Diamond DA40 (IO-360-M1A)

Diamond Aircraft was founded in Austria in 1981 and has built a global business in certified composite singles and twins. The DA40 Diamond Star launched in 1997 with the Lycoming IO-360-M1A as the primary engine. The brief was modern: composite construction for durability and reduced corrosion, control sticks instead of yokes for control feel, modern glass panel from launch, and predictable handling for training and recreational use.

The DA40 became one of the most successful certified four-seaters of the 2000s and 2010s. Flight schools adopted the airplane widely as a Cessna 172 replacement, particularly in Europe and Canada where modern training fleets had aged out of legacy designs. The DA40 XLS and various trim variants added refined interiors, updated avionics, and the larger MT three-blade composite propeller.

Diamond expanded the DA40 line with the DA40 NG in 2010, which substituted the Austro AE 300 turbocharged diesel for the Lycoming gas engine. As of mid-2026, both the gas DA40 (often DA40 XLS or DA40 NG-Lycoming variants) and the diesel DA40 NG continue in production from Diamond's Austrian and Canadian factories. The fleet is global with strong concentrations in Europe, Canada, and North American flight training operations.

The gas DA40 cruises at 145 to 155 KTAS at 75% power, burning 8.5 to 9.5 gph. Long-range cruise at 65% power drops fuel burn to 7.5 to 8 gph at 135 to 145 KTAS. The Lycoming IO-360-M1A runs at moderate stress in the Diamond installation and produces clean efficiency without exotic configurations.

Useful load is reasonable for a four-seat single. A typical DA40 has 850 to 950 pounds of useful load. Full fuel is 41 to 50 gallons depending on tank configuration (246 to 300 pounds), leaving 600 to 700 pounds for four people and bags. Four normal-sized adults with light bags work. Four adults plus camping gear gets tight. The cabin is competitive with a Cessna 172 in width and meaningfully better in visibility because of the canopy.

Handling is the Diamond signature. Light, responsive controls through the side stick. Predictable stall. The composite airframe is stiff and the airplane has very little of the airframe flex that legacy aluminum designs accept. Pattern speeds run 75 to 80 knots and approach over the threshold is 65. Most flight schools find that students transition cleanly between the DA40 and Cessna or Piper trainers.

The Lycoming IO-360-M1A (180 hp, parallel valve, fuel injected) is the standard gas DA40 engine. Lycoming's published TBO is 2,000 hours per Lycoming Service Instruction 1009 BE. The IO-360 in the Diamond installation runs at moderate stress and reliably reaches published TBO.

Field overhaul of an IO-360-M1A runs $30,000 to $45,000 in 2026 at a name-brand shop. Top overhauls between TBOs are uncommon on DA40 service profile. Cylinder work between 1,500 and 1,800 hours runs $3,500 to $6,000 depending on scope.

Propeller is typically an MT three-blade composite constant-speed on the XLS and later airplanes, or a Hartzell two-blade aluminum on earlier production. Both run on 2,400-hour or six-year overhaul cycles per Hartzell Service Letter HC-SL-61-61Y Rev 12. MT composite overhaul runs $4,000 to $6,000 in 2026. Hartzell overhaul runs $2,500 to $4,000.

The gas DA40 is moderately expensive to operate per hour, sitting roughly between a Cessna 172 and a Cirrus SR20 in operating economics.

Fuel runs $47 to $66 per hour at $5.50 to $7 per gallon and 8.5 to 9.5 gph. Engine reserve is $15 to $23 per hour. Prop reserve is $2 to $3 per hour. Airframe maintenance reserve is $15 to $25 per hour, the middle of the certified four-seat range. All-in at 100 hours a year runs $95 to $135 per hour, plus $4,500 to $8,000 in annual fixed costs.

The composite airframe and modern panel are durability advantages over legacy aluminum competitors. Composite construction resists corrosion in coastal storage and doesn't develop the wing-bend issues that older aluminum airplanes can show. Modern glass panels from launch mean most DA40 airplanes don't need expensive avionics upgrades to be IFR-capable.

Acquisition cost in mid-2026 runs $140,000 to $200,000 for an older DA40 with original avionics, $200,000 to $290,000 for an XLS with updated panel and recent paint, $290,000 to $400,000 for a low-time example with current G1000 panel. Factory new from Diamond lists $480,000 to $560,000 depending on configuration.