Pilot’s Report: The Diamond Twin Star

The Diamond DA42, also know as the Twin Star, is arguably the most advanced light twin on the market today. Since its introduction to the United States in 2004 it has been gaining a foothold in flight schools around the country.

I recently had the opportunity to fly one courtesy of Galvin Flying Services at Boeing Field in Seattle.

GETTING UP TO SPEED

The first step was getting up to speed on the G1000, the glass cockpit in the four-seat Twin Star. I recommend G1000 books and programs from Max Trescott, Sporty’s, ASA and King Schools. Garmin also has an online simulator that you can download from Garmin.com for a few bucks.

Galvin offers a six-hour DA42 course that focuses on systems, multiengine aerodynamics, normal procedures, emergency procedures and maneuvers.

The course points out some major differences between the DA42 and other light twins used for training. For example, the engines are diesel. Starting them involves a glowplug, which must be switched on and allowed to heat before hitting the starters.

Most important, the Twin Star is a Full Authority Digital Engine Controls (FADEC) aircraft, which employs single levers to control throttle and propeller.

The DA42 is an all-electric airplane. After you start one engine the voltmeter must show at least 20 volts before you attempt to start the second engine.

If you lose both of the alternators and are running strictly off the back-up batteries for the FADECs, “expect engine stoppage when the batteries are depleted,” the checklist warns. This was a big departure from the other twin aircraft I fly where loss of the electrical system is not necessarily a life-threatening event.

Galvin uses a DA42 Flight Training Device (FTD) to introduce pilots to the airplane. It recently took delivery of an FTD manufactured by Diamond that is a cockpit replica of a DA42, however I “flew” the first generation version, in which engines and propellers are projected on wrap-around screens. The instructor controls the flight from a computer station.

Under the guidance of Bill Martin, I received instruction in the FTD covering normal procedures, abnormal procedures – the polite term for emergencies — and maneuvers.

The emphasis was on developing flows for procedures and knowing when to refer to the checklist and when to refer to the Quick Reference Handbook, which includes detailed troubleshooting procedures.

Flows are different in the DA42 than in the Cessna, Piper and Beech aircraft I have flown. In those I learned a “sign of the cross” pattern to make sure I saw all the things that needed to be checked and adjusted in an emergency situation or before maneuvers. You know the drill: fuel on, set mixture, props, throttle, flaps, gear, carburetor heat, mags, fuel pumps and back over to throttle and prop.

In the DA42 the flow is a backward question mark. You start at the bottom of the mark and work your way up and to the left.

PREFLIGHT

The DA42 was intimidating to me when I walked up to it. It is made of carbon fiber and has winglets and a T-tail that make it look like something that Captain Proton flew when he did battle with Queen Arachnia’s forces.

It has a wingspan of 44 feet and the distance from the ground to the top of the winglets is just over 7 feet. Tail height is 8 feet, 2 inches. These dimensions are important because it makes the DA42 difficult to park on a crowded ramp. The Twin Star is still new enough that some unfamiliar line crews might try to park it in a standard parking space. A word of warning: It will not slide beneath the wing of a Cessna 172.

Climbing into it is done from the rear, using a step, and there is a lot of climbing in and out during the preflight. Climb up and unlock and unlatch the canopy, a bubble, flip-up type. There are several keys: One to open the fuel caps, one to open the nose compartment and one to open the canopy. Try not to fall off the airplane as you open that. There are non-skid strips to stand on but, if you lose your balance, try to fall backward so you don’t hit the propeller on the way down. Climb in and unlatch the control lock straps. Stow them. Make sure the gear handle is in the down position.

Pull out the checklist. Don’t rush through it because there is a lot to cover. Check the position of the alternate air source lever. Check to be sure the alternators are on, the Engine Control Units (ECU) Swap is in the “auto” position, the emergency battery switch is off and the safety seal intact, and the fuel pumps off. Next, turn on the master switch, then the avionics to check the GPS database, fuel, etc. Total fuel capacity is 52 gallons, 50 usable.

A call-out box on the checklist calls your attention to the deicing and anti-icing equipment check. The DA42 is certified for known icing in Europe and, according to Diamond Aircraft’s Cathy Wood, the company expects FAA certification soon.

THE WALK-AROUND

Pay special attention to the integrity of the carbon fiber. If a metal plane gets a dent, it may not be a big deal. If the skin of a carbon fiber aircraft is damaged enough to be seen, such as in a spider-web crack, it is a no-go issue.

The de-icing panels on the leading edges of the wings need close inspection, as do the slinger rings behind the propellers. You want to be sure they are intact and not blocked. The same goes for the three air inlets and one air outlet.

The DA42 is powered by Thielert Centurion TAE 125-011.7 turbo diesel engines, which are liquid-cooled, produce 135 horsepower each, and give the Twin Star a maximum structural cruising speed of 155 knots.

Those engines burn Jet A. Be careful when you sump because Jet A, unlike 100LL, doesn’t evaporate quickly and leaves a slimy mess on your hands and anything else it gets on. I was cautioned to wear gloves and to have a rag with me when I checked fuel.

TAKE HER UP

Run-up is similar to other twins except the Twin Star has two Engine Control Units (ECUs) rather than two magnetos per engine. You test the ECUs by switching from A to B, and making sure the other ECU picks up the load when its counterpart is switched off, much as you do with traditional mags.

Power changes in the DA42 are done in percentages. Taxi onto the runway, hold the brakes and throttle up to 50%. Make sure all engine gauges are in the green, then push the levers to full power. Release the brakes. After liftoff and when you are out of usable runway, pitch for 82 knots. When the gear comes up reduce power to 90%.

This power reduction is tricky. I learned to squeeze the power levers to make the reduction because if I pulled back consciously I reduced power too much.

The aircraft climbs out at 82 to 100 knots. Because the tapes move from the bottom of the screen to the top, there is a tendency to pitch down rather than up to achieve climb out airspeed of 82 knots. Martin kept repeating the mantras of “let the speed come to you” and “put the nose on the horizon” to help me get it.

The next challenge was the stick. I was over-controlling because all my other flying is done in yoke-equipped planes.

“I see that a lot,” Martin noted. “You want to really wrestle the stick when you have been flying a yoke, especially in a Cessna 172, for some reason.”

I found that if I rested my stick arm against something, like the armrest or my leg, I was less likely to over-control.

We used a checklist to set up for each maneuver. Like any other airplane, power settings are key and trim is your friend. Slow flight was easy and predictable. Stalls were generally benign.

The sight view during steep turns took some getting used to, though, because essentially you are in a bubble. I felt like I was over-banking the airplane, although the attitude indicator and some mental math showed otherwise. The old formula, TAS divided by 10 plus 5 to get the angle used for a standard rate turn, worked out that a standard rate turn at 100 knots took 15° of bank but, because of the greater visibility due to the bubble canopy, it just looks steeper.

About that canopy: While it gives you great visibility, it also makes for a very hot cockpit in the summer. Thankfully there is a “taxi” position that allows you to have a “cooling gap” when you are on the ground.

IS THERE A PROBLEM HERE?

All my other G1000 time had been in the dead of winter in IMC when there was no need for sunglasses, so it was a bit of a surprise when the G1000 displays disappeared in the DA42. They just went dark. Martin recognized the problem immediately and advised me to get a cheap set of shades that don’t polarize. Instead I learned to block the sun with the brim of a well-placed baseball cap.

In a steam gauge-equipped airplane if an instrument or engine fails, the pilot needs to figure out what went wrong. If something goes wrong with an engine in the DA42, it is accompanied by a loud BONG! and an annunciator light on the Primary Flight Display. The PFD will tell you what has gone wrong, eliminating the guesswork. If it is an instrument that has failed, a large red “X” will appear over it. This is a big help because you know immediately if something has failed and you need to switch to the back-up instruments.

Like any other G1000 aircraft, if you encounter an unusual attitude red chevrons appear on the screen pointing the way back to level flight. When the pitch or bank becomes extreme, the screen declutters, leaving only the most pertinent information, such as the attitude indicator, in place.

Having practiced emergencies in the FTD we were ready to try it in the air.

The left engine is the critical engine on the DA42. When Martin failed an engine there were the classic aerodynamic responses, such as the nose yawing toward the side of the aircraft that has the dead or weaker engine. There also was a BONG! and the annunciator light on the PFD.

For the Seneca and Travel Air, I learned the mantra “mixture, props, throttle, flaps up, gear up, identify, verify, check fuel, pumps on, fix or feather” when there was a loss of engine power. Because the DA42 is FADEC equipped, feathering the propeller and securing the sick engine is done with the flick of a switch.

The checklist carries the caveat that you must be below 6,000 feet pressure altitude to attempt restart. Trim will be your friend in single engine operations because it takes a healthy amount of rudder pressure to maintain directional control. Once the trim is in and the propeller feathered, the airplane is easy to fly again.

THE PROS…

The ease of feathering the propeller was one of the many things I liked about flying the DA42.

I also liked how the rudder pedals move back instead of the seat moving forward, so I was not cramped against the stick.

I liked the G1000 and, given the choice, I would take this airplane into a single-pilot IFR situation over the other twins I fly. The annunciator chime that calls your attention to a loss of engine power is a great tool. If your scan is not as sharp as it should be, it could save your life.

Fuel economy is another plus.

AND THE CONS…

I’m still a little skittish about composite aircraft. They are light and strong, but when they get a ding in them it can be cause for grounding them.

The height of the aircraft makes it hard to park and, for me, hard to climb into.

I also wasn’t too keen on the bubble canopy because it got too warm in the summer.

IS IT FOR YOU?

If you are looking for a fuel-efficient airplane that shines for single-pilot IFR operations, the Diamond Twin Star is for you. It definitely lives up to its marketing slogan: “Go where you want, when you want — fast and for less.”

If you are planning a career in the airlines and know you’ll only be flying glass panels, this is your airplane.

However, just to be on the safe side, you might want to get some experience flying older, steam gauge airplanes because you’ll probably be building your hours in those before you get that airline job.