Sixteen years after conception, a decade since its first flight and $1.4 billion dollars later, the Eclipse 500 finally is maturing into a full-fledged business jet, albeit the tiniest in current production. The world’s first VLJ was endowed with promising but untested DNA. As a result, it went through one of the most difficult and time-consuming development cycles in the history of business aircraft.

Its original 770-lb.-thrust Williams EJ22 turbofans were hyper efficient, but trouble-prone from the first ground run. The Avidyne components for the Avio computer system failed to live up to expectations. The tiny fire extinguisher bottles leaked, exposing the engine cases to highly corrosive phosphorus tribromide. The ice protection system was not certifiable in its original configuration.Pilots could not fly coupled approaches, requiring two pilots for Part 135 operations. The windshields cracked near their mounting holes. The autothrottles did not work, the tires wore out after a few landings and the air conditioning was weak. Flight into known icing approval was a distant promise.

Notwithstanding such setbacks, Eclipse still managed to book more than 2,000 orders, as many as 2,600 at one time. After several fits and starts, Eclipse Aviation managed to deliver 260+ aircraft from late 2005 to mid-2008, although they were far from full-mission capable. Buyers were hopeful that Eclipse would be able to deliver promised modifications and improvements to fix the glitches, which would bring up its aircraft to contract specifications.

Customers’ hopes were vanquished when the Great Recession of 2008 sealed the fate of the company. Vern Raburn’s  dream of mass producing the world’s first VLJ, a twin turbofan aircraft and pricing it below a Beech Baron evaporated in November of that year when Eclipse was forced into bankruptcy reorganization and then later into liquidation.

Bankruptcy not only dissolved the company, it also annihilated hundreds of purchasers’ order deposits for aircraft yet to be built. The sorry state of Eclipse Aviation also soured most would-be investors who might have tried to resuscitate the Eclipse jet program.

Health care software and employee benefits entrepreneur Mason Holland, however, saw great value in the assets of Eclipse Aviation as well as in the latent potential of the diminutive jet. Holland, along with other investors, some of whom personally had lost their deposits on an Eclipse 500, bought the Albuquerque, N.M., company’s assets for $20 million and assumed another $20 million in debt in mid-2009, forming Eclipse Aerospace. United Technologies Sikorsky Aircraft Corp. would later buy into Eclipse Aerospace, bolstering prospects for restarting new aircraft production as well as potentially providing global customer support services. Sikorsky also planned to farm out much of the Eclipse jet manufacturing to its Panstwowe Zakłady Lotnicze Mielec (PZL) subsidiary in Poland, thereby slashing production costs.

Holland shared Raburn’s original dream of building tiny VLJs able to climb to 41,000 ft. to top most weather, cruise 100-kt. faster than most turboprops and burn less than 350 lb. per hour. But, he knew he could not keep Eclipse Aerospace afloat using Raburn’s high-rate production, low-profit margin business model. That might work for Microsoft and Symantec consumer products, but it was unrealistic for a niche aviation product such as a VLJ.

Holland also wanted to upgrade the aircraft with better systems and wider safety margins. He also knew he would have to raise the purchase price by nearly 50% to ensure profitability.

The result is the new Eclipse 550: a second-generation Eclipse 500 that not only delivers on the performance and functionality promises of the original jet, but also adds new capabilities. However, there is still plenty of room for improvement, as I will discuss in this report.

Structure and Systems

The Eclipse 550 is not a new model from Eclipse Aerospace. It is the firm’s marketing designation for new production Eclipse 500 jets with standard upgrades such as approval for flight into known icing, glass outer ply windshields, Avio 2.7 total aircraft integration system with faster avionics processors, anti-skid brakes, dual integrated FMS, ADS-B OUT and stand-alone integrated standby instrument system.

The first Eclipse 550 aircraft are rolling off the assembly line as Eclipse 500 aircraft with s.n. 550-0263, -0264, -0265, -0268 and up into the -200s. Completed aircraft then are rolled into Eclipse Aerospace’s Part 145 MRO facility where STC modifications are completed, thereby converting them into Eclipse 550 aircraft.

Eclipse Aerospace plans to incorporate the STCs as modifications to the EA500 design, thereby enabling the firm to produce Eclipse 550 aircraft without additional changes. These aircraft will have s.n. 550-1000 and subsequent.

The primary airframes of all Eclipse 500/550 aircraft are high-strength aluminum semi-monocoque structures having components joined together using an innovative friction stir welding process as well as conventional mechanical fasteners. Composites are used for second structures such as the radome, fairings and floor panels.

Much of the aircraft, including several ship sets of wings built by Fuji Heavy Industries, is assembled from airframe components in inventory at Albuquerque, leftover from when the program was owned by Eclipse Aviation. That results in much lower production costs for Eclipse Aerospace while supplies last.

The current Eclipse 550 production line reveals much about how far the product has evolved in five years under the aegis of Eclipse Aerospace as the new owner. Changes to the production process resulted in much-improved fit of metal-to-metal and metal-to-composite joints. Manufacturing tolerances are considerably tighter and much less custom trimming and shaping is needed. Very little body filler is needed to cover seams and fasteners. 

The Eclipse jet originally was designed to be MSG3 compliant, but several manufacturing shortcuts sabotaged that goal. The forward equipment bay access door, for instance, was sealed in place to prevent moisture intrusion. But the door had to be removed regularly to service the start and system batteries, vapor cycle air-conditioning compressor and other systems. When the door was replaced, the seam had to be resealed and the aircraft left idle for 24-48 hr. for the sealant to cure. The Eclipse 550, in contrast, has a form-in-place seal that requires no downtime for curing. So removing and replacing the forward equipment bay access door is almost as routine as opening and closing the hood of an automobile.

In addition, stainless steel screws now are used to attach panels and components on the aircraft’s exterior. The fasteners are installed after the aircraft is painted so they do not tear up the finish when they are removed and replaced.

Eclipse Aerospace now uses a two-step paint process. The base coat is applied first, followed by stripes, accent colors and placard stencils. A second, clear coat then is applied, resulting in one of the smoothest and highest gloss finishes seen in the light jet class.

The aluminum windshield frames now are polished and coated with clear urethane rather than painted. This process change not only improves appearance, it also makes it easier to remove and replace fasteners should there be a need to replace any of the four transparencies.

The interior completion is just as impressive with top-notch leather work on the seats as well as high-gloss wood trim on the side panels and cabin upholstery work that is on a par with the best in the light jet class. 

The cabin has three 14.3-in.-tall by 10.4-in.-wide windows on each side. The main entry door, measuring 3.9 ft. high by 1.9 ft. wide, is a two-piece clam shell design. The upper opens first and closes last. It is counterbalanced with a pressurized gas cylinder. The lower door is supported by two cables and it has two integral steps that fold down when the door is opened. The right side of the aircraft has a 2.2-ft.-wide by 1.7-ft.-high plug design over the wing emergency exit.

Interiors are configured with two pilot seats having five-point harnesses, along with height, track and recline adjustments. Cockpit access is tight, but the right front seat can be temporarily moved back 4.5 in. beyond the aft track stop to help the pilot slide into the left seat.

The 160-cu.-ft. main cabin features three seats, two on the right and one on the left. They are staggered to provide more room for each passenger. A fourth passenger seat is available, but head, shoulder and hip room in the rear seat row is not generous. The seat backs fold forward to provide improved access for loading passengers and luggage.

Up to 26 cu. ft. and 260 lb. of baggage, firmly secured by an 11-point tie-down net, may be stowed behind the passenger seats in the main cabin. There is no external baggage compartment.

The Avio-integrated flight deck, developed for the Eclipse 500, is a design feature that sets apart the Eclipse 550 from its competitors. Major components include the EFIS displays, dual FMSs, digital flight control system, automatic pitch trim and autothrottles, among other avionics functions, plus airframe systems functions such as stall protection, engine fire warning, firewall shutoff and extinguisher activation, cabin pressurization control, gear warning, landing gear, fuel quantity management, heating and cooling, and flaps control.

The aircraft is an “all-electric” design powered by two 200-amp, 28 VDC starter generators and two 22-amp-hr., 24 VDC batteries in the forward equipment bay. The start and systems batteries were moved from the aft section of the aircraft to the forward end to offset a pronounced aft CG shift when the Eclipse made the switch from ultra-light Williams EJ22 engines to much heavier PWC PW610F turbofans in early 2003. The batteries have long cable runs that impose significant limitations.

Minimum temperature for a battery-only start, for instance, is 5C/41F. Below that temperature, a ground power cart must be used. In addition, if the aircraft batteries have been stored at temperatures below -15C/5F, flight is forbidden. They must be warmed before use. And each battery has a heater pad that activates if the OAT is below 10C/50F. The battery charging rate must be less than 7 amps before takeoff to assure there are adequate reserves to meet emergency power requirements.

Long term, the Eclipse 550 could benefit from more robust batteries, perhaps lithium ion designs, when they reach maturity.

The electrical power distribution system is impressively innovative, far ahead of other Part 23 aircraft designed in the late 1990s. It features six busses, split left and right sides, 127 electronic circuit breakers, automatic control and automatic non-essential load shedding. The two batteries function as start and system batteries for start, then become left and right side batteries during normal operations. The twin batteries function as electrical surge tanks to minimize voltage transients when electrical loads are added to or removed from the main busses.

The 1,682-lb. capacity fuel system has refueling ports in the left and right wing tip tanks. Boost and transfer jet pumps,
respectively powered by motive flow from the engine fuel pumps and boost pumps, supply the engines. Brushless, long-life, electric boost pumps provide fuel for engine starting and cross-feed. They also operate when the fuel level is low in the sumps and act as backups for the boost jet pumps. Anti-icing fuel additive is required.

The primary flight controls are mechanically actuated, with left- and right-side sticks controlling the ailerons and elevators. The ailerons have no servo or spring tabs, so lateral control force is relatively hefty at high speed. Conventional floor pedals actuate the rudder. The engines are mounted relatively close the longitudinal centerline, so VMC is below stall speed for all weights and configurations, and rudder pedal forces are relatively moderate during one engine inoperative conditions.

Brushless DC motors provide three-axis trim. The elevators and rudders have trim tabs. The ailerons have a spring bias trim system. Both angle of attack and angle of attack rate stall protection are provided by an aural warning system and stick pusher.

The three-position trailing edge Fowler flaps — up (0 deg.), takeoff (17 deg.), landing (34 deg.) — are powered by left and right linear electric actuators with asymmetry protection.

The aircraft has dual-zone climate control and a fully automatic, 8.3 psi pressurization system that provides an 8,000-ft. cabin altitude at FL 410. Cooling is provided by a more powerful and lighter-weight vapor cycle air-conditioning system with separate cockpit and cabin evaporators. It automatically switches off as the aircraft climbs through 29,000 ft. and turns back on when descending through 28,000 ft.

The emergency oxygen system has a 22-cu.-ft. capacity bottle with a quick donning O2 mask for the pilot and five drop-down masks for other occupants that automatically deploy if the cabin altitude exceeds 14,000 ft. The optional FAR 135 package has a 40-cu.-ft. bottle, a second side quick donning O2 mask for a co-pilot and four drop masks for passengers.

The landing gear is electrically controlled and actuated. The main mounts have trailing link geometry for smooth touch downs. Anti-skid braking now is standard, with the Eclipse 550 being the first aircraft to use a newly patented, lightweight system that uses highly compact left and right hydraulic power packs. The power packs do not run continuously with the landing gear down, but rather they activate within one-tenth of a second of pressing the brake pedals with weight on wheels. The anti-skid computer uses GPS ground speed, wheel rotation speed, weight on wheels and other inputs to activate pressure relief valves in each brake line in the event of wheel lockup. The system is disabled below 10- kt. ground speed.

Another innovative feature is the aircraft’s PhostrEx phosphorus tribromide fire extinguishing system developed by Peter Haaland. The chemical is highly effective, so only two teaspoons are needed to extinguish an engine fire, and it is an eco-friendly, non-ozone depleting chemical. Phosphorus tribromide, though, is highly corrosive to engine and human body parts. But, flushing surfaces exposed to PBr3 with fresh water causes the chemical rapidly to hydrolyze into phosphorus acid (H3PO3) and hydrogen bromide (HF).

Flying Impressions

Accompanied by Jerry Chambers, the company’s flight test director and chief test pilot, we strapped into the left seat of s.n. 550-0264, an Eclipse 500 that was upgraded to the Eclipse 550 configuration by the company’s Part 145 repair station after receiving its certificate of airworthiness. The OAT was 28C, but the interior was comfortably cool because the aircraft was connected to ground power enabling the vapor cycle air-conditioning to be used prior to engine start.

The single-pilot BOW was 3,956 lb., 132 lb. heavier than the spec base weight for an aircraft with no options. 

But, the aircraft was only 29-lb. heavier than the last production Eclipse 500, despite having heavier glass face windshields, a premium interior and custom exterior paint, among other options. With two people aboard and 1,145 lb. of fuel, ramp weight was 5,300 lb.

Chambers ran through the pre-start checklists. He used the Avio 2.7 system to compute weight and balance, along with 85-kt. rotation and 101-kt. V50 speeds, and the 3,681-ft. all-engine takeoff distance over a 50-ft. obstacle, based on using takeoff flaps. Notably, OEI climb gradient, with gear and flaps retracted, was a modest 2.0% as a result of Albuquerque’s 5,355-ft. elevation, 28C OAT and actual takeoff weight.

Engine start is simple. Just turn each of the engine control knobs on the overhead panel from off to start/run and the FADECs handle the rest. They turn on the fuel boost pumps, turn off the bleed air supply to the cabin, reconfigure the electrical system for start and send power to the starter generators. The FADECs provide full start protection.

We disconnected external ground power and taxied to Runway 21 for an intersection departure at Taxiway G, providing us with an available runway length of 7,660 ft. Avio 2.7, the latest version of avionics hardware and software, supports top-to-bottom electronic charts on the MFD. We used the airport diagram depiction to navigate to the active runway. But, the relatively large size of the electronic charts and their placement on the left side of the MFD pushes the engine vertical tape gauges farther to the right side, and therefore out of the pilot’s immediate field of view. We would like to see that arrangement reversed, with the EICAS on the left and electronic charts on the right side of the MFD.

Acceleration on takeoff was modest. Pitch forces on rotation were light and control harmony was excellent at low speeds. As speed increased through 170 knots, however, we noticed that while pitch control forces remained light, roll control forces increased significantly. The aircraft could benefit from the addition of servo or spring tabs to decrease roll control effort at high speed.

The throttle quadrant has no detents for takeoff, max continuous and max cruise. So, it is up to the pilot to hawk the engine gauges and make the appropriate thrust adjustments. However, once the autopilot is coupled, the autothrottles are available to manage thrust setting chores. Equivalent airspeed hold and pitch hold are the only two vertical modes available for climb. Avio 2.7 automatically sets the speed bug on the PFD for weight and OAT. But, changes in OAT cause the bug speed and equivalent airspeed to vary, so the autopilot chases nose attitude. 

In our opinion, the aircraft needs a vertical speed hold mode to dampen out autopilot pitch oscillations. Vertical speed mode allows the pilot manually to make changes to the rate of climb to hold the desired climb speed.

Once level westbound at FL 400, we accelerated to max cruise speed. At a weight of 4,984 lb. and in ISA-C conditions, the aircraft cruised at 344 KTAS while burning 372 lb. per hour. The AFM, in contrast, predicted a max cruise speed of 357 KTAS on 366 lb. per hour for a 4,900 lb. airplane at the same temperature. However, there were 70+ knots of wind at FL 400, so the cruise performance check may have been corrupted by high altitude wave currents.

Notably, the Eclipse 550 has one of the quietest interiors of any light turbine aircraft we have flown, quantifiably less noise than the Embraer Phenom 100 and, qualitatively, perhaps even quieter than any of the entry level Citations. Conversations between occupants can be done with low voices.

We then headed back toward Albuquerque and descended steeply. Using the flight guidance system’s altitude change (ALG CHG) mode causes the aircraft to descend at 3 deg., but the pilot can alter the vertical speed using the pitch wheel on the flight guidance panel.

Chambers deliberately exceeded the default 3-deg. descent to demonstrate the automatic speed protection built into the auto-throttle system. In the event of an over-speed condition, the auto-throttles automatically will engage and retard the thrust to help stabilize aircraft speed. Similarly, they automatically will engage if the aircraft approaches a stalling angle of attack, advancing the thrust to max continuous to help avoid the stall.

On the way down, we noted that Avio 2.7 lacked a coupled vertical navigation (VNAV) function and a multiple vertical waypoint feature. However, it did have an advisory VNAV function that provided vertical rate guidance to a single, pilot defined vertical waypoint.

Level at 15,500 ft., we flew a few steep turns to get more feel for the aircraft. Aircraft handling qualities reinforced our impressions about pleasantly light pitch forces, but heavy roll control forces at high speed.

We also flew an approach to stall, gear and flaps extended, to stick pusher. Handling characteristics and stability throughout the maneuver were excellent. The aircraft recovered promptly as we crisply lowered the nose and accelerated.

Proceeding to Albuquerque Double Eagle, we flew two IFR approaches in VMC. The first was a LNAV/VNAV GPS Runway 22 and the second was an ILS to the same runway. The aircraft’s WAAS receiver also supports LPV approaches, but none were available for us to fly.

Approach guidance in both FMS approach and ILS modes was smooth and precise. But, as soon as we extended the landing gear, the auto-throttles automatically disengaged. They also disengage if the autopilot is disengaged.

Thrust must be manually adjusted during final approach. We believe that auto-throttles are most useful as a workload-reducing device when they are available from the final approach fix to the runway threshold, either when the aircraft is coupled to the autopilot or during hand-flown approaches.

Landing approaches typically are flown at Vref+10, but they safely can
be flown at Vref with no padding. Crossing the runway threshold at 50 ft. AGL, thrust should be reduced so that the
aircraft touches down 1,000 ft. from the threshold, 8-16 kt. below Vref, depending upon landing weight, according
to the AFM. This technique prevents excessive float and assures the aircraft can be stopped in the published landing distance.

Returning to Albuquerque Sunport, we set up for a visual to Runway 26. After we touched down, we made a max performance stop. The Eclipse 550’s new anti-skid system worked flawlessly, alternately applying and releasing the brakes to prevent wheel lockup. This was a highlight of the flight.

We taxied back to Eclipse Aerospace’s ramp 1.8 hours after departure.

Conclusions

The Eclipse 550 is head and shoulders above the Eclipse 500 in fit, finish and functionality. Standard anti-skid braking is a valuable addition, particularly as the aircraft has no ground spoilers. Its new Avio 2.7 system provides features that customers long have wanted, such as full-size terminal, approach and airport charts, optional synthetic vision, takeoff and landing data computations and electronic checklists. Avio now supports XM satellite radio weather, stand-alone integrated standby display units and a full-function moving map. The system also provides optional, but limited auto-throttle functionality, including automatic low- and high-speed protection.

Eclipse jets are low-maintenance machines, having recurring 12-month inspections along with 24-month/300 hr., 36-month/600 hr. and 48-month/1,200 hr. flight-time inspections, whichever comes first. Engine hot section inspections are due at 1,750 hr. and overhauls come at 3,500 hr.

However, there are opportunities for improvement. Multiple waypoint, coupled vertical navigation will be essential for tight tolerance RNP procedures. The aircraft needs autothrottle functionality during the most critical phase of flight:  final approach fix to runway threshold with gear and flaps extended. Such upgrades will make the aircraft more competitive in the marketplace.

More challenging is the overall decline in new light turbine aircraft sales during the six years. Only 228 Citation Mustangs and CJ1 series aircraft, Embraer P100, Eclipse 500, single-engine turboprops and King Air 90 series aircraft were delivered last year, fewer than half the deliveries of 2008.

The Eclipse 550 now sells for more than $3 million, equipped with optional weather radar, autothrottles, traffic alerting system, Class B TAWS and synthetic vision, along with other popular upgrades. That nudges it closer to the $3.5 million Citation Mustang, $3.7 million TBM900 and $4.2 million Phenom 100 competitors that have more range, more tanks-full payload and better one-engine-inoperative climb performance.

Eclipse Aerospace officials, though, assert that the Eclipse 550 is the least expensive twin-turbofan business aircraft available and has the lowest operating costs of any twin turbine aircraft. Operators say they can fly the jet for $800 to $1,000 per hour., depending upon stage length. The Eclipse jet also has an excellent safety record with no fatal Eclipse 500 or 550 accidents.

Regardless of its merits, the Eclipse 550 faces a tough go in the light jet segment because it is the niche that has been hardest hit by the Great Recession of 2008 and it has been the slowest to recover in the ensuing six years. In the first quarter 2014, for instance, Embraer delivered three Phenom 100 jets and Textron Aviation’s Cessna unit delivered one Citation Mustang, according to GAMA.

But, Eclipse Aerospace officials are not banking on the Eclipse 550 alone to sustain company profitability. The plan is to build 17 aircraft in 2014 without having buyers for all of them. Some are being built on spec. The majority of company revenue continues to be generated by its MRO activities. Maintenance and upgrade programs have assured solid profitability during its first five years. The revenue stream will sustain the company, even if the Eclipse 550 production is scaled back in future years.

That could happen. A decade ago, buyers thought they could buy an Eclipse jet for less than half the price of a Citation Mustang or a TBM. Now that the gap is $500,000 to $700,000, it is a tougher sell.

But, Eclipse jet operators remain enthusiastic about the speed, efficiency and altitude performance of their aircraft. They may be the company’s most effective sales personnel. 

 

Interactive See graphs of some Eclipse 550 performance parameters and more on its engines and avionics—tap here in the digital edition, or go to AviationWeek.com/Eclipse550

 

Eclipse 550 Specifications

 

 

B&CA Equipped Price (without typical options)

$2,895,000
   

Characteristics

 
Wing Loading 41.6/58.2
Power Loading 3.33
Noise (EPNdB) 69.2/78.9/81.9
   

Seating

1+5
   

Dimensions (ft./m)

 
External see three view
   

Internal (ft./m)

 
Length 7.5/2.3
Height 4.2/1.3
Width (maximum) 4.7/1.4
Width (floor) 3.0/0.9
   

Thrust

 
Engine 2 PWC PW610F
Output/Flat Rating OAT�C 900 lb. ea./ISA+15C
TBO 3,500 hr.
   

Weights (lb./kg)

 
Max Ramp 6,034/2,737
Max Takeoff 6,000 2,722
Max Landing 5,600/2,540
Zero Fuel 4,922/2,233 c
BOW 3,834/1,739
Max Payload 1,088/494
Useful Load 2,200/998
Executive Payload 1,400/635
Max Fuel 1,682/763
Payload with Max Fuel 518/235
Fuel with Max Payload 1,112/504
Fuel with Executive Payload 800/363
   

Limits

 
Mmo 0.64
FL/Vmo FL 200/385
PSI 8.3
   

Climb

 
Time to FL 370 24 min.
FAR 25 OEI rate (fpm) 533 162 mpm
FAR 25 OEI gradient (ft./nm) 314 52 m/km
   

Ceilings (ft./m)

 
Certificated 41,000/12,497
All-Engine Service 41,000/12,497
Engine-Out Service 25,000/7,620
Sea Level Cabin 21,500/6,553
   

Certification

FAR Part 23 2006