Hello everybody,

 

I got a problem I can´t solve. I´m sitting at the ramp in PANC, trying to start the engines. Panel state is cold and dark. The engine oil temperature is the same as the outside temperature (-9)

 

Naturally the engine won´t start. Is there someting I´m not seeing here? I would be grateful for any solution... 

 

Thanks in advance, Arne...

 

 

 

 

 

-9 aint too bad. a lot of planes can go to -40. I don't own the 747, or have any experience with it, but try turning on your hydraulics and let them warm up. Then try starting the engines. they HYD fluid may be too cold.

Hi,

 

I'm not a real 747 pilot nor a engineer but I cannot see anything in the FCOM stating that oil temp could prevent the engine start. In the cold weather procedures, it is said that the normal engine start procedure is to be used with a mention to the oil temp rising slower than usual and the oil pressure being a bit higher (SP 16.3).

Are you sure that the hydraulics are correctly set up (pumps 1-3 auto and 4 to aux), fuel pumps on and APU and engines bleeds ON?

 

Can you post a screenshot of your overhead?

shure, thanks for the replies guys!

 

engine bleed, fuel pumps, packs  and hydraulics shoud be okay afaik...

 

Yes your overhead is correctly configured for an engine start.

 

What exactly happens when you pull an engine start switch then flip the corresponding fuel control switch? Do you see N2 rising?

 

Does the issue occur only with low oil temp or in any case?

Just restarted the sim & computer, working now. Funny. Thanks again for the help!

I believe that w/ autostart on you need to turn on the fuel switch for the engine you want to start or the start button on upper panel won't do anything.  Or else turn off Autostart and then do a manual start -- start button followed by fuel switch for the given engine.

 

Mike

When you autostart this beast make sure you also flip the fuel cutoff switches otherwise it wont start as stated above

PANC is a warm place compared to PAFA Fairbanks.  There is an annual military exercise (BRIMFROST) held about this time of year, and one year when I was expecting to be issued my bunny boots for the trip I learned it was cancelled because it was too cold for diesel.  Turns to jelly and our mobile generators wouldn't run.  Some outfits have gensets than run on JP-4/JET-A, which would work much better in that climate.

Arne, if you have hydraulic pumps #2 and #3 which are air-driven, it may be best to switch these off for engine start. They will be competing for APU bleed air... You need all the air you can get for starting the engines)

 

If the temperatures are really cold, it may be necessary to manually spin the engines for a certain time period to warm up the oil (before putting the fuel control levers to RUN). If the temperatures are super super cold, I believe engineering has to warm up the oil by other methods (I'm not sure how they do that.... Thankfully, I've never worked in such areas ) 

 

Cheers

John H Watson 

Definitely leave the #2 & #3 Demand pumps off for starting if they are air driven.

 

Depending on engine type and configuration, for cold weather starts we use ignition to both and allow 60sec for lightoff instead of the usual 30sec.

 

But, as others have mentioned, it sounds like you did not put the fuel control switch to run. On the -400s with autostart, you will not get spin up unless you place the fuel control switch to run after pulling the engine start switch. Interestingly, on the -8, the engine starts spinning right away when you pull the engine start switch. 

Curious... As far as I recall, there is no procedure to turn 2/3 hydraulics off during the before start amplified procedure. The cold weather operations supplements don't tell you to turn these off, either.

 

I understand the premise of your instruction, but I think there is no need to switch 2/3 off before start. The apu should manage the pneumatic demand so long as you have remembered to turn the aircon off.

(Hands up... who has forgotten to do this? Me - *both hands up*)

 

Actions relating to start switching are dependent on if autostart is fitted and, if it is, whether it's switched on or not. Judging by your pic, you have it fitted and on; good. All things considered, you should've had spool-up and light-off.

i do not know about that cold lol but ACA had some issues with their Embraer when it was -30c and below ...

 

for the diesel it will be below -45c where gas and diesel  truck and engine start to have some issues with ignition ...

 

up to -40c nothing special to do just to protect a little the batteries ...

i only found out (cold weather operation) that with GE engines with temp of -35c and below you need to let engines run 2 minutes before touching the thrust lever. the other info i found out for any kind of engines is that during cold weather engine start the oil presure rise may be higher than normal.

I'm flying now from RKSI to VOMM with the -400F fitted with GE engines. The SAT at RKSI was -7°C when I started the engines (with the oil at that temperature) and didn't have any issue to start them.

Anyway, the OP said the problem is solved on his side, so I guess the case is closed now.

I have a theory due to coming across some small bugs in the SHORT panel state. Are you using the short panel state? - David Lee