Eclipse’s jet evaluation tool has a broader use

 - November 26, 2007, 6:56 AM

Personal jets, mini-jets, ultra-light jets, very light jets. The category has many names and now many contenders. But no company has yet brought a very light business jet to certification and production. Several programs that have been displayed over the years at past NBAA conventions, such as the Alberta Phoenix FanJet and Century Aerospace Century Jet, are now “on the shelf” and may stay there forever.

Depending on how one defines the characteristics of the very light jet group, there are currently up to 11 contenders in this budding category: the Adam 700, Aerostar FJ-100, ATG Javelin, Avocet ProJet, Chichester-Miles Leopard Six, Cessna Citation Mustang, Diamond D-Jet, Eclipse 500, HondaJet, Maverick Jet and Safire Jet.

From this group, some contend that the ATG Javelin, with only two seats in tandem, should not be considered a business jet at all and that the Aerostar FJ-100, as a proposed turbofan re-engining of the Piper Aerostar piston twin, should not be included in the group either. One could debate both sides. And the Maverick Jet is a four-seat, twin-engine turbofan kitplane, manufacture of which has been moved to Russia, where experimental aircraft operate under much more liberal rules. It could possibly evolve into an FAA-certified normal-category airplane in the future, but this depends on many factors that are impossible to predict.

This is not to say that the success of the other programs is much easier to forecast than the above three. The current viability of all the programs ranges from extremely doubtful to very likely, but it is hard to pinpoint the viability of any one program with great accuracy. Their ultimate success, if one defines success as obtaining both certification and production certificates and producing at least 100 airplanes, is even more difficult to predict.

Interestingly, Honeywell’s 12th annual Business Aviation Outlook, announced at the NBAA show, included only the Citation Mustang in its very light jet category, relegating the others to ultralight status. The Mustang is the only model likely to attract flight department usage, say the Honeywell prognosticators. The others, according to a spokesperson, Honeywell believes will be flown mostly by owner-pilots.

Much of the success of the very light jet programs depends, of course, on the general economy. The old saw about a rising tide lifting all boats applies here. But even with the highest of tides, poorly constructed boats still sink, and sparsely funded, ill-planned new airplane designs crash, regardless of how gorgeous their computer-generated images are in their shiny four-color brochures.

But general predictions like this provide little meat for both owner-pilots and (Honeywell’s prognosticators notwithstanding) flight depart- ments that are itching to get their hands on the speed levers of a small turbofan-powered airplane. What they need is an analytical tool or model they can use to evaluate the various offerings.

The Eclipse Evaluation Tool
Eclipse Aviation has developed such a tool, although perhaps not intentionally for others’ use. Motivated by media hype in “the race of the very light jets,” as he put it, Vern Raburn, Eclipse president and CEO, presented the model to AIN last month during the NBAA Convention. Admittedly biased toward the Eclipse 500, the model nonetheless could easily be adapted by anyone wishing to do a more balanced evaluation of the various very light jets, or for that matter, aircraft in any category. It just takes a bit of research and work.

The tool consists of three parts, the third being the most involved. Before starting, however, one must first decide on the characteristics of the category in question. In the case of the very light jets, Eclipse settled on the following: mtow 8,500 pounds or less; capacity for between four and eight passengers; and acquisition cost $3 million or less.

The next step is to determine which jets fit the defined characteristics. In the Eclipse evaluation, the Adam A700, Avocet ProJet, Citation Mustang, Diamond D-Jet, Eclipse 500 and Safire Jet made the cut. Noted as “failing to get out of the gates” were the Century Jet, VisionAire Vantage, FJ-100 (although Raburn said it could perhaps join the race someday) and the CMC Leopard. The other very light jet models of the 11 noted at the beginning of this article were not mentioned in the Eclipse analysis.

The Plot Thickens
Eclipse first plotted these aircraft models on a graph with acquisition price on the vertical axis and a productivity index on the horizontal axis. The productivity index Eclipse defined as: (speed times range) divided by takeoff distance.

Cabin size is often included as part of other value or productivity indices used in evaluating the relative merits of business jets. But cabin size, Raburn figures, is not an important factor in the very light market because most stage lengths are not likely to be overly long. On the other hand, a short takeoff distance would increase the number of usable airports. Not surprisingly, the Eclipse 500 came out on top
in this evaluation.

The next part of the tool compares several characteristics of different aircraft in a circular graph that resembles string art (see Figure 2). At eight points on a circle (the number of points are up to the evaluator) one lists important characteristics, such as speed, range, ceiling, price and so on. A line from the center of the circle extends to each of the points. Each aircraft model is then evaluated for each characteristic and a dot placed on the appropriate line according to the airplane’s relative ranking. After all the dots are in place, they are connected with colored lines for each model. When the graph is complete, a quick glance discerns which aircraft model excels in most of the categories. Again, not surprisingly, Eclipse came out very well.

The third part of the evaluation tool helps answer two important questions: “What does it take to reach certification and production?” and “How well does the airplane meet the needs of the market?” This is divided into several key areas: aircraft development program; company status; FAA certification program; financial stability; aircraft features; costs; airport accessibility; training and insurance programs; maintenance and support programs; high-volume availability (which relates particularly to the air-taxi and air-freight markets); and airliner-like reliability.

In each of these areas, each company and each airplane program is given a rating from zero to 10. The ratings are totaled and the program with the highest total rating is the “winner.” You can guess which very light jet came out on top.

The most difficult aspect of this part of the analytical tool, indeed with the entire evaluation, is obtaining accurate data about so many aspects of so many airplane models. Much information is not available to people outside the companies, and assumptions must therefore be made. The better the data, the more accurate the ratings. Obviously, the ratings can be updated as more information becomes available.

Although not the only aircraft evaluation tool available and admittedly not perfect, the Eclipse analysis tool does give the potential buyer a way to separate the wheat from the chaff while reducing the emotional aspects of making a multi-million-dollar buying decision.