So, the simplest way to start up an F-16s engine is to flip the power switch to "main power" and then set the "jet fuel" switch to "Start 1" or "Start 2".

I have a very simple understanding of the F-16s systems but from what I remember, there is some kind of pressurized gas-bottle, which cranks one of the engine-shafts and gets it to pull fuel from the lines so the engine can be started up.

Is that right and where can I find a detailed set of instructions on how to start up an F-16 (maybe startup and pre-flight checklists) and resources that show how the startup works internally, from the tech side of things.

And if someone here has the knowledge and time, it would be super awesome, if they could also explain what happens, when you go to "main power" (the one before is Batt. and the next also engages the generators i think?!) and then select one of the JFS modes 1 or 2.

This question is asked by a pilot who flies gliders and piston-powered aircraft ;)

  • 2
    $\begingroup$ Googling "f-16 startup procedure" returns many detailed links. Like this one at f-16.net f-16.net/forum/viewtopic.php?t=283 $\endgroup$
    – WPNSGuy
    Jun 2, 2022 at 20:36
  • $\begingroup$ @WPNSGuy's link seems to be useful. Also, you could try the General Dynamics F-16 Fighting Falcon Manual. As of the time of writing, it is sold out on Amazon but there is at least one copy available on eBay. $\endgroup$ Jun 2, 2022 at 21:13

1 Answer 1


The START switch routes pressurized hydraulic fluid inside two canisters to the HSM (hydraulic start motor). This motor begins to spin up the JFS (Jet Fuel Starter, a small turboshaft engine) through a geartrain in the airframe-mounted ADG (Accessory Drive Gearbox). Once the JFS is lit and running, it provides torque through the ADG to the main engine through the PTO (Power Take Off) shaft. There are two canisters so that you should ideally get two chances of starting the JFS/engine by discharging one of them each time (START 1), but in certain environmental conditions and fuel types you need to use both cans to get the JFS to start (START 2). Once the JFS is started, it spins the engine up to ~20-25% RPM, and it can keep it up for quite some time. Depending on environmental conditions, the JFS is left to crank the engine for up to 2 minutes.

By lifting the throttle from the cutoff detent to idle, the pilot consents to engage the igniters and introduces fuel to the engine. The JFS continues aiding in spinning the engine until ~50% RPM, then cuts out (and the Start switch springs back to neutral). The engine stabilizes at ~65% RPM idle.

Coming to the MAIN POWER switch, it is used for before start checks to force the plane to use battery power instead of the engine-driven generators (which are not turning anyway) and ground power. The pilot checks that the battery can power the flight control system (FLCS) by pushing the FLCS TEST momentary switch with the MAIN PWR switch on BATT.

The engine may be started on BATT but nothing will be powered, if MAIN power is flipped from BATT to MAIN PWR after engine start the ELEC SYS warning lamp will light up in the annunciator panel. This may be cleared by the ELEC FAULT RESET button.

  • $\begingroup$ If this is the explanation, why are there no instruments in the cockpit to monitor the operation of the JFS? When starting, you monitor the RPM of the engine and its FITT. You don't monitor anything on the JFS. $\endgroup$ Oct 8, 2023 at 15:46
  • $\begingroup$ There's not much to monitor about the JFS. It's not operated in flight, and it isn't throttled (you can't select the JFS's speed), so all you need is to make sure it does not overspeed and does not overheat. JFS has monitoring (either mechanical or electronic) to make sure these don't happen. And, remember, an INOP JFS is completely safe, you just have no way of starting the engine. Therefore it is not worth the extra complexity of having gauges etc. to have the pilot monitor the JFS and intervene if necessary, also considering how cramped the F-16 cockpit already is. $\endgroup$
    – Efe Ballı
    Oct 9, 2023 at 19:19

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