The best way that I can think of to describe Cessna’s new light jet Mustang is that it is, in all respects, a Citation. That means it has pleasant and predictable flying qualities, uncomplicated and robust systems, good payload and range, and it delivers on all of the promises Cessna made when it introduced the airplane four years ago.
Cessna rejects the term “very” light jet for the Mustang and refers to it simply as a light jet. The Mustang is an attractive airplane designed from scratch, powered by new generation engines and equipped with the most advanced avionics in the category, but it is not a revolution. The real revolution happened more than 35 years ago when Cessna introduced the original Citation 500. The weights, performance and even the price of the first Citation are very close to those of the Mustang. Now, with 4,500 Citations delivered by the time you read this-nearly 3,200 of them single-pilot capable-Cessna knows more than any company about light jets, how to design them, build them and support them.
By my count the Mustang is the third generation light jet from Cessna. The first was, of course, the Citation 500, which has spawned an enormous family of models. The second came in the 1990s when the CitationJet was introduced. Engine prices and other costs had made it unattractive to continue building the Citation 501, so Cessna started over to create a new light entry-level jet with new engines. The CJ has been a success and, in the best Cessna tradition, has been stretched and improved into follow-on models that vastly increase the cabin size and performance of the original.
The Mustang is a repeat performance. The CJ has grown in all respects, including costs, and Cessna wanted a new jet at the entry level, so it started over, again with new engines. But, unlike the CJ, the Mustang borrows almost nothing from previous Citations except Cessna’s enormous experience at designing and building jets.
When you look at the Mustang you can detect a Citation family resemblance, but it’s slight. The reason the Mustang looks so different is that the nose section, including the windshield and canopy, is entirely new, while other members of the Citation 500 kin share a common forward fuselage shape. The Mustang nose section is fairly thick, allowing plenty of room for a forward baggage compartment and lots of space for pilots in the cockpit. The windshields are swept aft and smoothly faired into the canopy, while the other Citations have a much more upright windshield angle. And the Mustang has electrically heated windshields, so all of the apparatus that it takes to get hot bleed air onto the windshields of other Citations is gone. You will also immediately notice that the Mustang cabin windows are different. They are mounted well above the centerline of the fuselage and are oval shape. Moving the windows up puts them near eye level of a seated passenger and lends a grand feeling of spaciousness to a compact cabin. And for the oval shape, well, a famous and successful family of business jets-the Gulfstreams-have proved that passengers love the shape.
The Mustang wing is also all-new. Cessna correctly expected that many Mustangs would be bought by people who intend to fly the airplane themselves and wanted a jet with docile handling characteristics and approach and takeoff speeds at or below propeller twin numbers. Cessna created a new high-lift wing with a slight leading edge sweep. The wing has very low stall speeds, allowing typical landing approaches of 90 knots, but still has low enough drag to deliver the promised 340-knots true airspeed cruise. With a span of nearly 43 feet and a generous wing area of 210 square feet, the Mustang wing is also right at home at the certified ceiling of 41,000 feet.
Cessna engineers also used their decades of jet experience to make the Mustang systems the least complicated of any I have seen in a jet. For example, there is no overall hydraulic system. An electric motor powers a hydraulic pump only as necessary to pressurize the system to operate the landing gear and anti-skid power brakes. The flaps and speed brakes, typically powered by hydraulics, are electrically operated. The fuel system is as simple as possible. All fuel is in the wings, each engine draws from its side, and the only fuel management task is to make sure you have enough, and if you lose an engine you can rotate a knob to move fuel from one wing to the other. That’s it. No pumps to turn on or off or tanks to switch. The electrical system is just as easy to manage because either generator can operate everything, except maybe the air conditioning and full windshield heat. But if one generator fails, those two items are automatically shed, so there’s really no pilot action required.
The engines are, of course, key to any new aircraft design and the Pratt & Whitney PW615F turbofans continue the emphasis on ease of operation with the full-authority digital electronic controls (fadec). The fadecs manage all aspects of engine operation, so the pilot only needs to move the thrust levers to suit the requirement with no need to monitor engine limits. Fadec is now the norm in larger jets, but is entirely new at the entry level. The PW615F engines produce 1,350 pounds of thrust at sea level and can hold that level up to 77º F. The engine has twin-spools just like the large turbofans. Twin-spools means that the fan is driven by a low-pressure turbine on the opposite end of a concentric shaft, while the outer high speed shaft is connected to the compressor sections on the forward end and high-pressure turbine on the back end. A twin spool-engine has fewer moving parts which helps with reliability, a promise already delivered with the engine entering service with a mature 3,500 hour TBO with a single hot section inspection at mid-time, which can be performed without removing the engine from the airplane.
The Mustang cockpit is probably the most remarkable advance in light jet design with its Garmin G1000 system, which handles all traditional instrument and avionics functions, plus it is the pilot interface with aircraft systems. In the past couple of years we have all become accustomed to flat-panel primary flight displays in even light piston singles, but the full integration of the G1000 in the Mustang is at a level seen only in much larger and more expensive jets so far.
The biggest difference is the G1000 engine indicating and crew alerting system (eicas) capability. Gone are the rows of warning lights that announce the failure of a system or warn of an abnormal situation. In place of those lights are plain English alerts and warnings that you simply read off the giant 15-inch multi-function display (MFD) in the center of the cockpit. Master warning and caution lights draw your attention to the display, but after that there is nothing to decode because the message is in plain language.
There are many differences between the G1000 system in the Mustang and the systems installed in piston airplanes, with the enormous MFD being the most obvious. But the most important difference is that in the Mustang, the G1000 is a completely dual system with at least two of every necessary element installed, so that automatic comparisons can be made to detect faults, and no essential information is lost after the failure of any element. That even extends to the autopilot, which is a dual channel fail passive system, meaning that if the system detects a fault in any one channel in any axis, it shuts off that channel, and you can continue to use the autopilot for the remainder of the flight.
In late June I had a chance to fly Mustang number two, which is the third one built. Cessna does not count the prototype, even though it was built on production tooling, because it will never be sold since prototypes need extensive modification for early flight testing. The greatest initial impression of Mustang number two-other than its overall visual appeal and substantial size for a light jet-is the quality of the workmanship. Cessna has made giant strides over the years in fit and finish, and the Mustang is already right there at the high level of other Citations that have been in production for years. Computer-aided design and advanced tooling in the manufacturing plant are partly responsible for the excellent results, but there is also a huge element of experience gained from building so many thousands of jets.
Most of the skin on the wing and fuselage is metal bonded, which helps give the surface a very smooth and ripple-free appearance. The Mustang is made entirely from metal, except for the radome, of course, a couple fairings and the inverted-V-shaped ventral fins under the tail cone. The fins were added after the Mustang was in flight test and, as they do on so many other jets, improve low-speed and stall behavior, and also provide very positive yaw damping. Because of their highly swept leading edge the fins generate virtually no lift in steady cruising flight, so they add no drag. But when the angle of attack is high the fins produce gobs of lift, which pushes the nose down as the wing nears a stall. The same happens when the airplane yaws and the fins go from their neutral angle of attack and create lift to drive the nose back toward center. The fins are so effective that the Mustang meets the latest, and very demanding, yaw damping requirements even at 41,000 feet without the electronic yaw damper operating. The composite construction of the fins adds very little weight, and they do not need ice protection.
The Mustang uses pneumatic boots to deice the leading edges and hot bleed air to prevent ice formation on the engine air inlet. By early summer Cessna had completed all certification ice testing except for one natural ice condition that the flight test guys were still trying to find. As you probably know, icing is one of the hottest hot buttons with the FAA right now and the rules are being interpreted to mean that any new airplane must meet all stall and other flying qualities standards with residual ice on the airframe. The standards are exactly the same as for a totally clean airplane. Cessna had expected not to need to protect the vertical fin from ice as is the case on most jets, but to meet the heightened standards the Mustang now has a boot on the fin. Testing also revealed an unusual condition at the stall with residual ice on the wing, and that issue has been resolved by adding triangular “Wheeler” vortex generators to the wing boot.
Something as seemingly simple as a cabin door is anything but simple, but Cessna has drawn on its previous experience to create one of the easiest to operate that I have yet encountered. The door is symmetrical, the locking pins are huge, but the mechanism that extends and retracts the pins is so well designed that you can flip it with barely two fingers.
Once inside the Mustang cabin I think you will feel that you are in a much larger airplane. The cabin is actually five inches smaller than the cross section of the CJ, but the difference isn’t noticeable. The big oval windows with their high location get much of the credit, but the Mustang cabin is not a circle like other Citations, giving you more room at the floor and shoulder. The four seats are fixed but the aft-facing seats recline. There is a potty seat directly aft of the copilot but, as in all light jets, I think it will be an emergency use only device.
The Mustang cockpit is unlike any other light jet I have flown. The control wheels extend from the instrument panel instead of being mounted atop vertical columns as in most other jets. That really opens up the cockpit. And, there is only a very short center pedestal, and it does not extend to the cockpit floor. You can sit in either pilot seat and swing your toes under the pedestal, or in flight, if alone, you can stretch out your feet to the other side of the cockpit. I’m 6 ‘2 “and had as much or more headroom, and space in general, in the Mustang as I have found in any other light or even medium-sized jet. And the smooth wraparound windshields and side windows provide excellent visibility, even back to the wing tips and beyond.
Cessna retained its toggle switches to control primary systems, and that’s just fine with me. The toggle switch is both an actuator and, by looking at its position, a status indication. The lighted push buttons of much more expensive jets are wonderful, but to turn on the landing lights or pitot heat, for example, it’s hard to beat the simplicity and reliability of a toggle switch.
All other functions are handled by the G1000 avionics system, which has a keyboard mounted just aft of the power levers, or you can use the knobs on the display units to enter data. Even the cabin pressurization system is controlled via the G1000 by entering the landing field elevation. That’s it. No other pressurization management is required for the rest of the flight. The flight guidance panel is mounted on the center of the glareshield, exactly where it should be so you can see it without looking down.
Even though the Pratts are fadec controlled you start them like conventional engines, moving the power levers out of cutoff as the N2 speed spools up. Thanks to fadec the engine idle speed is very low, so low that it takes added power to taxi unless the Mustang is very light. The low idle speed also reduces landing distances and does away with the need for thrust attenuators that Cessna used on the original CJs.
Two of the most difficult design issues in a new jet are getting the nosewheel steering and brakes right, and the Mustang came out very well. The steering is purely mechanical through the rudder pedals and is smooth and precise, and pilots will master it the first time out. The steering system is an all-new design with the shimmy damper built into the mechanism, so nothing protrudes from the strut.
Cessna had initially considered using manual brakes on the Mustang, like those used on piston twins and turboprops where the pilot supplies the muscle by pushing on the pedals. But the Mustang is a jet, and Cessna decided that it deserves jet-type powered brakes complete with antiskid and locked wheel protection. The antiskid system detects impending wheel lock and releases brake pressure momentarily to prevent a skid and loss of brake effectiveness. The locked wheel protection prevents hydraulic pressure from reaching the brakes until the wheels begin to spin on landing. If a pilot mistakenly lands with his feet on the brakes, the system automatically allows the wheels to spin before brakes are applied so the tires don’t blow. This is standard stuff in a jet and the Mustang has it.
With four total people onboard and full tanks, Mustang number two-which has a full interior and all standard equipment, and is representative of the final airplane-weighed 8,600 pounds. Cessna has not set a maximum certified takeoff weight yet, but is holding to its promise of a full-fuel payload of 600 pounds, which is what we had, so it looks like the empty weight will be somewhere around 5,600 pounds including one pilot.
Runway performance data collection on the Mustang was not yet complete so we didn’t know a precise runway requirement for our takeoff, but testing so far shows the 3,120-foot guarantee is on target. And it’s important to know that the runway requirement in the Mustang, as in all jets so far certified, is for a balanced field, meaning there is enough runway to stop if an engine fails before V1 decision speed, or to continue the takeoff with certified minimum engine-out climb performance if the engine quits above V1 speed. That’s another reason Cessna insists on calling the Mustang a light jet, not a very light jet, because not all of the so-called VLJs anticipate being able to meet balanced field requirements that have been standard in jet airplanes. Takeoff speeds are pretty well determined and on a hot day in Wichita, at near maximum weight, they were 93 knots for V1 decision speed and VR rotation speed, and 97 knots for takeoff safety speed, the airspeed you fly if an engine fails at liftoff. The en route single-engine climb speed was 97 knots, all astonishingly low numbers.
There really isn’t much to say about my first takeoff in the Mustang except that it flies exactly as I expected, with medium control force and very positive response in all axis. Initial climb rates were close to 3,000 feet per minute at around 120 knots indicated, but I accelerated to a more reasonable 170 to 175 knots where it held around 2,000 fpm.
The first leg of the flight was the short hop down to Independence, Kansas, where the Mustang will be assembled and completed. The production line there is filling up with several Mustangs already looking like airplanes, not just parts. The assembly tools equal the most advanced Cessna is using for its other Citation production in Wichita and, in general, allow the airplane to be built from the outside in. The tools hold the major skin sections in the exact desired final shape while the ribs, frames, stringers and so on are added to the inside, guaranteeing exactness on the outer finished airframe. The wing is assembled and tested in one complete piece. The fuselage is built in three sections, with most of the plumbing and other systems installed before the sections are joined. All of the components and subsections of the Mustang are built in Wichita and shipped to Independence for assembly. My first landing in the Mustang was at about 8,300 pounds, which will almost certainly be at or above the final maximum landing weight, which had not yet been determined. Vref final approach speed, which is a function of stall speed that has been set, was 93 knots, undoubtedly the highest Vref anybody will see in a Mustang. My first landing worked out great, even though I was at least 10 knots fast on short final. I don’t approach that slowly in my Baron so it was hard to make myself fly that slow, but I turned off at the midpoint of Runway 35, a distance of 2,750 feet using moderate braking, so it looks like the guaranteed landing runway distance of 2,610 feet is in the bag.
Departing Independence without adding fuel, we weighed 8,240 pounds and takeoff speeds were 90 knots for V1/VR and 94 for V2. The air temperature aloft was hot, starting at 18º C above standard at the lower altitudes, but the Mustang turned in a solid climb of more than 2,000 fpm through 20,000 feet, and I was level at FL 300 in 17 minutes after takeoff, and the air temp there was 11º C above standard. During climb the power levers are left, logically enough, in the “climb” detent, and it says climb on the N1 engine gauges. There is no need to adjust power at any time, and the engines were in perfect sync of temperature, fan speed and fuel flow all the way up. The climb profile speeds had not yet been established, but I held 175 knots decreasing to 160 at 30,000 feet. The maximum rate of climb airspeeds will almost certainly be lower, but the speeds I used made a comfortable deck angle and produced nice results. Once level I allowed the Mustang to accelerate in climb power for a minute or two, and then pulled back to the maximum cruise detent. True airspeed settled in between 341 and 344 knots with fuel flow at 680 pph. Air temp was still 10º C or more above standard so the Mustang clearly makes its speed guarantee of 340 knots.
|The airplane flown for this report was the second production unit and third built, counting the prototype. It was complete with all interior and cockpit furnishings and equipment, and is the airplane that will be used for the FAA certification function and reliability testing. Most certification testing was completed in early June, but takeoff performance testing at various weights and conditions had not yet been finished. Very few options are offered on the Citation, but a popular selection will be Chart View to see Jeppesen charts on the G1000 system. All data here is preliminary, except that Cessna guarantees to meet the takeoff and landing distances noted, the full-fuel payload and the IFR no-wind range.|
Instead of climbing to the Mustang ceiling of 41,000 feet, I chose to use the available time for stalls, steep turns and other airwork. Engineering test pilot Scotty Jergenson, who was in the right seat, assured me that all flight envelope corners had been tested at 41,000 and the flying qualities were as predictable as in any other Citation. I did wrack the Mustang into a 45-degree bank turn at 30,000 feet, pulled hard to load up the wing, and there was no rumble or complaint from the wing at all. Perfectly solid and stable.
The speed brakes are well done with an easily manageable nose-down pitch with extension, and only a little buffet. The speed brakes can be used at any altitude, airspeed or configuration and are operated using your thumb on a switch mounted on the outside of either throttle. A high speed descent was easy to manage with the speed brakes in or out. If you could ever want more drag you can fly all the way up to the Vmo airspeed limit of 250 knots with the landing gear extended.
Stalls are a total nonevent. The Mustang does not have a stick shaker or pusher. Stall warning is provided by an indication on the airspeed tape and a loud horn. To recover, push the throttles to the takeoff detent and the airplane accelerates with little or no loss of altitude. The Mustang is very easy to manage in the terminal area with its 184-knot approach flap extension limit and essentially unlimited gear speed. The Vref approach speeds will fit in with piston airplane traffic, but the Mustang can also keep up with other jets to the outer marker. The airplane is so stable that holding the approach path is as easy as in any airplane I have flown, be it piston single, turboprop or jet. And with the trailing link landing gear there is just no excuse for anything but a great landing.
One trait of the CJ1 and 2 that has always annoyed me is that with an engine out at low speed, they roll toward the dead engine even with the rudder pushed to the floor. This is the norm in propeller twins and you need aileron input to control the roll, but it is unusual in jets. I am very pleased to report that the Mustang does not do that. With a throttle pulled back at rotation I could take my hand off the control yoke and hold the airplane straight with only rudder pressure. And the single-engine landing was my best of the day.
Cessna has well over 200 orders for the Mustang and believes that about 80 percent will be flown by their owners. After flying the Mustang, I can say that any pilot will be safer in it than the same pilot would be in propeller twins or other jets. The Mustang’s flying qualities, logical and redundant systems, and low airport speeds are all easier to manage than in other multi-engine airplanes. And the jet safety of balanced field takeoff performance gives the Mustang a big edge.
The Mustang isn’t a miracle, but it is certainly the result of decades of experience in building light jets. At about $2.6 million in today’s dollars it costs $2 million less than the next least expensive jet in production, and that is a result of efficiencies at all levels including design and manufacturing, engines and avionics. The Mustang is the logical next step from the company that invented the original light jet. Cheers for the third generation of Citation light jets.