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Testing the Embraer E2
Jens Flottau
Embraer is about to deliver the first Embraer 190-E2 to its launch operator Wideroe. Just prior to certification, reached at the end of February, Aviation Week was invited to fly the third prototype at Gaviao Peixoto and Sao Jose dos Campos. Evaluation pilot Tim Wuerfel tested the aircraft's maneuverability and the protections built into the new fly-by-wire system.
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When Embraer designed its second-generation E-Jet E2 commercial aircraft family, it had to keep in mind two main criteria crucial for pilots. It needed a high degree of cockpit commonality to ease the transition for the large pool of E-Jet E1 pilots. But at the same time, it wanted to take advantage of technology improvements since the first generation entered service to provide pilots with better tools for safe and efficient flight.
After a day of flying both the E1 and E2 from Embraer facilities in Brazil, I believe it is fair to say the manufacturer has achieved both targets. Flying the E2 is a pleasant experience.
In February, Aviation Week was invited to fly the third prototype of the E190-E2, the 97-114-seat middle member of the new three-model family and first to be certificated. The aircraft is scheduled to enter service in April with Norway’s Wideroe.
- Closed-loop fly-by-wire provides flight optimization and envelope protection
- Flight-deck commonality eases transition for pilots of first-generation E-Jets
The E2 is to a large extent a new-design aircraft, using an Embraer-developed closed-loop fly-by-wire (FBW) system, new high-aspect-ratio wing, updated maintenance procedures, as well as Pratt & Whitney geared-turbofan engines, to improve fuel burn, flight control and maintenance intervals. About 75% of the parts in the E2 are new, and 46,000 ground-test hours were needed in addition to 2,200 flight-test hours to complete certification.
The E2 is Embraer’s fourth FBW program following the original E-Jets, Legacy business jets and KC-390 military transport. Armed with data from applications in different markets, as well as the experience of 22 million flight hours accumulated by the E1, Embraer felt confident enough to design a closed-loop system.
This uses a feedback system to optimize control throughout the flight envelope and reduce fuel consumption, not only through smoother flying characteristics with more limited interventions, but also because several aircraft components could be reduced in size and weight. The E1 family has open-loop FBW control that lacks the feedback, and the ailerons are not part of the system.
One of the most important necessities for Embraer was commonality with the E1. A common type rating allowing mixed-fleet flying of E1 and E2 aircraft was a precondition, and the goal was to keep changes to a minimum and transition as short as possible. It is now down to 2.5 days of training, for E1-rated pilots, with no need for a full-flight simulator. This was achieved because Embraer did not take advantage of all the technical possibilities of full FBW but instead made the new system mirror the behavior of the E1.
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| High-aspect-ratio wing and high-bypass geared turbofans externally distinguish the second-generation E-Jet. Credit: Embraer |
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Before we flew the aircraft, I was invited to “fly” the fixed-base simulator used for development and certification. Their engineers showed me the full capabilities of the FBW system, with some maneuvers that were not going to be repeated in the air. I also gained initial insight into the flight control system’s two modes: “normal” and fallback “direct.”
On the first takeoff, we simulated an engine failure in normal mode and watched the FBW system reduce pitch, yaw and climb in a turn due to a slight bank, without our input. This was an impressive demonstration of the system’s capabilities, because in direct mode without the protections, the aircraft needs immediate pilot input to remain controlled.
In our second simulator test, at flight level (FL) 200, we pulled the nose up to 30-deg. pitch and rolled the aircraft onto its back. Without our intervention, the aircraft pitched down, rolled out of the inverted attitude and smoothly recovered from the overspeed during the steep descent—another impressive demonstration of fully functioning protections.
Our evaluation flight would take place from Embraer’s own airport at Gaviao Peixoto. We flew there using the original E190-E1 prototype, registered PP-XMA. Around 15 years ago it was used for certification of the E190 and was the first of the E-Jets to fly.
I took the left seat, alongside Embraer test pilot Gerson de Oliveira Mendes. The 1-hr. flight provided an opportunity to sample the first-generation E190 before flying the latest version, making comparisons easier. Most of the flying was manual before starting a visual approach to the field, which is located 2,000 ft. above mean sea level (MSL) between large cane fields.
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| The E190-E2 cockpit provides commonality with the E2, says Aviation Week pilot Tim Wuerfel. Credit: Jens Flottau/AW&ST |
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At Gaviao Peixoto, where Embraer’s flight-test center is based, we were briefed by Mendes and Murilo Pinto Ribeiro, manager for aerodynamics, flight sciences and aircraft performance, as well as Capt. Jose Penna, an instructor pilot. After the briefing, we went out on the ramp for an outside check of the E190-E2 prototype.
On first impression, the aircraft looks like the E-Jet we have become familiar with since 2005, when the original E190 was introduced. But closer examination reveals some changes from the first generation. The E190-E2 stands on a taller landing gear that lifts the fuselage by around 20 in. so that the PW1900G engines have enough ground clearance below the wing. While the E1 engines always looked a little small, that is no longer the case. The PW1900G’s fan is 73 in. in diameter, providing a bypass ratio of 12 and delivering up to 22,000 lb. of thrust.
The elegant wing is notable. With an increased span of 33.7 m (110 ft.), it is reminiscent of a glider wing and, at just over 11, boasts the highest aspect ratio of any large commercial aircraft. The wing is still made of aluminum, as Embraer concluded only an even larger wing would have warranted a composite structure.
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| The E2 brings significant improvements in maintenance processes. Credit: Embraer |
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Another major change visible from the side, and important for handling characteristics, is that the wing has been moved forward relative to the E1, shifting the center-of-gravity (CG) envelope aft. This reduces the downforce required on the horizontal stabilizer, and lowers fuel consumption by 1.5%.
The larger E195-E2 has a different, longer wingtip section, while the smaller E175-E2 has a downsized version of the same wing as the E190-E2. The large CG range on the E1 leads to slightly different flight characteristics at the edges of the envelope, an effect eliminated on the E2 by the new FBW technology.
The higher lift coefficient of the new wing required a more efficient means to reduce the lift when necessary during descent over demanding terrain or in high-density arrival areas, as this is an issue with the E1. An additional speedbrake panel was added on the upper side of each wing that is usable in clean configuration and with the Flaps 1 setting.
On the main landing gear, two changes immediately attract attention: There are now wheel doors, which reduce fuel consumption by 1%, and the gear has a trailing link that extends aft. As the CG envelope has shifted aft, the trailing link ensures there is always enough weight on the nose gear to guarantee dependable steering during ground operations.
The trailing link was used by Embraer on the ERJ-145, in a much smaller form. Once airborne, with no weight on the wheels, the link and gear hang down almost vertically, allowing retraction without requiring extra space in the rear side of the wheel well.
The new fly-by-wire system now includes the ailerons. They are used for load alleviation to reduce stress on the wing through small inputs in flight. After touchdown, the ailerons are deflected upward to augment the ground spoilers, adding load onto the wheels and allowing smaller brakes to meet deceleration targets, in turn saving weight.
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As I sat down in the left seat of our E2, the first impression of the cockpit layout was that I had been here before, just hours ago when I flew the E1. The four large screens of the Honeywell Primus Epic 2 avionics system dominate the flight deck. In the middle, between them, there is only space for the standby instrument and gear handle, so the large clock is gone.
The primary flight display (PFD) shows a synthetic-vision image of the landscape, plus the horizontal terrain profile already available on the E1 for additional situational awareness. As the screens can be tailored by the pilots, they can mirror the display setup on the E1. A lot of information is selectable and, with all that is being made available, it will be up to the pilot to determine which data should be displayed at what time.
The cockpit design is well thought out. There are no more switches than necessary, because multifunction displays and a cursor control device (CCD) are used. As a new option, the pilot can use the CCD to move a pointer onto the inboard screen of the other pilot. This can be used to indicate something or to activate a function on request of the pilot, who might be flying the aircraft manually at the time.
The cockpit design philosophy is unchanged from the E1, and straightforward, with most of the switches in the same place and Embraer’s practice of using a switch’s 12 o’clock position to indicate the normal setting. But three switches have changed their positions on the glareshield as a result of customer feedback. The knobs for speed, heading and altitude are now arranged from left to right on the panel, as are the indications on the PFD. The switches to change QNH (altimeter) setting and landing minimum have swapped places to reflect their positions in the lower right corner of the PFD.
A head-up guidance system is optional, as is the use of electronic flight bags. Our test aircraft still carried some certification test equipment, including a button to switch between FBW normal and direct mode. That will not be on production aircraft, as direct mode is a backup that activates automatically in the event of severe system failures. Embraer has calculated that this mode will only be needed once every 10 million flight hours.
Before we were pushed back from the hangar, the test engineers onboard showed me new applications that are part of Embraer’s goal to significantly reduce maintenance costs. Faults can now be simulated, and systems and conditions tested by software. An example is switching of the ground/air mode, where in the past elaborate procedures had to be used.
After we started both engines with the assistance of the auxiliary power unit, we checked the free motion of the flight controls using the traditional Embraer horn-type yoke and the rudder pedals. After I released the parking brake, the aircraft started to move without any input due to the high idle thrust of the powerful engines.
Nosewheel steering is activated by pushing down the small steering wheel outboard of the left seat. I forgot about that at first and for a split second was concerned when I could not turn the aircraft with wheel input. But with this mechanism, the maximum 70-deg. input to the nosewheel is only possible while actively pressing on the wheel.
We approached Runway 2, ready for takeoff at a weight of 50,000 kg (110,000 lb.), with a CG at 20% mean aerodynamic chord and 7,950 kg of fuel in three tanks. A third had to be added because of new certification requirements for higher redundancy in case an uncontained engine failure ruptures a tank. The center tank feeds into wing tanks, which feed the engines. A nitrogen inerting system also had to be added, as this is now required.
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| The E190-E2’s taller trailing-link main gear provides ground clearance for larger engines. Credit: Embraer |
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Mendes and I quickly reviewed the tailstrike protection provided by the angle-of-attack (AOA) limiter. This is unchanged from the E1, but the information for activation is now derived from different sources so the radio altimeter is no longer needed for this purpose.
We used the Flaps 2 setting, which results in a V1 (takeoff decision speed) and VR (rotation) of 131 kt. and V2 (takeoff safety) of 138 kt. with a VFS (final segment) of 192 kt.
Setting takeoff thrust, we heard the typical low, deep sound of the geared turbofans accelerating us rapidly. The initial target for rotation is 15 deg., and I used light counterforce into a crosswind of about 10 kt. from the northwest. On Embraer aircraft, the pilot needs comparatively high forces on the control column, but this is not uncomfortable and allows accurate inputs.
The gear was raised, and we accelerated for our climb up to FL240 (24,000 ft. above MSL). The design of the control column requires a little familiarization, with its low turning point. This also requires you to keep your knees close to the column so it does not hit you during steering inputs to counteract gusts. The yoke design kept my hands in a natural position, allowing accurate inputs and the necessary force with well-balanced steering.
During the climb, we entered clouds and turned to stay within the 80 X 40-nm box reserved for our flight. Leveling off, I slowed to “green dot” speed (minimum clean speed) then accelerated to 300 kt. indicated airspeed (KIAS), still hand-flying the aircraft to experience the necessary trim inputs, the varying pitch and to feel the handling.
In a slow descent, I accelerated to the VMO (maximum operating speed) of 320 KIAS and watched the overspeed protection smoothly lift the nose to stay out of the red/white band of the speed indication on the left of the PFD. It fulfilled its task nicely as we extended the speedbrakes to feel a slight pitch-up moment as expected. Importantly, the protections never make use of autothrust and work with autopilot engaged or off.
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| The E190-E2 received Brazilian, U.S. and European certification on March 1, the first of the E-Jet E2’s. Credit: Embraer |
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We reached FL180 at 250 KIAS and steered the aircraft into a 45-deg. bank turn for a spiral stability demonstration. The envelope protections allow this maneuver with slightly increased forces on the control column, to enable the pilot to use high bank angles when necessary. At lower angles, the FBW will hold the bank when you let the controls go; here it actively reduces the bank to 33 deg. if the pilot eases off.
Next we slowed the aircraft to 1.3 VS (stall) to see the behavior at low speed. We stayed at FL180 in a clean configuration as I reduced the speed slowly by 1 kt./sec. and increased the backpressure on the column beyond trim speed, watching the pitch limit indication on the PFD as we reached the stickshaker.
As briefed, I kept the backpressure at the mechanical limit for about 2 sec. before unloading the aircraft and carefully adding thrust. As expected, the large-fan engines needed about 4 sec. to reach high rpm, then delivered impressive thrust to push us out of the low-speed situation without losing more altitude. We repeated the maneuver, this time reducing speed at about 3 kt./sec., and then again in landing configuration with gear down and flaps fully extended. All these maneuvers can be flown smoothly, almost easily, and at all times the pilot can rely on having full control. The E2 was not required to have a stickshaker as the AOA limiter is sufficient, but Embraer chose to keep it for commonality with the E1.
We descended into the traffic pattern to start our first visual approach to Runway 2, with a planned flap setting of 5, the corresponding VAPP (approach speed) of 137 kt. and the VREF (reference) of 132 kt. We planned a touch-and-go maneuver. After a soft touchdown that would have needed only a little more backpressure on the main gear to land the nose gear, Mendes retrimmed the aircraft for takeoff and set the flaps to 4 as I advanced the thrust levers and set full takeoff thrust on his command.
We turned back into the approach pattern on the western side of the field and prepared for a missed approach and go-around at about 400 ft. above ground, with Mendes reducing thrust on one engine to idle just after initiating the maneuver to simulate an engine failure at this critical point.
We approached the runway again with Flaps 5. Reaching 400 ft., I called out “go-around,” advanced the throttles and called for flap retraction. Mendes set the flaps to 2 and reduced right-engine thrust to idle. As thrust declined, I reduced pitch to avoid losing speed and stepped into the left rudder to counteract asymmetry and keep the aircraft on its heading.
To better judge the rudder input force required, I looked at the top of the PFD where the white sideslip indication is shown below the roll pointer. But with the gear up, it changes into a blue beta target indication on the new Embraer. This does not indicate zero sideslip when centered, but minimum drag, taking into account rudder, aileron and spoiler deflection and the airplane body angle. I checked that we were still on the desired heading or if a correction was needed to stay on an obstacle-free flightpath. The maneuver can be flown precisely, and the aircraft feels pleasantly relaxed with a lot of thrust available from one engine.
In the traffic circuit at 1,500 ft. we returned both thrust levers to the same position and used the test aircraft’s switch to change the FBW from normal to backup direct mode. With all protections removed, we would fly an approach with flaps set to full followed by a touch and go. As we had used some fuel, our landing weight was slightly reduced, giving a VREF of 123 kt. In direct mode, we planned to fly the final approach at VREF +10 (133 kt.).
The aircraft handled as well as in normal mode and steering felt unchanged, with the same trim inputs. Pilots just need to keep in mind that the protections are gone.
After climbing back to 4,000 ft. and accelerating to 200 kt., normal mode was restored without any perceptible switchover. We now flew from Gaviao Peixoto back to Embraer’s main base at Sao Jose dos Campos, a 160-nm route. With flight instructor Jose Penna now in the right seat, I again manually flew around some developing clouds, as is typical in the summer afternoons. We were flying at FL130 and a speed of 270 kt.
Coming over the mountains to the northwest of the airport on our arrival route, we reduced speed and extended flaps for a steeper descent and smaller turn radius to intercept the instrument landing system for Runway 15. With a slight tailwind during descent, we planned to use flaps full with a VAPP of 129 kt. and VREF of 124 kt.
Upon landing, a 10-kt. crosswind gave me another opportunity to experience the direct and precise handling of the E2. After touchdown, we used idle reverse and wheel brakes to smoothly slow the aircraft, which now weighed 46,600 kg with 4,600 kg of fuel remaining.
This last approach was flown with autothrust engaged. The moving throttles provide good tactile feedback, and not only to the pilot flying. As any inputs on the control column are also observable for the pilot monitoring, he also is kept in the loop about what is happening.
The many pilots flying the nearly 1,500 first-generation E-Jets in service today will enjoy the substantial fly-by-wire upgrade in the latest aircraft, as this offers more and better envelope protections. The E190-E2’s powerful PW1900G engines provide added thrust, paired with distinctly less noise and lower fuel consumption.
And, most important, while making the E2 a much more technologically advanced aircraft than the E1, Embraer has still followed its basic philosophy of ensuring ultimate pilot authority rather than allowing aircraft systems to take over. This gives flight crews the maximum technical support in routine operations and in responding to critical situations.
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