Mustang Magic

Citation Mustang Designed for Simplified Maintenance

The maintenance philosophy is to replace moving parts with moving electrons.

For MROs, the term "new and improved aircraft" is synonymous with "more complicated, requires new tools, and is guaranteed to be much harder to maintain." So when a manufacturer such as Cessna Aircraft Company develops a new business jet--the six-seat, twin engine Citation Mustang--that is specifically designed for simpler, easier maintenance, it's impossible not to sit up and take notice.

"In designing the Citation Mustang, we've tried not to bury anything," said Christopher Webber, Cessna's supervisor for Mustang customer support. "Everything is easy to get to." Add an emphasis on using digital equipment, to reduce the number of mechanical parts to service and repair, as well as a scheduled maintenance program developed using fault analysis, and the Mustang is meant to make life easier for its owners, and the MROs who service their aircraft.

How Strategy Influences Specs

The $2.4 million, single-pilot certified Citation Mustang is a scaled-down extension of the Citation business jet family. It joins a new category that aims to woo single and turboprop pilots into entry-level business jets. (Some refer to these aircraft as VLJs, Very Light Jets, although Cessna doesn't tag the Mustang with this acronym.) As a result, the Mustang's design and form is all about simplicity and performance combined. With an interior akin to a luxury automobile, including a well-appointed "driver's seat," it is meant to impress potential owners with its elegance and user-friendliness.

This explains why the Mustang has an all-glass flight deck, built around the Garmin G1000 integrated avionics system. With its 15" central multi-function display (MFD) color screen and two 10-inch color primary flight display (PFD) screens, the G1000's layout is both accessible and impressive. Looking at it reminds one of the dashboard in a top-end Mercedes Benz automobile, enhanced by leather and wood grained surfaces, which is exactly the feeling Cessna is trying to inspire.

The G1000 is designed to provide the pilot with less readouts, and easy-to-understand situational awareness information, using a combination of sophisticated visuals and onboard diagnostic data. Collectively, it is meant to make the piston/turboprop pilot look closely and say, "That's not so complicated after all. I can fly this airplane."

"It's no accident that the Mustang is a clean sheet airplane," said Webber. "It does follow the Citation family line, but we have done things to this airplane to make it more maintainable and field-friendly, so that prop pilots will feel comfortable flying it." This said, "We realized that for the Mustang to be user-friendly for entry-level pilots, it had to be very easy to maintain, especially so that they didn't have to take the aircraft to a service center if they didn't want to," he added. "Some pilots like to do their own hands-on maintenance; the Mustang makes that possible."

Making for Easier Maintenance

Cessna's decision to install the Garmin G1000 avionics package was part of its overall plan to "go digital wherever we could, to reduce moving parts and thus reduce maintenance requirements," said Webber.

In going digital, Cessna has examined every component and process used on a business jet, to see where moving parts could be replaced by moving electrons. This has resulted in some innovative redesign of typically mechanical systems, such as the Mustang's hydraulics system.

"On this aircraft, we've gotten away from traditional gear-driven hydraulic pumps wherever possible," Webber explained. "In fact, hydraulics are only used for the landing gear and the wheel brakes. The rest of the components, such as flaps and speed brakes, are all controlled by electric motors. This means that there are no fluids to worry about; no extra nuts and connections that can spring leaks."

"The second most changed element is the Mustang's environmental pressurization system," he adds. "Here we've gone with a digital system that we've taken from our other aircraft. All the pilot has to do is enter the landing field's elevation data, and the Mustang's automated planning controller does the rest."

For the Mustang's fuel system, the fuel is monitored using digital electronic sensors. "This means that you don't have to do a periodic calibration to ensure that your fuel tank readings are accurate," said Webber.

Cessna's simplification of maintenance has even extended to areas that most would miss. A case in point: "You don't have to remove the interior and take out the floor boards to get to the flight controls," exlaimed Webber. "That's because we have put the turnbuckles behind the instrument panel at one end, and behind the aft fairing at the other. These two points are where you make any adjustments. You can leave the seats and floorboards in place."

The company's attempts to reduce maintenance requirements have gone as far as the aircraft's interior lighting, and the use of light emitting diodes (LEDs). "We're using LEDs in many parts of the cockpit and cabin instead of incandescent lamps. They last a whole lot longer, resulting in far less replacement," said Webber.

On the flight deck, the aircraft's onboard diagnostic systems uses active capacitance sensors to keep a constant eye on the Mustang's system performance and health. This means that the aircraft is constantly monitoring itself to watch for problems, rather than waiting to alert the pilot whenever a fault is detected.

The Engines

The power that keeps the Mustang airborne is a pair of Pratt & Whitney Canada (P&WC) PW615F turbofan engines. Controlled using a dual channel FADEC (Full Authority Digital Electronic Control), the PW615Fs are new to the aviation world. Cessna has been flight testing them on a Cessna Citation Jet test bed for over a year.

Scaled down from Pratt & Whitney Canada's full-sized PW625F engines, the 16" fan diameter PW615F delivers 1,350 pounds of thrust at ISA conditions up to +10�C. The PW600 family of turbofans, which deliver from 900 to 3,000 lb. of thrust, have been designed to provide "low fuel consumption, high durability and reliability and low maintenance cost," according to Pratt and Whitney.

For entry-level VLJ customers, these qualities should prove to be important selling points. To win their confidence, Cessna is be backing the PW615Fs with a three year/1,000 hour warranty.

Getting Up to Speed

Clearly, what interests MROs most about the new Citation Mustang is persuading owner/operators to bring them into the shop for professional servicing. But what will it cost MROs to support this new business opportunity, will it be worth their while to chase this business?

According to Cessna's Webber, the answer is a definite "yes." Cessna has designed the Mustang to be technologically advanced, but not too advanced to service using current MRO technology.

In fact, Webber said, "If you're an existing Citation maintenance facility, or just a technician with Citation experience, you'll find the Mustang easy to work with. We've kept new tools to a minimum; that's how committed we are to keeping it simple."

What's Coming

Although the Cessna Citation Mustang is still undergoing flight tests, it won't be long before this entry-level business jet is a common sight in American skies. Cessna already has over 200 orders for this VLJ, and more are on the way. Given the reputation of Cessna's existing Citation business jets, this demand comes as no surprise.

If the company succeeds in wooing a substantial number of propeller pilots to its new jet, the demand could be huge.

The Mustang is coming, and its arrival looks to be good news for pilots and MROs alike.

Sidebar 1:

Citation Mustang: The Specs

External length: 40 feet 7 inches

External height: 13 feet 5 inches

Wingspan: 43 feet 2 inches

Full fuel payload: 600 pounds

Maximum cruise speed: 340 knots

Maximum range: 1,150 nautical miles

Takeoff runway length: 3,120 feet

Landing runway length: 2,610 feet

Certified ceiling: 41,000 feet

Cabin height: 54 inches

Cabin length: 117 inches

Cabin width: 55 inches

Engine: Two Pratt & Whitney Canada PW615Fs (16 inch fan diameter)

Take-off rating:

Thermo T/O Thrust 1,568

T/O Flat Rated 1,350

Service Intervals:

Basic HSI (HR) 1,750

Basic TBO (HR) 3,500

Sidebar 2:

Other VLJs to Watch For

Whether you call them Very Light Jets (VLJs), "microjets," or "downward extensions of existing business jet lines," VLJs may soon be a common sight in American skies and MRO shops.

So what precisely is a VLJ? According to one website (http://en.wikipedia.org/wiki/VLJ), "A Very Light Jet (VLJ) is a small jet aircraft approved for single-pilot operation. With a maximum take-off weight of under 10,000 lb (4,540 kg), they are lighter than corporate aircraft and seat between three and six passengers."

As for the target market segment? "VLJs are intended to have lower operating costs than conventional jets, and will be able to operate from runways as short as 3,000 feet (900 m), NASA and the FAA encourage the development of these light jets and foresee their widespread use in point-to-point air taxi service. This Small Aircraft Transportation System would provide air service to areas ignored by airlines."

Enough specs: Here's some of the VLJs that may turn up on your shop floor:

Adam A700 AdamJet:

Powered by a pair of Williams FJ33 turbofans, the seven seat A700 AdamJet is derived from the A500's twin-piston model, known for its unique high-mounted rear tail. In a test flight staged on April 26, 2006, the A700 flew to 41,000 feet and achieved a speed of 340 knots.

"This flight signifies the continuing progress of the A700 program," said Bill Watters, Adam Aircraft vice president of Flight Operations in the news release that announced the flight. "Serial Number 001 has demonstrated the aircraft's flight capabilities, Serial Number 002 remains on track for FAA Certification, and collectively the two aircraft have flown more than 500 hours. A700 Serial Number 003 is currently in production." (www.adamaircraft.com)

Aviation Technology Group Javelin:

Like the A700, the ATG Javelin Mk.10 is powered by a pair of Williams FJ33 turbofans, but the resemblance between the two VLJs ends there. Visually, the two-seat ATG Javelin looks like a T-38 jet trainer, thanks to its seat-behind-seat cockpit arrangement, fighter-style fuselage, and clear fighter-style canopy.

With a certified ceiling of 45,000', a cruise speed of 0.90 Mach, and a rate of climb of 10,000' per minute, the 36' long ATG Javelin MK.10 will be the preferred toy of well-heeled private jet pilots. As such, you can expect to see it being babied in the best MRO shops; just as Ferraris and Lambourghinis are typically tended by high-end auto dealerships. The manufacturer says initial customer deliveries of the FAA-certified Javelin are slated for 2008. (www.avtechgroup.com)

Diamond D-JET:

Diamond Aircraft Industries' D-JET is a five-seat, single engine VLJ equipped with a Williams FJ33-4 turbofan. It is a sleek passenger jet that cruises at 315 knots at a ceiling of 25,000'. D-JETS/N 001 made its first flight on April 18, 2006, at the London International Airport, west of Toronto, Canada. According to a Diamond statement, "The 1 hour 6 minute test flight was conducted according to test plan with the evaluation of 19 distinct test points." (www.diamond-air.at)

Eclipse 500:

Eclipse Aviation's Eclipse 500 is a six-seat business-style powered by two Pratt & Whitney PW610F FADEC-controlled turbofans. "They are flat rated at 900 pounds of takeoff thrust," says the company. With a cruise speed of 375 knts and a ceiling of 41,000', the Eclipse 500 features a glass cockpit and military-style sidestick controls. Eclipse has taken the luxury car paradigm to its logical extreme by hiring BMW Group DesignworksUSA to help design the Eclipse 500's interior. Can we say all-leather seats? Yes, we can. On March 1, 2006, Eclipse Aviation began building the first Eclipse 500 jet that will be delivered to a customer. (www.eclipseaviation.com)

Embraer Phenom 100:

Brasil's entry into the VLJ market, the Embraer Phenom 100, seats 6-8 people and equipped with two Pratt & Whitney Canada PW617F turbofans. The Phenom 100 will have a high cruise speed of 380 kts and a ceiling of 41,000'. The Phenom 100 is expected to enter service in mid-2008. With an onboard washroom and refreshment center, this aircraft is meant to pack a business jet experience into a VLJ-size aircraft. (www.embraerexecutivejets.com)

Excel-Jet Sport-Jet:

Powered by a single Williams FJ33 rear-mounted turbofan, Excel-Jet's Sport-Jet is a 4+1 seat all-glass aircraft . It will cruise at 340 kts at a ceiling of 25,000', and it will sell for about $1 million. The Sport-Jet is currently in the testing phase. When it becomes commercially available, it will be a natural choice for air taxi and small corporate aviation customers. (www.sport-jet.com)

TAM-AIR Epic Jet:

The TAM-AIR Epic Jet is a seven-seater powered by two Williams FJ33-A4 turbofan engines. With a maximum cruise speed of 390 kts, a certified ceiling of 41,000', and a luxury interior, the Epic Jet is intended to challenge larger business jets and piston planes alike. (www.epicaircraft.com)