The Citation CJ4 has done quite well in the light-jet market, carving out a profitable niche for Textron Aviation with a well-performing capable jet serving both owner-pilots and professional fliers, alike.
Entering service in 2010, the $9.41 million CJ4 is the largest of the CitationJet series and the company’s largest Part 23 airplane, and it brought some new design features to the lineup that set it apart from earlier models. Like larger Citations, the CJ4 has some wing sweep, 12.5 degrees, but it also retains the CJ’s short-field capabilities. Other larger-jet features include electrically heated windshields instead of the bleed-air-heated systems on the M2 and CJ3+, as well as single-point refueling. The CJ4 also has an externally serviced flushing lavatory, which was optional until serial number 100, then became a standard feature.
The biggest difference between the CJ4 and its siblings is the larger jet’s Collins Pro Line 21 avionics suite, which also features the MultiScan radar, which combines short-, mid-, and long-range radar images into a single easy-to-interpret picture of weather and turbulence. The Pro Line 21 avionics tend to be more familiar to pilots who grew up flying with traditional flight management system (FMS) interfaces and thus the CJ4 is well appreciated by professional pilots. The CJ4 is one of only two current-model Citations not equipped with Garmin-based G3000 or G5000 touchscreen-controlled avionics; the other is the XLS+. This may be a factor in why the CJ4 isn’t as popular among the owner-flown crowd, especially those who learned to fly with Garmin avionics.
With more than 300 CJ4s delivered since 2010, the model has another advantage in its shared heritage, a common single-pilot type rating with other CJs, with just two days of differences training required when moving up to the CJ4.
The CJ4’s cabin is available in two configurations, with either eight or nine passenger seats. The eight-seat interior has a single seat opposite the main door, one double-club seating area, a single forward-facing row of seats behind that, then a belted seat in the lavatory. The nine-seat cabin replaces the single side-facing seat near the entry door with a two-seat couch with an armrest between the two seats. If flown single-pilot, the right seat on the flight deck is available for passengers, bringing the total capacity to nine or 10 passengers. The eight-passenger floorplan is standard, but there is no extra charge for the nine-passenger layout, and it even weighs slightly less, cutting 10.4 pounds from the empty weight.
The cabin width is 58 inches, and height is 57 inches, but that is from the ceiling to the recessed dropped aisle. By comparison, the Phenom 300’s cabin measures 61 inches wide by 59 inches, also with a dropped aisle, and the airplane can carry up to 10 passengers. The PC-24 can carry 11 passengers, with 10 in the cabin and one on the flight deck. Cabin width is 67 inches and height 61 inches, but the PC-24 has a flat floor, which gives it a more roomy feel.
The CJ4 flown for this report had the nine-seat interior, which cuts down on the storage space next to the two seats opposite the entry door. There is a double cupholder between the two seats.
Some of the added length of the CJ4 fuselage compared to the CJ3 comes in the flight deck and refreshment center area. Between the door and flight deck is a compact but spacious refreshment center, with plenty of space for a divided ice drawer, coffee container, disposable cup dispenser, trash container, bottled water and can storage, and snack areas.
The pedestal seats in the cabin all swivel and track forward/aft and inboard/outboard, but the two center forward-facing seats also are floor-tracking. Between the double-club seats are two bi-fold tables, and there are slimline bi-fold tables for the rear seating area. The club seat area can easily be expanded by moving the rear-most seats all the way back.
The cabin-management/entertainment system is the Collins Venue with a Blu ray media center with single-channel SiriusXM radio, a monitor on the right forward bulkhead, two side-ledge monitors, and environmental system controls. All lights are LED, and each seat has cabin-management and entertainment system controls. There is also a master panel on the left forward side at the top of the refreshment center. The two side-ledge monitors can be moved to docking stations at other seating areas.
For airborne connectivity, Gogo’s air-to-ground system is an available option for U.S. operations, and international travelers may want to add the Cobham Inmarsat SwiftBroadband satcom.
Two external storage areas are available, one in the nose with 15 cu ft capable of up to 400 pounds, and in the tailcone with a 20- by 26-inch door and a capacity of 55.6 cu ft and 600 pounds.
What sets the CJ4 apart is its performance, a big step up for pilots graduating from the smaller siblings and competitive with Embraer’s Phenom 300 and the Pilatus PC-24. Runway performance of the CJ4 is similar to that of the CJ3+, according to demo pilot Mark Vanderpool, who is Textron Aviation’s manager of flight operations, but the CJ4 is 3,000 pounds heavier and can fly 200 nm farther.
“It’s designed as the ultimate owner-operator airplane,” said Ben Nofziger, a Textron Aviation demo pilot who flew with Vanderpool during this trip. “It has so much flexibility, it’s really the hot rod of the entire fleet.”
Maximum takeoff weight (mtow) of the CJ4 is 17,110 pounds, and with full fuel (5,828 pounds) it can carry 1,000 pounds of payload. The heavier Phenom 300 (mtow 18,387 pounds) has a larger full-fuel payload at 1,561 pounds, while the PC-24’s is 715 pounds (PC-24 mtow is 18,300 pounds).
The CJ4 is powered by two 3,621-pound-thrust Williams International FJ44-4A Fadec engines with a 5,000-hour TBO.
With a full load of fuel, taking off at mtow with five occupants, the CJ4 can fly 1,926 nm (NBAA IFR range, 100 nm alternate) while at high-speed cruise, which is 430 ktas at FL450. The Phenom 300 can fly 1,971 nm with six occupants, and the PC-24 2,000 nm with five occupants. With eight passengers, the CJ4’s range drops to 1,701 nm.
At mtow, the CJ4 needs 3,410 feet to take off and can climb to its maximum altitude of FL450 in 29 minutes. Maximum cruise speed is 451 ktas, and this comes at FL310 and a weight of 14,000 pounds. On a sample 580-nm trip with eight passengers, the CJ4 needs 2,756 feet to take off and can then climb directly to FL450 in 17 minutes. Landing distance is 2,940 feet.
Systems and Avionics
The CJ4 is conventional in its aluminum structure with a T-tail empennage, moderately swept three-spar wing with hinged, three-position flaps, and trailing-beam landing gear. Wings and engine inlets are deiced by bleed air while the horizontal stabilizer uses pneumatic boots. Speed brakes are available for use at any speed, extending to 40 degrees, and spoiler panels extend to 54 degrees for lift-dump on the ground. Air-conditioning is via a vapor-cycle system.
The electrical system runs off two 300-amp engine-driven starter-generators, but each engine also drives an alternator to provide power for an AC flight deck windshield and side window anti-icing and defogging system. The alternators can also back up the electrical system in case of dual generator failure, with a transformer rectifier converting power to DC. Each engine Fadec has its own permanent magnet alternator.
No icing inhibitor is needed in the fuel as it is kept warm via a fuel-oil heat exchanger.
The CJ4’s two lead-acid or nickel-cadmium batteries are accessible from outside the airplane, unlike the batteries in the earlier CJs, which are inside the tailcone.
Avionics are the Collins Pro Line 21 suite, which includes four 8- by 10-inch displays in portrait orientation. Two display control panels under the glareshield are for controlling the two outboard PFDs, while two cursor control panels manage functions on the two center multifunction displays. FMS control and radio tuning is via two control display units mounted forward of the throttle quadrant. Collins’s MultiScan radar, which automatically displays a merged picture of weather no matter the airplane’s attitude, is standard. ADS-B Out with a single TDR-94D transponder is now standard. A second FMS is an option, but WAAS LPV is included as standard, whether the buyer chooses one or two FMSs. Also standard is emergency descent mode, which activates if the system detects depressurization above 30,000 feet with the autopilot engaged.
The Pro Line 21 system is sophisticated and does everything needed in a modern business jet, but it is a little surprising that Textron Aviation doesn’t offer a synthetic vision option for the CJ4, especially considering the M2 and CJ3+ both offer synthetic vision with their Garmin G3000 avionics.
In fact, the company does get requests from potential buyers about moving the CJ4 to G3000. “It’s a frequent ask,” said sales engineer James Beeson during a pre-demo description of the CJ4. “But we definitely see that there’s space in the market for this aircraft.” Customers like the Collins MultiScan radar, he explained, and many pilots who flew earlier CJ versions with Pro Line 21 are already used to the Collins avionics. “We are always innovating and talking to customers,” he said, “and looking for things they are wanting and improving our products. It’s not just features, but manufacturing processes, and from an ease-of-maintenance standpoint.”
On the maintenance end, Textron Aviation offers its ProTech program for the CJ4, which fixes the cost of labor for scheduled and unscheduled maintenance (based on the consumer price index). By signing up for all the Textron Aviation ProAdvantage programs, Beeson said, customers get predictable costs and can write one check for maintenance.
Flying the CJ4
Vanderpool and Nofziger flew the CJ4, a recent model with only 700 hours logged, to Morristown Municipal Airport in northern New Jersey for my demo flight.
The left seat is well furnished and it’s easy to adjust it to fit, especially with the adjustable rudder pedals. Like the previous CJs that I’ve flown, the CJ4 fits comfortably and makes me feel like I’m part of the airplane.
We taxied to Morristown’s Runway 5 and took off carrying 3,500 pounds of fuel. With three occupants our takeoff weight was 14,078 pounds, 3,032 pounds less than mtow. Calculations on the Citation CPCalc app showed that we needed a takeoff field length of 2,711 feet. Flaps were set to 15 degrees, and at this weight, decision speed was 94 knots and rotation speed 97 knots.
After lining up on the runway, I advanced the power levers all the way and the Williams engines spooled up quickly. At VR I just had to pull back slightly on the yoke and the CJ4 launched into the air. Vanderpool had warned me to watch out for rapid acceleration after takeoff, and I had to pull the power back smartly to keep the pitch to the desired 10 degrees and speed at 200 knots. I turned to the north towards New York Stewart International Airport near Newburgh.
I hand flew until we climbed above the FL180 transition level, setting FLC mode and 240 knots. As we passed through 17,000 feet, rate of climb was 3,200 fpm, and it was still 2,700 fpm at FL230. We leveled off at FL330 for a speed check and had to pull the power back to 93.2 N1 to keep the speed below the redline. The CJ4 settled at Mach .762 for a true airspeed of 447 knots, with each engine burning 775 pph.
After some shallow turns to feel the CJ4’s handling at altitude, I pulled the power back for a rapid descent and engaged the speed brakes. There was a subtle rumble but no pitch change, and it was easy to keep the speed at 250 kias while descending at 5,200 fpm, then leveling off at 13,500 feet for some airwork.
I set up for steep turns at 200 knots at 13,500 feet and did a 180-degree turn to the left then right. The CJ4’s handling overall is comfortable, not too light on the controls and requiring more muscle than the entry-level M2, but that is appropriate for a high-performance airplane. To me, it felt closer to a Latitude than a smaller CJ. At slower speeds, the controls are well harmonized, and flying in the traffic pattern was more pleasant.
Vanderpool pulled the power back on the right engine so I could feel the yaw, which wasn’t too apparent due to the rudder bias system that automatically compensates for a failed engine while requiring a small amount of rudder pressure by the pilot.
We set up for the ILS Runway 9 approach at Stewart. Vref was 99 kias, and I hand flew the approach with the flight director guidance. The CJ4 was perfectly solid during the approach, and the landing on the 11,817-foot runway was easy, just a small amount of nose up pull as the main wheels neared the pavement, and then a smooth touchdown and gentle braking for the turn off the runway.
We taxied back to Runway 9, then took off and flew in the pattern for another landing, which was even easier than the first. After the next takeoff, we flew back to Morristown and flew the RNAV Runway 5 approach. By this time, the CJ4 felt like an old friend, although I’ll admit that I would need some of that differences training to learn how to run the Collins Pro Line 21 avionics efficiently.