I cant figure this damned thing out, lets just fly the VOR approach and be done with it.
We dont have any hard data on the subject, but judging by reader comments weve heard, this phrase has been uttered more than once by airplane owners checking themselves out on a new approach-approved GPS receiver.
For various reasons, during editorial trials and flight training with these devices, weve hurled our share of epithets as well. Theres little disagreement that IFR-certified GPS-the best the industry currently has to offer-are by degree enigmatic, hard to use, inconsistent from brand-to-brand and occasionally unpredictable.
Like personal computers, their mysteries yield to studying the manual and practice in the airplane. Yet none of the approach-approved receivers have what we would call elegant operating logic, although the Northstar M3 comes close. According to our interviews with owners, pilots who buy these things resign themselves to the learning curve grind and eventually master the boxes at some level, even if its just direct-to navigation. Although the average IFR GPS installation costs about $6000, we dont hear any buyer remorse from owners who bought in early. Despite the complexity, owners seem satisfied with their purchases.
Nonetheless, the industry, the FAA and alphabet groups have heard the grumbling about unreasonable complexity and theres a move afoot to make the next round of GPS receivers easier for the manufacturers to certify and easier for owners to operate, to include a degree of standardization. Thats encouraging news but given the way the best intentions can go awry-especially when the FAA is involved-were not ready to shout hallelujah just yet.
Complicating the buy-now-or-buy-later decision is the FAAs Wide Area Augmentation System (WAAS) or lack thereof. Some would-be buyers are delaying their conversion to GPS until the manufacturers can absolutely, positively guarantee that a GPS receiver bought today will be upgradeable to work with WAAS. In our view, thats like waiting for the Titanic to tie up at the 34th Street Pier in New York. (Okay, so thats an unfair comparison: at least we have pictures of the Titanic.)
If youre serious about GPS, our advice continues to be shop for the best combination of price and features and get the thing installed now, without worrying about WAAS or waiting for the simpler gear that may be just over the horizon.
The History
Understanding why approach-approved GPS receivers are so complex is akin to unraveling a ball of yarn whose core is the FAAs TSO C129, the technical standard order which governs these devices. As one of the most complex TSOs ever written, it was intended to merely describe how approach GPS receivers were supposed to work. But as with most things designed by committee, the TSO ballooned out of control to the point that it all but instructed manufacturers in how to build the boxes. Unfortuately, the instructions were missing a few pages.
Because GPS was terra incognita for the FAA, it pushed the TSO in the direction of something it had experience with: High-end Flight Management Systems found in airliners and business jets. As many airline Captains will tell you, these little jewels arent necessarily paradigms of simplicity, either. Crews often complain about poorly conceived and inconsistent operating logic and some of the old hands are happy to transition back to steam-driven jets such as the 727 when seniority gives them the choice.
One element of FMS design found in little-airplane GPS is the notion of canned routes based on TO-TO navigation for approaches. In other words, the receiver is supposed to be idiot proof; the approaches exist as named procedures, with the fixes arranged only in the order theyre supposed to be flown.
The pilot cant fat finger the wrong approach fix or screw up the order and the receiver always navigates toward fixes, only on published legs and it automatically sequences from fix to fix. Further, the TSO required SIDs and STARs to be included in the receivers database, just as they are on the typical airline FMS.
One tiny little glitch related to the fact that when the TSO was conceived, no standalone GPS approaches existed so the receivers would have to be capable of flying conventional VOR and NDB approaches overlayed with GPS waypoints. On paper, this made sense. It allowed pilots to gain some experience with GPS operations while having the comfort of a back-up in the form of the underlying conventional approach. In practice, the idea had an ugly wart: Conventional approaches often have course reversals-procedure turns-so the receivers would have to have some way of temporarily suspending autosequencing while the course reversal was flown.
At this juncture, the notion of consistent operating logic fell apart. Bendix/King and Garmin, for example, were the first to certify their receivers and they used a manual, dedicated switch for the so-called hold function. But they used different terminology to describe what was essentially the same task. Along came Trimble and IIMorrow with partially automated designs for the hold function. Northstars M3-pulling up the rear-adopted a highly automated operating scheme that figures out the hold function on its own; very little pilot input required.
SIDs and STARs? All the receivers have them, yet while Bendix/King, Garmin and Trimble list them as named procedures, just like on the plate, IIMorrow and Northstar simply provide the fixes. You string them in the proper order yourself. And we wont even address the inconsistencies between the various brands in database organization, button and knob nomenclature, annunciator labeling and terminology.
FAA No Help
That the FAA was ill-prepared for certifying GPS receivers is to describe its performance generously. It began the process with a debacle in 1994, when the Long Beach certification office blessed the Magellan SkyNav 5000 with a VFR TSO, a bogus approval that showed that even some in the agency didnt quite get the concept. With considerable embarrassment, Washington HQ quickly overruled the Long Beach office.
As legitimate certifications progressed, it became obvious that the agency was creating the manufacturers worst nightmare: The terms of the GPS TSO were being unequally applied by dint of geography. For example, Garmin proposed autoarming of the approach function and wanted to at least consider a resolverless CDI design. No way, said the local FAA certification office. TSO doesnt allow it. Yet a year later, Trimbles 2000 Approach was approved with those very features, by another certification office 400 miles away.
On the west coast, IIMorrow certified its 2001 Approach receiver such that it doesnt require a 28-day database for approaches, but allows the pilot to manually check the approach fixes. Doesnt meet the TSO, sniff the other manufacturers, whose boxes do require the expensive 28-day revisions.
Northstar, working with the Long Island certification office, was subject to yet another set of rules. Off the record, the manufacturers complain bitterly about the FAAs inconsistent application of the TSO where variances to the agreed-upon specs were the rule more than the exception. Theyre terrified that vocal complaints will raise the ire of the very agency that can make or break an expensive product development with the stroke of a pen.
A Better Way?
One of the benefits of rapidly advancing technology is that if you screw up the first try, you soon get a second chance, a third, a fourth and so on. At present, the industry and the FAA are deeply enmeshed in GPSs second chance, the TSO which will govern WAAS-type receivers. Its expected to be completed by the third quarter of 1998. It appears to us that this time around, theres a sincere effort to streamline certification and to simplify the button pushing and knob twisting that make C129 receivers such a nuisance to use.
Stung by criticism of its handling of C129, the FAA has assigned new headquarters personnel to the WAAS project with an eye toward improving if not fixing the human factors problems. (Bruce DeCleene, the FAAs navigation program manager, gets respectful praise from GPS designers who arent otherwise particularly fond of FAA HQ types.)
AOPAs Air Safety Foundation, having heard the complaints about maddening operating logic, has taken an aggressive stance, holding the FAA and the manufacturers feet to the fire on simplification and standardization.
Although we havent heard anyone say simplification and standardization of GPS is a bad thing, we also havent heard anyone say it will be easy. At a meeting last summer at AOPA headquarters involving the FAA and the major avionics manufacturers, the notion of standardization got an arms-length reception from the manufacturers.
The reason? Theres no evidence that simplicity sells but features above and beyond the basics definitely do. Thats proven true in handhelds and it has proven true in panel mounts. Whether they use higher features or not, buyers insist that they want them and are willing to pay the price. (Just ask Garmin; its stripped down GPS 89 handheld proved to be a tepid seller compared to the feature-packed 195, which costs more than twice as much.)
When C129 boxes hit the street three years ago, customers did the Beta testing. We suspect that wont be the case with WAAS receivers. Last year, working with the U.S. Navy, ARINC came up with something called the Gamma receiver, a test-bed device designed as a proof-of-concept simulator for the WAAS TSO. AOPAs Air Safety Foundation got involved with the project and encouraged manufacturers to give the Gamma box a try.
It looks vaguely like a Bendix/King KLN 90B, but with a two-line rather than a seven-line display. Programmed with experimental approaches and routes, each of the manufacturers were given a shot at trying it out. Nice idea, say the box makers, but they worry about being forced into dumb mode standardization that would yield look-alike receivers.
Features Sell
The manufacturers are willing to agree on some standard terminology-such as a D with an arrow for direct, NRST for nearest and RTE for route, and so on, but these dont necessarily describe identical functions from box to box. Further, the manufacturers we spoke to are loathe to sign on to what many call the lowest common denominator box.
Its a wonderful idea to get everyone together to review terminology, says Garmins Gary Kelly, but what sells boxes is not sameness, its uniqueness.
He says every manufacturer has pride of authorship in its own featureset and believes the market will vote with its dollars. In other words, competition-not government fiat-should determine design.
We have to build a box that will sell. Its absolutely key to our survival. If it doesnt sell, then were not going to build another one, adds Kelly.
IIMorrows Robert Grove, who oversaw the certification of the Apollo 2001, sees the quest for standardization as roughly equivalent to a mid-east peace negotiation, in that everyone is for it but no one is sure how to get there. On second thought, he says its a good idea only by degree.
You could write a TSO that says some basic functions should be all the same, then let the manufacturers embellish in any way they want. But the examples where this can work break down very quickly, argues Grove.What you end up doing is sticking the customer with a bad solution, he adds.
For manufacturers, the customer loyalty issue looms around every corner. Avionics buyers have long formed cultish tribes which give the manufacturers a captured audience for the next generation of equipment. Buyers tend to stick with what they know, thus Northstar M1 owners are likely to buy M3s, IIMorrow loran owners favor the 2001.
A common-denominator standard, no matter how well-intentioned, would alter that, especially if it represents a clean break with the previous design. Worse, if an owner already has a C129 navigator and wants to displace it to the number 2 position with a new WAAS receiver, hed have to suffer two very different operating logics in the same panel.
Yet another argument that leaves the manufacturers unimpressed is the VOR-DME paradigm, that being that you can climb into an airplane with any VOR-DME-Bendix/King, Sperry, Collins, Narco-and make it work without a second thought. So why not GPS?
That makes no sense to me at all, says Grove. What VOR receiver has the capability of a GPS? So how can it be as simple or standard to operate? Further, VOR receivers never had databases with navaids, airports and intersections, but simply required the pilot to tune a single frequency.
AOPA Air Safety Foundations Doug Helton believes that future GPS can be as easy to operate as VOR, or, at the very least, the navigators can and should share common operating logic across a small but important handful of functions. He rejects the argument that the old, often cranky operating designs be retained in the cause of customer loyalty.
At some point, you have to make the transition to the new. If we let the old boxes drive the next generation, well have this [complexity] problem for a long time to come, Helton argues.
Theres always the chance that the FAA will take an iron-fisted approach and insist on strict and spare operating logic, with limited add on features. Unfortunately, the iron-fist standard could be designed by some committee in an airless room in FAA HQ, a prospect which makes the current receivers look far more friendly.
Although nothing has been set in stone, the industry may adopt a lose standard in which a group of core functions are virtually identical between brands, to include common terminology. Just what the core will contain remains to be decided.
FAA View
For its part, the FAA does seem interested in easing the strain on GPS certification and is well aware of complaints about its handling of TSO C129. This time around, the FAA says it will be different. I have pledged that the WAAS TSO will be held to five pages, says Bruce DeCleene, the FAA staffer charged with shepherding the TSO through the bureaucracy. (By comparison, TSO C129, at 36 pages, was one of the most complex the FAA ever produced.) DeCleene agrees that forcing the manufacturers to adhere to an over-strict standard will constrain innovation and competition.
Thats the last thing I want to do, he says. But he also insists that its possible to design an operating logic to avoid the negative transference that makes the current receivers so frustrating to use and with enough standardization such that once a pilot learns to operate one receiver, he should be able to operate another with little or no training. Its the VOR paradigm.
I absolutely think GPS can be as easy to use as VOR, DeCleene says.
How to achieve that standard of easiness? Preferably by consensus among the manufacturers, says DeCleene, based advice from the RTCA, an industry group which develops the operational specifications for avionics which form the technical basis for the FAAs TSOs.
The Outlook
Since the WAAS TSO is still over the horizon, we can only guess what the receivers will be like. But consider this: If WAAS-type navigators are to be the be-all, end-all the FAA promises and if theyll ultimately usher in the era of primary, sole means navigation by satellite, theyll have to do everything that TSO C129 receivers already do, plus precision approaches. Call us skeptics, but we cant imagine how this will equate to markedly simpler operation.
We agree with one marketing director who says that simplification is relative. Unless the FAA does the regulatory version of Shermans march to the sea and mandates look-alike operating systems, which we see as unlikely, each manufacturer will devise whatever version of simpler operation will give it an edge in an intensely competitive market.
While these new designs will certainly be somewhat easier to use than the current navigators, we dont expect the improvements to be night and day. As long as receivers have databases, the operator will have to figure out how to use and retrieve the data. Bells and whistles will still drive the marketing effort and until someone perfects pilot-to-panel telepathy, that means twisting knobs, mashing buttons and learning how the receiver thinks.
IIMorrows Robert Grove makes a direct comparison to the high-end FMSs found in jets. You dont see much standardization between what Boeing uses and what McDonnell-Douglas uses. The differences are addressed with training.
The manufacturers argue that the same strategy will have to be applied to GA navigators. Garmin already does traveling GPS seminars, Trimble has developed a CD-ROM based training system for its 2000 Approach and Bendix/King and IIMorrow have produced training videos.
The AOPA Air Safety Foundation has sponsored hands-on GPS training seminars but demand for such programs hasnt been overwhelming. Although we havent heard the FAA say it, the idea of a GPS logbook endorsement-similar to that already required for high performance airplanes-has been mentioned.
Our view is that if youre hoping the new WAAS navigators will be simple as a bag of rocks and cheaper than C129 receivers, youre going to be disappointed. Expect some simplification and standardization between brands, but were skeptical of the claim theyll be as easy to use as VOR. Further, we see no reason to expect WAAS receivers to be cheaper than whats available now. Our guess is theyll carry 20 to 30 percent higher price tags than current certified models.
When you buy into IFR GPS-whether now or later-resign yourself to cozying up to the manual and doing serious practice and training. Weve found them to be occasionally difficult but hardly impossible to master. Given how much the typical GPS navigator is expected to do, one-knob set-and-forget approaches are definitely gone for the moment and probably gone forever.
Also With This Article
Click here to view “Wait for WAAS? We Don’t See Why.”
-by Paul Bertorelli
