Diamond Star DA40reviewed by Philip Greenspun, ATP, CFI, and former owner, in August 2002, updated August 2010
Diamond's DA40 is a low-wing 4-seat composite airplane that is suitable for everything from primary flight training to personal transportation through hard IFR conditions. The airplane can cruise as fast as 140 knots on 9 gallons per hour of fuel through its 4-cylinder 180hp fuel-injected Lycoming engine. The DA40 sells for between $206,000 (conventional instruments, basic Garmin avionics, no autopilot) and $280,000 (Garmin G1000 glass cockpit, autopilot, satellite weather, most of the rest of the options).
The things that distinguish the DA40 from its competitors such as the Cirrus SR20 and the Cessna 172/182 are the following:
Occupants of Diamond-built aircraft have survived terribly violent crashes and mid-air collisions with remarkably light injuries. Diamond has never been sued for a product defect. The April 2001 issue of AviationConsumer.com carries an article titled "The Safest Trainer" (Jane Garvey and Paul Bertorelli) that gives top marks to the Diamond DA20 (shared with the Cessna 172). No Diamond airplane has ever caught fire after an accident.
Safety in the DA40 begins with the superb visibility afforded by the wrap-around canopy and low panel. The long narrow wing is just behind the pilot and therefore you can see up, left, right, and down and sideways. The one blind spot is down and straight ahead, where your view is blocked by the panel and cowling.
Safety continues with extremely forgiving handling. Stalls are gentle with virtually no tendency for a wing to drop. Although the DA40 is not currently spin-certified it has been spin tested and can be recovered from a spin via a standard opposite rudder procedure. A non-factory pilot who intentionally (and illegally) spun a DA40 reported that it "spun gently" and was "not as much fun as spinning a DA20-C1" (the DA20s are spin-approved).
Either of the DA40's wing spars can carry the full load of the wings, thus leading to the FAA certifying the composite airframe with no life limit. Composite materials are not subject to metal fatigue and therefore a mid-air break-up seems virtually impossible.
Suppose that, like the unfortunate pilots of a DA20 involved in NTSB accident ATL98LA006, you find yourself misunderstanding ATC and wandering into the wake of a MD-80 jet, resulting in being flipped over then smashed down onto the pavement from 200' AGL? You too may walk out of the hospital a few days later thanks to the DA40's massively overbuilt cockpit.
One fly in the safety ointment is that the DA40 has 3-point harnesses. The lap belt portion is manually adjusted so that turbulence can't bump your head against the canopy. The shoulder belt portion is on an inertia reel for comfort. The harnesses are very comfortable and convenient but give the rigidity of the airframe it would be nice to decelerate against two shoulder straps rather than one. It would be even nicer to see Diamond install the airbag seat belts from www.amsafe.com.
Preflighting the airplane takes less than 10 minutes. If it is cold you probably want to plug in the Tanis engine preheater.
The DA40 interior is spacious and cramped at the same time. Getting in and out is easy with no need to step on the seats. Rear seat passengers have their own gullwing door, which is very handy for dogs. Once the rear seat passengers are in place, they have an awesome amount of space and plenty of legroom even for a 6'-tall person. Like the front seats, the rear seats are equipped with car-style 3-point inertia-reel seatbelts. The view from the rear seat is an amazing 180-degree panorama out the teardrop . One could be happy riding in the back seat all day.
What's the cramped part? Sadly it is the pilot's seat. The composite seats are part of the airframe, which makes them fantastically strong but prevents them from sliding forward and back. Rather the pedals are adjustable. That's fine except that 6' pilots can't get a good leg stretch even with the pedals pushed back all the way. A 6'2" height limit is probably sensible for long flights. Note that the Austrian-built 2001 DA40s had an instrument panel that came down to touch the tops of one's thighs; the 2002 and later DA40s are built in Canada with a redesigned panel that affords greater thigh clearance.
Taxiing the DA40 in a straight line via differential braking is remarkably easy, much easier than in some other planes of similar design.
The standard DA40 with 40-gallon fuel tanks does not have the world's largest rudder so expect to be stomping pretty hard on the right rudder pedal. The 50-gallon model needed a larger rudder to pass spin certification and therefore might not need quite as heavy a foot.
If you have the three-blade MT Prop, you are required by the POH to pull the prop back to 2400 RPM as soon as practical, typically at 500' AGL when the flaps are retracted or at 1000' AGL. The limitation of 2400 RPM continuous relates to European noise certification and not to safety. You can safely run the engine/prop at 2700 RPM and the POH encourages you to do just this in an inadvertent icing encounter. Most of the DA40s being delivered in the U.S. have the two-blade metal Hartzell prop. If you look at the supplements in the very back of your P.O.H., you'll discover that the STC for the Hartzell prop removes the 2400 RPM limitation. The Hartzell prop can legally be run continuously at 2700 RPM, though I don't recommend this unless you have a high tolerance for noise or are trying to climb out of 12,000' on a hot day.
Whether or not you have a physically comfortable flight in the DA40 will depend primarily on two factors: turbulence and outside air temperature. The DA40 has relatively large wings for its weight, i.e., its wing loading is light. Aircraft with heavier wing loading will be less affected by turbulence. The DA40 is very stable in smooth air and a pleasure to fly on instruments but it becomes a handful to manage on a bumpy summer afternoon. Why not design the plane with smaller wings, like a Mooney or a Cirrus? Planes with heavy wing loading are unforgiving at low airspeeds.
A paper airplane is a good illustration of the pluses and minuses of light wing loading. It has small wings but the total weight is that of one sheet of paper, thus resulting in a wing loading much lighter than any general aviation airplane. The paper airplane may be stable when flown indoors but the smallest gust of wind can pick up that paper airplane outdoors. Trying to push a paper airplane through turbulence to land on a specific spot would be impossible. On the other hand, the paper airplane can fly at very low airspeeds. It would be very unusual to have a stall/spin accident in a paper airplane.
The light wing loading of the DA40 makes it an excellent primary trainer. The airplane is extremely forgiving at low airspeeds; the DA40 may take care of you even if you don't take care of yourself. I flew with Michael Feinig, general manager of Diamond's Austrian operation. He had me close the throttle, take my hands off the stick, and pull my feet back from the rudder pedals. Then Feinig trimmed the airplane all the way back, full nose up. We mushed down at 500-700 fpm for several minutes. The DA40 rocked a bit but never dropped a wing or threatened to spin, despite the fact that we never touched the rudder.
The downside of light wing loading is most apparent when you're flying instruments in turbulent conditions, for example when training under the hood on a summer afternoon when the sun beating down on fields and parking lots generates convection. Tom Wardleigh, my 77-year-old CFII, would say "The PTS standards are minimums; tell yourself that the width of the needle is all the tolerance that you need." A small updraft, however, can lift the DA40 100 feet within a few seconds. You need a rapid scan and constant attitude adjustments to stay on course and at altitude. Holding forward pressure on both rudder pedals cuts down on the tail wagging back and forth to some extent.
Instrument training on a summer afternoon brings us to the second major factor determining en-route comfort in a DA40: outside air temperature. Like other airplanes with great visibility you pay a price in terms of great heat gain. The later DA40s have tinted windows and probably aren't as hot as mine was but on a sunny day you'll want to either open the front vents (effective but noisy) or climb to 7000' where true airspeed picks up to 135 or 140 knots on less than 10 gallons per hour with the mixture set 75 degrees rich of peak.
Rather than having soft keys, Garmin's user interface relies heavily on the pilot taking his or her eyes away from the task of flying the airplane to use knobs to position a cursor on the screen. Once the pilot has verified that the cursor is over the desired choice, the pilot is expected to press the Enter key. What would be a single glance and button push on a soft key-equipped system such as the Apollo CNX 80/MX20 or Avidyne becomes on the Garmin a task more akin to moving the mouse around the screen of a personal computer and selecting an option from a pull-down menu.
For folks who are considering buying a used DA40, the VM1000 is a large flat panel that displays the following information:
Pulling the tach time out of the Vision Microsystems display is something most mechanics won't know how to do. You turn on the master switch but don't start the engine, the VM1000 first goes through a few seconds of self-test in which all the segments are lit and then the field labeled "RPM" shows the tach time.
We did appreciate the VM1000's individual temperature readouts when the engine was running rough on climb-out one evening from Bar Harbor, Maine. The bar graphs showed that cylinder 3 was cooler than the other cylinders but its exhaust gas was hotter. We conjectured that one of the spark plugs in that cylinder wasn't firing, leading to less combustion in the cylinder (lower CHT) and delayed combustion as the air-fuel mixture was leaving the exhaust valve (higher EGT). As we circled the field we confirmed this hypothesis by running the engine on just the left mag (smoother and the VM1000 bar graphs evened out) and the right mag (rougher and the VM1000 bar graphs showed cylinder 3 further out of line with the others). We aborted our planned return to Boston, grounded ourselves in the local Holiday Inn, and the next morning a mechanic at Acadia Air found a bad plug in cylinder number 3, just as the VM1000 was suggesting.
Experienced pilots know never to trust fuel gauges. What they want is a fuel totalizer. The VM1000 incorporates one. If you read the manual you can learn the unlabeled button functions necessary to tell the VM1000 "this airplane has a 40-gallon gas tank" and "I just filled up the gas tank". From there the VM1000 uses its fuel flow meter to calculate how much fuel is remaining. In my airplane this number was consistently off by about 5 percent but in a safe direction: the VM1000 would show 0 gallons remaining when the plane was still capable of running for 20 minutes.
"In the complex world of instrument flight, an autopilot is almost a requirement; some day they will probably be standard on all except pure sport airplanes; they are certainly very desirable, as they turn a busy hand-flying task into a relaxed experience where the pilot is well in command of the situation and always ahead of the airplane. The lower a pilot's experience level, the more an autopilot becomes a serious need, or, of course, a good copilot." ...By early 2007, Diamond is supposed to have a new Garmin autopilot available for the DA40. In the meantime they are selling the Bendix/King KAP-140 autopilot that came with my airplane. This is a two-axis autopilot with altitude preselect. If you're becoming disoriented in the clouds or need to take a breather for some other reason, press the AP button to turn the unit on in "ROL" mode (levels the wings) and press the ALT button to instruct the KAP-140 to hold your present altitude.
"A copilot during serious instrument flight is a necessity - not required by regulation, but without a doubt, flying instruments without a copilot is a very tough job. I've flown small aircraft in serious weather, on instruments, alone and it's much more difficult than flying a 747 with a crew."
-- Robert N. Buck, retired TWA captain, Weather Flying, pages 91 and 102
When precision is necessary, such as when on an instrument flight plan, the KAP-140 can be set to track a course determined by a VOR or the GPS. The altitude preselect feature let's you say "please climb at 200 fpm until you reach 5000'".
For ILS approaches, the autopilot can track both localizer (heading) and glide-slope (altitude). As a pilot you can't go to sleep, though. This is not a jet where the autopilot also has "autothrottles". If you don't back off the power you might find yourself zooming down the glide slope at 160 knots; if you back off the power too much you'll find the airplane hanging on the edge of a stall at 50 knots.
The KAP-140 gets its information about airplane attitude from the turn coordinator, not the attitude indicator. If you are flying in turbulence, therefore, it is best to take the unit out of "altitude hold" mode and into "VS 0" mode where the autopilot isn't fighting to stay at a precise altitude and therefore making turbulence even worse.
More: KAP-140 pilot guide from bendixking.com
The landing gear on the DA40 are fixed, simple, and strong. Prior to certification Diamond flew a DA40 prototype for more than 16,000 touch-and-goes without wearing out the gear. This is a good thing because most people flare too high in the DA40 at first. The low panel and all-around visibility makes the runway look awfully close. So you'll pull up on that stick 5-10' too high and, if you don't have enough sense to go around, drop the plane onto the runway from 5' AGL.
The DA40 can be landed by pilots of average ability in less than 1000' of runway under most conditions at low density altitudes. If in an attempt to land short you come in slow and flare too aggressively you'll hit the tail skid but won't bruise anything other than your ego. By contrast a friend who purchased a Cirrus SR20 reports that the factory instructors spend a lot of time training owners to land relatively fast and nose-low. This chews up 3000' of runway but is necessary to avoid striking the tail, which in a Cirrus is unprotected by a skid plate.
One distraction when landing my DA40 in slightly gusty conditions was the intermittent sounding of the stall warning horn. The airspeed indicator would be right on 67 knots and supposedly the stalling speed with full flaps is 45-49 knots. Despite this wide disparity the stall warning horn would sound when the plane was hit by a gust and it was tough to avoid the temptation to push the stick forward a bit and land too fast, thus chewing up excess runway.
In my old plane the six flight instruments came from different vendors. Each one was supplied with the same voltage for lighting and the brightness of the instrument was a function of whatever bulb the manufacturer chose to include. The G1000-equipped DA40s should be nicer for night flying if only because everything important will be consistently illuminated.
The landing and taxi lights are out near the left wing tip, which isolates them from engine vibration. A flight school with four DA20s reports that they've only had to replace one landing light bulb in five years.
Once in the air, however, the DA40 is wonderfully warm and well-sealed. On sunny days the greenhouse effect from the canopy means that you won't even need to use the cabin heat.
The latest DA40s are available with choice of 2-blade Hartzell metal prop (easy to service) or 3-blade MT prop.
(Do watch for damage on the back flat surfaces of the MT prop; any holes in the epoxy should be filled in with 15-minute epoxy glue.)
Portable music players over the years have been getting quieter and quieter. The maximum voltage coming out of the headphone jack is no longer sufficient to damage eardrums. Portable music players are also not super powerful; a typical Sony being spec'd at 5 mW and an output impedance of 24 Ohms. Sadly the folks at Garmin are selling a product that, out of the box, demands a tremendous amount of voltage (because the gain is so low) and a tremendous amount of power (because the input impedance is so high). A brand new portable Sony CD player plugged into the GMA 340 produces a sound level at least 20 dB softer than the communications radios. It all started because older Garmin units had high-impedance, high-gain music inputs that picked up noise from the other avionics. If your GMA 340 is older it might need to be returned to Garmin for "Mod 5" and then your avionics shop can ground a wire on the back connector to up the gain by 20 dB.
If you're flying around the crowded Northeast with ILS marker beacons everywhere you'll need to push the marker mute button twice on the audio panel otherwise the GMA 340 will mute your music even when you can't actually hear the marker beacon.
I offer two versions of the checklist:
Note that the hot starting instructions in my checklist are totally different from what you find in the POH. The POH recommends priming the engine for 1-3 seconds with the electric fuel pump on and the mixture at full rich, before cranking. This kind of priming for 3-5 seconds worked well for my plane with cold starts but any kind of priming with a hot engine leads to flooding. I could reliably start my plane when hot simply by turning on the electric fuel pump and advancing the mixture while cranking.
My cold starting instructions differ subtly from the POH: the engine seems to start just as easily, and be less likely to flood, if one turns off the electric fuel pump before cranking and advancing the mixture. I primed my plane with the fuel pump on but after the 3-5 seconds of priming, the supplemental fuel pump went off and stayed off until I was ready for takeoff.
Here are some examples of the spreadsheet in use (fields in italics are user-entered; everything else is part of the downloadable spreadsheet):
|Weight and Balance for a sample Diamond DA40|
|Example: Two fat guys in front, full fuel|
|Mass (kg)||Arm||Moment||Mass lbs.|
|Oil not added||-1.7||1||-1.70||-3.75|
|Total Mass w/empty fuel||972.1||2341.50||2143.09|
|On-board usable fuel (gallons)||40.000||109.0||2.63||286.79||240.40|
|Total Mass w/fuel||1081.1||2628.29||2383.49|
|CG position right now||2.431|
|CG position when tanks run dry||2.409|
|Under max gross weight?||yes|
|CG upper limit||2.590|
|CG lower limit at takeoff||2.436|
|CG lower limit w/dry tanks||2.400|
|takeoff CG within limits?||no|
|empty tank CG within limits?||yes|
|okay to fly?||no|
|Weight and Balance for a sample Diamond DA40|
|Example: Three people, one dog, 30 gallons fuel|
|Mass (kg)||Arm||Moment||Mass lbs.|
|Oil not added||-1.7||1||-1.70||-3.75|
|Total Mass w/empty fuel||1067.1||2686.00||2352.53|
|On-board usable fuel (gallons)||30.000||81.8||2.63||215.09||180.30|
|Total Mass w/fuel||1148.9||2901.09||2532.83|
|CG position right now||2.525|
|CG position when tanks run dry||2.517|
|Under max gross weight?||yes|
|CG upper limit||2.590|
|CG lower limit at takeoff||2.460|
|CG lower limit w/dry tanks||2.431|
|takeoff CG within limits?||yes|
|empty tank CG within limits?||yes|
|okay to fly?||yes|
The first example is contrived to show more or less the only situation where it is possible to fly my DA40 under gross but out of CG: two guys weighing 420 pounds or more in the front seats, full fuel, and absolutely nothing in the rear seats and baggage compartment. Either a survival kit in the ski tube, some water and a flight bag in the back seat, or a laptop in the baggage area would put the plane back into the legal CG envelope.
In a fully equipped DA40, which carries the weight of all of the optional avionics, it is very difficult to get into the utility category (under 980 kg/2161 lb.). Basically the only way that my DA40 could be flown with utility certification limits for G forces was with only the pilot on board and less than full fuel tanks.
I just got checked out on my the DA40Tdi in my club in Oslo, Norway. Prior to this I have flown variations of PA28, PA18 and gliders (modern and old).
When flying the DA40, I felt that motorplane producers finally had learned from the glider producers when it comes to use of modern technology.
When it comes to the diesel engine: The simplicity is astonishing! The workload is very reduced thanks to the FADEC (Full Authority Digital Engine Control) and thanks to water cooling.
Best regards, Fred-Johan Pettersen
-- Fred-Johan Pettersen, September 23, 2003
I haved now ownes a Diamond Star DA40 D for just over a year. I have found Phillips commments most helpful. The Deisel versionhas been a pleasent surprise and although we have had some engine and autopilot issues they have been less than expected for a new type of aircraft.Modifications to the KAP 140 Autopilot resoloved the continual problem of the Autopilot "Trim Fail" alarm constantly fireing off in benign conditions. The Theilart centurion Engine has caused a few problems especially with the fuel injector connectors. Three in flight failures with the resultant loss of one fuel injector concentrates the mind some what. I am assured the problem is resolved. Diamond have now estabished a number of service centres for the aircraft in the UK (with the DA42 arriving shortly this is an important move). No news yet on the issue of life extension on the engine to 2400 hours TBR (yes they are replaced) from the existing 1000 TBR. I am assured its in the pipe line (as of March 2005). Nick Lamberts excellent articles in "Pilot"" magazine gives an accurate description of flying the aircraft.- It's been a dream . Oh one other small point- With Jet A1 fuel prices are half that of AVGAS in the UK Flying costs now become sensible.
Tony Realff March 2005
-- Antonony Douglas Realff, March 4, 2005
Excellent resource Philip!
As I started the process of transitioning from the Cessna Skylane (flying for Uncle Sam) to the Diamond, I found your web site to be an excellent resource.
Thanks for sharing your experience.
-- CAP blog, April 30, 2005
Hi Phil, first, thanks a lot for your pages, I read a lot of them before starting my own conversion to DA40. I do agree on many things, and your tips helped me somehow when I converted to DA40, so I decided to publish my own experience, including IR(A) renewal on a G1000 DA40 TDI. It gives a european view on the whole process, from differences training to IR experience.
You can find all of it under http://plasticflying.blogspot.com PlasticPilot
-- Plastic Pilot, August 2, 2007
Hello Phil, thanks for the great article which definitely helped me to make a decision on purchasing a DA40 two years ago. May I suggest you take out the link to dapo.org (it's dead) and would you mind linking back to the Diamond Aviators Net, a forum we made up as there was no free forum available for Diamond Aircraft owners and pilots. Also, at this page the interested Diamond pilot will be able to upload G1000 logfiles and read them out and display logged trips in google maps also showing any engine parameter during the flight. The forum is completely free of charge and any advertisements and always will be. Thank you very much, Kai
-- Kai Kern, August 3, 2010