Cessna Longitude – The long-awaited Cessna Flagship finally arrives in South Africa
Guy Leitch
The first Cessna Longitude to arrive South Africa has finally been delivered, arriving from the Wichita factory in late September. Interestingly, the South African CAA has made it so difficult, time consuming and expensive to register the aircraft here that it is registered in San Marino – hence the T7-KFL registration, and the owner is trying to keep a low profile.
The Longitude is Cessna’s parent company Textron Aviation’s largest jet. It is aimed squarely at the competitive super-midsize bizjet market and has raised the bar in terms of performance and passenger appeal. As October 2023, Cessna has delivered 100 Longitudes.
Development
The Longitude is a natural progression of the Cessna Latitude, which we reviewed about ten years ago when we got to sample it on a sales demo tour to Southern Africa.
The Longitude shares the same cabin profile as the Latitude but is otherwise in all respects a big step up. The cabin is more than a metre longer than the Latitude’s and the aircraft is 3.4 metres longer in overall length. Its distinguishing feature is a full T-tail – rather than the Latitudes (and Sovereign’s) cruciform tail.
For bizjets based at the bottom end of Africa, key performance numbers are range and useful load. The size of the step-up from the Latitude can be seen in that the Longitude has an additional 8,700 pounds in max takeoff weight over the Latitude, which enables it to carry another 3,706 pounds of useful load. Most of this goes to fuel (14,500 pounds total, or an extra 3,106 pounds compared with the Latitude). That provides a significantly increased range, enabling the Longitude to carry a full-fuel payload of 1,600 pounds (1,000 more than the Latitude) and fly 3,500 nm, compared with the Latitude’s 2,700 nm (each with four passengers).
Powered by a pair of 7,665-pound thrust Honeywell HFT7700L turbofans, the Longitude’s maximum cruise speed is 483 KTAS and maximum operating limit speed Mach 0.84, putting it ahead of the Latitude’s 446 KTAS and Mach .80.
The Competition
Although some buyers loyal to the Cessna line may consider upgrading from a Latitude to a Longitude, the real choice comes from its super-midsize competitors, which include the Gulfstream G280, the Challenger 350, Falcon 2000S, and Embraer’s Praetor 600.
Embraer’s Praetor can fly about 500 nm further, albeit at a 16 knots slower long-range cruise. Both share the same flat floor six-foot cabin height, but the Praetor is wider at 6.8 feet versus the Longitude’s 6.4 feet and the Brazilian’s cabin is a useful 2.5 feet longer.
Perhaps the closest competitor is the Challenger 350. The Longitude is slightly faster and has greater range (3,500 nm with four passengers versus the Challenger 350’s 3,200 nm with eight passengers), but the 350 has a wider cabin by about 9.5 inches.
Compared to the Falcon 2000S, the Longitude’s smaller cabin size is apparent. The French jet has a 7.7 feet wide cabin vs the Longitude’s 6.4 feet, and the Falcon has two inches more headroom. Both offer the same high-speed cruise of around 480 KTAS, but the Falcon’s maximum speed is also significantly higher at Mach .862. The Falcon’s range with six passengers is 3,350 nm compared with the Longitude’s four-passenger 3,500 nm. So by the numbers the Falcon trumps the Cessna – but at a higher fuel burn and initial cost.
Gulfstream’s G280 has slightly more height than the Longitude, but the G280’s cabin has a dropped floor instead of the flat floor of the rest of these competitors. Its cabin is six inches wider and just over six inches longer. With a maximum operating speed of Mach .85, the G280 is slightly faster than the Longitude’s Mach .84, and its range is also 100 nm further.
The Walk around
The wing is a thing of beauty. When Textron announced the Longitude in 2012 many assumed that they would combine the wing of the Hawker 4000 with the Latitude fuselage. However, the Longitude’s wing is a clean-sheet design with a rakish sweep of 28.6°, a sweepback angle exceeded in Cessna’s range only by the Citation X.
The partially supercritical wing features a fixed leading edge and almost 1 metre tall swooping upturned winglets that add 2.6m of span.
On the tail is a pair of Honeywell HTF7000 engines – which are also used by most of the Longitude’s competitors and, usefully for South African operators, have good hot and high performance. The engines deliver 7,665 pounds of thrust a side, flat-rated to 34 degrees C. On-condition maintenance means there is no formal time-between-overhaul requirement. The engine features include a wide-chord fan, low-emissions effusion-cooled combustor, and transpiration-cooled high pressure turbine blades.
The Longitude features single-point refuelling, providing complete control of the fuelling process from outside the cockpit. The system allows selection of the fuel load at the panel and so does not rely on the truck’s metering system.
A remote oil-level sensor for the engines shows engine and APU oil levels at the fuel panel, although pilots can also check oil levels with traditional sight glasses.
Another aspect of simplified systems are the two ice detectors mounted just below the windshield. Instead of watching for ice buildup somewhere vulnerable on the airframe, now pilots simply wait for the icing message then switch on the ice-protection systems. Pitot-static heat turns on automatically when needed, another feature that pilots don’t have to worry about.
The sturdy trailing-link landing gear features what Cessna calls, ‘a special blend of corrosion-resistant stainless steel’. For simplicity, the emergency landing gear is entirely mechanical, with no nitrogen driven pneumatic backup.
The dual mainwheels feature anti-skid carbon brakes which are electronically controlled and powered by dual hydraulic sources, each of which can power the brakes by itself. Emergency braking is from a hydraulic accumulator.
The hydraulically steered nose wheel is controlled by a tiller, which can move the nose wheel up to 80.5 degrees. The steering is smooth and precise and when combined with the 7.5 degrees of rudder steering allows a turn radius of 81 feet.
The Cabin
The boss who pays for it sits in the back, so the cabin experience is all-important. Here the Longitude really shines. The two key metrics are comfort and quiet. And of course all the now standard bells and whistles, including fast wi-fi interconnectivity and in-flight entertainment for every seat.
For some obscure reason most gran-fromages seem to prefer sitting in the back, of their jets which gives them the engine noise in stereo. This is where you are most likely to get an unpleasant thrum from the turbofans and it is one of the reasons airliner designers put the engines out on the wings. A Cessna demonstration pilot told our reviewer that Cessna engineers made a maximum effort to deal with this thrum by mounting the engines on an insulated circular frame that absorbs much of the vibration and harmonics from the engines.
The engineers’ effort has paid off as, according to Textron, the back of the Longitude cabin is a significant two decibels quieter than its closest competitor. For the Longitude’s first demonstration flight in South Africa, the back seaters remarked that they were able to talk easily with pax in the front cabin seats. A further key comfort parameter is the pressurisation differential. Here again Cessna have raised the bar with a cabin pressure of 9.66 psi, which means that at the maximum operating altitude of FL450 the cabin altitude is 5,950 feet. At a more standard FL410, the cabin altitude is typically 4,800 feet, which is lower than many Highveld density attitudes.
The seating configuration can be customised to the owner’s preference. Two double-club seating arrangements are standard, but many buyers replace the two seats on the left rear with a three-place berthable divan. A single side-facing seat can be fitted opposite the main entry door, but this reduces galley space.
The pairs of opposing seats can fold flat to create a bed, so that means four beds for the double-club configuration – or three plus the berthable divan. The divan has seatbelts for three passengers, which can be used for takeoff and landing, but it is wide enough to fit four while in flight. Opening the couch into a bed is a simple matter, with just a single handle to pull it out like a sleeper couch.
Ahead of the cabin door is a 14-cubic foot cupboard with hanging storage and removable shelves. Another option is a stowable jump seat. The lightweight (40 pounds) jump seat can be removed when not needed. The jump seat can face forward for flight deck observation, or aft for a cabin crewmember and is useable during takeoff and landing.
The extra cabin length of the Longitude enables a larger galley with plenty of workspace and dedicated glass storage. Two hot water tanks are standard. An optional high-power electrical outlet is available for appliances such as standard coffee makers, eliminating the need to spend vast amounts on built-in custom Cessna approved appliances. The outlet is mounted inside a stainless-steel surround to protect the galley from fire risk. This option allows use of appliances that draw up to 15 amps of AC power. A convection or microwave oven are also optional.
Both the galley and cabin are available with optional stone flooring. What that does to the aircraft’s empty weight and useful load is not specified.
There are two USB ports at each seat. Universal AC power outlets are available in the cabin, in the toilet vanity, and the flight deck. For worldwide connectivity, optional dual-channel Iridium or Inmarsat SwiftBroadband satcoms are available.
Rounding out notable cabin enhancements is the air recirculation system. Cabin air is sourced from the engines’ bleed air, whose high temperatures have sterilised the air. This clean air is then cooled before distribution in the cabin. After flowing through the cabin, 78% of the air is vented overboard via outflow valves at the rear. The remaining air is recirculated to the cabin, which reduces engine fuel burn.
The cabin management system (CMS) with surround-sound is controlled wirelessly from a smart device app. The app also controls temperature, lighting, and window shades, but separate controls for the latter two are also available at each seat. The audio/video system stores up to 400 GB of movies which can be Bluetoothed to smart devices. An HDMI and auxiliary audio input port are available to display how-goes-it moving maps, and an optional 22-inch monitor can be mounted on the rear cabin wall.
The toilet can be used as a seat, but unfortunately not for takeoff and landing. An externally serviced vacuum freshwater toilet is a first for a Citation. Its 6.4-gallon heated holding tank is outside the fuselage pressure vessel, which the demonstration pilot claims helps keeps odours out of the cabin.
The large 98-cu-ft, 1,000-pound capacity baggage compartment can be accessed from the cabin. Exterior access to the baggage compartment is made easy with a low threshold (about 1.5 metres above the ground). For overwater operations, the life raft has a dedicated storage space in the baggage area.
The Cockpit
The Longitude’s cockpit shares a common flightdeck with the Latitude and it is a model of modern functionality. It is based around the Garmin G5000 avionics suite and features three 14-inch wide‑format LCD screens. As with the Latitude, there are four GTC575 touchscreen controllers (TSCs) handily placed in the pedestal. As with the Latitude, the overhead panel is kept small.
Navigation within a primary flight display is via cursor control sticks on the bezel of the TSC. The flight guidance panel (FGP), to control the autopilot (AP) and flight director (FD), is mounted on the centre of the glare shield.
A single-gauge electronic standby flight display, with an internal back-up battery, is mounted between the FGP and the multi-function display (MFD).
Garmin’s synthetic vision technology comes as standard, as does an auto-throttle (A/T) system.
Also standard is Garmin’s new solid-state GWX 8000 StormOptix weather radar with a 14-inch antenna. The radar features a high-definition 16-colour palette with "greater colour contouring," 3D volumetric scanning with automatic tilt adjustment to scan and depict hazardous weather, hail and lightning prediction, turbulence detection, advanced ground clutter suppression, and predictive wind-shear detection (which is optional). The wind-shear detection feature provides aural notifications and visual indications.
Certification approval is pending for an optional Garmin GHD 2100 head-up display (HUD), which will show imagery from an Elbit enhanced flight vision system (EFVS) and also Garmin’s synthetic vision system. The HUD will be a $284,000 option, while the EFVS will add another $550,000, according to the Longitude’s optional equipment guide.
With a predominately DC electrical system, the Longitude shares electrical architecture with the Latitude and earlier Sovereign. The split-bus design has the left engine generator running the left electrical system and the right generator the right hand system independently, unless there is a failure requiring the systems to be tied together. Two TB44 lithium-ion batteries are standard.
For backup, the Honeywell 36-150 APU has a 500-amp DC generator and can operate at up to FL350. In a first for a Citation, the APU can be operated unattended on the ground.
Fly-by-wire
The Longitude’s flight-control system is typically conservative American. It takes the French and the Brazilians to be truly innovative with fly-by wire (FBW) control systems for bizjets.
When Embraer developed its Legacy 450 and 500 (now called the Praetor 500 and 600), it pioneered a full FBW control system, incurring considerable cost and time over runs on the development. Textron/Cessna has been more cautious incorporating FBW technology into the Longitude, which still has mechanical ailerons and elevator, yet a FBW-controlled rudder. The open-loop FBW applies rudder deflection as a function of airspeed, while performing full-time yaw damper and turn co‑ordination functions.
Six wing-mounted spoilers – three per side – are the Longitude’s only other FBW control surface. These secondary surfaces augment roll authority, act as speed brakes (SBs) while airborne, and dump lift when weight is on the wheels to improve wheel braking.
These three FBW functions reduce mechanical complexity and weight. Runway performance is also enhanced, as an auto-deployment brake schedule is programmed.
The key benefit of FBW is envelope protection and advances by Garmin have make this available to conventionally controlled aircraft. Garmin’s electronic stability and protection system offers attitude protections in both pitch and roll, along with high- and low-speed protections. For the Longitude’s G5000 avionics suite, however, Cessna elected to implement high- and low-speed protection schemes that utilise the autopilot (AP) and autothrottles (AT) which are standard equipment.
Flying the Longitude
Due to the owners desire to maintain maximum anonymity about T7-KFL what follows is a synopsis from multiple sources who have flown the Longitude.
The first step to waking the aircraft and getting its systems up and going is to start the APU and get its generator online. With the flightdeck powered up, you enter the flight plan and weights for takeoff performance into the flight management computer (FMC).
The start is a single push-button affair and is simplicity itself. Bleed air from the APU is used to turn both engines, with the FADEC-controlled fuel flow and ignition stabilising each engine at idle in under 30 seconds.
The Longitude’s steering tiller falls readily to hand and you can track your taxi position on the airport layout display.
Flaps are set to 2. Once the aircraft is on the runway and cleared for takeoff, release the toe wheel brakes and advance both thrust levers (TL) to the takeoff detent. The FADECs set takeoff power to 89.3%, and the Longitude gets going briskly.
A typical mid-weight Rotate is 110kt and the yoke forces needed to raise the nose are moderate. With a typical takeoff weight of 31,00lb, including 3,420kg of fuel and three occupants, it needed just over 1,000m of runway to unstick. At its 17,917kg maximum take-off weight, the Longitude would require a balanced field length of 1,466m at sea level on a standard day.
Control yoke force changes during clean-up and acceleration to the initial 200kt climb speed are low and easily countered with yoke-mounted pitch trimmer.
In level flight at FL410, the PFD showed a true-to-book Mach .84 at ISA -3 degree C, giving a true airspeed of 479 knots. Fuel flow was 980 pph for each engine. Cabin altitude was just 4,900 feet.
Slowing to a long-range cruise of Mach .739 dropped the true airspeed to 421 knots and fuel flow to 700 pph per engine. But typical long-range cruise is at Mach .80, which would deliver 457 KTAS at FL410 and fuel burn not too much lower than maximum cruise. The Longitude, with its near super critical wing likes to go fast.
Slowing the Longitude in level flight all the way to stick shaker, activates the autothrottles which power up to bring the speed back into the envelope.
With gear and flaps down, the controls feel lighter at slower speeds, but the Longitude is a large aeroplane and sprightly handling isn’t a feature in larger jets with conventional manual elevator and aileron controls.
On final the autothrottles bring the power back to idle as the nose is raised for the flare. Landing the Longitude smoothly is easy with its big trailing-link main gear, leaving no temptation to try to massage the flare to touch down gently. Reverse thrust is hardly needed and it stows below 85 knots.
Summary
The Longitude is Cessna’s flagship with excellent performance, a latest-tech pilot-friendly flight deck, and a cabin that fully delivers passenger convenience and comfort.
That the Longitude has achieved significant sales into the fractional-share operations such as Netjets underscores its overall utility and passenger appeal.
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