Pilot Report: Cessna Citation Longitude Preflight
A little-known secret outside the world of business jet pilots is that we are more than the occupants of the front two seats, pushing throttles, magically seeing through clouds, and circumnavigating the world. Sure, there is that. But we are also the flight planners, baggage loaders and flight pursers. In some cases, we are the flight attendants and flight-line service technicians. If we aren’t the mechanics, we are the mechanic’s diagnostician or assistant. It is with due respect to all these “hats” that I measure the effectiveness of a new business jet: How does the design make the pilot’s life easier? Under these metrics, the Cessna Citation Longitude is a winning design.
My introduction to Cessna jets was more than 40 years ago, flying the Cessna T-37 “Tweet” as a U.S. Air Force student pilot. We lieutenants were told that Cessna took the lessons learned from the primary jet trainer and turned those into the first Cessna business jet, the Citation I.
So when Textron Aviation offered me the chance to fly a new Longitude, I jumped at the chance. With 31 Longitudes already delivered as of early 2021, the aircraft may be setting a new standard in the super-midsize business jet class.
The Exterior Preflight
The Citation Longitude has an elegant ramp presence, with its 68 ft., 11 in. wingspan and 73 ft., 2 in. length, a graceful 28.6- to 31.8-deg. wing sweep and T-tail perched 19 ft., 5 in. in the air. Crews can comfortably plan on starting flight preparations with as little as 30 min. before departure without feeling rushed. As this was an introductory flight for me, Textron Aviation demonstration pilots Capts. Alan Pitcher and David Bodlak allowed for an hour.
Not too long ago, a typical exterior preflight inspection took about an hour and often left the pilot or flight engineer dirty with grease and oil. Even today, many preflights require pilots to open panels, examine engine accessories and get into wheel wells with a flashlight. There is a certain satisfaction from all that, but it gets old quickly. I got the sense we could have it done in 5 min. if not for all my questions.
The main entrance door is electrically closed by a DC-motor and allowed to free-fall on its own while unspooling the motor. The door includes a sight glass to ensure the ramp is clear prior to opening and a sensor to prevent the door from closing if anyone is still standing on it. (I will be adding this to my wish list on my future aircraft!) The door is surrounded by a “blade type” seal that simply uses cabin pressure to seal the door to the aircraft’s maximum pressure of 9.66 lb. per sq. in. differential (PSID). That is a recurring theme with the Longitude: If there is a simple solution to something that is traditionally handled in a more complex way, go with simplicity. The door doesn’t require an inflatable seal and all the pneumatic plumbing between it and bleed-air sources required to power it. Despite all that, the pressurization system is capable of delivering a remarkable sub-6,000-ft. cabin altitude at the aircraft’s 45,000-ft. maximum altitude.
Just about all of the inspection panels are accessible without a ladder or the need to crawl underneath the aircraft. But only one really needs to be opened on a routine preflight inspection: the refueling control panel, located in the fairing just forward of the starboard wing. The aircraft is capable of carrying 14,300 lb. of fuel in two integral wing fuel tanks. If fueled using the over-wing filler caps, total fuel increases to 14,500 lb. The control panel doesn’t require a long boot process and took less than 5 sec. to report the fuel onboard. The pilot need only turn on the fuel panel switch and select the total amount desired. The system will ensure the fuel between each wing tank remains within 500 lb. balance until the desired fuel is loaded.
For our flight, we loaded 9,200 lb. for a short local flight with three of us onboard, expecting a takeoff weight of 32,965 lb. Our takeoff from Dwight D. Eisenhower National Airport (KICT), Wichita was at 12C, on a dry runway. The aircraft’s published performance at a maximum takeoff weight of 39,500 lb. from a sea level, ISA airport allows for a takeoff field length of 4,810 ft., a 3,500-nm range flying at Mach 0.80, with four passengers and NBAA IFR reserves. For today’s flight, we would need just 3,583 ft. of runway.
The wings appear clean from the front and top, with no leading edge devices needed to achieve its short runway performance. The polished leading edge uses hot pneumatic bleed air to provide evaporative anti-icing. This system is also used for the ring cowls of the engines. Two full-time ice detectors, a first in the Citation series, are used to advise pilots of the need to activate anti-ice systems. The wing, from root to the gentle upsweep of the winglet, struck me as beautiful. Beautiful, that is, until I got to the aileron.
The right aileron outboard and three spoilers inboard. Photo credit: James Albright
I asked Pitcher to tell me about roll control. He explained that the aileron system was strictly cables and pulleys between a conventional yoke and the aileron surfaces. That is augmented by fly-by-wire spoilers above the wing that are electrically controlled and hydraulically operated. The two outboard and midboard spoilers act as roll spoilers and speed brakes. A set of inboard spoilers teams up with the other four as ground spoilers for landing or aborted takeoffs. The setup appeared similar to that of many of the aircraft in my logbook, but I wondered about any drag or aileron buzz caused by the abrupt shape of the wing-to-aileron union. I made a mental note to fly the aircraft at its highest speed to find out.
The two Honeywell HTF7700L turbofan engines are installed on pylons just aft of the wings. They incorporate dual-channel, full-authority digital electronic controls (FADEC), producing 7,665 lb. of thrust on an ISA day at sea level, flat rated through ISA+14C. The engines are just above eye level for me; I would need a ladder to install intake covers.
Walking aft I noticed the polished leading edges of the horizontal stabilizer as Pitcher talked about the EMEDs. “E-whats?” I asked. The electromagnetic expulsion deicing (EMED) system uses DC electrical power to pulse magnets mounted inside the leading edges to create skin movement to free ice from the leading edge of the horizontal stabilizer.
Next up was a view of the auxiliary power unit (APU) exhaust mounted at the aftmost point of the fuselage. Moving the APU exhaust as far aft as possible is credited with lowering cabin noise significantly, as is moving the cabin pressurization outflow valve to the aft bulkhead in the baggage compartment. The Longitude’s cabin noise level is less than 68 decibels, as compared to between 69 and 72 for its nearest competitors.
Of course, most of us business jet pilots spend a great deal of time handling baggage and the Longitude’s external and internal baggage compartment access are designed with this in mind. The external compartment door can be opened and closed without a ladder and the baggage compartment floor is just over 4 ft. off the ground. The internal door also gives access from the cabin to the entire baggage compartment, which has a flat floor.
The port-side fuselage behind the wing is home to potable water and lavatory water service. The lavatory is a vacuum type with gray water contained outside the pressure vessel in a 6.5-gal. heated tank. A 14-gal. potable water tank can be serviced internally or externally. It also can be purged while in flight by a selection from cockpit screens, reducing a pilot’s postflight cold weather chores to having the gray water dumped and removing any freezables from the cabin.
Finishing the external preflight, I again thought the overall theme had been simplicity: How can we make these necessary chores as painless as possible for the pilot? It was a theme that was to continue in the cockpit.
The Internal Preflight
For a pilot coming from larger aircraft, the Longitude’s cockpit can seem a bit small. The fuselage, at its widest point, is 77 in. wide and 72 in. tall. Pilots without previous Citation experience, like me, will be impressed by the large windshields and windows, providing excellent visibility. I lowered myself in the left seat and felt immediately at home with the five-point restraining harness and comfortable leather seats.
With the press of two battery switches, the cockpit came to life and the boot process was no more than a few minutes. The flight management system (FMS) comes up automatically, and with it, the navigation lights turn on. It appears the G5000 Garmin Integrated Flight Deck (GIFD) includes the maximum amount of glass that could fit in front of both pilots. Three 14-in.-diagonal, high-resolution LCDs in widescreen, landscape orientation are home to two outer primary flight displays (PFDs) and a single, centrally located multi-function display (MFD). Each display can be split with a push of a button.
Four full-color touchscreen LCD control panels, called Garmin Touchscreen Control (GTC) panels, are used to manipulate G5000 system features such as radio tuning, transponders, intercom, flight planning, selected aircraft systems such as environmental control and internal lighting, and MFD windows to display desired information. If a control panel becomes inoperative, the remaining control panels can take on additional control responsibilities.
While I’ve spent most of my flying career using cockpit avionics from Honeywell and Collins, I felt immediately at home with the Garmin setup. The GTCs are much easier to use than a conventional mechanical button control panel, and even easier than the touchscreen controls that I normally use. The Garmin version puts far less information on any given screen, meaning the numbers and letters displayed can be larger. Because your fingers have larger targets to hit, the chance of punching a wrong number or letter are decreased as a result. You rarely have to dive in more than a few levels to find what you want.
Unlike many AC driven aircraft, the almost entirely DC Longitude is “full up” on batteries only, except for the windshield heats. Once the avionics boot up, you have a cockpit ready to go. The only thing remaining before starting the engines is to connect external air or fire up the APU. The batteries are good for at least 10 min. prior to APU start, so pilots do not need to hurry through any procedures before getting to the APU.
The Honeywell 36-150 APU is certified to start up to 31,000 ft. and operate to 35,000 ft. It provides electrical power as well as bleed air for environmental controls and engine starting while on the ground and at lower altitudes in the air. Unlike any APU I’ve ever operated, this one is certified for unattended operation. Pilots can start the APU with full confidence that it will not only shut down on its own if needed, but it will also discharge a fire extinguisher. I immediately added this to the wish list for my aircraft.
Starting the APU could not be easier. You simply rotate the APU control switch from OFF to ON, wait about 15 sec. for a self-test to complete, and then rotate the switch to START. Pilots are relieved of the normal prestart routine (turning on navigation lights, selecting fuel pumps, running a fire detection test), and the entire process takes less than a minute.
The Longitude can be equipped with inertial reference units that automatically update off of the installed dual GPS receivers, or two Litef LCR-100 gyrocompassing attitude heading reference system (AHRS) computers. The units come to life automatically during power up, and flight plans and weather information can be downlinked by ground or satellite links. The system automatically favors VHF terrestrial sources, if available.
Preflight checks were straightforward and easily accomplished, and we were ready for engine start in just a few minutes. A trained crew can routinely go from a dark cockpit to engine start in less than 10 min. Even with my incessant questions and Pitcher’s detailed answers, we were ready in 20.
Three minutes after the APU is started, bleed air will be available, and the engines will be ready for start as soon as the Before Start Checklist is completed. Pushing either engine’s FADEC RUN/STOP button sends air to the starter and as soon as 32 psi is indicated, the START button can be pressed. We got the 32 psi in just a few seconds and it seemed to me that each engine start took less than 30 sec. I could barely hear the engines from the cockpit.
After engine start, I checked the flight controls in each axis, as well as the speedbrakes. I was a little surprised by the amount of force needed to move the ailerons full throw, but the elevator moved more easily. (Both are fully mechanical with no hydraulic assist.) The rudder is electrically controlled, hydraulically actuated and it moved easily.
Taxi was effortless with the airplane gently starting to roll as I released the brakes. The nosewheel steering uses a mechanical linkage from a left seat tiller and from both sets of rudder pedals to drive a hydraulically assisted nosewheel steering assembly. The tiller provides up to 80- to 81-deg. nosewheel deflection, the rudder pedals provide up to 7.5 deg.; both can add up for a total of 88 deg. left or right of center. The tiller felt heavier than I expected, but that made it easier to make smooth movements.
The wheel brakes are actuated conventionally. The multi-disk, anti-skid carbon brake system is electronically controlled and hydraulically actuated. This kind of “brake by wire” is new for the Citation lineup, but they seemed to have gotten it right. Brakes are not overly sensitive and were effective.
We selected “Flaps 2” for takeoff. The electric flaps are motor driven to three positions: Flaps 1 gives you 7 deg. of flaps, Flaps 2 gives you 15 deg., and Flaps Full gives you 35 deg. The difference from minimum to maximum can reduce approach speeds by as much as 33 kt.
The two center Garmin Touchscreen Control panels. Photo credit: James Albright
Switching from clearance delivery to ground control and to tower frequencies made me appreciate a design decision Garmin made with its touchscreen control panels. They placed primary radio data information on top and included mechanical interfaces on bottom. With other designs, pilots are required to activate the communications page with a swipe of the screen, then punch in the frequency and then select the appropriate radio. With the GTC, the frequency is always in view and can be changed by simply selecting it. Volume changes are as simple as a twist of the knob. The three physical controls on the bottom have myriad uses, all making the pilot-to-avionics interface simpler.
This kind of mix between glass and physical switches can seem to be a step backward to the days of partial glass cockpits a few decades ago. But I think it might be a correction from other designs that have gone too far. My “other job” is flying a Gulfstream GVII where almost all conventional “hard” switches have gone “soft.” Responding to a request to ident, for example, has become somewhat more complicated in the brave new world. Depending on which page a touchscreen is left, getting to an ident button can involve a swipe of the screen or a press of page tab before the ident button can be found. The process gets easier with practice and muscle-memory, but you have to add all the other tasks requiring similar screen gymnastics to your learning curve. With other, more conventional aircraft, you simply find the physical button and press it. With the Longitude, most of these conventional “hard” switches remain hard. Of course, hard switches are more expensive. But it does make pilot tasks easier.
James Albright will evaluate the Longitude in flight in a subsequent article.