Embraer’s ‘E-Jets’ halfway home

Aviation International News » February 2005
December 10, 2007, 10:29 AM

No one said it would be easy, but Embraer seems to have hit its stride after struggling early on to meet development and certification targets for its new four-airplane series of commercial jets. Last year saw the program speed past a number of milestones, starting with the February certification of the 70- to 76-seat Embraer 170 and culminating at the end of the year with Brazilian approval of the 78- to 86-seat 175–the latest model of the new single-aisle quartet to pass muster with the authorities.

Flying just 450 hours in two prototypes before winning certification, the Embraer 175 differs little from its smaller sibling. The only real structural distinctions involve a pair of fuselage plugs fore and aft of the wing box and some minor frame reinforcements to allow another 2,000 pounds of basic operating weight. Both airplanes use the same GE CF34-8 turbofans, rated for between 13,790 and 14,500 pounds of thrust each, as well as all the same line-replaceable parts.

According to Embraer, the two airplanes handle identically, and pilots certified to fly the 170 will have to undergo virtually no extra training to fly the 175. “We’ve already had meetings on that and we are optimistic we will have the same type rating with level A, which is the highest commonality two airplanes can have,” Embraer director of the 170/190 program Luis Carlos Affonso told AIN.

Of course, the performance of the 175 suffers somewhat from the extra weight it carries–its basic operating weight of 48,083 pounds exceeds that of the 170 by more than 1,900 pounds. Consequently, the 170 can fly some 200 nm farther than the 175.  Meanwhile, on a typical mission the 175 burns 20 more gallons of fuel per hour than the 170. It also needs another 771 feet of runway to take off at mtow, sea level and ISA, and another 118 feet to land under the same conditions.

Although by no means a minor accomplishment, the 175’s certification didn’t seem to generate the same fanfare as the 170’s, perhaps because the two airplanes bear so few differences and the market has yet to really embrace the bigger jet as a distinct product. Now expected by Embraer to serve mainly as a “growth vehicle” for airlines already flying its smaller sibling, the 175 seems unlikely to collect many sales until existing 170 routes mature beyond their present capacity.

So far having drawn just a single order for 15 copies from Air Canada, the 175 might not exist at all if not for the prior incarnation of Fairchild Dornier and its failed 728JET. That airplane–abandoned by the company’s previous owners after they drained all of the $1 billion or so set aside for the project–held five more passenger seats than the 170, a gap prospective customers asked Embraer to close. Out of that effort came the 175.

Unseen Influence
Although not yet an overt commercial triumph, the 175 has produced less obvious benefits to the program as a whole, both for Embraer and for existing customers. For one thing, Embraer has incorporated some of the bigger airplane’s structural reinforcements in the 170, allowing engineers to increase its payload by 750 pounds, to 19,842 pounds. Of course, the production line will also benefit because the types’ fuselages now share even more of the same parts.

Embraer also used the 175 flight trials to test modifications that will allow the airplanes to share avionics and fly-by-wire software, a benefit that will extend to the 190/195 program as well. Developed by Honeywell, the software will allow the systems to recognize the type of airplane in which they operate and automatically adjust the tuning parameters needed for either the 170’s or 175’s flight controls and autopilots, for example. Consequently, Embraer won’t have to keep track of two separate sets of part numbers for either the hardware or software. Such commonality will also simplify maintenance for any airline that flies both types.

As with most new programs, the 170 still suffers from FMS nuisance messages, resulting in a somewhat less than stellar dispatch reliability rate of roughly 97 percent across the fleet. However, the type’s completion rate has risen to 99.3 percent–a figure that is more typical of much more mature airplanes.

By the time Air Canada takes delivery of its first 175 in July, Honeywell will have released yet another software load to activate still more FMS utilities. For example, the 170/190 series will carry a cost index function, designed to pinpoint automatically the most cost-effective flight path, climb rate, altitude and cruise speed given the airplane’s destination and weight, for example. Affonso said the feature could cut fuel use by as much as 2 percent on a given trip.

The new software load will also allow airlines to pre-program their routes, cutting the time it takes for a crew to set a new flight plan if they suddenly need to switch airplanes at the gate, for example. That function should further help dispatch reliability, said Affonso.

As with its decision to remove the “ERJ” prefix from the entire line’s product designation, such features illustrate Embraer’s attempts to distinguish its 70- to 108-seat airplanes from “conventional” regional jets and heighten their appeal to major and low-fare airlines. So far yielding big orders from JetBlue and Air Canada, the newly dubbed E-Jets seems to have set a trend. Whether or not it holds its appeal remains a question the market must answer.

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