Avionics will not come on with Just Battery Power and without Ground Unit Attached

[charlieg 0]

I have tried searching the forums on this problem. My J41 started a problem yesterday where I can't power up the Avionics unless the Ground Unit is attached. I am sure that when I first got this model it did. And I have read you can start the plane on the Batteries,

 

Battery Condition is 25.5 when I load a fresh aircraft and not a saved file.

 

Thanks in advance.

 

Charlie G.

[PHXMD-11 86]

 

My J41 started a problem yesterday where I can't power up the Avionics unless the Ground Unit is attached

 

I don't think the batteries will power the avionics on the ground. You need to connect the ground power unit or start an/both engine/engines.

 

 

And I have read you can start the plane on the Batteries,

 

You can perform a battery start but it takes more power to start the engine.

[charlieg 0]

Thank you for the respons. I must have been mistaken when I thought it had brought the Avionics online without the GPU.

[charlie130 196]

Its interesting to note, the Avionics draw 14 Amps from the Batteries, but will not power up.

 

The starter motors draw 56 amps when starting the engines from the batteries. So its not a supply issue.

 

So the implication is if you are without a GPU, you have to start at least one engine and go on the generator, in order to use the avionics.

 

The avionics have to be off (by the book) before engine start anyway so perhaps its a way of safeguarding the circuits from surges when the engines are started and put on the generators? Who wants to be at a field with no GPU and broken avionics?

 

Incidentally, number one generator is supplying 140 amps, after start. Number two generator gives 150 amps after start. Number one then goes down to 100 amps!

 

This is an amazing little aircraft.  A superb sim, a pleasure and a challenge to fly well!

 

Best regards

David

[charlieg 0]

David you are correct as with all PMDG models this one is great. I really like the plane and the different way it has to be flown and as you say is difficult to fly well but very rewarding.

 

I see on the cockpit dash a big red message not to push back with engines running, I have not read the manual on this part yet as only got the model Friday but I guess that means a sequence like this, connect gpu, power up avionics, enter fp into fms etc, then wait for avionics positioning, then turn off avionics, push back start left then right, power up avionics?

[PHXMD-11 86]

 

sequence like this, connect gpu, power up avionics, enter fp into fms etc, then wait for avionics positioning, then turn off avionics, push back start left then right, power up avionics?

 

I haven't flow the J41 or read the manual in a while but that sounds like the normal procedure.

[hopskip 253]

I havn't watched any J41 real world ops, but the Merlin Metro op I have seen tended to start an engine, and sit on the ground for 10 minutes before starting another engine and taxying off. My assumption that they started the engine first, then started doing avionics stuff afterwards.

[ckyliu 1,749]

I see on the cockpit dash a big red message not to push back with engines running, I have not read the manual on this part yet as only got the model Friday but I guess that means a sequence like this, connect gpu, power up avionics, enter fp into fms etc, then wait for avionics positioning, then turn off avionics, push back start left then right, power up avionics?

hat "do not push back with engines running" placard was only a temporary thing in reality, once the appropriate updates had been carried out on the airframe.

 

If you have ground power, you can power up the FMS (but not the rest of the avionics) and programme it, then you start engine 1 and turn it's generator on. Disconnect GPU, start engine 2 and it's generator, and then you can finally turn the avionics on. If you don't do it in that sequence the FMS will lose power during engine start and you will forget everything you programmed in to it!

 

If there's no ground power you will need to start one of the engines and its associated generator before programming the FMS or turning avionics on. In a real life battery start, they keep the aircraft electrically dead until a few seconds before they're ready to start the engines.

 

 

The starter motors draw 56 amps when starting the engines from the batteries. So its not a supply issue.

Are you sure? Without checking in the aircraft, I thought it was more like 1000 amps and up - that's why whenever a battery start is done they leave it until the last possible minute to turn the batteries on, because they'll need most of the capacity!

[scandinavian13 5,192]

 

I see on the cockpit dash a big red message not to push back with engines running, I have not read the manual on this part yet as only got the model Friday but I guess that means a sequence like this, connect gpu, power up avionics, enter fp into fms etc, then wait for avionics positioning, then turn off avionics, push back start left then right, power up avionics?

 

The proper procedure would be to:

Connect GPU

Power avionics (and let it align)

Make appropriate FMS entries

Turn off avionics

Start #1 engine and transfer the elec to the #1 GEN

Disconnect GPU

Start #2 engine

Taxi out

 

Note that nowhere in there did I say "push back."

Also note the positioning of the GPU in the external view.  That is why you start the #1 engine first, so that the rampies can move the GPU without getting cooked.  While they're not going to get blasted away like jetblast, that engine is still throwing out some high temp air out of the back of it.

 

Ask me how I know...

 

 

This comes up from time to time, so luckily I've saved this image:

 

See how the J41s are not all facing towards the terminal (at the bottom) like most aircraft are?  You can see the CRJ at the bottom right is facing the bottom of the frame, whereas the J41s second from the left are not facing the same way.

 

You can also see that the lead-in lines are not all straight like a lot of them are now.  Basically, they would taxi in, and turn so that the number 1 engine was closest to the "finger" (those walkways that extend from the bottom of the image).  This shortened the walking distance from the finger to the door of the aircraft, but it also allowed the pilots to start both engines, turn right, and taxi right out.  No push back needed.

 

The comment somewhere in the manuals (I think the tutorial, actually) was that the aircraft had a very small turning radius, so it could turn out of tight parking spots easily, without needing a push.

[kevinh 409]

The comment somewhere in the manuals (I think the tutorial, actually) was that the aircraft had a very small turning radius, so it could turn out of tight parking spots easily, without needing a push.

Pushback only came into common use with large airliners and jetways.  It also saves apron space.  Before then it was a case of taxi to the terminal and turn right, parking sideways on to the gate.  That's probably where the convention of boarding from the left started.

 

However I've been on turboprops where the plane taxied in and parked nose to the terminal but with enough space to turn right and taxi out without a push.

[Adam T Lutley 12]

This little aircraft has a soft spot in my heart as its the first one I gained a lot of experience with as an aircraft technician. PMDG did a great job modeling it. The GPU hookup on the examples I worked on was on the L/H side rear fuselage. There also was no FMS installed so I never use it in the sim. Anyway, powering up the avionics bus can only be done via an eng generator or a GPU

[charlieg 0]

Thank you all for clarifying so much detail. I will in future make sure I park turning right before gate so I have the ability to turn out without a push back.

[Bobykim 2]

I would like to ask a question regarding the OP's topic. Im not able to power the avionics at all after i loaded the tutorial flight. I have batteries on / GPU connected. As i flick the avionic switches (page 17 from the tutorial)...everything is still dark.

I reinstalled the jetstream but it stays the same. Somewere i have red that a recycle of the FSX.cfg will probably solve the problem. I dont want to do that cause it's full with customizations.

 

Greetings for Boby K.

[Steven_Caffey 23]

I would like to ask a question regarding the OP's topic. Im not able to power the avionics at all after i loaded the tutorial flight. I have batteries on / GPU connected. As i flick the avionic switches (page 17 from the tutorial)...everything is still dark.

I reinstalled the jetstream but it stays the same. Somewere i have red that a recycle of the FSX.cfg will probably solve the problem. I dont want to do that cause it's full with customizations.

 

Greetings for Boby K.

 

The GPU is connected, but is it selected on in the flight deck?

[Bobykim 2]

The GPU is connected, but is it selected on in the flight deck?

Do you mean if i set the GPU switch to "on"?, if so than yes, its on. I even hear the GPU engine ratteling. But still, no avionics. I have purchased this craft a few month ago together with the NGX.

I tried the tutorial but i had the " grey flicker screen problem". I left it alone and moved on to the NGX which i flew for the last couple of month. As for today i thought: Lets give the Jetstream another try but i ran into this problem. I reinstalled the Jetstream without any luck.