Start a Douglas DC-3 cold and dark: fuel switches, priming, mixture and ignition order, plus practical fixes when the engines do not start.
To start a Douglas DC-3 cold and dark in a flight simulator, secure the aircraft, select fuel, apply battery power, set both propellers full fine, build fuel pressure, prime, crank with ignition on, move the mixture to auto rich as it fires, then confirm oil pressure and repeat for the second engine, unless its checklist differs.
This Aviation & Real-World Flying answer covers simulator operation. It is not an approved procedure for a real DC-3 or C-47. Engine, starter and fuel-system installations vary, so an operational aircraft requires its approved checklist, trained crew and proper ground support.
What does cold and dark mean on a DC-3?
A cold-and-dark DC-3 has its engines stopped, main electrical power off and systems not yet configured for flight. It may not be physically cold: detailed add-ons can retain oil temperature, battery charge, fuel state and engine condition between sessions.
Begin at a parking position rather than on the runway. A runway spawn normally loads the engines running, while a parking spawn, saved flight or dedicated aircraft-state menu can produce different switch positions. Our explanation of what a cold-and-dark aircraft state includes covers these simulator-level differences.
DC-3 cold and dark startup sequence
This procedure is a practical simulator baseline, but the checklist supplied with your exact aircraft package takes precedence.
- Secure the aircraft. Set the parking brake or chocks, confirm the landing gear control is down and make sure the simulated propeller area is clear. Switch off radios, cabin heating and unnecessary lights to reduce the starting load.
- Set the engine controls. Put both mixtures at idle cut-off, propeller levers at full fine or maximum RPM, throttles slightly open, carburettor heat cold and cowl flaps open. Use different positions only where the aircraft checklist specifies them.
- Select usable fuel. Place each fuel selector or fuel switch on the main or starting tank named by the checklist. Confirm that the selected tank contains fuel, any separate shut-off control is open and crossfeed is in its normal starting position.
- Apply electrical power. Switch on the battery or master. Use external power if the add-on provides it and the battery cannot maintain adequate cranking speed. A weak battery may turn the propeller without producing a reliable start.
- Build fuel pressure. Select the engine to be started and operate its booster pump. Check that fuel pressure registers before priming; a running pump cannot supply an engine if its selector is closed or pointing to an empty tank.
- Prime for the engine condition. Apply the quantity specified by the package. A genuinely cold engine normally needs more prime than a warm one, but there is no universal number that suits every DC-3 simulation. Repeated priming after each failed attempt is a common way to flood the engine.
- Select starter and ignition. Choose the correct engine on the starter selector. Set the magnetos and booster coil as directed by the model. Some detailed aircraft separate inertia-starter energising, engagement and ignition; simpler versions combine these actions into one starter switch.
- Crank and introduce mixture. Engage the starter and watch for propeller rotation. In many DC-3 simulations, move the mixture from idle cut-off to AUTO RICH when the cylinders begin firing. If the supplied checklist calls for rich mixture before cranking, follow it instead.
- Release and stabilise. Release the starter once the engine runs independently, then set the lowest smooth warm-up RPM specified by the checklist. Confirm that oil pressure rises promptly and remains within the marked limits. Shut the engine down if pressure does not appear; increasing RPM is not a remedy.
- Start the second engine. Repeat the fuel-pressure, priming, ignition, starter and mixture sequence for the other side. Bring generators and other electrical loads online only in the order specified for that aircraft.
For a compact companion procedure, use our switch-by-switch DC-3 simulator starting sequence. The broader piston-engine starting checks explain priming, starter use and why oil pressure must be verified immediately after the engine catches.
Where should the DC-3 fuel switches and selectors be set?
The fuel switches should connect each engine to a tank containing usable fuel, normally the main or starting tank identified by the aircraft checklist.
Do not treat the fuel selector, booster pump, primer and mixture as interchangeable controls. The selector opens the supply path, the booster pump creates pressure, the primer supplies starting fuel and the mixture control meters fuel once the engine begins running. Turning on the pump alone will not correct a closed selector.
- Fuel selectors: select the checklist's normal starting tanks and verify their quantities.
- Fuel shut-off controls: open them if the model provides separate shut-off levers or switches.
- Crossfeed: leave it in the normal or closed position unless the checklist specifically requires crossfeed.
- Booster pumps: use them long enough to establish and retain the required starting pressure.
- Mixtures: keep them at idle cut-off until the point specified for introducing fuel.
A mistake we see often is selecting a tank that looks full on the loading screen while the cockpit selector remains on a different, empty tank. Check both the fuel quantity and the physical selector position.
Which DC-3 engine should be started first?
Start the right engine first when the package uses the common right-then-left DC-3 sequence, but reverse the order if its own checklist instructs you to do so.
The order often reflects ground servicing, passenger access or electrical arrangements rather than a mechanical requirement of the radial engines. A C-47 conversion, custom systems model or aircraft connected to ground equipment may use a different sequence.
Does the same startup work in FSX and MSFS?
The basic fuel, ignition, starter and mixture logic is the same, but the exact controls depend more on the aircraft package than on whether it runs in FSX, MSFS, Prepar3D or X-Plane.
| Aircraft model | Typical behaviour | Best approach |
|---|---|---|
| Simplified or default aircraft | Several starter and ignition actions may be combined, and generic simulator commands usually work. | Use the included checklist and cockpit tooltips; do not add unmodelled steps. |
| Detailed systems add-on | Fuel selectors, primer, booster coil, starter stages and magnetos may be independent. | Operate the virtual-cockpit controls in the documented order. |
| Persistent-state add-on | Battery charge, engine temperature, fouling, damage or hydraulic lock may carry over. | Use the add-on's preflight or maintenance functions before another start attempt. |
Hardware can also override the cockpit. A duplicated mixture axis may pull a lever back to idle cut-off as the engine fires, while a physical magneto switch can silently return the virtual magnetos to OFF. Temporarily disconnect suspect controllers or remove duplicate assignments when troubleshooting.
Why does the DC-3 cold and dark startup not work?
When a DC-3 startup does not work, identify whether the propeller fails to turn, turns without firing, or fires and stops; each symptom points to a different system.
| Symptom | Likely cause | What to check |
|---|---|---|
| Propeller does not move | No electrical power, low battery voltage, wrong engine selected or an unengaged inertia starter | Check the master, voltage, external power, starter selector and starter-engagement stage. |
| Propeller turns but there is no firing | No fuel, insufficient prime, magnetos off or booster coil omitted | Verify the tank quantity, fuel selector, pressure indication, primer and ignition controls. |
| Engine fires and immediately stops | Mixture remains at idle cut-off, throttle is fully closed or fuel pressure is lost | Introduce AUTO RICH at the required moment, crack the throttle and retain pump pressure as directed. |
| Rough firing, smoke or backfiring | Over-priming, excessively rich mixture or a fouled engine state | Stop adding primer and use the package's flooded-engine procedure. |
| Controls move back by themselves | Duplicated hardware bindings, a noisy axis or automated assistance | Neutralise the controller, remove duplicate assignments and disable conflicting assistance. |
| One engine starts but the other does not | An engine-specific fuel, primer, magneto or starter-selection error | Compare the failed side's controls with the running side instead of changing both engines. |
| Engine runs without oil pressure | Incorrect saved state, simulated damage or a systems fault | Shut down and inspect failure or maintenance settings before trying again. |
What should you check if it does not work at all?
If there is no propeller movement at all, troubleshoot electrical power and starter selection before adding more primer. Extra fuel cannot make a disengaged starter turn and may flood the cylinders once cranking finally begins.
- Confirm that the battery or external-power source is connected and showing voltage.
- Verify that the starter selector points to the intended engine.
- Use the virtual-cockpit starter to rule out a bad keyboard or controller assignment.
- Check whether an inertia starter must be energised before it can be engaged.
- Inspect saved failures, persistent damage and package-specific maintenance messages.
In Microsoft simulators, Ctrl+E is commonly assigned to automatic engine start. It is useful as a diagnostic where the aircraft supports it: if automatic start succeeds, the manual attempt probably missed a control or was overridden by a binding. If it also fails, investigate fuel state, battery power, failures and custom aircraft logic.
How do you clear an over-primed DC-3 engine?
To clear a flooded simulated engine, stop priming, switch off the booster pump, return the mixture to idle cut-off and crank using the throttle position specified by the aircraft checklist.
Observe any modelled starter duty cycle and allow cooling time between attempts. Do not keep adding prime after every unsuccessful start; first determine whether the original problem was actually missing ignition, a closed fuel selector or incorrect mixture timing.
What should you check after both DC-3 engines start?
After both engines start, verify oil, fuel, electrical and hydraulic indications before taxiing or applying high power.
- Hold the checklist's smooth warm-up RPM and monitor oil pressure and temperature on both engines.
- Confirm fuel pressure and leave booster pumps in the position required by the aircraft, rather than switching them off automatically.
- Bring each generator online and verify that the battery is charging.
- Check hydraulic or pneumatic pressure if the package models those systems.
- Switch on radios, navigation equipment and lights in stages.
- Keep cowl flaps open for ground operation unless the checklist specifies otherwise.
- Wait for the required oil-temperature indication before run-up or sustained high power.