Diamond DA40 Diamond Star

This page describes the Lycoming-powered DA40 — sold historically as the DA40-180 and DA40 XLS, and currently as the DA40 XLT. The Austro-diesel DA40 NG is a separate purchase, burning Jet-A rather than avgas, with its own page: Diamond DA40 NG (diesel).

Why this is a separate page — the split fires on more than one test. Applying the splitting rule against the diesel variant:

• Step 2 (numeric threshold) fires on fuel_capacity_gal: 50 gal usable (this airplane) against 39 gal usable (the diesel NG) is a 28.2% spread, over the rule's 20% threshold — confirmed identically in both FAA TCDS A47CE and Diamond's current spec sheet.
• Step 3 (the buyer test) also fires, independently: a Lycoming DA40 and a diesel DA40 need different pre-buy advice (Lycoming TBO and overhaul economics vs. Austro's shorter TBO and specialist-only maintenance), a different fuel logistics conversation (avgas everywhere vs. Jet-A, which is actually the CHEAPER and more widely available fuel outside North America), and — the reason this matters structurally, not just editorially — this catalogue's cost model has no field to mark a piston engine as burning Jet-A. src/components/aircraft/cost-calculator.tsx decides the reference fuel price by engineType === "turboprop" || engineType === "jet"; a piston_single diesel falls through that check and would be priced as if it burned 100LL. Keeping the two engines on one page with one fuel_burn_gph would either understate the diesel's real per-gallon cost advantage or overstate this airplane's — conflating them makes BOTH numbers wrong in the site's own cost calculator, not just imprecise on the page.

Both pages remain live. diamond-da40 was never retired — it now describes ONE variant (Lycoming) instead of conflating both, and the new diamond-da40-diesel page carries supersedes: "diamond-da40". No SPLIT_REDIRECTS entry was added, because nothing 404s; see the comment in src/lib/aircraft/split-redirects.ts.

Diamond's current configurator offers only the diesel "DA40-NG" as a new build — no Lycoming configurator page was found this session. If Lycoming production has genuinely ended, this page describes a used-market-only airplane going forward; this was not independently confirmed with Diamond and is flagged rather than asserted.

No single row of Diamond's current spec sheet states cruise speed, fuel burn and range together at one power setting. The sheet gives "Cruise speed at 75% (6,000 ft)" — 137 kt — with NO matching fuel-consumption figure at 75%; the only fuel-consumption figure given is labelled 65% (8.2 gal/h), and the only range figure is at yet another setting, "10,000 ft, 55% PWR, best eco" (847 nm). Rather than assert a false shared condition, cruise_percent_bhp and cruise_altitude_ft are left BLANK: the three stored numbers (cruise_speed_ktas, fuel_burn_gph, range_nm) are each individually sourced from Diamond's current spec sheet but describe three different power settings, not one flight. This is the largest, most explicit judgment call on this page — see the confidence note.

V-speeds corrected from the previous version of this page. The prior vne_kias: 178, vno_kias: 150 and va_kias: 117 do not match FAA TCDS A47CE at all. The certificate states 173 / 128 / 109 KCAS for this airframe (Section I, confirmed against the page image after pdftotext -layout shifted the value column off its labels — see the raw passage). vno_kias moves 17% from the previous figure.

Stall speed is stated as IAS, not CAS, on Diamond's current spec sheet ("96 km/h IAS / 52 kts IAS") — unusual among this family's Diamond documents, most of which state CAS or KEAS. Stored as-is; no conversion applied.

DA40 XLT (180 hp Lycoming IO-360, 50 gal usable, 2,646 lb gross):

900 lb useful load matches the manufacturer's own stated figure exactly. Four average adults with full fuel is tight, consistent with the previous version of this page's assessment — that judgment survives the re-sourcing unchanged.

• Flight Training (8): Docile, modern four-seat trainer with an excellent safety record; widely used by flight schools worldwide.
• Backcountry (2): Low-wing, fixed gear, hard-surface airplane.
• Business Travel (4): 137 kt cruise is moderate; four seats with modest baggage.
• Aerobatics (1): Not aerobatic certified.
• Cross-Country (6): Good efficiency and a genuinely useful range once flown at the best-economy setting.
• Cargo Hauling (2): Limited baggage capacity.
• Local Fun Flying (7): Comfortable, modern feel; good visibility.
• Surveying (5): Reasonable slow-flight platform; not specialized for it.

• DA40-180 (early): Basic panels, common retrofit to a G1000-class glass panel or a GTN stack.
• XLS/XLT: Garmin G1000 (NXi on later production) standard.

Very limited — composite construction restricts the aftermarket. No engine conversion path exists between the Lycoming and Austro variants once built; they are certificated on different certificate sections (Section I vs Section III of A47CE) with different equipment requirements.

• Parts availability: Lycoming IO-360 parts are universally available; Diamond's own service network supports the airframe.
• Mechanic familiarity: Any A&P familiar with Lycoming engines can service the powerplant — no specialist required, unlike the diesel variant.
• Engine overhaul cost: $45,000, from reference/engine-overhaul-pricing.md (O-360/IO-360 family, basis B — positioned within the specialty band by displacement, not a dash-specific published quote).

Prices are asking-price data from the site's own listings sync (2026-07-14), not a Vref or Aircraft Bluebook considered value — no guide access this session. Early DA40-180s ask roughly $150,000-$290,000; current XLT asking prices in the same snapshot run to $580,000-$600,000 new-condition. A Vref/Bluebook subscription would settle a considered value across this spread, which this session could not obtain.

• Castering nosewheel: requires differential-braking technique; a common source of ground-handling incidents during early training, not itself an AD.
• Composite repair: requires a certified composite shop.
• No dedicated Lycoming-DA40 AD research was carried out this session; this should not be read as a complete AD history.

No fresh insurance-broker quote sourced this session; typical_hull_insurance_annual_usd is intentionally left blank rather than repeating the previous page's uncited $1,800 figure.