01 Limitations Chapter 2

This is the EASA-approved chapter — the numbers you don't argue with. Read it once knowing that a handful of them move depending on which modification is installed on your particular airframe, and the rest hold for every DA42 NG built.

V-speeds AFM 2.2

The two speeds worth knowing before anything else are the pair that only exist because there are two engines: vMCA and vYSE. Lose an engine below vMCA and the rudder simply cannot out-vote the yaw the good engine is producing — you lose directional control, full stop, no matter how good your technique is.

Power-plant limits AFM 2.4

Two Austro Engine E4-C diesels, each putting out 100% (123.5 kW) for take-off — limited to 5 minutes — and 92% (114 kW) continuous. Learn these as a set; they're what the G1000's color arcs are drawn from.

Engine instrument color arcs AFM 2.5

These are the arcs you'll actually see on the G1000, per engine. The pattern to notice: RPM has no yellow band at all — it's green straight to red at 2300. Everything else gets a cautionary yellow band before its red line, sized differently for each parameter.

Mass, CG, load factors AFM 2.7, 2.8, 2.10

The DA42 NG's take-off, zero-fuel and landing masses all depend on which mass-related modification is installed on your specific airframe. Never blend the two configurations together — always ask "does this aircraft have that MÄM?" before you answer.

Minimum flight mass is fixed regardless of any modification: 1450 kg (3197 lb).

Fuel & capacities AFM 2.14

Autopilot & G1000 limits AFM 2.16.6, 2.16.7

This is where the DA42 NG's manual gets noticeably longer than a single's — a lot more of it is about what the autopilot and the G1000 are and are not certified to do.

• Autopilot speed range: 90–180 KIAS. Disconnect it for take-off, landing, and any single-engine operation.
• No altitude-select capture below 1200 ft AGL; disengage below 200 ft AGL on approach/departure, or 800 ft AGL everywhere else.
• ILS coupled approaches: Category I only.
• G1000 GPS is not WAAS-approved — no LPV, LNAV/VNAV, or LNAV+V, and SBAS must stay disabled.

02 Emergency Procedures Chapter 3

This section covers everything Chapter 3 handles that isn't specifically about losing an engine — that gets its own section next, because it deserves one. Here it's G1000 warnings, fire, electrical failure, and the odds-and-ends emergencies every pilot eventually meets.

G1000 warning alerts AFM 3.2

Every one of these is prefixed L/R because it can happen on either engine independently — that's the whole shape of a twin. Know the trigger value and the same three-step logic applies almost everywhere: reduce power on the affected engine, increase airspeed, and if the value doesn't return to green, start preparing for that engine to fail.

Electrical & fire AFM 3.10, 3.11

A complete electrical failure isn't the emergency it would be in a simple single — the ECU backup batteries keep both engines' control systems alive for at least 30 minutes on their own, and a separate dry emergency battery keeps the standby attitude module and flood light lit for at least 1.5 hours. Know where those numbers come from and a total electrical failure stops being frightening and starts being a checklist.

The maximum demonstrated airspeed for cracking the front canopy in flight — for smoke, for CO, for an autopilot malfunction diversion — is 117 KIAS, in every one of those procedures.

Other emergencies worth knowing cold AFM 3.9, 3.12

• Landing gear unsafe light on for more than 20 seconds during a cycle → re-cycle the selector below vLOR (152 KIAS).
• Manual gear extension works up to 152 KIAS and can take up to 20 seconds by gravity alone.
• Spin recovery steps 1–4 (power IDLE, opposite rudder, elevator forward, ailerons neutral) must be simultaneous — this airframe was never spin-tested for certification, so the recovery is built from general experience, not a demonstrated maneuver.
• Emergency descent: flaps UP, gear DOWN (for drag), power IDLE, never above vNE (188 KIAS).

03 One Engine Inoperative AFM 3.6–3.9

If you only really internalize one section of this whole guide, make it this one. Everything else on this aircraft is a variation on something you already know from single-engine flying. Losing an engine on a twin is not — it is the single scenario the entire multi-engine rating exists to prepare you for, and it is entirely unforgiving of hesitation.

Recognizing it AFM 3.7.1

An engine failure on a twin doesn't announce itself with silence — it announces itself with yaw and roll toward the dead engine, because thrust just went asymmetric. The memory aid the AFM itself gives you: "dead foot, dead engine." Once you've re-established directional control with rudder, the foot pushing hard on a pedal is on the side of the good engine; the foot feeling nothing is on the side of the failure. The left engine is the airplane's designated critical engine for handling and performance purposes — worth knowing which side that puts you on before you're ever surprised by it.

The decision flow AFM 3.7.2–3.7.7

Feathering & restart windows AFM 3.7.3, 3.7.4

Feathering only works above 1300 RPM — shut an engine down slower than that and the blades stop short of the start-lock position, so you'd need to bring RPM back up first. Once it's feathered and secured, the remaining fuel in that tank isn't wasted: set the operating engine's selector to CROSSFEED and it draws from the dead side too, stretching range and keeping the wings laterally balanced at the same time.

Landing and going around with one out AFM 3.7.7, 3.7.8

A one-engine-inoperative go-around is not recommended below 800 ft AGL — below that, committing to land is safer than trying to climb away on one engine with flaps and gear still hanging out. And keep flaps at UP for the approach itself unless the landing is already assured: more flap means more altitude lost transitioning into a single-engine go-around, exactly when you can least afford to lose it.

04 Normal Procedures Chapter 4A

Two engines means twice the checklist items in some places, but the logic doesn't change from a single — it's still preflight, start, taxi, takeoff, climb, cruise, descent, land, shutdown. What's new is the ECU/fuel-pump test sequence, and doing everything symmetrically, left then right.

Pre-flight numbers worth memorizing AFM 4A.5, 4A.6.1

The ECU/fuel-pump test AFM 4A.6.6

This is the one check a single-engine pilot has never done. With the power lever at IDLE and RPM below 900, holding the ECU TEST button forces the system through both ECU channels while cycling RPM above 1800 and back — proving each channel, and its fuel pump, can run the engine alone. Both caution lights need to extinguish at the end, and the whole thing has to complete without error or you don't fly.

Then the available-power check: power to MAX for 10 seconds, RPM should stabilize 2250–2300 RPM, LOAD 89–100%. Do this for both engines, and compare — real asymmetry here on the ground is exactly what you don't want to discover for the first time at rotation.

Take-off & climb speeds AFM 4A.6.7, 4A.6.8

05 Abnormal Procedures Chapter 4B

Abnormal is Chapter 3's quieter sibling — problems that need a response but aren't yet an emergency. On a twin, most of them are about the redundancy actually doing its job: one ECU channel acting up while the other keeps flying the engine, one alternator down while the other carries the bus.

ECU cautions AFM 4B.4.2, 4B.4.3

An L/R ECU A FAIL or B FAIL caution doesn't mean the engine is about to quit — it means the system has already switched to the other channel automatically. The clearing procedure itself (VOTER to the failed channel, wait 5 seconds, back to AUTO) carries a real warning: doing it in flight can briefly rough-run the engine or cause a momentary power loss, so it's only attempted with a landing site within gliding distance if the single-engine climb rate would otherwise be negative.

STICK LIMIT — the variable elevator stop AFM 4B.4.11

This one is unique to how this airframe manages power-on stalls. Both power levers above ~20% and the stop fails to engage: stall characteristics with power on are degraded and the airplane must not be stalled in any configuration. At least one lever below ~20% and the stop stays engaged when it shouldn't: elevator authority is reduced, so approach speed must not go below vREF (84 or 86 KIAS, by weight).

Numbers to hold onto AFM 4B.3, 4B.4, 4B.11

06 Powerplant AFM 7.9.1, 7.9.3, 7.9.4, 7.9.6–7.9.9

Two Austro Engine E4-C liquid-cooled, four-cylinder, turbocharged diesels, each making 123.5 kW at 2300 RPM. Each one is its own complete, independent power source — the twin's whole safety case rests on that independence actually holding up.

Cooling, oil and turbocharging

A bypass keeps coolant flow off the radiator until it reaches roughly 88 °C, letting the engine warm up quickly; only then does the thermostat open the radiator circuit. Each engine actually runs two separate oil systems — one lubricating the engine and turbocharger, a completely separate one serving the gearbox and the propeller governor. Check both during preflight; they're not the same fluid and not the same inspection hole.

The turbocharger's waste gate is positioned by the ECU itself, reading a manifold pressure sensor behind the compressor — that's what keeps manifold pressure from spiking at low density altitudes, entirely without pilot input.

Fire detection AFM 7.9.9

One overheat detector per engine, tripping at 250 °C (480 °F) in the nacelle. Test it the same way you test the gear warning horn — one button next to the gear selector, checking both an aural alert and the fire message for each side.

Controls that serve BOTH engines at once

• ALTERNATE AIR — a single lever under the panel that opens alternate air to both engines simultaneously; there is no independent left/right control for it.
• VOTER switches — one per engine, set to AUTO for normal operation, letting the system pick the better ECU channel automatically.

07 Propeller AFM 7.9.2

Two mt-Propeller MTV-6-R-C-F hydraulically regulated, 3-bladed, constant-speed, feathering propellers — the feathering part is what makes single-engine flight survivable at all, by letting the dead engine's blades turn edge-on to the airflow instead of windmilling and dragging you down.

The pitch logic is simple once you see it: more gearbox oil pressure to the hub means lower pitch and higher RPM; less pressure means higher pitch, lower RPM. Shutting an engine down opens the governor valve, oil drains from the hub, and the blades move all the way to the feathered stop — but only if propeller speed was above 1300 RPM when you did it. Below that, the pitch stalls short of the start-lock position and you'd need to spin the engine back up before it will feather properly.

08 Fuel System AFM 7.9.5

Symmetric about the fuselage centerline, each side normally feeding its own engine — but joined by crossfeed lines so either engine can draw from either tank when it matters.

The rules that keep it safe

• Two independent electric low-pressure pumps feed each engine — normally one runs, the ECU switches to the other on a pressure fault, and both can be forced on together with the FUEL PUMP switch.
• The OFF position on each selector needs a safety guard twisted first — a deliberate friction against selecting it by accident.
• Never shut an engine down with the fuel selector — always ENGINE MASTER — or you risk damaging the high-pressure fuel pump.
• Both AUX PUMP switches must be run together, never one side alone, to avoid adding lateral imbalance on top of whatever the mains already have.

09 Electrical System AFM 7.10

A 28 V DC system built around the same idea as everything else on this airframe: two of everything that matters, cross-connected so a single failure doesn't take the whole airplane dark.

Generation and backup

Notice the two very different backup numbers: 30 minutes for the ECUs (from the ECU backup batteries) and 1.5 hours for the standby attitude module and flood light (from the separate emergency battery). They're not the same battery, they don't share a runtime, and mixing them up is an easy way to lose points on an exam.

ECU electrical redundancy AFM 7.10.1, 7.10.2

Each ECU BUS reaches its MAIN bus through a diode and connects to its own alternator through a diode and a 30 A breaker, powering ECU A and its fuel pump directly. ECU B, and its fuel pump, get their power the same way — plus a second path, through a diode and fuse from the opposite engine's ECU bus. That cross-tie is deliberate: it means even a fairly deep electrical fault on one side doesn't necessarily take out both ECU channels on that same engine.

Bus structure

• HOT BATTERY BUS — permanently wired to the main battery, feeding the map light and ELT RCPI, with no switch able to disconnect it.
• BATTERY BUS — reached via the battery relay (ELECT. MASTER), supplying both MAIN buses and heavy-duty starter power.
• LH/RH MAIN BUS — the RH one reaches the AVIONIC BUS only through the AVIONIC MASTER relay.

10 Avionics & Autopilot AFM 7.13, 7.14

The Garmin G1000 (or G1000 NXi, if MÄM 42-978 is installed) ties flight, engine, nav and comm together on the DA42 NG exactly as it does on the DA40 — but the GFC 700 autopilot section reads longer here, because so much of it is written specifically around what has to happen the moment one engine quits.

GFC 700 modes and disconnect logic

Vertical modes: ALT, VS (limited to 1500 ft/min climb, 3000 ft/min descent), and FLC (limited to 90–180 KIAS). The autopilot disconnects automatically on AHRS malfunction, loss of air data, or internal failure — and manually via the AP DISC button, the MET switch, the GA button, pulling the AUTOPILOT breaker, or simply switching AVIONIC MASTER or ELECT. MASTER off.

Disconnect colors, worth telling apart

The standby attitude module AFM 7.15

The Mid Continent MD302 gives you an artificial horizon on its left display and airspeed/altitude on its right — powered by the same emergency battery as the flood light, for the same 1.5 hours. It isn't ARINC-429 connected to the G1000 here, so don't expect heading information or automatic baro sync from it; those parts of the Pilot's Guide simply don't apply to this installation.

11 Flight Controls AFM 7.3

Ailerons, elevator and flaps run on control rods; the rudder alone runs on cables — worth remembering exactly because it's the one exception.

The feature that matters most here is the variable elevator stop: once both power levers exceed roughly 20%, an electric actuator limits elevator-up travel to 13° (versus 15.5° full deflection), specifically to keep power-on stall characteristics manageable. Drop either lever below 20% and full elevator authority comes back immediately. A caution on the G1000 flags either failure mode — the stop staying disengaged when it should hold, or staying engaged when it should release.

12 Airframe & Landing Gear AFM 7.2, 7.4, 7.5–7.8

CFRP fuselage, GFRP/CFRP wings and a 'T' tail, same design language as the DA40 — but with two nacelles built into the center wing, each with its own firewall between the engine and everything else.

Landing gear AFM 7.5

Unlike the DA40's fixed gear, the DA42 NG's is fully retractable and hydraulically operated — extension normally takes 6–10 seconds, held retracted by system pressure backed by a gas accumulator so the pump isn't cycling constantly in cruise. Lose that hydraulic pressure for any reason and gravity alone will bring the gear down; the emergency extension lever just releases the pressure holding it up. Retract before 152 KIAS; it may be re-extended at any speed up to 188 KIAS.

Canopy & heating AFM 7.8

A detail worth knowing cold: the RH engine's waste heat serves the front seats and cabin floor, while the LH engine's heat is what defrosts the canopy. It's an easy fact to get backwards under pressure, and exactly the kind of asymmetric-systems detail that separates a twin from a single.

13 Mass & Balance Chapter 6

The mechanics are identical to any other airplane — moment arms, a datum plane, empty mass from the Mass and Balance Report — the only twin-specific wrinkle is that fuel and heavy items now sit on two wings you have to keep in balance with each other, not just fore-and-aft.

Empty mass is established with both engines' oil full (2 × 7 liters), plus unusable fuel in both main tanks (2 × 1 US gal) and, if fitted, both auxiliary tanks (2 × 0.5 US gal) — every one of those quantities doubled from what a single-engine equivalent would carry.

14 Performance Chapter 5

The number that should genuinely change how you think about this airplane: at max take-off mass, sea level, ISA, on both engines you get about 1337 ft/min of climb with flaps up. Lose one, and the AFM's own OEI table shows only about 269 ft/min under the same conditions — roughly an 80% loss of climb performance from a 50% loss of power. That's not a rounding error; it's the aerodynamic penalty of asymmetric thrust and drag stacked on top of losing half your power, and it's the entire reason this section of the manual, and this guide, exist.

Crosswind & fuel flow