Ramp start with ground power

[Mt5_Roie]

If I want to use ground power, I turn on the battery and the inverter, then set my radio and frequency and dial to INT. Connect ground power. Now my question is, what is the procedure for the start up? With ground power I do not need the the apu generators Left and Right on correct? I can go ahead start the engines?

 

I did this today and when I turned on the APU generators after starting the engines I got the Master caution light going off after I disconnected ground power.

 

What procedure do you follow if you want to use ground power instead of the startup tutorial procedure?

[Hamblue]

There isn't a right and left APU Generator. Those are for the main engines.

Since you need the APU anyhow, why not just use the APU generator. Going with ground power will only slow the process since you have to wait for comms and the ground crew to do it's job.

Also with the canopy open you should't have to select int to talk to ground crew.

The only time I use ground power is during repairs if there is major damage.

[r813]

The left and right switches are actually for generators on the engines to provide power.

 

The APU GEN switch provides power from the APU generator.

 

You will get a master caution light if you try to turn this switch on having started the engines with the left and right switches on as APU GEN power is a lower priority power source. The aircraft see that you have tried to turn on this switch but the power is prevented from coming online, usually by a set of hold-off relays. Whatever controls the APU gen will then see this as a failure giving you the warning, even though it is not really an issue. It appears that APU gen power and ground power are set up to operate on a "first come, first served" basis , with neither having priority.

[Mt5_Roie]

I managed to just use ground power, start the engines, and then as each engine started up, I would switch on the left engine generator, then as right engine started, switch on right engine generator. Afterwards, switched off the APU and disconnected ground power. Seems like no matter if you use ground power, the APU must be used to light up the engines.

[Hamblue]

The APU is needed because it's not the electricity but exhaust gases that are needed to start the motors moving.

[Luzifer]

Almost, "bleed air" isn't exhaust gas but pressurized air from a compressor stage.

[Mt5_Roie]

For me it seems like wherever ground power is possible, it is quicker in some way. After ground is on you can turn on the cdu and IFFC and let the align process continue while doing all the other pre-flight procedures.

[MTFDarkEagle]

For me it seems like wherever ground power is possible, it is quicker in some way. After ground is on you can turn on the cdu and IFFC and let the align process continue while doing all the other pre-flight procedures.

 

Just fire up the APU once you have the battery online and switch on the APU generator. You can power all electrical systems in the aircraft from the APU generator.

[Lange_666]

I have never asked to connect ground power on a cold start, only asked for it to be disconnected after startup otherwise some dude would say: "Hey, what are you doing" (or something like that) when you start to taxi.

[MTFDarkEagle]

I have never asked to connect ground power on a cold start, only asked for it to be disconnected after startup otherwise some dude would say: "Hey, what are you doing" (or something like that) when you start to taxi.

 

When the guy complains you have your radio selector set to intercom. Set it to VHF AM and he's not gonna whine :)

[Comrade Vodka]

Ok, ...The APU (Auxiliary Power Unit) is a separate small gas turbine, that drives it's own generator, and produces compressed air (Bleed Air)

 

The Engines (Two of) need Bleed Air (to rotate them during start), and generated power (to power the ignitors (through HEIU's), and also for the fuel pumps etc) to ignite the fuel.

 

Once the engine(s) are idling are all settled, then you can select the Engine Generators to on.....thereby negating the need for the APU Generator, or Ground Power. You STILL need APU bleed Air to start the second engine.

 

So, to start the main engines, you need the APU running for your Bleed Air, and you need a source of Electric Power (APU Generator OR Ground Power unit)...no need for both, but you definatly need ONE of them.

 

If using Ground Power (generally used for a prolonged period of the Aircraft sitting on the ground)....then you need to remember to ask for it to be disconnected before taxiing.....otherwise you are trying to drag a big piece of ground equipment down the taxi way.....connected by a big power cable to your Aircraft.....hence the groundcrew asking "Hey....what are you doing?"

[r813]

In game the second engine can be started using bleed air from the first engine without having the APU on. I don't imagine this would be a recognised start-up procedure in real life though.

[Snoopy]

In game the second engine can be started using bleed air from the first engine without having the APU on. I don't imagine this would be a recognised start-up procedure in real life though.

 

If needed yes it can but it's not the norm. You also have to throttle #1 up to almost max to get enough bleed air to start #2.

[Mt5_Roie]

Thanks for the clarification guys. I'll just use the apu from now on. I have not started campaign yet as I don't want to be overwhelmed and then land and not know what to do in case I need a repair or something. I'm still working on using JTAC to get targets.

[Guest Izoul123]

Just fire up the APU once you have the battery online and switch on the APU generator. You can power all electrical systems in the aircraft from the APU generator.

 

True, but you can still save 'a few seconds' by not waiting for the APU to spin up to 100%, and start alignment right away shaving more off that 4 minute mandatory window from the second you 'start' /however you want to phrase it. There's still a delay (all be it we are talking 10-15 seconds) vs doing it the way you described. Even if you start APU, then instantly hit APU GEN, it won't instantly power items until APU spins up more. Not really a huge benefit from what we use in the simulator. Sometimes I do it for fun/immersion, but 99% of the time ground power really isn't much of a benefit, but I'm glad it's modeled at least.

[sparkie66]

you can use ground power to speed up the startup.

 

1 ask for ground power (inv to stby)

2 cdu on so it can boot and align

3 rest of the startup (you need the apu for the bleed air)

[Mt5_Roie]

Yea I like that its available in the sim. Very realistic and I find it more fun to have everything modeled that way. If I had time I would spend everyday messing around in this sim but I don't. I get to play maybe once or twice each weekend due to work. Glad there is a lot of help here :)

[BBall]

Hey guys,

 

Yeah, interesting topic, right?

 

In the airline world, we call it "external electric" (or "external power"), and we obviously use it all the time. We keep the APU use to a minium to conserve fuel, but depending on the circumstance, ground power can be quite helpful.

 

For instance, I made an MP mission whereby we spawn in on the "Alert Pad" with no real tasking and are just sitting around chatting with the JTOC controller... (we don't respond of course, the chat is simply them sending us messages through the "Message to All" text that is available in the Mission Editor. I'm still trying to get the beautiful "Mrs BBall" to do some voice-overs for me, but no luck so far....lol). The pre-mission breifing actually suggests that you have the ground crew hook up "ground power", so you can turn on all your electrical systems and begin the IRU alignment process.

 

As you can probably guess, after a bit of time, all the while being entertained by watching a SEAD flight of Vipers launch, and an overfly of a CSAR helo flight, we recieve a message from JTOC that a reccee bird has been shot down, and we're now tasked with starting up the engines, departing and becoming the RESCAP for the downed pilots. In this case, having 99% of the cockpit duties done can be a real advantage.

 

Oh, and paulrkiii is exactly right, we call it a "cross bleed start" and although not the norm, we actually do it on a fairly regular basis. Due to APU issues (the entire APU inop, or even just the pnuematic systme on the APU), we will do it with certain restrictions. On the Boeing 757/767, the manual suggests AT LEAST 70% N2 on the operating engine for enough bleed pressure to turn the other engine, and that's a ton of thrust for just sitting on the tarmac. We are required to have the area behind the jet clear of personnel, vehicles, etc. before we begin the procedure. I'm guessing I do one or two cross bleed starts per month...

 

Have a great day all,

 

BBall