Size may or may not matter, depending on who you ask, but to Embraer the final stretch of its new E-Jet family, the E-195, is a vital gambit aimed at building on the bridgehead established with the E-190 and penetrating new 100-seat market sectors above and beyond the company's traditional regional roots.
The sheer size of the E-195 distinguished it from the start, and in today's bi-polar world of Airbus and Boeing airliners, the sleek looks of the advanced twinjet will attract more than just a curious second glance when the first aircraft enter service over the next few months. Measuring an impressive 38.6m (120ft) long overall, the E-195 is almost identical in length to the McDonnell Douglas DC-9-40, around 1m longer than an Airbus A320 and about 1m shorter than a Boeing 737-800.
The latest Embraer E-Jet is also 2.4m longer than its E-190 stablemate, enabling it to seat between 108 and 118 passengers. The first is to be delivered in August - in its highest seat-capacity configuration - to UK-based Flybe, which ordered it in June 2005. Flybe placed orders and options for 26 E-195s, saying it chose the aircraft over 150-seat types after being convinced by its size, economics and performance benefits. The $870 million deal included 14 firm orders and 12 options.
At the time of the order announcement, Flybe chairman and managing director Jim French seemed to back up Embraer's assertion that the E-170/190 family and its derivatives are the right aircraft for airlines looking to "right size" their fleets. He said that Flybe rejected larger aircraft types: "We looked at the classic 150- to 180-seat aircraft from Boeing and Airbus, but decided that these were simply too big, in our belief, for our market. We needed to meet the needs of the regional market."
French said the carrier had been attracted by the E-195's projected performance figures in 2003, and had nearly opted to acquire the type at that time. The figures included predictions the E-195 would have 20% lower fuel consumption per seat than the BAe 146s Flybe now flies. Delivery of the E-195s will give Flybe a single-type jet fleet to complement its single-type turboprop fleet of Bombardier Q400s. French said: "That's very important to us - we wanted a two-fleet strategy."
But it has not all been plain sailing and, as with so many 100-seater hopefuls, the E-195 has had a protracted and uncertain birth. Conceived as the ERJ-190-200, the higher-capacity variant was launched in June 1999 by now defunct Swiss carrier Crossair with a commitment involving 60 firm orders, covering 70-seat ERJ-170s and up to 15 108-seat ERJ-190-200s for delivery from late 2002.
However, following Crossair's merger with the former Swissair to form Swiss International Air Lines, and the financial problems that hit the carrier, Embraer was forced to shift development priorities towards the 100-seat E-190 for US low-cost carrier JetBlue, which came to the rescue with a massive order for the smaller variant in July 2003. Meanwhile, Swiss's outstanding order morphed into 15 E-170s and E-190/195s with 15 options, but is on hold as the carrier keeps its focus on strict cost-cutting measures imposed by soon-to-be parent Lufthansa. While Embraer casts the net for more sales, Swiss is optimistic it will eventually take the new aircraft in the long term, saying its Lufthansa takeover "dramatically altered our purchasing power and we will be looking at this closely". All being well, Embraer is maintaining plans to deliver one E-170 a month to Switzerland, starting in 2008, and begin initial E-195 deliveries there the following year.
Against this uncertain background, however, the E-195 has already marked its place in aviation history as something of a redoubtable survivor. Since its inception, this slender jet has outlived the BAe 146/Avro RJ/RJX, Bombardier BRJ-X, the still-born Fairchild Dornier 728/928 and Fokker 70/100. It has also established a good head start and penetrated the market well before rival projects such as the yet-to-be-launched Bombardier CSeries, AVIC ARJ21 and Sukhoi RRJ-95, while effectively helping seal the fate of the now-closed Boeing 717 production line in California.
Unlike the leap from the E-170/175 to the E-190, which involved a significant fuselage extension as well as enlargement of the vertical fin and development of an entirely new, larger wing, the last growth step to the E-195 has been achieved by the simplest of stretches. Notwithstanding the schedule swop with the E-190, the E-195 development plan has plodded steadily along since 13 months of preliminary design studies were completed in the second quarter of 2001. Embraer's now traditional joint definition phase saw detailed design completed over the rest of 2001, with manufacturing starting in early 2002.
Powered by its General Electric CF34-10E engines, the aircraft flew for the first time on 7 December 2004, staying airborne for almost 2h on its maiden flight from the company's São José dos Campos headquarters. Nearly all remaining flight tests have been conducted at Embraer's rapidly expanding Gavião Peixoto test and production facility 425km (265 miles) from São José dos Campos. The prototype aircraft, 0005, had accumulated almost 400 flight-test hours by mid-June and the first production aircraft for Flybe, 0029, had so far notched up more than 30h with basic certification flight testing completed on 4 May. Embraer received Brazilian CTA certification at the end of June and expects to secure US Federal Aviation Administration certification by "year end".
Shorter range
Compared with the E-190, which seats between 98 and 108 passengers, the longer model is designed to take up to 118 passengers in a four-abreast cabin. Without changes to the basic 16,000 litres (4,220USgal) fuel capacity of the wing and fuel tank system, the extra weight and capacity of the E-195 is therefore traded off against range, which is reduced to 3,890km (2,100nm) from the shorter-bodied aircraft's 4,260km.
Structurally, the changes are accommodated by extensions to what Embraer terms "plug A" and "plug B" either side of the unchanged, locally made 5.98m-long fuselage centre section. The Embraer-made nose section remains common, as does the Latecoere-built "centre fuselage I" section. Plug A, also called centre fuselage section IIA on the E-190, is increased in length by two fuselage frames to 3.22m, versus 2.41m for the same extension on the E-190.
Aft of the centre section, Plug B is increased in length by four frames and measures 5.31m, compared with the 3.7m of section IIB on the E-190. Aft of the new section is the common 6.48m-long aft fuselage section, also provided by Latecoere. The forward section comes complete with built-in cargo door, while the aft common section contains a cargo door on the lower right side, as well as right and left passenger doors and service doors.
The rear fuselage, built by Aernnova (formerly Gamesa Aeronautica) of Spain, along with the rest of the empennage, incorporates a dome-shaped pressure bulkhead fabricated from a forged and rolled ring with 10 radial sections. The aft section also contains a cutout for the horizontal stabiliser that remains unchanged from the E-190, with a 12.08m span, itself more than 2m wider than originally planned by Embraer. This was altered to improve pitch authority early in the design while the vertical tail, originally 9.67m high overall, was increased to almost 10.5m as a result of lessons learned during the E-170 flight tests. The aftmost frame consists of two separate upper and lower "D" shapes joined by duplicated stabiliser hinge fittings.
The fuselage therefore retains the cross-section that Luis Carlos Affonso, now senior vice-president, Embraer executive jets, describes as "one of the most innovative aspects of the design". Affonso, who oversaw the E-Jet development as senior vice-president of engineering and new development, says the decision to adopt the four-abreast layout was driven by the need to avoid the middle seat of a five-abreast layout. The resulting cross-section "has nothing to do with smaller jets. We wanted to get the same seat width and overhead bins that you would find on the big jets," he says (Flight International, 20-26 July 2004).
The cross-section, which comprises a double-bubble made up of two circular arcs of different radii, provides a 2.74m-wide cabin with up to 2m interior headroom and a 0.94m deep underfloor hold below the main deck. Although more structurally complicated than the purely circular cross-section adopted by some of its competitors, Embraer says the market response has proven the popularity of the design.
Shared wing
The E-195 also shares the same 28.7m span as the E-190. The wing is 2.72m longer than that of the E-170/175, and has an area of 92.5m2 (995ft2). The wing is with a dihedral of 5º, has an aspect ratio of 8:1 and a modest sweepback at 25% chord of just under 23.5º. The wing is made in two main parts; an inner-wing stub and an outer-wing section. Both are made by Kawasaki Heavy Industries (KHI) by its subsidiary Kawasaki Aeronautica do Brasil, which opened a 5,400m2 factory at Gavião Peixoto in 2003, where it assembles E-190 wings using parts shipped from Japan and skins made by Vought.
However, citing the increased pressure on its production capacity from its commitments to the Boeing 787 programme, for which it is making wing and fuselage parts, KHI recently negotiated for Embraer to take an unspecified portion of the E-190/195 wing work back in-house. KHI will incur a one-time loss of ¥15.8 billion ($140 million) to cover the cost of the partial transfer of E-190 production to Embraer, but as the Farnborough air show loomed, had yet to detail the handover process or its timetable.
Part of the decision to hand wing assembly back to Embraer was the Brazilian company's plan to raise production of the E-190/195 to as many as eight a month by mid-2007 to cope with rising demand. Mauro Kern, airline market programmes vice-president, says: "We are ramping up to four a month of the larger aircraft and will be going up to five or six a month later in 2006, and seven to eight [a month] by mid-2007. It's an aggressive ramp-up."
The decision to boost rates comes on the heels of a spate of new orders for the larger E-190/195 models since January. The E-Jet backlog, which previously stood at 322 (106 E-170s, eight E-175s, 179 E-190s and 29 E-195s) has since surged with the US Airways-Embraer agreement to convert 25 undelivered E-170s on firm order to E-190s, as well as convert the remainder to the larger models. The restructured agreement also adds 50 more options. Other new business includes five firmly ordered and 20 optioned E-190s from Colombian carrier Aero Republic. The orderbook was also bolstered in March by a Royal Jordanian order for seven E-195s. Kern says the acceleration of the E-190/195 is planned so that it "does not compromise our ability to produce the E-170".
Ensuring commonality
To fit in within its "right sizing" concept, in which airlines can trade up and down within the E-Jet family to suit capacity and performance needs, Embraer has attempted to ensure as much commonality between the variants as possible. In terms of line replaceable units (LRU), the avionics commonality between the E-190/195 is 100%, with slight differences only in the Honeywell Primus Epic flight management system (FMS) database, to suit the specific performance changes associated with the E-195, and a new radar-altimeter antenna position.
The dual-channel automatic flight control system (AFCS) takes charge of flight guidance and control, thrust management and some AFCS processing within the Primus Epic modular avionics unit. Flight guidance and control includes autopilot, automatic pitch trim, yaw damper and Mach trim, as well as turn co-ordination, flight director guidance and windshear escape guidance. Although the basic architecture and requirements for the system are identical to those for the E-190, the extra length of the E-195 is reflected in a modification of the take-off angle for flap setting 4 from 12º on the E-190 to 11º on the E-195.
The Parker Aerospace-developed fly-by-wire flight-control system governs the ailerons, rudder and elevators, as well as secondary flight controls including three outboard pairs of multifunction spoilers, two inboard pairs that act only as ground spoilers, four pairs of leading-edge slats, two pairs of trailing-edge flaps and the horizontal stabiliser. The system is virtually identical to that of the E-190, with 100% LRU commonality and identical operational characteristics, but the aileron command cables are 0.8m longer on the stretched aircraft. "There are small changes in the notch filter and gain for the angle-of-attack limiter function, but otherwise even the autopilot adjustment is the same for both the 190 and 195," says director of development engineering Emilio Matsui. "We thought we'd need a tail bumper, but in flight test we showed it wasn't needed," adds Kern. "The aircraft will be certified without it."
The Hamilton Sundstrand-developed air management system (AMS) is one of the few areas where some changes are found, particularly in the controller, which has a different flow schedule from the E-190 at altitudes above 20,000ft. The AMS combines the environmental control, pneumatic, ice-protection and oxygen systems into a single, integrated system with one controller. The cabin pressure-control system is also part of the AMS, although it has a separate controller. Specific hardware changes include longer air-conditioning ducts and a longer water-tank pressurisation line, which is re-routed to the forward area, and a longer auxiliary power unit (APU) bleed line.
The Parker-provided electrical system is a primary three-phase 115/200V AC, 400Hz system made up of two engine-mounted 40kVA integrated drive generators, an auxiliary generator at the APU, a 15kVA ram-air turbine (RAT) emergency generator and two nickel-cadmium batteries. The system is made up of two independent networks that, in the event of a power generating source failure, automatically tie the networks to maintain an adequate power supply for the electric buses.
The fuel system is made up of integral wing tanks that extend into the wing stub with continuous flow through to the baffle rubs by the outboard ailerons.
Each wing has a fuel capacity of 8,000 litres with a maximum refuelling rate of 760 litres per minute at normal fuelling pressure rates of 2.41-3.45bar (35-50lb/in2). Average refuelling time is around 10min. A dedicated electrical DC booster pump is provided to feed the APU during ground operations when the engines are off. The fuel feed line to the APU, a Hamilton Sundstrand APS 2300 unit identical to that used in all E-170/190 family members, is 160cm (63in) longer on the E-195 than the E-190 due to the aft fuselage plug.
Hydraulic systems
The hydraulic system is made up of three independent systems operating at 207bar. System one and two between them power the thrust reversers, ground and multifunction spoilers, elevator actuators, brake systems, rudder and parking brakes. The second system also powers the nose wheel steering and nose/main landing- gear extension and retraction. The third system powers the outboard actuators on the left and right ailerons, right-hand elevator and lower actuator on the rudder. In the E-195, system one and three lines are 120cm longer due to the aft fuselage extension, while system two lines are stretched by the same amount aft and a further 81cm forward due to the forward fuselage plug.
The landing gear, produced by Liebherr, is a conventional tricycle configuration with the main gear retracting inboard, pivoting around a mounting on wing spars two and three. The nose gear, which retracts forward, is mounted in the forward fuselage by means of two spherical bearings and when in the down position has an inclination of 8º forward. The only differences in the E-195 landing-gear system compared with the otherwise identical system in its siblings are longer emergency/parking brake and free-fall cable lengths.
General Electric expects to secure US FAR 33 engine certification for the CF34-10E7, the latest, highest-thrust rating variant of the powerplant, on 31 July. Although sharing a common bill of materials with the other CF34-10E variants powering both the E-190 and E-195, the newest version pushes take-off thrust capability to 20,000lb (90kN), up from 18,500lb on the E5. "So this thrust level is now available to the operators when they need it, and will enhance the range capability," says GE CF34 programme manager for Embraer applications John How.
The engine rating change, which is made via a new software load in the full-authority digital engine control, is "not exclusively required for the 195, and is also available for the 190", says How. GE says the growing success of the -10 family, which is also being developed to power the ARJ21 from 2008, is a testament to its decision to completely redesign the engine around a scaled version of the core of the CFM56-7B developed for the Boeing Next Generation 737. "It's definitely paid dividends," says How, who adds the "wise decision" is paying off both in terms of performance and lower maintenance costs.
The engine was first flown on GE's Boeing 747 testbed in November 2003, and began flight tests on the E-190 in early 2004. The engine has a 1.3m-diameter wide-chord fan, a three-stage low-pressure (LP) compressor, nine-stage high-pressure (HP) compressor, single-stage HP turbine and four-stage LP turbine. GE is also certificating the engine at a new lower-thrust E2A1 rating for the E-190 later this year, and with the introduction of the E7 rating, will make the engine available at six different thrust settings between 16,650lb and 20,000lb.
Longer-range XLR
GE is also in the forefront of Embraer's studies of a longer-range E-195XLR variant that is aimed at combating what some observers see as the only potential Achilles heel of the aircraft when it comes to sales in the North American market.
Embraer developed similar range improvements for the ERJ-145 family and "AR" versions of the E-Jets, and has been studying an extended-range variant of the E-195 to attract the interest of legacy carriers such as Delta Air Lines and Northwest Airlines, both of which are in the hunt for DC-9/MD-80 size replacements.
Although Embraer earlier looked at a possible Pratt & Whitney PW6000-powered variant of the E-195, it subsequently remained loyal to GE, which says "the current -10E engine could be modified for a thrust bump of 5% or so - which is around 1,000lb". How adds that this would require "significant changes" to avoid incurring unacceptable durability and maintainability penalties, and says with these improvements the baseline architecture is capable of around 21,500lb "without having to grow fan diameter". He says the materials upgrade will require a sizeable investment, so "we are studying the market", says How.
In the meantime, GE - which delivered its 100th production -10E engine to Brazil in May - is ramping up engine assembly rates in lockstep with Embraer's rate increase. Up to 180 engines may be delivered to support around 90 aircraft currently scheduled for delivery in 2007, although the rate is sufficiently flexible to go beyond this should Embraer opt for increased deliveries, says How.
Embraer, meanwhile, continues to aggressively update the E-Jet series, with the E-195 destined to take advantage of all the latest improvements. Ongoing certification flight tests of the Rockwell Collins head-up-guidance (HGS) unit, for example, are aimed at full Category 3 low-visibility operations clearance on the E-190 later this year and will be rolled over to the E-195. The tests, expected to take place in July, follow the completion in late April of engineering development flight tests in Portland, Oregon.
Clearance to use the full capability of the HGS to make landings in poor visibility is expected to be a major operational benefit for carriers operating in weather-prone areas like Europe - such as Flybe, which will be launch customer for HGS on the E-195. Embraer market intelligence vice-president Luiz Sergio Chiessi says: "We hope to have Cat 3 with the HGS for Flybe for the 195 in 2007." Chiessi adds that, aside from Cat 3 with the HGS for JetBlue on the E-190 "later this year", Embraer also plans to complete Cat 3A certification work for the E-175 by around the same time. Unlike the dual HUDs in JetBlue's E-190s, the Flybe configuration will be single installation only.
With Brazilian certification now in the bag and European and US approval to follow, Embraer hopes the hectic activity marks only the beginning of a very busy decade for its mainline twinjet. ■
Source: Flight International
