Embrace the change

To better understand passenger requests Cessna formed a committee of CJ4 owners/operators to listen to their wishes and complaints. The results of that research led to the announcement of the Gen 2 version of the CJ4 in 2021. More than 80 Gen 2s have been delivered. The Gen 2 that I fly left the factory in June of last year and is serial number 416.

The most prominent passenger complaint was the entry door and stairs. The bottom boarding step was too far off the pavement for many. And there was nothing to hold onto while climbing aboard. That may sound trivial to pilots, but remember, the business jet owner/passengers—the ones who pick up the tab—are not often youngsters. Their issues with getting into the cabin are real. 

The CJ4 door is different from that in other members of the CJ family, and for most other models in the Citation 500 series. When Cessna designed the CJ4 it created an entirely new forward cabin section and cockpit. Since nobody could remember why the original Citation door was oddly shaped engineers did the obvious and created a rectangular opening. That made space for larger entry steps, but the original 4 didn’t make full use of the space. 

For Gen 2 Cessna created a four-step entry with wider treads and a bottom step very close to the ramp. And to complete the ease of entry improvements there is a sturdy boarding assist handle that swings out from the aft edge of the door frame. 

Passengers love the new entry system. In fact, I was chatting with the pilot of an early serial number CJ4 last summer who told me his airplane owner had a new Gen 2 on order for delivery by the end of last year. The reason? The new door/stair system. Cessna demonstrated the new entry to the owner and a purchase order was signed on the spot. 

For pilots, the new stair system adds to the workload. First, you pull up on a For pilots the new stair system adds to the workload. First, you pull up on a lawnmower style cable to fold the bottom two steps into the top two. Then you grab the cables that support the deployed stairs and pull the whole thing into the aisle. The box the folded stairs form intrude somewhat on movement in the forward cabin and rob legroom for anybody in the optional side facing seats. 

Deploying the steps is where the hapless pilot could really embarrass himself. The easy part is pushing the folded “box” of stairs out. A gas cylinder breaks the fall. But then you need to bend way over, grab the edge of the bottom two stairs, and throw them toward the ramp. Lean over a little too far, or a little off balance, you could follow the unfolding stairs out the door. That’s something long-time Learjet pilots are familiar with when dropping the bottom half of that jet’s clamshell door. But remember, passengers love it, and it’s their opinion that matters. 

The other prominent improvement of Gen 2 is in the lavatory. The 4, from the beginning, had external lav service, and that’s great, and a huge improvement for everybody compared to other light jets. 

The lav on the 4 is private and convenient given the size of the cabin, but it lacked any natural light and a sink. The Gen 2 solves that with two small sky lights overhead. They don’t provide any kind of view but let in a remarkable amount of light that does wonders for making the lav seem more spacious. 

The new sink and vanity with its running water makes the lav a full-service unit. The sink water storage tank is not huge, and it’s not heated, but we’ve found passengers have never run short of water, and the flow of water and drainage has been flawless. 

Overall, the Gen 2 cabin has improvements in materials, seats, lighting, and lots of outlets for charging any device. Passengers can control cabin temperature, lighting, and window shades through an app on their phone. The GoGo air-to-ground communication system works great providing Wi-Fi access throughout the airplane with no need for special software or adapters for the passengers. You can opt to pay by the hour for internet access if you fly shorter trips or your passengers do not want, or need, constant internet access. Or GoGo offers unlimited subscriptions. 

CJ4 pilot’s wish list

I have yet to meet the pilot who doesn’t enjoy flying the CJ4. It’s stable, easy to handle, and the trailing link landing gear makes any reasonable touchdown a passenger pleaser. And it has the best thrust-to-weight ratio of the Citation family so climbs can be spectacular. On a cool day it’s common to see rates greater than 5,000 fpm at 200 KIAS. 

But the Collins Pro Line 21 avionics suite is at least two generations out of date, and Cessna didn’t touch the system when making Gen 2. And because the CJ4 was originally designed and certified as the first business jet to have a lithium main battery its pilots are constantly on edge about battery health with either of the current options of a lead acid or nicad battery. The Pro Line 21 avionics system is capable of handling all necessary navigation and flight control functions. But the system dates back more than 30 years. Its displays—which were originally CRT—are now flat panel screens, but they are small portrait format units while the rest of the avionics world moved on to large landscape screens years ago. 

The Pro Line 21 maps are rudimentary, there is no touch control of anything, and there are buttons and knobs spread across the cockpit used to dig several steps deep in old fashioned menus to find what you want. And for whatever reason, the displays are not as bright as more recently designed systems, including those from Collins. If you’re wearing a light-colored shirt, the reflection from the bright sunlight on the screens at altitude can make them almost impossible to read. One veteran CJ Pro Line 21 pilot I know told me the solution is easy, just put in the cockpit sun screens at altitude to keep the light off the displays. That would work. 

Enough kvetching about the avionics. Cessna simply had other priorities when it created the Gen 2. The company is selling all the CJ4s it can build—the company I work for waited a year and half—and there are some customers moving from legacy Pro Line 21 airplanes that simply don’t want to learn a new avionics system no matter how advanced the capabilities it may bring. The CJ4 is the last airplane in the entire Citation line up that doesn’t have Garmin avionics now that the XLS is being transformed into the Ascend. I’d bet my house that the CJ4 gets Garmin avionics one day, I just don’t know what day that may be. 

Battery worries

As for the battery issues, a short history is necessary. When the CJ4 was certified in 2010 it was the first business jet to have a lithium battery. The battery saved many pounds of weight and delivered juice a nicad or lead acid battery couldn’t match. Lithium was the future and Cessna was first. 

But after the CJ4 was in service for a while, a wildly out of spec ground power unit overheated the lithium battery and there was a fire. The result was an AD that forced removal of the lithium battery and replacing it with either a nicad or lead acid battery. 

The fundamental issue is that lithium batteries designed for aircraft operate nominally at more than 26 volts. The battery charges at 29 volts instead of the 28 volts we’re all accustomed to. So, the entire CJ4 electrical system was designed to function at a higher voltage than the 24 volts the conventional batteries can output. Because 26 volts was the originally expected battery level the minimum starting voltage is set at 24 volts. Now, with a conventional battery, 24 volts is the best you can ever get, so any minor discharge that knocks a volt off the battery output means you can’t start without a GPU. 

And everyone involved is very clear that the Williams FJ44 engines on the CJ4 require all 24 volts for a safe battery start. Attempt a light off with less power and the risk of a hot start and engine damage is very real. And the FADEC computers controlling the engines record available voltage at the attempted start so if there’s less than 24 and something goes wrong, engine warranty and the engine maintenance plan probably won’t pay for the damage. 

We use a GPU for starting whenever possible. We’ve had no issues with battery starts when the GPU isn’t available or practical, but nobody is going to push the start button with 23 volts showing on the MFD. 

The solution will be a return of the lithium battery. The Pilatus PC–24 already has lithium power and there appear to be no issues. In fact, the tailwind/crosswind starting limits for the same FJ44 engines on the Pilatus are double or more of the 10-knot limit on the CJ4, and most or even all of that difference is said to be the extra starting power from the lithium battery. 

The first 200 hours

We’ve flown our Gen 2 about 200 hours in the six months since it left the factory and there have been only two significant failures. One was an intermittent failure of the flap position sensor system, and the other was a rudder trim knob that simply broke internally. 

The flap sensor issue showed up after a three-hour-plus leg at high altitude cruise. I was descending at near the 305-knot red line when a “flaps fail” CAS message appeared. Oops. That’s 100 knots over the flap extension limit. The flap position indicator was yellow. But I felt zero pitch change so I was pretty confident that flaps hadn’t really moved. But I did slow down. 

When we did move the flap control handle to approach the flaps extended normally and all warnings disappeared. Cessna’s mobile maintenance team came and read the system history and asked us to hit the “event” recorder button if we saw the warning again. We did, only after long cruise legs, and we hit the event button each time. That pointed to a failing flap position sensor on the right side. Replacing the sensor didn’t eliminate the problem, but a new circuit card in the monitoring system appears to be the solution. 

The rudder trim knob failure was some sort of manufacturing flaw. Instead of coming up against a stop when turned the knob would spin around and drive the trim tab all the way over. Fortunately, the trim knob broke while running the pre-taxi checklist on the ground. It took Cessna a few days to get a replacement switch panel installed which left us AOG. The delay was blamed on a shortage of manpower to get to the somewhat remote airport where the failure happened. 

What a great airplane

Overall, the CJ4 Gen 2 has lived up to our expectations. Often it exceeds handbook performance numbers and our trip times and fuel burns as calculated by FltPlan.com are spot on, and if they miss by a little, it’s on the positive side. 

The single-point fuel system, automatic fulltime heated windshields, very effective infinitely variable speed brakes, high flap and landing gear speeds, spectacular climb performance, effective ground spoiler system, dual alternators that heat the windshield and backup the generators, and on and on make the CJ4 top of class in the light jet market. 

Gen 2 did satisfy passengers requests. Will a Gen 3 deliver for pilots? I certainly expect it will.
J. Mac McClellan is a corporate pilot with more than 12,000 hours, and a retired aviation magazine editor living in Grand Haven, Michigan.