait for the CDI needle to center. Once it does, twist the OBS another 10 degrees, and consider turning the aircraft 10 degrees toward the station. Whether or not you change heading depends on the winds aloft and what the distance readout says.

Stop the Arc, I want to get off ...

To exit the arc on the desired radial or course, you need to make another big turn. Many instrument approaches with DME arcs depict a lead radial to alert you that your exit is approaching. Just like the turn to join the arc, exiting the arc require approximately 90 degrees of heading change.

This bring up the fact that there are four basic DME arc variations:

• Fly TO the station, join the arc, exit the arc flying TO the station.
• Fly TO the station, join the arc, exit the arc flying FROM the station.
• Fly away FROM the station, join the arc, exit the arc flying FROM the station.
• Fly away FROM the station, join the arc, exit the arc flying TO the station.

Additional Challenges

There are many places (the SF Bay Area being one) where there are few published DME arcs. That means a pilot on a check ride or proficiency check may be asked to demonstrate a made-up DME arc with no charted representation. When flying a made-up arc, your examiner or instructor should have specified either a left arc or a right arc, so figure out which way you'll need to turn to keep the station on the left or right side of the aircraft.

A particularly challenging DME arc can be found in the MTN VOR/DME RWY 15 where you arc right to the runway threshold, complying with various step-down fixes as you go. You'd obviously want to fly this arc very accurately. And if you need to fly the missed approach, you get to fly another arc to the missed approach holding waypoint. I've only flown this approach on a simulator, but would welcome the opportunity to try it in a real aircraft.

The Easy Way

If you're using an IFR-approved GPS receiver to fly an arc, here are your options:

• Load the instrument approach defines the arc, specifying the appropriate transition
• Make the VOR/DME station the current waypoint (proceed direct-to)
• G1000 and G530 can display distance to any VOR station that has been tuned

The obvious choice with most late-model GPS receivers is to load the approach with the appropriate arc transisition and let the GPS guide you.

Practice Makes Perfect

The best way to maintain proficiency with DME arcs is to practice in a simulator or in a real aircraft. Like a good crosswind landing, there's a satisfying feeling to flying a good DME arc. Try it, you'll like it.

iPad EFB Gotchas

Pilots everywhere have been using iPads as Electronic Flight Bags for over a year now in all kinds of aircraft and some ... umm ... interesting incidents are starting to be reported. The iPad, combined with one of several EFB software packages, is a very useful device. But perfect it ain't. Here are a few common iPad gotchas and ways to avoid them.

Out-of-Date/Missing Charts

You haven't flown in a few weeks, so you make plans to get airborne, head out to the airport, but the weather isn't cooperating. You are IFR current so you launch your favorite EFB app to prepare an IFR flight plan only to learn your charts have expired. This happens more often than you might imagine, especially for infrequent flyers. If you have internet access, go ahead and start the update but expect a delay. If you don't have 'net access or if the access is really slow, you could be inconvenienced in a big way.

Solution? Do a dry run a day or two before you plan to go flying: Launch your EFB app and ensure your chart data is up-to-date. You can also keep track of the chart expiration dates in your electronic or paper calendar as a reminder so you aren't blindsided.

GPS Reception

If you purchased a 3G iPad and rely on its built-in GPS, you may find in some circumstances GPS satellite lock can be lost. Depending on the aircraft you fly and satellite coverage at a particular point in time, you may be fine or you may not. Of course you shouldn't be relying on your iPad for anything other than situational awareness, but losing GPS coverage can be seriously distracting at a high-workload moment.

Solution? Trying to keep your iPad from being shadowed by aircraft structures may help, but there are only so many ways you can hold your iPad in flight and still have it be usable. Another solution is to use an external, bluetooth GPS such the GNS 5870 MFI GPS Receiver or the newer Dual XGPS150 Bluetooth GPS Receiver  that comes with it's own rubber mat for laying on the glare shield. If you prefer a plug-in solution, the Bad Elf GPS Receiver  could be just the ticket.

Bluetooth Blues

Another distraction is discovering that your bluetooth GPS receiver is not connected to your iPad. I see this fairly regularly since upgrading to iOS 5.0.1, but futzing around with bluetooth settings isn't something you want to try while hand-flying in IMC.

Solution? I find going into the iPad settings, turning off bluetooth and then turning it back on to be the most reliable way to reestablish the connection. If you are using a bluetooth GPS receiver, make sure it is communicating properly with your iPad before you takeoff.

All EFBs are Equal?

Flying through the LA Basin is a heck of a time to discover that your chart app doesn't have a graphic depiction of the VFR transition that Socal is asking you to fly. If you're using ForeFlight and you don't have a back-up paper VFR terminal area chart (TAC), this could happen to you.

Solution? For one, Skycharts Pro does include the VFR TAC marginalia as well as the fly charts from the back of the TAC. If you haven't purchased that app then you may want to invest in a paper TAC or print out the necessary information from a site like SkyVector.

Hold Your Cards

If you own a 3G iPad and you rely on the built-in GPS, be advised that if the SIM card rattles loose you'll see a "no sim" alert and you'l loose GPS, too.

Solution? Reseating the sim card usually fixes this issue, but you might want to consider an external bluetooth or plug-in GPS as a back-up.

App Crash

Most iPad apps seem to be pretty stable, but having your EFB app crash at an inopportune time can be a real drag, especially during an instrument approach. Witnessing this happen to an instrument student of mine was an eye-opener. He not only had to re-launch the app and wait for it to initialize, he had to navigate back to the approach chart he was using.

Solution? There's no way to completely immunize yourself from app crashes, but there are a few preventative things you can do. Some folks feel it is a good idea to shutdown and restart your iPad every few days. Same goes for syncing your iPad on a regular basis. Next, become familiar with your EFB app's user interface while sitting in your living room in a nice comfy chair. If your EFB app allows you to mark favorite approaches or create binders of approaches for a trip, by all means use these features. Anything that helps you better organize charts will also help you locate those charts more quickly if you have to re-launch and start over.

Overheating

In hot weather it is possible for an iPad to overheat since the device is cooled solely by conduction. When this happens, the iPad shuts down until it cools off. You can't control the weather, but there are a few things you can do.

Solution? Put your iPad to sleep when you aren't using the display. Keep the iPad out of direct sunlight. During refueling stops, don't leave your iPad in the sun. Avoid folio cases that completely enclose the iPad and cases that are dark in color since they trap and absorb heat. If your iPad does overheat, get it out of the sun, direct a fresh air vent toward it, and wait.

Getting Juiced

The iPad has outstanding battery life, but the battery might not last very long if you forget to charge your iPad the night before you fly. The same problem can happen with external bluetooth GPS receivers, especially the GNS 5870 since its capacitive-touch power switch makes it all too easy to turn on accidentally.

Solution? Invest in a USB charger solely for use in the aircraft. Some adapters take a long time to re-charge the iPad, but at least they'll power the iPad and keep the battery from draining further. Turning the brightness down can also reduce the iPad's energy consumption.

What's Your Problem?

Had an interesting iPad technology moment? Post a comment and let others learn from your experience.

Diversion, Conversion

Cruising along at 5,500 feet, en route to the Columbia airport, my student had good reason to believe he’d never get there. Sure enough, in preparation for his upcoming private pilot check ride, I asked him divert to another airport. He began circling over a chosen landmark, produced a VFR chart, drew a course line, estimated the heading, distance, time, and fuel required to the new airport, all the while maintaing altitude and looking for traffic. His juggling of these priorities was impressive, but he soon discovered that his chart had been folded so many times that the frequencies for the new destination airport had been rendered illegible. Flustered, he scrambled to locate his Airport/Facility Directory while I kept an eye out for traffic and mused about how many times a day pilots must now be asking their instructors “Is it okay for me to use my iPad?”

I’ve logged nearly 1200 hours since my first flight with the iPad 1 and frankly, I’ve never looked back. When I was still searching for the ideal EFB back in 2009, I explained how the FAA doesn’t require any certification or qualification for EFBs under most Part 91 operations. Just recently, the FAA’s own Safety Briefing publication had yet another article making the same observations. Given that pilots are adopting EFBs faster than you can say “decommissioned NDB,” it’s time for instructors to start making EFBs part of the training they offer as well as part of their own training. I tell student pilots I train “Go ahead and use an iPad if you want, but be prepared with a credible back-up strategy in case your iPad fails or your instructor decides to simulate a failure.”


Before you start gnashing your teeth, complaining about newfangled gadgets, and pining for the good old days of slide rules, cigarettes smoking in the cockpit, and navigating via A-N Range, consider that combining old techniques with new approaches can actually aid in teaching pilots to that elusive correlative level of knowledge. The key concept here is combining approaches, not rejecting one in favor of the other. Here’s an overview of the old school approach, followed by some mash-ups of familiar approaches with new tools and software.

Old School Planning

The first half dozen times through the cross-country flight planning process, I like student pilots to do navigation calculations manually so they’ll understand and appreciate what their EFB or flight planning software will eventually be doing for them. My favorite nav log form is available for free from Dauntless-Software. The two basic variations in nav logs involve whether the True Course (TC) is first corrected for magnetic variation or for the wind correction angle.

ATC uses and refers to magnetic directions, so I say cut to the chase and go magnetic. Winds aloft forecasts are provided with true directions, so you'll need to account for that if you choose the TC-VAR-MC-WCA-MH format.

Virtually all nav logs end up with a Compass Heading (CH), to which I say “Who cares?” If you always set your aircraft's heading indicator using the compass correction card, calculating a CH is simply gilding the lily. If your aircraft doesn't have a heading indicator, then by all means compute the CH until such time as you manage to catch up with the later half of 20th century aviation technology.

I teach students to complete a paper nav log in this general sequence.

1. Calculate climb performance and ground speed
2. Determine the location of the Top-of-Climb (TOC)
3. Calculate cruise performance and ground speed
4. Determine the location of the Time-of-Descent (TOD).
5. Divide the course between the TOC and TOD into legs of equal length.

Aircraft consume more fuel and have a slower ground speed during the climb to altitude, so calculating where you'll reach the top-of-climb (TOC) is important. And if you want to avoid arriving high and hot, the time-of-descent is something you’ll want to plan for. Want to use an electronic E6B instead of a slide rule to do these calculations? Fine by me.

With TOC and TOD marked on your chart, try dividing the remaining course into legs of equal length. Sometimes this works, sometimes there aren’t good landmarks. If defining equal leg distances does work, you only need to calculate time, fuel, and distance for one leg to have the numbers for the other legs. Choosing landmarks on a paper chart is the ultimate in flexibility: You can choose whatever you want. With an EFB or internet-based planner, waypoints selection is as simple.

High-Tech Planning

The sad fact is we're well into the second millennium and there aren’t many computerized flight planners that account for the time- or fuel-to-climb. A few internet-based planners that do (to varying degrees) include DUAT (not to be confused with DUATS), AOPA’s Flight Planner, and FlightAware.

Once you’ve entered a profile for your aircraft, the DUAT flight planner will provide the location TOC and TOD in latitude/longitude format. Not terribly handy, but it also provides a magnetic course and distance which does turn out to be useful. More on that later.

The browser-based flight planners from AOPA and FlightAware both account for fuel consumed in the climb and descent, but they don’t tell you where TOC and TOD are located. Bummer about that.

FlightAware’s planner adds some value by including the estimated fuel costs for various altitudes, winds aloft forecast, and routes. In this example you can see that you’d only save a few bucks by climbing to 11,000 feet versus 9,000 feet. To access FlightAware’s flight planning features, you’ll need to set up an account. Don’t worry, it’s a free and simple process. Be advised that FlightAware’s planner doesn’t work completely on the iPad browsers I’ve tried.

So what about specifying waypoints that aren’t pre-defined objects like airports, VORs or airway intersections? Most planners allow you to enter your own waypoints as Lat/Long coordinates or as a VOR-radial-distance. That’s not terribly user-friendly, but it works.
You can add custom checkpoints in ForeFlight’s map view by tapping on the map view. A dialog will appear allowing you to add the location as a user-defined coordinate. If you tap on your course line, it’s easy to inadvertently change the course slightly and you won’t know the leg distance until you’ve tapped, but there you go.

If you know the lat/long for a waypoint, you can enter that into a ForeFlight route. Below, the lat/long that DUAT calculated for TOC has been entered as a TOC waypoint.

If you know the distance and radial from a VOR, you can enter a waypoint in ForeFlight using theta/rho format: VOR_id/radial/distance. This approach also works with airport identifiers. Below, I’ve taken the TOC and TOD data from the DUAT flight planner output and entered them as waypoints in the format KOAK/133/16 and KSBA/315/29.

Nav Log in Action

Using a paper nav log in flight starts with recording your departure time. For short trips, just record the two-digit minutes after the hour. Then to calculate estimated time of arrival (ETA) for the next checkpoint, add the time your off time to the estimated time en route (ETE) for the first checkpoint. When you reach the checkpoint, record the actual time of arrival (ATA), add that to the next ETE and you have the ETA for the next checkpoint. If your ETA calculations consistently differ from the ATA, consider doing an winds aloft and TAS calculation.

ForeFlight kinda-sorta follows the paper nav log tradition, but the assumption is that ForeFlight will use GPS information to calculate your estimated time en route for each leg in real-time based on your current ground speed. I find ForeFlight’s nav log display a bit cumbersome and difficult to read in flight, but that could be due to my 50-something eyesight. If you want a historical record, why not combine a paper nav log with your EFB?

Electronic Diversion

Planning an in-flight diversion with an app like ForeFlight is the height of simplicity.

1. Tap and hold on the airport to which you wish to divert
2. A dialog will appear showing the known waypoints in the area
3. Tap on the orange D-> button for the selection you 

EFBs can provide real-time calculation of the desired track, ETE, and fuel consumed, but you can do the same sort of thing with many panel mounted GPS. Electronic diversions are so easy and with no plotter, pencil and calculator to juggle, it's no wonder some pilots feel they are cheating. Hand-calculated diversions can be just as dangerous as fixating on pretty colors on a moving map. Having a quick way to calculate a diversion in real life gives you more time to look outside for traffic and manage whatever emergency or urgent situation you're facing. That seems like a good thing, not the work of the devil.

Combine and Conquer

Whether it be in paper format, electronic format, or a combination of the two, preparing and using a nav log in flight can be a curiously satisfying experience. Teaching student pilots the old ways is still a valuable part of the aviation education equation, but introducing and integrating new tools doesn't need to detract from the experience. High tech solutions can enhance accuracy and safety. As with anything in aviation, understanding the limitations of technology is a more productive approach that rejecting new techniques out-of-hand. To my mind, if a pilot can learn the basics and then combine old school and way cool, that strikes at the heart of the vaunted correlative level of knowledge.

Is Cross-Country Flight Planning Passé?

The widespread availability of sophisticated GPS receivers, digitized aviation charts, and internet-based weather information is changing the way student pilots are learning cross-country flight planning. The introduction of new technology and techniques always raises questions: Should student pilots be taught to use paper charts, plotter, pencil, and a slide rule E6B or encouraged to switch entirely to electronic charts, calculators, GPS and computer-based weather briefings? Don’t throw out that plotter and slide rule just yet because the best approach to learning the complicated process of cross-country flight planning involves combining old school with waay cool. Here’s the first installment of a multi-part series on the revolution in VFR cross-country flight planning, written with student pilots and their instructors in mind.

Drawing the Line

One of the first steps in cross-country flight planning is to get a rough idea about the general direction and the distance involved. With a current paper chart, just plop your plotter down and draw a course line between your departure and destination airports with a pencil. Sounds easy enough until you need to plan a route that begins on one side of the chart and continues on the other side, which actually provides a good scenario for comparing paper and digital charts.

FAA VFR charts include instructions for extending a course line from one side of a chart to the other using a pencil and a spare sheet of paper, but it's a Catch 22: You determine the magnetic course by drawing a line between the two points, but you can’t draw the course line because the points are on opposite sides of the chart.

One solution is to purchase a World Aeronautical Chart (WAC), which covers a larger geographic area at a scale of 1 to 1,000,000 as opposed to the sectional chart scale of 1 to 500,000. Good luck finding a WAC anywhere but on-line. One could purchase two versions of the same sectional and piece them together, being careful to account for the 2 minutes of longitudinal overlap on each side. You could cut the Gordian Knot by using Victor airways or choosing a landmark that appears within the overlap on each side of the chart. Or you could use your current chart and an expired chart that you just happened to have saved, just don’t mix them up!

Or simply combine paper with plastic: Use a handheld GPS or any of a variety of web sites to determine the magnetic course between the two airports, then use your pencil and plotter to replicate that course. Which approach is best? That's really up to the pilot. The goal in teaching student pilots is not to preserve hallowed aviation traditions for their own sake. Whether a student is using paper or plastic or a combination of the two, the goal is for them to understand what they're doing and why they're doing it. Using a combinational approach with old and new products may actually end up teaching the student to a correlative level of knowledge.

Digitized charts provide a big, mostly seamless chart and you'd think that would make plotting a course line on a digitized chart easier, but plotting a digital course line can be less flexible and more abstract than doing it by hand with pencil and paper. EFB apps like Skycharts Pro and ForeFlight Mobile as well as online planners like FltPlan or FlightAware will draw a course line representation, but your choice of waypoints may be limited to the VFR reporting points, intersections, navigation aids, and airports contained in the application’s navigation database. Some products allow you to define your own waypoints using lat/long, but that's not terribly convenient.

VFR Sectional and Course line using FltPlan.com

Doing the Coursework

With the course drawn on a paper chart, you use your plotter to measure the true course, locate the nearest isogonic line and apply the magnetic variation shown (subtract Easterly variations, add Westerly variations) to determine the magnetic course. If your destination or departure airport has a VOR on the field, get the magnetic course from the compass rose surrounding that VOR. Either way, with a bit of care and attention will provide the magnetic course on a paper chart within ±1˚, though simple arithmetic errors can result if you’re in a rush.

Old school pilots and instructors rightly claim that never drawing a course line on a paper chart can rob student pilots of an important learning experience about Magnetic declination. Yet with the right input data, computers tend to do a faster and more accurate job with arithmetic and geometry than humans: Waypoints entered, the digital course line drawn, determining the magnetic course is a foregone conclusion. A good approach for student pilots is to plan first on paper, then check your results using a digital source.

Go the Distance

Plotters offer a variety of scales and if you mistakenly measure using the wrong scale ... you won’t be the first pilot to do so. So look carefully, choose the correct scale for your chart and line up the correct marks.

Getting the distance on a digitized chart is a forgone conclusion, but errors are still possible. You can enter the wrong waypoint or misspell the waypoint. One tipoff is a digital course line that makes a sudden, severe turn off the edge of the map you're viewing.

If the digital product you are using provides recently assigned ATC routes, remember that these are instrument flight rules (IFR) clearances and these routes may involve altitude requirements that are beyond capability of the average GA aircraft. If you will be flying IFR, remember that there may not be any recently assigned ATC routes for the departure and destination airport that you have chosen.

Some EFB apps are better than others at drawing a course line that is visible, yet doesn't obscure important information.

FFM course line obscures airway radial

SCP course line is more ... subtle

Overcoming Obstacles

With a preliminary course line drawn, consider the appropriate altitudes one could fly. You'd think that pilots would know and apply the hemispheric rule, but it's surprising how many pilots (intentionally or unintentionally) fly WAFDOF (wrong altitude for direction of flight).  Whether you remember "Odd birds fly East" or simply refer to the diagram etched into many kneeboards, do other pilots a favor: Fly the correct altitude for your magnetic course.

Minimum elevation figures are shown on VFR charts and these provide the lowest altitude that will clear the highest charted obstacle within a specific quadrangle by 300 to 400 feet. Depending on how close your route is to that highest obstruction, flying at or just above that altitude may be the safe thing to do or it may be hopelessly foolhardy. I don't know of any app that will make the assessment of a safe altitude for you: You're going to have to use your little gray cells.

Whether you are using paper or digital charts, a nifty course line that goes to your destination won't necessarily keep you clear of special use airspace. One cool feature in SkyCharts Pro is the ability to get information on special use airspace by tapping. Locate the red circle next to an MOA, prohibited, or restricted area and tap twice to get the effective times, altitudes and the frequency of the controlling agency.

ForeFlight offers a similar feature, but it requires more taps to get the same information. ForeFlight does offer a quick way to create or change course lines by tapping and dragging.

Acquire, Combine, Conquer

Paper chart adherents often claim that paper is foolproof because paper charts don’t require batteries, they can be folded and handled, and are less intimidating to pilots who may be less computer savvy. True, but paper charts have some serious disadvantages: They can be torn, damaged, lost, or hopelessly riddled with marks from previous flight planning efforts. Last, but not least, all paper charts eventually expire and become obsolete.

Even before the FAA changed the structure for chart retailers, it was often difficult to get a paper chart unless you planned ahead. With a reduced number of chart retailers, your odds of acquiring a current paper chart at the last minute from a local retailer is tantamount to winning the lottery. A chart subscription is obviously the best bet, but that’s not much help if you’re away from home on a longer trip, need an oddball chart, or you lost your chart a week before it was set to expire.

The chart retailers who remain have to deal with unsold, expired paper charts. Charts have to be printed and physically shipped which adds to the cost and carbon-loading. Old school pilots are familiar with the various paper chart subscription services available through Aeronav or a variety of on-line retailers, but they may not be up-to-speed on the various options for digital charts.

Digitized charts, whether viewed on-line or on an iPad, tablet, laptop or desktop computer can be acquired at a lower cost (some are available on-line for free), they are easy to update, and they can cover large geographic areas without folding, flipping, or ripping. There’s no physical shipping required and no paper to recycle. The disadvantages of electronic charts basically boil down to all the possible failures to which electronic devices are heir to, including screen readability in bright light, software/hardware failures, and drained batteries. There are also some problems with how digitized charts are stitched together, but that really just reflects the limitations with how the FAA generates the charts. Hopefully that process will continue to be modernized and soon we'll see seamless VFR and IFR charts become a reality.

FAA VFR charts can be downloaded to your computer as raster files for free, and a simple, free, and platform-independent solution for viewing them is Google Earth. Follow the instructions in this WikiHowTo  and overlay sectionals and terminal area charts in Google Earth. While this approach has limitations, it does offer pilots the ability to view charts for large geographic areas at little or no cost. You can even do some rudimentary flight planning activities, like determining the course and distance between airports.

Several products are available for the iPad that allow you to access VFR charts, including ForeFlight and Skycharts. The cost of these products varies from $20 per year to $80 per year or more. Like all cockpit resource management issues, one size does not fit all. Both of these apps allow you to create flight plans that will draw course lines on the digital charts and give you magnetic courses, but old school paper chart planning provides more flexibility and, dare I say it, precision.

If you are a Mac user, MacGPS Pro provides another option for importing FAA raster charts. MacGPS Pro lets you define user waypoints, integrate with an external GPS receiver, and measure distances and courses. Similar solutions probably exist for the Windows world, but not being a Windows user, well ...

Paper and Plastic

After a student pilot has been through the flight planning process a half dozen times using paper charts, it's not clear that any more learning is likely to take place by restricting them to old school planning. While I do believe that a students' primary experience should involve pencil, plotter, and paper chart, that doesn't mean they should be discouraged from branching out to the high-tech solutions once they understand flight planning basics. Looking at the strengths and weaknesses of paper and digitized charts it’s easy to conclude that the best approach is to understand and use both. Having a paper back-up strategy in flight is the prudent advice offered by the FAA’s AC on Electronic Flight Bags.

Some pilots may still resist using digitized charts for the understandable reason that they simply prefer holding a chart in their hands. Nothing wrong with that, but charting and flight planning is changing. Time waits for no one, not even old school pilots, so don't be afraid to explore and experiment.

In future installments, I'll discuss how technology is changing calculators, navigation log preparation, and in-flight diversions.

Can LightSquared 4G and GPS Coexist?

There's a common line of thinking among some folks in the aviation community that the federal government doesn't restrict cellphone use in an airborne aircraft, that cellular telephones do not interfere with radio navigation, and that it's fine to use a cellphone or have it powered on in flight. The usual reasoning I hear from pilots who leave their cellphones on or use them in flight is that since they've never seen any problems, no such problems exist. The fact is that we are surrounded by an ever-growing sea of radio frequencies and detecting interference requires a more rigorous approach than casual observations made by individuals. If you need more convincing that radio frequency (RF) interference can be serious, look no further than the proposed LightSquared 4G broadband network and the impact it may have on GPS users.

Never Seen a Leprechaun

It's understandable how some pilot's come to the conclusion that cellphone use is okay in an airborne aircraft since the relevant aviation regulation, 14 CFR 91.21, appears to permit cellphone use if the operator or pilot-in-command has determined there's no interference or if the flight is conducted under visual flight rules. The regulation provides no guidance on how one is to test for interference and that could lead one to conclude that the FAA doesn't care if you use your cellphone in flight. Consult the portion of the Code of Federal Regulations that deals with the FCC to find the regulation, 47 CFR 22.925, that clearly and specifically forbids the use of cellular telephones in flight. The FAA may not care, but the FCC clearly does care.

The common follow-up argument is that the FCC ban is out-of-date and that there's absolutely no problem with leaving your cellphone on or using it in flight. Folks who make this assertion usually do so based on their personal experience in their own aircraft. An important element in this line of thinking is a strong desire to do what is convenient, not so much on any rigorous measurements of radio frequency (RF) interference. While I haven't made any specific measurements with sophisticated equipment, I have noticed several basic types of cellphone interference in aircraft.

In one aircraft I occasionally fly, one of the two VOR receivers will show a 15 degree error at a ground VOR checkpoint whenever an iPhone 4 is turned on and placed in the console directly below the radio stack. Put the iPhone 4 in airplane mode and the VOR error goes away.

I've also demonstrated interference between cellphones and my portable Zaon PCAS MRX traffic detector that manifests as false traffic alerts. It took me a while to correlate this, but on several occasions the Zaon MRX gave continuous traffic alerts for an aircraft within a mile and at the same altitude. Asking ATC if they saw any traffic in my area always resulted in the same response: "Negative." On one such occasion, we heard the unmistakable sound of cellphone data transmissions over the intercom (dit-da-dit-dit-dit-dit-dit ...). When we located the offending cellphone and put it into airplane mode, the intercom interference went away and so did the phantom aircraft that the Zaon MRX had said was within 0.3 miles and at the same altitude.

Just because you've never seen a leprechaun, that doesn't mean they don't exist.

4G vs GPS

While I've never been able to correlate cellphone interference with GPS receivers, at least one next generation 4G network system appears to pose a widespread threat to GPS accuracy. The FAA has been issuing NOTAMs over the past several months warning of potential GPS unreliability related to the testing of new 4G network equipment created by LightSquared.

In January of this year, the FCC issued a waiver to LightSquared allowing them to move forward with plans to deploy transmitters that uses the L band 1 spectrum to provide a high-power terrestrial broadband service. While this could be great news for people in remote areas that want high-speed data transfer on their mobile device, GPS experts and users are concerned. The 1525 MHz-1559 Mhz band is very close to the 1575.42 Mhz band used by GPS.

Recent tests of LightSquared's 4G equipment has inconvenienced many users of GPS. On one occasion, I was unable to get a clearance to fly an RNAV approach because the NOTAM prevented ATC from allowing such approaches during the testing. Imagine aerial survey companies who rely on WAAS GPS to do their mapping or ships that rely on GPS for maritime navigation. Aside from acquiring the necessary equipment and databases, GPS is provided without charge. The LightSquared 4G product will undoubtedly be a commercial product and user's will understandably have to pay for data access. Whether it's the profit motive or a large number of lobbyists, the implementation of LightSquared's network is continuing at a rapid rate.

Hope you like Jammin' Too

Testing done by Garmin showed that an automotive nuvi 265W GPS receiver was jammed when within a 3 to 4 mile distance of a LightSquared transmitter. Garmin's aviation GPS receiver tests were even more sobering with jamming of a 430W occurring within 9 to 13 miles of a LightSquared transmitter and a total loss of position occurring within 5.6 miles.

The waiver granted to LightSquared by the FCC requires that a working group identify and reconcile conflicts between 4G and GPS, but the onus appears to be on the GPS community, not LightSquared:

Because the GPS interference concerns stem from LightSquared’s transmissions in its authorized spectrum rather than transmissions in the GPS band, the Commission expects full participation by the GPS industry in the working group and expects the GPS industry to work expeditiously and in good faith with LightSquared to ameliorate the interference concerns.

The FAA has gone to considerable lengths over the past several years to create RNAV approaches with vertical guidance and to expand the WAAS service volume. With the number of LPV approaches outnumbering the number of ILS approaches, the potential conflict between GPS users and companies that want to provide satellite-based broadband is very, very serious. For my money, it's more important to have accurate RNAV than to be able to update my Facebook page while hiking the John Muir Trail.

LightSquared reportedly wants to install up to 40,000 high-power transmitters operating at up to 15,000 watts (42 dB). So the latest threat to the integrity of GPS isn't solar flares or aging satellites, it's wireless broadband. Until this gets resolved, be sure to check those NOTAMs. And if you haven't practiced navigating with VORs lately, you might want to dust off those skills.

Sound of Ten Thousand "D'ohs!"

NORCAL: Cessna 123, verify you're direct ALTAM at this time?
Cessna 123: Not yet, we're still wrestling with our GPS ...

Never shy to point out the shortcomings in Garmin's 430/530/G1000 user interfaces, I'll admit I'm all excited to see the announcement of the GTN 650 (MSRP $11,495) and GTN 750 (MSRP $16,995) products. The 430/530/G1000 were, in a sense, a victim of their own success. So many units were sold that the user interface, as bad as it was, became something of a standard. Not unlike Microsoft Word, many of us got used to the dance of cursor-mode-big-knob-little-knob-enter and tended to forget how bad the user interface (UI) really was. To their credit, Garmin has done the sensible thing: Confronted with a bad UI that suffers from the Tyranny of the Installed Base, they started over from scratch with a touch-screen interface. While I've yet to actually handle one of these units, a lot can be gleaned from the videos that have been released and the information at Garmin's website.

Same Market, New Interface

The GTN 750 and 650 clearly target the aging GNS 530W and 430W, both in size and features. The new units provide the same basic stuff for aircraft owners and operators who want to freshen up their panels: Communication transceiver along with a WAAS GPS and VOR receiver as well as a moving map with some additional features.

Both units can provide an interface to remotely control a Garmin GTX mode C or mode S transponder. The GTN 750 can also control a remote audio panel. These interfaces to remote devices have the advantage of reducing the panel footprint, but the downside is that they can increase the complexity of the user interface. When a GTN unit becomes the single lens through which you access other important functions, the advantage of a smaller panel footprint doesn't look quite as attractive.

Why a different keypad? Why not one style of keypad with the 8 & 9 disabled for transponder use?

Out with the Old

A recurring problem with avionics designs is that, in an effort to reduce production costs, manufacturers are motivated to limit the number of buttons and knobs. With fewer knob and buttons, the UI designers must overload the function of those knobs and buttons: Depending on the state of the device (which is not always obvious), a knob or button will do different things. Overloading creates user interface complexity because the user must be cognizant of the device's state (which is not always obvious). One only has to witness a 100 different pilots experience the same UI frustration at high workload moments to know that overloading and convoluted, deep menu structures are B A D.

Manufacturers next tried to overcome the shortcomings in overloading by using softkeys - physical buttons whose displayed function changed depending on state of the device. The success of this was limited in the G1000, as an example, because different modes take control of different softkeys and the precedence is seldom clear. Try adjusting the flight plan on the MFD while the other pilot is using the lean-assist function and you'll get the feeling that there were different groups of programmers working on the different G1000 areas: They don't seem to have worked that closely with one another.

No Place like HOME


At the center of the new GTN units is a capacitive, touch-sensitive screen. There are just two knobs, two physical buttons, and an SD card slot (presumably for terrain and aviation databases). Grip points are provided on the sides and bottom of each unit so you can steady your hand in turbulence. And there are suggestions (but no details yet) on voice control features in the future, but for now the UI flexibility comes from having a touch-screen.

Both units clearly display the com and nav frequencies at the top of the screen. The active frequencies are at the top with the standby frequencies underneath. From the demonstrations it appears you swap the active and standby frequencies by tapping on the active frequency, which seems a bit counter-intuitive. Tapping on either standby frequency causes a pop-up a keypad to appear in the middle of the screen and you just tap in the new frequency. I hope there's an option for eliminating having to enter the leading "1" since all VHF nav and com frequencies are in the 1##.### range.

Different number keypad than for the transponder. Why?

The HOME button allows you to return to the main screen which is the starting point for a refreshingly simple and relatively flat menu structure. Unlike the subtle context indications in the 430/530/G1000, the HOME screen gives you a clear idea of the top level of functions. To access a function, just tap on the icon.


A dedicated Direct-To button is provided and this is a really, really good design choice because pilots, depending on your perspective, become creatures of habit or slaves to their devices.  In a high workload moment, there are few things worse than having an important button buried in a row of not-so-important buttons.

The knob in the upper left corner adjusts the volume and squelch for the com radio while the knob at the bottom allows you to change either the Nav or Com frequency. This a shame because the location of the bottom knob violates a basic UI concept: Whenever possible, physical knobs and buttons should be located directly adjacent to the display item they affect. If you need proof, witness someone trying to adjust the barometric pressure setting on a G1000 at a high workload moment.

Having a physical frequency selection knob means there are multiple ways to change frequencies. Alternate ways to accomplish the same task isn't necessarily bad, but it is something that earlier Garmin interfaces suffered from because some of the methods were Easter Eggs. Examples in Garmin's older interface designs? Pressing Direct-To once provides one feature while pressing it twice provides another feature. Or being transported into a hidden set of options when turning the small knob counter-clockwise (instead of clockwise) while in insert mode. If describing a user interface in words is this complicated, something in the design isn't right.

At the bottom of the screen are some icons for displaying system messages as well as a relatively small status line that tells you the GPS course sensitivity as well as which NAV source (GPS or VOR) is being displayed on the CDI or HSI.

Map View

The map view is similar to what we've become used to with the G1000 and one suspects it will offer similar options for North- or Track-Up, a compass rose ring around the aircraft, a fuel endurance ring. In one of the demonstration videos, the refresh rate of the map looked a bit slow. Not sure if this was an issue of the screen refresh rate interacting with the video camera's sampling rate or a limitation of the GTN's processor speed. I hope it's the former and not the latter.

Terrain, Traffic, Weather, Music, Intercom

The terrain features look pretty nice. And with the appropriate remote hardware installed, both units give you access to traffic and XM weather. Presumably TIS traffic data is available from a mode S transponder (for as long as the FAA radar sites continue to support it), from a dedicated transponder-based TAS system, or from the much vaunted (but yet-to-be-widespread) ADS-B facility that NextGen is supposed to have. If you choose the XM subscription that includes entertainment radio, you can access that, too.

One of the shortcomings of using the GTN 750 to provide an audio panel or other interface is that you lose the moving map when you access one of these features. The simple act of adjusting the pilot or co-pilot intercom volume will temporarily hide other features, like the moving map display with traffic, weather, or terrain data. It also appears to be a single point of failure: Lose the touch screen and you'll be hard pressed to change your transponder code, adjust your intercom volume, and so on.

One assumes that if there's an imminent traffic or terrain threat, that display will override any trivial function you might be performing. Hard to say without actually handling one of these units in flight.

Terminal Procedures and Taxiway Diagrams

Aeronav and Jeppesen charts can be displayed on the GTN 750, but the size is pretty small and requires scrolling around. Geo-referencing is offered, though the subscription costs tend to be high and much more cost-effective options are available on the iPad or other off-the-shelf consumer devices.

Crux of the Matter

With all GPS designs, the ease with which one can enter and modify a flight plan is what makes or breaks a user interface design. While there are many pilots out there who just fly VFR and only use Direct-To, there are IFR pilots who'll need to enter a sequence of waypoints that match the clearance they just got from ATC.

Assuming you have a steady flight path, the GTN 750 lets you enter waypoints into your flight plan by simply tapping on their representation on the moving map. You can also enter waypoint using a pop-up keypad. No more singing the alphabet as you scroll through adding a waypoint with the big-knob-small-knob interface. Last but not least, you can drag an existing flight plan course line on the map to add a new waypoint to the flight plan. I'll have to use this in person before I can say whether it rocks or is just more usable than the old big-knob-little-knob interface, but these flight plan features alone may be worth the price of admission.

With the GTN 650's small screen, there's an odd kludgey selection process. Bummer about that ...

Grace Under Pressure?

My initial research hasn't turned up any examples of  loading procedures and I'm particularly curious to see if the vectors-to-final behavior has been improved.

Simulator, Please!

One of the really smart things that Garmin did with the 430/530 was they made a PC-based simulator available to download at no charge. It is my contention that having a simulator to practice with was one of the driving forces behind pilots' and aircraft owners' widespread acceptance of the 430/530 series. As of this writing there is no such simulator available for the GTN series. Surely Garmin will see that it is in everyone's best interest to provide one. Soon.

A New Leaf

As to whether or not these units are a good deal or attractively priced, I'll leave that assessment to the aircraft owners and other pundits out there. After all, I'm but a humble, professional flight instructor and freelance writer who rarely has more than a couple of coins to rub together and the mere prospect of owning an aircraft is beyond my ken. Garmin doesn't invite me to their media events, so I've taken an academic yet honest approach in this review because I hope this is what my readers have come to expect. I'd certainly like to fly one of these units in the near future, perhaps even train the next wave of instrument pilots to use them. Who knows, maybe the introduction of the GTN series will transform the sound of 10,000 pilots crying D'oh! to the sound of a single Ommmmm ...

iPad2 Takes Flight

Between weather and aircraft maintenance, getting the iPad2 into the air has proven more difficult than anticipated. Yesterday's afternoon flight was scrubbed due to a dead battery, but I did manage one flight in the morning. The iPad2 performed just fine during the 1.9 hour flight, leaving me confident enough to box up the original iPad for shipment to its new owner. Here are my impressions of the iPad2 in flight along with some thoughts for current iPad owners on the relative advantages of upgrading.

Size and Weight

The iPad2's slightly smaller size and thinner profile not only makes the iPad2 lighter, cases like the semi-rigid one that I'm using are also smaller and lighter. This means my minimalist flight bag is noticeably more minimal when I pick it up. The iPad2 feels lighter when you hold it and it's definitely lighter when strapped to my leg. The thinner profile makes the 30-pin connector look a bit precarious when inserted. Same for the audio port. This could be a consideration for folks who use the Bad Elf GPS Receiver with a 30pin extention cable.

Thin profile means plug connections could be more fragile?

The new size means some of the iPad1 kneeboard solutions may require modification. For more details, see my previous post on this topic.

Lights, Camera ...

The iPad2 has two built-in cameras, one rear-facing and one front-facing. If you are familiar with the iPhone4, it's a similar set-up. I say similar because the quality of the rear-facing is not very good at all (actually, it sucks). One would assume that a lower quality camera kept the iPad2 unit cost down, but it makes one wonder why Apple bothered at all.

Here are some photos I took and while the quality is not great, using the iPad2 camera did provide a déjà vu moment. The iPad2's screen is so large and bright that while framing a photo I was reminded of bygone days (back when dinosaurs roamed the earth) when I regularly used a large format view camera, except the iPad2 image is right side up. Oh, and you don't need a mammoth tripod and dark cloth. Of course the iPad2 camera can't provide view camera features like swing, shift, and tilt that architectural photographers rely on.

I haven't tried the iPad2 video capability, but the front-facing camera lets you make video calls using FaceTime and one imagines that eventually Skype will provide video support for the iPad. The addition of these cameras doesn't really add much value for pilots. I guess when trying to electronically copy a large sheet of paper it could be easier to frame with the iPad2 as opposed to an iPhone4. The image quality is undoubtedly better with the iPhone4's camera.

Speed & Clarity

The faster graphics performance of the iPad2 is evident when loading a terminal procedure in ForeFlight, SkyCharts Pro or Jeppesen's app. Scrolling around on charts is also faster. Downloading chart updates seems quite a bit faster, too.

The iPad2 screen is not terribly different from the original iPad except that it offers a wider range of brightness. You can make it much dimmer and a tad brighter than the original. Note these images have been adjusted to try to capture the relative brightness settings.

Brightest setting ...

Dimmest setting ...

Certify This

Some have observed that operators who just received OpSpec authorization for using the iPad1 as an electronic flight bag (EFB) may now be faced with certifying a new device if they wish to upgrade. I'm not certain of the particulars, but it does seem incredibly inefficient and expensive for the FAA to require individual operators to replicate decompression and electromagnetic testing on the self-same device. At least they won't have to change the approved training programs since it will be the same software, just running on a slightly different device.

Other Features

The GNS 5870 Bluetooth GPS Receiver worked just as well with the iPad2 as it did with the old iPad1. As before, ForeFlight showed my position on approach charts and airport diagrams. With both SkyCharts Pro and ForeFlight the groundspeed and heading readouts closely (often exactly) matched the KLN 94 GPS displayed values. The GPS-derived altitude was within 50 feet of the altimeter most of the time. The GNS 5870 achieves satellite lock so quickly that I don't really know how long it's taking. My only complaint continues to be the touchiness of the swipe-style on/off switch. It's just too easy to inadvertently turn the thing on when stowing it in your flight bag.

For non-aviation use, there are some other features of interest. Using a HDMI connector (available separately), you can mirror your iPad2's screen on a larger monitor.

Battery life of the iPad2 seems on par with the earlier model; about 10 hours.

The new magnetic cover looks cool, but it isn't designed to work with a case and than makes it a non-starter for me. It's interesting to note that the iPad2 itself contains 10 magnets and the cover contains 21 magnets. Call me old-fashioned, but lot of magnets seems like a bad idea in a cockpit. I haven't done any testing with the magnetic cover in the cockpit since I don't plan on using it, but my anecdotal observations are that with the iPad2 strapped to my leg there didn't seem to be any adverse effects on the compass in the Piper I was teaching in yesterday. I observed the aircraft compass on the ground through 360 degrees of heading change and it seemed to accurately indicate known headings. The aircraft compass aligned correctly with three different runways at two different airports. This is something I'll continue to watch in the coming weeks.

Preliminary investigation of the iPad2 accelerometer, gyroscope, and compass features seems to indicate that there isn't an app at the moment that can provide accurate Attitude Heading and Reference (AHARs) features. The idea of using an iPad in flight as a back-up attitude indicator may seem ridiculous, but keep in mind that only a year ago a lot of things seemed farfetched.

Apps 'n Stuff

People new to the iPad game always ask what apps I recommend. Here are the apps I've used on the iPad2 so far:

SkyCharts Pro - Limited wx features, but best chart-based EFB app around.

ForeFlight Mobile HD - Interface is a bit cumbersome, but this EFB app does it all from weather to approach plates.

ForeFlight Checklist Pro - Fly a lot of different aircraft? With a bit of effort on your part, this app can help you keep it all straight.

Jeppesen Mobile TC - Limited features right now, but if you must have Jepp charts ...

AvCharts - Low cost way to carry and access terminal procedures. Only app that allows you to make notes on a chart.

LogTen Mobile - This logbook app may actually have too many bells and whistles, but if you have a special logging requirement, this app can probably do it.

DUAT - Simplified way to access your DUAT account, get weather briefings, file flight plans, etc.

Square - Cost-effective way for self-employed professionals to accept credit card payments.

Penultimate - My favorite note taking app.

PFMA - Easiest-to-use electronic E6B I've found.

GoodReader - Not just good, this is a great PFD reader. Use it to read all those FAA handbooks you're carrying inside your iPad.

Atomic Web Browser - Does a few things the built-in Safari browser can't do.

 Numbers - Not exactly like Excel, but if you need spreadsheet capability on the iPad then this is a good choice.

 Pages - Solid word processing app, though a bluetooth keyboard makes it more usable.

 Keynote - Let's you give PowerPoint presentations with your iPad. Add this app and you'll have your audience yawning in no time!

 EverNote - Great way to take, save, and distribute notes across multiple platforms.

As for accessories I'm using or have used and recommend:

GNS 5870 MFI Bluetooth GPS Receiver
Tietco Kneeboard
Square Credit Card Reader

Upgrade or Wait

More speed is always better, but for frugal pilots I'm not sure the iPad2's speed bump and lighter weight are worth the cost and trouble of upgrading. Pilots who already have an iPad1 or who are considering acquiring a used iPad1 may actually get more bang for the buck. If you do decide to purchase a new iPad2, I personally don't see a need for more than 32Mb of memory. I chose the 16Mb version. I don't store music or videos on my device, but with several chart apps and associated data, lots of FAA handbooks, a PDF version of the AIM, and so on, I still have 8Gb of free space out of 14Gb. So why did I upgrade, you ask? Well it's obvious! Nerds like me must do whatever we can to preserve what little blogosphere cachet we possess. We must!