Saturday, November 21, 2009

Surprise, Surprise

The concept of automation surprise has been around for years in the large aircraft world and now it's part of the GA aircraft that you are flying or might soon be flying. Automation surprise occurs when a system, such as a GPS receiver and/or autopilot, does something the pilot neither expected nor intended. The result is that the aircraft deviates from an assigned heading, route, altitude, or approach path and the pilot may lose situation awareness, too. Actually, it's the pilot-in-command who is considered to have deviated, not the plane or it's systems and blaming the machine is an argument that's probably not going to hold water. With all the technically-advanced GA aircraft out there, automation surprise is now something that GA pilots must understand and be ready to handle.

While I don't pretend to be a human factors expert, I've both witnessed and been on the receiving end of automation surprise on several occasions. Most of the surprises I've seen in GA aircraft resulted from the pilot making mode errors - not fully understanding the consequences of their knob twisting and button pushing. Yet I have also seen deviations result from equipment failures and even from shortcomings in the design of an instrument procedure. There can be a seemingly endless number of ways for things to go wrong in a complex, automated environment and while we may want to never make any errors, mistakes are going to happen. I'll provide just a few examples of how things can get out of hand when technology is busy making the pilot's job easier and what you can do when the magic turns evil.

Operator Error
Here's a mistake I've witnessed many pilots make with the two-axis KAP-140. ATC instructs "... climb and maintain 7000." You decide it's time for George to do some flying. So you press and hold AP for 1.5 seconds, then press HDG, then select 7000 feet, then press ALT, and are subsequently confused as to why the KAP-140 won't allow you to use the UP button to select a vertical climb rate.

The key is understanding that the KAP-140 goes into VS (vertical speed) mode by default when your press the AP button. The mistake was pressing ALT, which engages altitude hold mode irrespective of the altitude you just dialed in - an odd design, to say the least! Pressing ALT a second time restores VS mode and allows you to enter a vertical climb rate. The problem is that the second time you press ALT to enter vertical speed mode, the altitude you selected is not armed. That means you'll climb, but the KAP-140 will not capture the selected altitude and if you're not paying attention, you'll bust your clearance. Blast!

Having your own SOP (Standard Operating Procedure) for autopilot use, combined with actually looking at the modes being displayed, can help circumvent this problem. A better knobology sequence would be: Dial in 7000 feet, pitch up for the desired climb rate, press and hold AP for 1.5 seconds, then press HDG, then press ARM. This results in the following KAP-140 display: HDG [AP] VS 7000 ALT Armed. The KAP-140 will climb at 500 feet per minute, fly the bugged heading, and level off at 7000 feet.

Unexpected Mode Changes
In an effort to make the pilot's job easier, Garmin's G1000 will automatically switch the navigation source from GPS to a localizer on an ILS, LOC or LDA approach. Interestingly, the G1000 won't automatically switch back to GPS for the missed approach procedure - you must manually switch the navigation source back to GPS. While this may sound like a good feature, it actually creates unintended consequences in aircraft equipped with a Bendix/King KAP-140 autopilot. Here's the setup.

You're flying the Concord LDA RWY 19R approach, approaching from the South, you've requested pilot navigation, Travis Approach has approved, and you're cleared to "cross KANAN at or above 4000' cleared LDA 19 right approach." You've selected and activated the approach on the G1000 with KANAN as the IAF. Your KAP-140 autopilot is engaged in NAV and ALT modes and it is flawlessly tracking a direct course to KANAN.

Crossing KANAN, the GPS sequences to fly the procedure turn and the KAP-140 continues to do a great job. You select 2500 feet, press ALT to enter VS mode, press DN a few times to command a 400'/min descent, and remove some power to keep the airspeed under control. The GPS and the KAP-140 turn the airplane to the outbound procedure turn, then after a minute, they turn the airplane inbound to intercept the approach course.

Reaching 2500 feet, you restore some power and the G1000 then automatically switches the navigation source to the localizer. If you're not observant, you will miss this mode change. The HSI needle changes color from magenta (for GPS) to green (for the localizer) and the switch in navigation source causes the KAP-140 to silently enter ROL mode. That's right, there's no aural alarm to alert you that this mode change has happened, just ROL flashing on the KAP-140 display - which is out of your primary field of view. If you don't realize the KAP-140 is in ROL mode, the airplane will fly right through the localizer. Ooops!

One SOP you could use to prevent this is to always change the KAP-140 to HDG, manually change the navigation source to the localizer, and follow the GPS prompts to manually command the procedure turn using the heading bug. Once you've turned inbound to intercept the localizer, press NAV and the KAP-140 will capture the localizer course.

Missing the Missed Approach
The Garmin G1000, as well as the 430/530 GPS receivers, can help you fly the missed approach using GPS navigation as long as everything goes as planned. For an ILS approach, the GPS must handle two possible cases: The full ILS and a localizer-only approach. The GPS considers the MAP to be at the runway threshold, even though the MAP on an ILS is technically at decision height, on glide slope, and on the localizer course.

For these GPS receivers to suspend waypoint sequencing, you need to fly over the MAP at the runway threshold. Only then can you press the OBS key (or softkey) to re-enable waypoint sequencing, switch the navigation source back to GPS, and fly the missed approach using the GPS. If you don't fly over the MAP, waypoint sequencing won't be suspended and you'll need to do some more work to activate the missed approach. If you don't understand this GPS behavior, you could find yourself very confused at a high workload moment. Do'h!

Procedure Problems
Though rare, automation surprise may occur due to the way an instrument procedure was designed. This is exactly what happened to a pilot I was flying with recently on an approach I had flown many, many times before. The thing is, it had been quite a while since I flew this approach and the procedure had changed. Here's what happened.

The pilot requested the Sacramento Executive ILS RWY 2 practice approach with the published missed approach. Approach responded "... cross COUPS at or above 3000, cleared ILS 2 practice approach." The pilot selected the approach and activated it with COUPS as the initial approach fix. The autopilot was engaged in NAV mode and flew us to COUPS. What happened next was both dramatic and unexpected.

Reaching COUPS, the GPS commanded a 41 degree heading change to the left from a 015 track to a 334 track to navigate to the newly added Computer Navigation Fix (CNF) UBIYI: A 41 degree heading change for a leg that is only 0.2 miles long! The groundspeed was only 110 knots, but there was no time for GPS turn anticipation to smooth this out. As soon as the GPS commanded a turn to the left, it commanded a turn back to the right as the airplane blew through the approach course. It happened so fast that we both wondered what was wrong. Was this a GPS error or an autopilot error?

No sooner had we begun to doubt the automation, the plane was headed back to intercept the localizer. You have to look really closely at the chart to see that the GPS and the KAP-140 were just trying to fly the approach as it is coded. I emailed the FAA to suggest they take another look at the unintended consequences of the change that was made. Good idea!

Ounce of Prevention
The primary ways a pilot can prevent automation surprise are both simple and straightforward:
  • Know your own limits with regard to currency/proficiency
  • Know thy aircraft's equipment
  • Monitor what the automated systems are doing
  • Stay ahead of (or at least be in synch with) ATC's game plan
  • Maintain situational awareness
  • Develop and use SOPs (standard operating procedures)
  • And be prepared to catch and correct errors.

I'd like to be able to tell you that the average pilot can fly a G1000-equipped aircraft once a month and maintain instrument proficiency. Sadly, this is usually not the case. Unless you are practicing regularly with a G1000 PC Trainer or other simulator, you'll get rusty - fast! Part of this erosion of skill is due to the vast number of features the G1000 offers, but much of the problem lies in the user interface's annoying design that requires you to recognize subtle changes in operational modes. I don't want to mince words here: The G1000 and other GA GPS receivers are not easy to use. They require regular use and practice for pilots to maintain proficiency.

PC-based simulators can be an effective and inexpensive way to maintain your instrument chops, but you need to have a plan. Sitting down and just screwing around is not going to serve you well. As they say in the music world: "If you play when you practice, you'll practice when you play."

A suggestion I've made before is to treat your autopilot and GPS like you would a low-time private pilot. It's okay to trust the systems, but monitor them to ensure they are doing what you intended. This is particularly important during transitions to climbs, descents, level-offs, turns to a heading, and intercepting and tracking a navigational course. So periodically interrupt whatever you were doing to ensure George is still flying the plane the way you intended. Did it capture the altitude you programmed? Has it intercepted the navigational course you intended? Is the autopilot still operating in the mode(s) you intended? If not, promptly drop what you are doing, intervene, fly the plane, and then try to determine why or George will trim you into a stall, flying you into the ground, or take you off course.

Remember that you are the last line of defense when automation goes bad. Never, ever forget that fact.

Sunday, November 08, 2009

ForeFlight Checklists for the iPhone

After the ditching of US Airways 1549 in the Hudson River earlier this year, an interesting fact came out of the review of the accident: In order to apparently save some money, the index tabs on the aircraft check lists had been removed, making the check list more difficult to use. Now in emergency situations there isn't always going to be time to run the appropriate check list, but I kept wondering "wouldn't it be nice if there was as electronic way to quickly access and display this information?" This would be especially nice for frequently used, non-emergency check lists.

Well ForeFlight has created two iPhone apps, Checklist Lite and Checklist Pro, that allow you to create your own aircraft check lists in an easy-to-access format. The Lite version of the app is free and the Pro version costs $19.99. Either app will function just fine with your iPhone in airplane mode. Again, let me disclose that I was provided a complimentary version of ForeFlight Checklist Pro by the developers in consideration for my reviewing their product.

I suggest that if you're serious about check lists on your iPhone (or iPod Touch) that you spring for the Pro version because it allows you to create, edit, and sync check lists on a web site using your browser as an editor. I found this much easier than editing on the iPhone itself (which is all the Lite version supports). Once you have created a check list on the web-based editor, you can sync it with your iPhone. The Pro version also gives you access to a variety of check list templates for a select number of popular aircraft.

In this review I'll just be covering the Pro version, discussing how to use the ForeFlight Checklist web site to create a new check list, then how to sync the checklist with your iPhone and use it with the aircraft in question. ForeFlight has also produced this how-to video.

After purchasing the Pro version, you register a checklist account on ForeFlight Checklist web site. The first thing you'll see when you log onto the ForeFlight Checklist web site is a list of checklists. Their scheme is to name the checklist with the plane's tail number, but I fly a lot of different aircraft with different tail numbers and many of those aircraft are of the same type. So I chose to name my check lists after the type of aircraft, rather than the registration number, so I could have one check list for each type. Your mileage may vary ...

The ForeFlight Check Lists are organized in a three-level hierarchy: The top level, called Group, contains Normal and Emergency/Abnormal items, You can't add, delete, or change items at the Group level. Now I like the check lists I create and use to have a comprehensive list of all the V-speeds in one place, so I created my own Subgroup called "V-Speeds" that contains a List group with those speeds.

You can decide what items you want in the Group and List levels of the hierarchy by using the the icons to the right of each header. You can move items up or down, rename, or delete, them. You can even copy List items to another Group within your check list or to a different check list altogether. The List level contains the actual check list items, organized in a Challenge/Response format along with a provision for notes on each item. If you want to create a header to separate lists of challenge/response items, just type something in the Challenge field and leave the Response and Notes fields blank.

Once you have created your check lists on the ForeFlight Checklist web site, it's time to launch the app on your iPhone (or iPod Touch). That's when you'll see this splash screen reminding you that a check list on your iPhone is not a substitute for the manufacturer's supplied data that should be in the aircraft.

You won't see any check lists when you first launch so you can tap the + button in the upper left and start editing on your iPhone or do what I did and tap on the sync button in the lower left edge of the screen (shown circled in red).

Syncing is pretty fast, but it can be unexpectedly destructive and the process currently provides no warning if the sync action you are about to do will delete a check list entirely. I found this out the hard way - D'oh!

Once the sync is complete, you'll see all the checklists that you created on the web site are now on your iPhone (or iPod Touch).

I tapped on the GA7 check list and this brought up a list of the normal check list Groups by default. To see the emergency/abnormal Group, tap on the red emergency button on the lower right corner of the screen.

Here's how the V-speed list I created on the web site appears when displayed on the iPhone. Granted this is not a check list per se, but hey, it works for me.

To use a check list, select it from the Subgroups list, simply tap on each item as your complete them, and you'll see a green checkmark appear next to the item and the screen will automatically scroll to the next item. No more losing your place in the check list!

If you exit a check list before completing all the items, ForeFlight will remind you: Notice the icon next to that Group item is only partially green, which means you have some unfinished business to attend to.

Return to an uncompleted check list and the display automatically scrolls to the first incomplete item. Pretty foolproof way to recover from the "interrupted check list" syndrome.

Finish all the items in a check list and you'll see the icon next to that Subgroup item shows it is complete. If you want to reset all the check lists in this Subgroup, simply tap on the reset button on the lower right edge of the screen.

From an instructional standpoint, the Notes feature for check lists items is particularly useful. Take the GA7 engine start procedure, which specifies that only left magnetos are turned on until after the engine is started. Placing a brief explanation in the Notes field is a great way for a pilot to learn (or remember) why something is being done the way it is.

For flexibility, you can consciously choose to skip a check list item by tapping the yellow Skip button instead of tapping on the item itself. Be aware that when you exit the check list containing one or more skipped items, ForeFlight will show the check list as being completed as long as all the other items were completed. You can also use the reset button to reset a single check list or an entire group of check lists. Pretty darn flexible, if you ask me.

To display the emergency/abnormal Group of check lists, tap on the red emergency button on the lower right of the screen.

Tap on a particular Group, like Engine Failures, and you'll see the list of Subgroups.

Then just tap on a Subgroup item to access the check list you want to complete.

And after you've gone to all the trouble of creating a check list, wouldn't it be nice to be able to share it with another pilot? ForeFlight has thought of that, just tap on the Share button on the bottom of the check list screen and select the check list you want to share.

The app will prompt you for the pilot's email address and email them a link to use for accessing your check list. The other pilot just needs to open the email on their iPhone and click on the link it contains to get a copy of your check list. Now all that's needed is a way to bill the other pilot for your time and effort!

Like all the ForeFlight apps, I found Checklist Pro to be well-designed and executed. So if you're an iPhone or iPod Touch user with a check list fetish, I recommend you check out ForeFlight Checklist Lite or Pro.

Monday, November 02, 2009

ForeFlight Charts for iPhone

ForeFlight recently released two new apps for the iPhone, ForeFlight Charts and ForeFlight Checklist Pro. As promised, here's my take on the charts app, including who might benefit from using them, and what I like along with enhancements I'd like to see in future version. As before, I want to disclose that I was provided with complimentary versions of these iPhone apps in consideration for reviewing them. Expect a review of ForeFlight Checklist Pro soon.

The premise behind ForeFlight Charts seems simple: Provide pilots the ability to quick access VFR Sectionals and Terminal Area Charts on their iPhone even if it is in airplane mode and doesn't have a 3G or WiFi connection. Aside from the limited screen size of the iPhone, this $9.99 app succeeds. You can enter an airport, route or just select your current location and in no time you're looking at the VFR chart for that area. Use the usual gestures to zoom in or out and scroll. The screen refresh rate is good on my 3G iPhone and is probably faster on a 3GS phone.

Consider the problem faced by a student pilot (or any pilot for that matter) who needs to plot a course between two airports, but the airports are on different sides of the chart. With ForeFlight charts you can enter the departure and destination airport to quickly find out the straight-line distance and the magnetic course for a direct route between the airports.

It would be cool to be able to do this in flight from your current position, but the iPhone's airplane mode disables the GPS and it's illegal to leave a cell phone active while in flight. I'm told that users who jail-break their iPhones can disable the phone while leaving the GPS receiver active, but this is an issue that Apple really needs to appreciate and address.

You can configure a cruise airspeed and fuel burn (in gallons, liters, or pounds per hour) and, enter a route, and get a rough estimate on the flight time and fuel requirements. Of course this does not take into account winds aloft or the fuel required during climb or descent, but it gives you a rough idea.

The routes you can enter a somewhat limited since ForeFlight Charts doesn't seem to understand Victor airways, VORs, or other waypoints, but you can enter a string of three or more airport identifiers to create a direct route between each. It also a bummer that ForeFlight Charts does not support IFR low-altitude en route charts. Perhaps they'll consider that for a future release.

One unfortunate design assumption is that you already know the ICAO or FAA identifier for each airport. There is no search feature, but remember this app is only $9.99. If you want a more robust search feature, I guess that's what ForeFlight Mobile is for.

So my short laundry list of what I'd like to see in a future release:

  • IFR Low-altitude En Route Chart support
  • Search for airports by name, city, or state
  • Ability to understand Victor airways, VORs, and intersections

All in all, I think ForeFlight Charts is a usable package at a reasonable price. Keep in mind that you'll need to pay $9.99 each year to be able to continue to get current charts, but that's a heck of a lot cheaper and more convenient that what NACO has given us. While this app won't yet replace a paper chart, pencil, and plotter for student pilot use, it is still a great learning and teaching tool. It's also handy for arm-chair flying when you want to imagine all those cool trips you'll be taking in the future. And when the Apple tablet computer finally becomes available, these sorts of apps will become that much better.