Flying the Phenom 300
Eduardo Menini, a senior test pilot with Embraer, walked us around EMB 505-101, the first production-conforming aircraft to enter the flight test program, during the preflight inspection. He pointed out some of the Phenom 300’s high-utilization and operator-friendly design features.
Basic maintenance intervals, for instance, are 12 months or 600 flight hours. The aircraft’s MSG 3 maintenance-friendly design makes it possible to replace windshields in two hours. The third-generation L-3 SmartProbes eliminate tubes and pipes between probes and ADC boxes. All antennas and other external sensors, including the SmartProbes, can be changed from outside the airplane. Gel gaskets eliminate the need to use liquid sealants that must cure before flight.
All flight control cables and linkages are designed so that they cannot be reversed during installation. The front and rear batteries slide out on trays for easy access and replacement. The aircraft uses only one type of grease. The fuel boost pumps have brushless motors for long life and they are mounted in dry canisters so they may be changed without defueling the aircraft. The winglets are mounted with screws, making them easy to remove and replace.
All main electronic and avionics components, including the engine FADECs, are located inside the pressure vessel where they are protected from pressure and temperature extremes. A central maintenance computer (CMC) simplifies fault identification. The CMC can even check autopilot servo torque, thereby eliminating the need to remove them for bench tests.
The Phenom 300 is designed for easy access to systems and high-frequency utilization, similar to Embraer’s jetliners. The design expedites the crew’s preflight inspections. Credit: EMBRAER
Most line service tasks are easy. If needed, the oxygen bottle may be refilled through a port in the nose baggage compartment. The single-point pressure refueling panel has a utility light for nighttime operations and it has a selectable refill quantity feature. Engine oil quantity can be checked with sight glasses visible through doors in the nacelles. The toilet is externally serviced. The baggage compartment has a large, counter-balanced swing-up door and the sill is waist high for easy loading.
Menini, though, didn’t show us how to install and remove the landing gear pins without getting dirty. The gear must be pinned if the aircraft is towed and unpinned prior to flight. One must go on hands and knees to get access to the pins in the main landing gear wheel wells. The nose gear pin is mounted high in its wheel well, so it’s almost necessary to lie down on the ramp to reach it.
In addition, while the toilet is externally serviced, fresh water reservoirs in the galley and lavatory must be replenished internally. Those systems weren’t installed in the flight test aircraft we flew, so we could not assess the associated workload issues.
Still, because of all the flight test equipment and a ballast tank, 505-001 had an empty weight of 11,900 pounds, or about 450 pounds heavier than a completed production aircraft with standard equipment.
With my strapping into the left seat and Menini in the right, flight test engineer Leandro Bigarella at the console and Daniel Bachman at the videocam, the aircraft’s zero fuel weight was 13,000 pounds, including forward water ballast to keep it in the c.g. envelope. Loaded with 4,400 pounds of fuel, ramp weight was 17,400 pounds.
Bigarella computed takeoff V speeds for Flaps 1 (eight degrees) and a 17,300-pound takeoff weight or 96 percent of MTOW. He called out 107 KIAS for the V1 decision speed, 110 KIAS for rotation and 120 KIAS for the V2 OEI takeoff safety speed, based upon São José dos Campos’ 2,119-foot field elevation, 29.94 inch Hg barometer setting and 20°C OAT. Computed takeoff distance was 3,050 feet. Estimated OEI takeoff field length over a 35-foot obstacle was not available.
We plugged in ground power to save the batteries and to allow all the onboard test equipment to warm up before engine start. During cold weather operations, the batteries must be warmed to at least 0°C before engine start, even if external power is available. This assures adequate battery performance to meet the 45-minute emergency power requirement.
Menini pointed out that the aircraft’s automated electrical system requires only one button push to connect external power. All other system switches can be left in the “on” or “automatic” positions.
After electrical power is turned on, pre-start checks are quick, consisting of fire protection, baggage compartment smoke detector, annunciator light, stall protection and ice protection checks performed with a rotary test switch. Embraer also requires that the crew manually set in OAT as a reference for the FADECs, a procedure that dates back to the EMB-145. This provides a backup reference for the FADEC’s temperature sensor in the engine inlet. We also checked individual battery voltages to assure ample power reserves.
Once the cabin door was closed, we turned first the right, then the left, engine operating switch from Off to Run to Start. The vapor-cycle air conditioner automatically turned off during start to conserve electrical power. The FADECs handled all the starting tasks as we monitored the engine and systems indications on the MFD.
After engine start, the air-conditioning automatically came online and we disconnected external power. We checked battery reserve power, free control movement and proper takeoff trim and flap setting. We verified that the FMS had programmed in the landing field elevation of São José dos Campos for proper cabin depressurization upon our return and set Flaps 1, verifying the flap movement on the MFD.
Getting the aircraft to roll out of the chocks required very little thrust increase. Wheel brake action was smooth with the cold carbon brakes, but the aircraft required heavy pedal pressure, typical for Embraer aircraft. Nosewheel steering authority through the rudder pedals was adequate for most taxi maneuvering, but differential braking and thrust was required for tight maneuvering. Since the aircraft doesn’t have a tight turning radius, care must be taken when taxiing on crowded ramps.
We also checked the emergency brakes. Pulling up partially on the parking brake T handle actuates the emergency brakes smoothly and progressively through a secondary hydraulic circuit, but no differential braking or anti-skid is available.
Prior to takeoff, Menini pressed the takeoff configuration check button and we heard the integrated Prodigy avionics system say, “Takeoff OK,” verifying that flaps, spoilers, pitch trim and parking brake were in the proper position for departure. Having 10,200 feet of pavement available on Runway 15, we were not concerned by accelerate-stop distance. Using the Flaps 1 configuration results in lower drag than Flaps 2, thereby improving second-segment OEI climb performance.
On the runway centerline, we pushed up the throttles to the takeoff and go-around (TOGA) position, the third detent in the quadrant. There’s also a maximum thrust position, forward of the TOGA detent, but how much extra thrust it will command, and under what conditions, has yet to be determined.
Acceleration was smooth, but not sporty. Rotation forces were moderate, if not hefty, another trait of Embraer jets. We rotated to 12 degrees nose up and retracted the gear with a positive rate of climb. In the process, we had to increase pitch attitude to 25 degrees to prevent exceeding the 140 KIAS Vlo limit speed imposed on the test aircraft. Production aircraft will have more-robust landing gear doors and thus a considerably higher landing gear operating speed.
At 400 feet agl, we accelerated to 136 KIAS and retracted the flaps. We continued the climb, leveling off at 5,000 feet for air traffic control while we exited the local traffic area to the northeast. We noted that while the aircraft has a heavy stick force per g, it’s not particularly sensitive in pitch to speed or configuration changes. Pitch and roll control forces were moderate, well harmonized and more in line with what we’d expect from a midsize jet than a light jet.
Winter storm clouds created a choppy ride up to 10,000 feet, but the flexible wing structure seemed to soak up most of the bumps. At that point, we noted an anomaly in the weather radar display. Garmin has yet to develop the capability of overlaying the flight plan route on the onboard radar display. That makes it difficult to determine if the programmed flight plan track will steer clear of storm clouds. However, the flight plan track is displayed together with XM radio weather graphics, if one is operating in the continental U.S. coverage area.
When stabilized at 10,000 feet, we recorded a weight of 16,975 pounds, started the clock and began a direct climb to FL 450. Menini said best climb performance would be obtained using a 225 KIAS/0.60 IMN climb schedule.
During the climb we checked roll control response, noting heavy control forces at maximum yoke deflection, but achieving 60-degree-per-second roll response, according to Bigarella’s instruments. The effect of the roll spoilers on roll rate and roll control effort seemed negligible.
Later, we checked short-period stability, noting that the aircraft is well damped. We also noted that the current version of SmartProbe software has very little dampening, thus the VSI readout often jumped ±50 feet with no change in aircraft attitude or speed.
Eight- to 10-degree warmer-than-standard outside air temperatures during most of the climb didn’t help climb performance. OAT didn’t cool off to ISA until we crossed FL 400. But OAT dropped to ISA-6.5°C by the time we leveled at FL 450, stopping the clock at 22 minutes and recording a 550-pound fuel burn for the climb.
We accelerated to 0.66 Mach long-range cruise at FL 450. We attempted to use the aircraft’s cruise speed control (CSC) function, a feature that provides limited authority thrust adjustment, with the trim range of the FADECs, when altitude hold is engaged. But CSC wouldn’t hold speed without uncoupling, so it appeared to need more development work before it’s ready for service.
Once stable, we recorded 372 KTAS while burning 840 pph at a weight of 16,340 pounds (91 percent of MTOW) in ISA-6.5°C conditions. We also noted that the aircraft’s pitch trim seemed a touch sensitive, providing plenty of pitch trim change with very little movement of the trim switch.
We then evaluated high-speed buffet margins. We rolled into an increasing angle of bank, holding altitude. Flight test restrictions limited us to using a maximum 45-degree angle of bank. But we still recorded 1.5 g of load at 16,200 pounds with no evidence of buffet.
Capt. Menini demonstrated the operation of the counter-sprung airstair door. Credit: EMBRAER
We also checked spiral stability. When we rolled into bank angles up to 30 degrees, the aircraft gradually returned to wings level. At bank angles greater than 30 degrees, the aircraft slowly would roll off.
Long-period pitch (phugoid) stability proved to be a strong point for the aircraft. We trimmed for cruise at 180 KIAS at FL 435, pulled up until the speed decreased to 156 KIAS and let go of the yoke. After five up-and-down cycles, averaging 74-second periods, aerodynamic damping almost had eliminated the porpoising.
The Phenom 300 also exhibits strong Dutch roll damping, a product of its having primary and secondary rudder dual yaw dampers. While the primary rudder yaw damper can be shut off, the secondary dorsal fin rudder is activated automatically anytime the primary yaw damper is inoperative and it cannot be shut off.
After our checks at high altitude, we descended to FL 300 for a high-speed cruise check. On the way down, we evaluated the performance of the two-position air brakes. When extended, the air brakes produce moderate buffet and mild pitch-up. Retracting them produces the opposite effect. A software interlock prevents air brake extension with the flaps extended.
Setting the throttles at max cruise at FL 300, the aircraft stabilized at 448 KTAS at a weight of 16,000 pounds (89 percent of MTOW) while burning 1,586 pph in ISA+6.5°C conditions. The final static source error correction curves have yet to be programmed into the SmartProbes, so the aircraft actually was cruising at 453 KTAS, according to the onboard flight test instrumentation. Book cruise performance predicted 451 KTAS under those conditions, Bigarella said. Both numbers back up Embraer’s claim that the aircraft will cruise at 450 KTAS at 90 percent of MTOW.
Descending to 15,000 feet, we put the aircraft through some basic air work maneuvers. A couple of near 60-degree bank angle turns revealed that the aircraft had the heavy stick force per g pitch control feel that’s characteristic of most Embraer aircraft with conventional flight controls.
Make a note: Trim into the turn or be prepared to use both hands on the yoke for your checkride.