Countdown to 2010

Ordinarily, aviation technology proceeds at a cautious pace, at a speed befitting the conservative approach that safety demands. But since 1990, when GPS receivers hit the market en masse, this nifty new way of going from A to B has shaken up the avionics industry, the FAA, the airspace system, and users alike in ways that haven't occurred since the advent of ATC radar in the 1950s. In less than 10 years, VHF-based navigation has been steadily supplanted — first by the loran units of the 1980s, then by handheld GPSs, then by panel-mounted ones — to the extent that nonprecision instrument approaches may now be performed by using approach-certified versions of panel-mount GPS units.

GPS has come a long way, baby, and there's more to come. When the wide area augmentation system (WAAS) is completed, its ability to provide more enhanced, accurate satellite signals will permit precision instrument approaches. WAAS will be a network of three satellites in geosynchronous orbit, coupled with 24 ground-based monitoring stations. The ground stations check GPS satellites for data errors, then transmit any corrections to the WAAS satellites. The WAAS satellites then pass these corrections along to WAAS-capable GPS receivers.

According to the FAA's radio navigation plan, we may start saying our farewells to ILS approaches by 1998 or so. That's when planners estimate the first ILSs will be phased out and precision GPS approaches may make their debut.

All of this change is for the good. GPS provides unprecedented levels of accuracy — to within 100 meters in its current state, and to within 10 meters with WAAS in place. The features in even the simplest GPS would boggle the minds of pilots of a generation ago. Furthermore, GPS has brought about a refinement of the practice of direct-to navigation and initiated the "free flight" concept. Under this scheme, pilots would basically fly along direct routes of their own choice. The bottom line: greater efficiency of movement and the potential for tremendous savings for all concerned.

For these and many more reasons, AOPA has been in the forefront of the GPS movement. Those who doubt that should consult the July 1982 issue of AOPA Pilot. In an article titled "Satellites Instead," author Gerard K. O'Neill reiterated the views first expressed in AOPA policy papers two years earlier — that the military's Navstar constellation of GPS satellites could be used for civilian navigation and air traffic control. The preface to O'Neill's article states, in part, "...Satellite-based navigation and position reporting is well beyond the futurist stage...the technology exists to provide a system for civil users (including surface vessels), but the military has been reluctant to share its system with others for a variety of reasons. Or, it has wanted to limit the accuracy of position-finding and to charge civilian applications enormous service fees." Though some may not like to admit it, AOPA has been the central organization in the push to formalize the use of GPS in all phases of flight. Without AOPA, it's doubtful that GPS would have come as far as it has.

With that political advertisement out of the way, it's also important to emphasize our understanding that technological change can bring about uncertainty, confusion, and problems as system designs grow and mature, and as users and government agencies deal with the challenges implicit in any high-tech shake-up. For GPS, these challenges center on two main aspects. One is the sheer speed with which GPS has taken hold. Another is the ability of the FAA and other governmental bodies to make the transition to the brave new world of GPS-only navigation an orderly one.

As it now stands, the FAA's implementation timetable has a target date of 2010. That's the year that we'll supposedly make the switch to an all-GPS navigation system. No more VORs, no more NDBs, no more loran, no more Omega, no more anything but GPS. In 2010, all precision approaches will be GPS/WAAS, meaning that they will have the necessary 10-meter accuracy.

Actually, the changeover won't be as cold-turkey as that may sound. Overlay GPS approaches (those that use existing VOR or NDB approach fixes, final approach courses, and procedural elements) will continue in effect until 2010; but beginning in 1998, no new overlay approaches will be published. By that time, GPS/WAAS approaches — both precision and nonprecision — will begin to be developed, as will departure procedures. However, for all procedural purposes, the move to GPS/WAAS nonprecision approaches will be invisible. These approaches will use the same fixes and courses as do today's standalone GPS approaches. On the economic plane, however, the move to GPS/WAAS will be a severe one.

Today's approaches are performed with approach-certified GPS boxes that comply with Technical Standards Order (TSO) C129 (a) (1). WAAS-augmented receivers of the future must, of course, be able to process WAAS signals in order to be legal. Since many of today's approach-certified GPS receivers weren't designed with WAAS in mind, those receivers will become insta-junk on implementation day. (Well, almost. A transition period will make the switch more user-friendly, and some of today's newer approach-certified boxes are being advertised as WAAS-compatible and ready for the big day.) But for those without WAAS-capable receivers, the year 2000 — when the non-WAAS, C129 approaches that we know today will begin to be phased out — will be the year that many pilots will be faced with a serious buying decision. On or about 2005, every aircraft owner will become a GPS buyer. That's when the government is supposed to begin shutting down all the nation's VORs and NDBs.

The really good news about the all-GPS-approach world of the future is that its procedures are designed with standardization in mind. Except in cases where terrain, airspace gerrymandering, and other considerations prevail, most future GPS approaches are supposed to follow what's being called the "basic T" design. Ideally, there will be two initial fixes (IFs), each situated 4 nm from the initial approach fix (IAF), which itself is 5 nm from the approach's final approach fix (FAF). The missed approach point (MAP) will always be at the runway threshold — and always 5 nm from the FAF. The MAP holding waypoint will be 5 nm away from the MAP, and flight from MAP to the MAP holding waypoint will be a straight shot. A plan view of this typical arrangement shows a T, with the IFs forming the crossbar of the T, and the line from the IAF to the MAP holding waypoint forming the elongated element of that letter.

The whole idea here is to avoid procedure turns and make each approach predictably simple and predictably alike. Under this scheme, there won't be today's hassle of having to remember to punch a Hold or OBS button to disengage a GPS receiver's autosequencing feature while performing a procedure turn or holding pattern, or while being vectored for an approach. Vectors won't go away, though, and we're happy to hear that. In fact, the FAA anticipates that radar vectors to final approach fixes will be the usual means of commencing an instrument approach. The basic T will mainly prevail in nonradar environments.

Sound good so far? We think so. But it's na?ve to ignore the implications and repercussions of all this change.

First off, the schedule has already slipped. The FAA let a contract for the WAAS to Wilcox Electric. But Wilcox wasn't working hard or fast enough, so it was given the axe — and now the torch has been passed to Hughes Electronics Corporation. Ergo, an automatic delay in that 2005 target date for the beginning of WAAS-augmented approaches. With this as prologue, who can say with any degree of assurance that future delays aren't possible? Two presidential elections, plus Senate and congressional races, plus budget debates and appropriations wrangling also await, and future GPS implementations may well become political fodder.

Moreover, events may overtake the transition, making GPS as a sole-source means of navigation seem imprudent. Let's say a major conflict begins. Count on the military to remind us whose system we've been using and to alter its signals in ways we never imagined, in order to confuse an enemy targeting system. Is it wise to put all our navigation eggs in a basket that's been handed to us out of a forbearance that can evaporate in the face of national security issues?

Even if we ignore military issues, there is still the matter of redundancy. Let's say you're flying along in 2010 and your GPS receiver fails, or a couple of satellites that you happen to be using start sending out flawed information. Now would be a good time to have an alternative form of electronic navigation. Planners are currently thinking about retaining a skeletal network of 200 VORs as fallbacks that would help pilots fly to alternate airports. There is some talk on the street that loran should serve this backup function, and AOPA is attempting secure loran funding for well into the next century.

It's also worthwhile to note that the GPS revolution has been largely a manufacturer-driven one. After the initial groundswell created by the loran revolution, the GPS tsunami hit full force. As soon as AlliedSignal, Garmin, Magellan, Northstar, Trimble, and II Morrow began cranking out their receivers, competitive forces refined successor models. The FAA, struggling to keep certification standards abreast of technology, began to officially incorporate GPS into the airspace system. The ultimate goal: IFR certification of GPS for use in Category I precision approaches.

But first things first. Initially, GPS was blessed for IFR use on en route and oceanic segments of flight. Then, it was approved for use on nonprecision approaches, as long as certain conditions were met. The GPS final approach course had to overlay the final approach courses of existing VOR and NDB approaches, and pilots flying these so-called "overlay" GPS approaches had to have the VOR or NDB navigation information dialed into their panels just as though the GPS data didn't exist. Eventually, the requirement to have the old-fashioned navigation data up and running was dropped. Under the second phase of this transition you simply need to have usable VOR or NDB signals available (but not punched up for the approach) in order to fly an overlay approach. Now, approaches labeled with the "(or GPS)" notation appended to their titles do not require that the avionics or ground-based navaids even be operational; these are the so-called Phase III approaches. With the advent of more and more standalone GPS approaches, the requirement for backup VOR or NDB information will, of course, eventually disappear altogether.

However, the overlay days left manufacturers to deal with a big problem: How to make a GPS box act like a traditional nav box during procedure turns, vectors, or other types of course reversals and changes. The FAA's TSO said that there must be a way to disable a GPS's autosequencing so that outbound passage over a final approach fix, say, would not be misinterpreted as passage inbound.

But the TSO let each manufacturer call the shots when it came to the design philosophy, labeling, function, and operation of its GPS boxes. When it comes to compliance with the appropriate TSOs, all meet the letter of the law (but perhaps not the spirit). Some say that the TSO itself is poorly written. Others think that it would have been best to sit the manufacturers down to develop a consensus on better standardization before issuing a TSO. However, the pace of GPS receiver technology made this impossible. That's how these wonderfully capable, mini-flight management systems came to mature — in an atmosphere of controlled chaos.

As a result, GPS receivers can be hell to learn how to operate. They demand a great deal of head-down time, a lot of their switches and prompts are not intuitive, and the correct sequence of switch and knob operations needed to fulfill a given task requires both cognitive skill and somatic memory. In some cases, up to 30 inputs may be required to set up a GPS instrument approach.

Experts have called GPS receiver controls and operations human factors disasters. Knobs have multiple functions, none of which are common from one manufacturer's receiver to another. Buttons and knobs don't have common labels or functions. The prompts can be misleading or nonexistent. With one unit, you exit the flight plan function by pushing a button labeled Select, a move that runs counter to the action promised by the label. Some units have a dedicated "nearest airport" button; others require pushing a combination of buttons in a specific sequence to call up the list of nearest airports. The list of anomalies could go on and on, but the point is that there is an abysmal lack of standardization. For the pilot who owns his or her own airplane and has time to become completely familiar with the nuances of a specific GPS receiver, this may not be a major issue. For renters who may face one brand of unit one day and another the next, it's an Excedrin headache.

For human factors experts, the bottom line is to standardize the labeling and function of certain critical GPS controls. All boxes should have a Direct To button that brings up a prompt to dial in a fix's identifier, they say. Same thing with Waypoint and Flight Plan buttons. There's also a strong argument for an Undo button that would erase the last input in one motion and, most important, for a flashing prompt at the MAP. Push the flashing button and messages guiding the pilot to the MAP waypoint should automatically come up on the display screen and the CDI head, experts emphasize. A missed approach is no time to ask a pilot to push a bunch of buttons in a specific sequence. It's too stressful and too close to the ground. For that matter, neither is the beginning of an instrument approach a good time to require sequence recall.

In the name of innovation, each manufacturer defends its own specific approach to software design and panel layout and to labeling as the best solution. Standardization discourages innovation and product improvement, they say, and they may be correct. But in the meantime, what about the pilot struggling in the soup, flying a new box, punching buttons like mad, and hoping against hope that he hasn't made a bad entry?

Last, but certainly not least, is the issue of training. If we're going to strut into an all-GPS future, we'd better all be in step. Right now, formalized (i.e. nonvideo) training in the operation of GPS receivers is virtually nonexistent. The only organization performing that function is the AOPA Air Safety Foundation. The ASF has been holding 4-hour seminars on GPS operations (including instrument approach operations) at various locations around the United States. Seminar instructors report that students (many of whom own approach-approved receivers) have a discouraging lack of awareness about their units' operation. For $100, the ASF course is designed to make pilots savvy enough to fully understand the most important functions. As the manufacturers have taken the technological lead in GPS implementation, so the ASF leads the way in GPS education. So far, the FAA has developed no educational guidelines on GPS usage, and practical test standards are mute on the subject. Inasmuch as so many flight instructors fail to pass along GPS operating tips, the ASF remains the sole-source educator for the foreseeable future.

Is the GPS world of 2010 a good thing? You bet. Are we right in thinking that the transition will be flawless? No way. The transition will take place later than 2010, we predict. Loran will be necessary as a backup; manufacturers have miles to go to make their boxes user-friendly; and pilots, manufacturers, and government agencies still have a lot of cooperating to do if the switch is to be a truly safe one.

Top contenders

Of all the IFR approach-certified GPS receivers available today, AlliedSignal's Bendix/King KLN 90B appears preeminent. In spite of its hefty $8,595 price tag (competing models go for some $2,000 less), the 90B has become the premier original equipment GPS box of choice for most light airplane manufacturers — and some not- so-light.

Among other attributes, it's the 90B's vast display capabilities that push this unit ahead of the pack. The cathode-ray tube display screen is six lines deep and divided into two halves. This lets you put up to 12 lines of information or other readouts on the screen at a single time — more than any other panel-mount GPS receiver. What's more, that CRT gives a great high-resolution picture. In addition, the 90B lets you call up a moving map display using its "Super Nav 5" screen. In this setup, the left side of the screen shows time, speed, distance, and track information while an enlarged right-hand portion of the display shows your track and waypoints graphically. The scale of the map can be changed, manually or automatically, with selections running from one to 1,000 nm (i.e., the distance from the diamond-shaped airplane symbol to the top of the display), and you have the choice of a north-up, track-up, or heading-up display format. Important note: the 90B does not display the boundaries of special-use airspace.

Each half of the display screen is controlled by its corresponding cursor button and set of concentric rotating knobs. Move the outer knob to select various modes of operation (there are eight for the left knob, 10 for the right), then rotate the inner knob to call up additional display pages and functions within the mode group. Use the cursor button to highlight any fields you need to change; the outer and inner knobs come into play once again for making data entries.

Does any of this sound intimidating? Don't worry, you're not alone. Newcomers to the 90B are often overwhelmed by what seems at first glance to be a complicated control setup and methodology. The pilot's guide is an inch thick, the abbreviated operation manual is 52 pages long, and there is a total of four knobs, seven push buttons, and not one, but two display views to worry about. No wonder that neophytes hesitate to go much past the "Direct to" operation for the first few hours of flight.

But if the unit is a challenge to master, it's only because of its vast capabilities. And while the pilot manuals will tell you everything you need to know, there is simply no substitute for hands-on, trial-and-error learning. As with any GPS receiver, mastery of this unit is as much a product of book learning as it is of memorization of the sequences of movements necessary for manual entries and display manipulations. Maybe more.

Speaking for myself, I never cracked a single book to learn the 90B. Instead, I dialed and poked at it during an intense four-day series of cross-country, overseas flights. After a total of about 36 hours, I had it down pat. This may not be the best way to learn how the 90B works, but it could be the fastest. More formalized training is the recommended path to understanding GPS operations, and that goes double for learning how to operate the 90B (or any other IFR-certified box) during GPS instrument approaches.

With the 90B, you select approaches by dialing the right outer knob to the Airport (APT) or Active (ACTV) mode, then rotating the inner knob to the eighth page. This mode and page — like every other — is annunciated at the bottom edges of the display, so you don't have to worry about remembering your whereabouts in the system architecture. In this case Apt 8 would show up in the lower right segment of the display.

That done, you activate the right cursor and twirl the right outer knob to highlight the approach you want to shoot. Hit the Enter button at the bottom of the box to confirm your selection, hit it again to load the approach into your flight plan, and hit it yet again to approve and finalize the selection process.

After you've selected the approach, it's time to pick the initial approach fix. For this, you punch the right cursor button, scroll through the list of fixes with the outer right knob, pick one, and hit Enter once more. Now the 90B will autosequence you (or your autopilot, if it's on line) through the approach fixes once it arms — 30 nm from the destination airport. Once you are on approach, the moving map can be called up on one of the display screen halves, and this extra bit of information helps a great deal in situational awareness.

In the en route phase of flight, the 90B offers any number of ways to set up the display screens. Many pilots like the Super Nav 5 display because of the moving map; you select this display by dialing in Nav 5 on both knobs. Others like to have the track information on the left screen (select Nav 3) and the mini-CDI display (Nav 1) on the right side. Then again, selecting Nav 1 on both knobs is nice. This gives you a full screen-width CDI display, along with the standard time, speed, and distance readouts. On a few Third World trips I found making estimates to upcoming fixes a snap in nonradar environments. I just put my flight plan in the left display and dialed up D/T (distance/time) on the right. This listed the distances and times to every fix. The E- 6B stayed in the flight case.

Can you gripe about the 90B? Yes, but it's tough picking those nits. Depending on its location, the screen can be a chore to read, what with the six lines and comparatively small characters. But when mounted in the center stack — as most are- -the 90B is easy to read. Also, the knob-twirling can definitely be a pain. Making a lot of flight plan entries in flight is no picnic, because you really have to get busy with the knob-cursor-enter action. In turbulence, it can be easy to foul up your entries, go a few clicks past where you want to be, make mistakes, and so on. Best to get the 90B squared away as well as you can before takeoff.

In the final analysis, the 90B is an exemplary receiver. Yes, it's demanding, but balance this against the unit's strengths and it's difficult to find any real flaws.

KLN 89B

OK, let's say you want an IFR-certified GPS and like the 90B idea, but its price tag puts you off. Then it's time to check out the KLN 89B. Introduced in 1995, this $4,895 receiver is a virtual clone of its bigger brother and has nearly all of the same features. Operating the 89B seems a bit more intuitive than the 90B, due in large part to the unit's simpler controls. For this reason, many find the 89B easier to deal with and a good deal less intimidating to boot. There's just one set of concentric knobs, for one thing, and selecting the modes of operation is a matter of turning the big knob. The mode and page are annunciated by two means: large letters at the left of the display, and a small, lighted bar above a row of mode identifier abbreviations at the display's bottom edge.

The few differences between the 89B and 90B are improvements over the earlier model (the 90B was introduced in 1994). There is a push button dedicated to a nearest airport search right on the front of the panel; the display itself is larger; and there's a front-loading data card. With the 90B you have to hit the Message, then the Direct push buttons to call up nearest airports. The 89B's less expensive gas plasma discharge display is almost twice the width of the 90B's, and while the display does have that strange orange glow, the AOPA Pilot staff never found it objectionable. Its resolution, however, is much less crisp than the 90B's. But for a $4,000-odd savings over the 90B, it's doubtful that customers will gripe too much over seeing amber. The data card lets you update the 89B's database by simply popping in a new card every update cycle. With the 90B, you have two update options: remove the unit and install a new data cartridge 12 times a year, or download the new data via personal computer through a panel-mounted data port. PC updates for the 89B are also available, but many enjoy the convenience of the data card, in spite of its slightly higher cost. Data card updates cost $449 per year; PC diskettes carry a $430 annual cost.

By far, the best of all the improvements is the 89B's ability to show special- use airspace boundaries. As mentioned earlier, this is a feature that the much more expensive 90B simply doesn't have.

Like the 90B, the 89B has an OBS switch. This lets you interrupt the unit's autosequencing, a feature that kicks in on a GPS approach and automatically calls up fixes as you progress along an instrument approach. Push OBS and you're free to fly vectors, procedure turns, or holding patterns without "tricking" the 90B or 89B into thinking that it should autosequence when flying outbound from a final approach fix, for example. With the 89B, the OBS switch is located on the box itself. The 90B's OBS control is a switch/annunciator located in a separate group of annunciators, situated directly in the pilot's view.

The 89B gives customers a no-compromises, lower-cost alternative to the top- of-the-line 90B. In a tight market it gives other manufacturers' lower-cost IFR- certified GPSs a real run for the money. If you don't mind the display's color, this could be the box for you. By the way, owners of straight KLN 89s — the $3,895, VFR version of the same unit — can upgrade their boxes to IFR-certified status for $1,250. In the end, the price works out almost the same as though you had bought an 89B in the first place.

AlliedSignal claims to have sold more than 4,500 IFR-certified GPS receivers. That's far more than any of its competitors have sold — and an endorsement of the 89B and 90B that speaks volumes. — TAH