The very light jet revolution beckons with the first generation of players in flight test and other manufacturers eager to bring aircraft into the market

Within just two weeks in late April and early May, the promised very light jet (VLJ) revolution took a few giant strides towards reality. Eclipse Aviation flew its third Eclipse 500 conforming test aircraft, the prototype Cessna Citation Mustang made its maiden flight at Wichita, and Embraer announced plans to enter the market (see P26).

Amid this flurry of activity, Eclipse revealed firm orders for 239 aircraft, plus 70 options, from DayJet, an on-demand jet service that will offer travel on a "per-seat" basis. It will provide services to outlying US regional markets that have limited, if any, scheduled airline services, offering places on a per-seat, shared-ride basis at prices slightly above full-fare economy.

The emergence of DayJet, which has been in "stealth mode" since originally signing for the aircraft in 2002 while it completed its preparations, is just one aspect of the VLJ phenomenon, says Eclipse president and chief executive Vern Raburn. "That's one of the things that is getting to be exciting. People are talking about using the aircraft in ways we never fully envisioned."

That is quite an admission for Raburn, the former Microsoft executive and high-tech entrepreneur at the helm of Eclipse, who is widely considered the "father" of the VLJ. The growth in air service, sky-taxi and private ownership is just the start, says Raburn. "We also see a huge expansion in its use in the corporate market, but in a non-traditional way." He says that the emerging growth is in outsourced and "managed" aircraft.

Big business

"The idea is you own it, but fundamentally you outsource the flight department and you don't share the aircraft," says Raburn. "We're seeing a huge level of interest from people who are saying ‘we want to buy your airplane – how do we do it?' Yet they don't want to be flying it or maintaining it, or have to go out and find a pilot." Raburn adds: "We are talking to a lot of people and fixed-base operators around the country who are seeing the same thing. I think it's going to be a big, big business. It's not fractional, and it's not ownership – it's the evolution of a new kind of aircraft management."

Pure corporate operators, attracted by VLJs' low price and good economics, are also a key market, says Raburn. "They see it is an augmentor to their fleets. Basically, anyone in the company can travel, and if you already have the infrastructure, it works well."

In the first three years, however, the general mix of the 2,200-plus announced firm orders for the Eclipse will comprise individual owners, air-taxi operators and more traditional corporate aviation users. Beyond this "there is a lot of interest from the training and logistics market", says Raburn. "The ‘positively, definitely has to be there overnight' isn't fast enough any more. I'm convinced it's a market that's out there. It might take a couple of false turns before it finds the right fit, but you now see the odd FedEx [Cessna] Caravan flying during the day, and a lot of belly cargo on airlines. If we read the tea leaf signs properly, we think it's a big business that the UPSes and FedExes of this world are not properly equipped for."

So what does all this mean for possible Eclipse production rates? "The site is sized to have capacity for 1,500 aircraft a year, but we have no current plans to do that," says Raburn, who is used to the sniggers when he mentions rates that most people associate with wartime bomber production. The initial production figures are more modest: about 50 in the first six months and just over 100 in the second phase. Full-rate production is two years out, and although precise figures are not revealed, the business plan is built around stable annual production of up to 750 aircraft.

"However, 600-700 is really just to fulfil the replacement market," says Raburn. "We have an impending airworthiness crisis in the general aviation market. Many of them out there are 40- to 50-year-old aircraft built to Second World War standards. They were never designed to last this long.

"Then we have the corporate world. We didn't think there was a big, big corporate business out there. Ultimately, we thought we might sell one for one, but now it could be three or as many as six to one. That's 500 to 600 aircraft a year for the corporate world. That's before we count aircraft for the air-taxi and logistics markets. This is no longer Vern's wild-haired fantasy – this is turning into reality," he says.

Supply hurdles

Yet the transition from fantasy to reality still faces big hurdles – not least the ability of the supply chain to keep pace with the logarithmic rate increases suggested by Raburn. "We don't underestimate the production rate ramp-up and the challenge it presents," he says. "The question is, will suppliers invest and keep up with the increases we need? Obviously, with big suppliers like Pratt & Whitney Canada and Fuji Heavy Industries [wings], they're on top of it. It's the second-tier and smaller companies we have to be careful about."

Given the dire times most of the industry suffered in the 1990s and early 2000s, Raburn sympathises with the concerns and indecision of many of his suppliers, who have been burned before. However, "this is the time that separates the men from the boys", he says, adding that consolidation is a growing trend – particularly with the low value of the US dollar and the acquisitiveness of European-based companies in the market.

The third conforming Eclipse 500 (N504EA) made its maiden flight on 21 April, one week after the second aircraft (N502EA) joined the test programme. Up until then, the effort had rested on the first conforming aircraft (N503EA), which flew for the first time on 31 December 2004. "Our test fleet accumulated a record 37 sorties for 54.8h of flight testing in April, and we achieved several major milestones," says Raburn. "This brings the total, including [now-retired test aircraft] N500EA, to 112 sorties and over 127 flight hours. We expect the fourth aircraft to join at the end of May, and the fifth three weeks or so after that."

The faster tempo is a welcome relief from the frustrating period in February and March when bad weather and foreign object damage to one of the engines on N503EA slowed progress. Having racked up early hours in January, the aircraft flew just 3h in five days in February. Despite the short hours, the test team expanded the landing gear in the normal and emergency operating envelope and opened the flap operational envelope to 200kt (370km/h). Minimum speed was lowered to 72kt at maximum weight.

The target calls for the test aircraft fleet to achieve 500 flight hours by August and 750h by late October. Certification remains on track for 31 March 2006, although there are "a few teething problems with 108 [N503EA]". These include snags with door-seal cabin pressurisation and a nose-gear shimmy.

The next two aircraft into the programme, N505EA and N506EA, will serve as the hard-working "beta" test aircraft, proving the basic reliability of the systems and the design in simulated day-to-day operations.

The aircraft are, respectively, the fifth and seventh off the line, the sixth being the static test airframe that is due to begin a 10-week test programme in early August. Fatigue tests, using the eighth airframe, are set to start at the end of November.

Fatigue tests

Meanwhile, N502EA will be used to explore the top of the flight envelope in terms of flutter and speed. "We have already filled out most of the envelope, but this one will be used to perform VDIVE tests [115% of VNE – never exceed speed]," says Raburn. The dive speed is therefore expected to be around 315kt indicated airspeed, while maximum operating Mach number is set at 0.64.

"It's going remarkably smoothly, but this isn't the last of the flight tests. We have found issues, and there are still some turning up," says Raburn, citing recent adjustments needed to aileron and elevator springs to balance flight control forces.

Weather has also been a factor in delaying the progress of Cessna's Citation Mustang flight tests in Wichita, Kansas, which began with the maiden flight of the prototype on 23 April. The entry-level aircraft, which almost everyone but Cessna describes as a VLJ, underwent an unusually long first flight lasting 2h 21min, during which stability and control were assessed, as well as cycling of the landing gear, flaps and speedbrakes. "The first flight was well ahead of schedule," says Mustang project engineer Jon Carr. "The third quarter was the target for that."

Mustang progress

Up to 29 April, Cessna had put 11.5h on the clock over six flights, but progress was slowed by unseasonably heavy rain and low ceiling. "We have not lost flights due to any failures," says Carr. "This proto­type we believe to be the best and most complete we've ever made, and the length of the first flight gave us an idea of that."

The Mustang prototype will be joined later in the test programme by two production-standard aircraft, P1 and P2. P1 will be used primarily for avionics systems development and certification, while P2 is to undergo function and reliability (F&R) tests, and post-certification "service" tests.

"Before we do P1, we're putting together a fatigue article, which will be completed in May. It will go through a lot of testing and we will put five lifetimes on it before certification," Carr says.

P1 is to make its first flight before the end of September, and P2 is expected to follow in the first quarter of 2006. The fast-paced flight-test schedule calls for up to three test flights a day, says Carr. "We will essentially kill two birds with one stone," he adds, referring to the increased emphasis on F&R tests. Certification to US Part 23 is expected around mid-2006, with first deliveries starting in December next year.

The aircraft will be capable of reaching 340kt and a maximum operating altitude of 41,000ft, and is the second application after the Eclipse for the new P&WC PW600 turbofan, using the 1,350lb-thrust (6kN) PW615F variant. The aircraft also features a fully integrated Garmin G1000 avionics suite.

Cessna's reluctance to call the Mustang a VLJ is based partly on its close association with the legacy Citation market and a tacit acknowledgement that the projected direct operating costs of the aircraft will suit traditional owner-operators rather than air-taxi companies.

Although the first Mustang airframes have been assembled at Wichita, the plan calls for production at Independence, Kansas, where Cessna's piston singles are made. Production tooling is due to be transferred in mid-2005, with full production starting in the fourth quarter of 2005 – the first time any of the Citation lines will have been built away from the Wichita area. Current firm orders for the little Cessna jet stand at 220.


Source: Flight International