Juergen

RR ENGINE START

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Hi,

I am trying to start a British Airways PMDG BAW 747-400 with Rolls Royce engines. I have the APU running; Pack 1 Normal, Pack 2 & 3 OFF; Duct Pressure of 29 PSI. However, if I pull the engine start switches, there is no airflow to the engines even though the Bleed Valves are OPEN and the duct pressure increases to 51PSI? Also the Engine Start Switches do NOT illuminate (see screenshots)

https://www.flickr.com/photos/141330124@N05/shares/J99y1q

If I do the same on a Lufthansa PMDG 747-400 with GE engines, the start up works properly; APU running; Pack 1 Normal, Pack 2 & 3 OFF; Engine Start switches Pulled (will illuminate) and I can see airflow from the duct to the open engine bleed valves (see screenshot.

Is there a different procedure to start Rolls Royce engines?

Thanks for help

 

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One of your screenshots shows no Autostart fitted. Is this the GE?

When Autostart is available and selected ON, the engine will not begin starting until you have pulled the start switch and moved the fuel cutoff switch to RUN.

Actually, according to Boeing Wiring Schematic 80-11-02, you shouldn't have got a pressure rise in the bleed ducts without both actions. Can you confirm you had a pressure rise?

Cheers

JHW

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one thing i noticed...in the first pic the 1-3 hydraulic pumps are set to off,..all 4 are off in the 3rd pic,maybe that is part of the issue? setting 1-3 to auto and 4 to aux is one of the steps listed in the tutorial before engine start..(page 102)... i don't know if it is actually a requirement as i haven't tried it without setting them.. 

also in the 1st pic the IRS is not aligned, although not sure if that matters either. the 3rd pic also shows most of the fuel pumps turned off which may be related..

good luck!

cheers,-andy crosby

 

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Hi,

Picture with no Auto-Start feature is a Lufthansa fitted with GE engines and starts according to the manual.

The other 2 pictures are of a British Airways fitted with Rolls Royce engines. I tried with Hydraulic pumps ON, all Fuel Pumps On but NO engine start. I am not sure if the engine start switches are to illuminate once pulled?

I will try again and confirm settings and pressure rise.

Thanks

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7 hours ago, Qavion2 said:

One of your screenshots shows no Autostart fitted. Is this the GE?

When Autostart is available and selected ON, the engine will not begin starting until you have pulled the start switch and moved the fuel cutoff switch to RUN.

Actually, according to Boeing Wiring Schematic 80-11-02, you shouldn't have got a pressure rise in the bleed ducts without both actions. Can you confirm you had a pressure rise?

Cheers

JHW

That's the way I discovered to start a BA R-R version as opposed to a GE-version yesterday. I was slightly perplexed when I first encountered the same as the OP.

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As John says, you need to place the fuel control switches to RUN in order to initiate the start. The start switches will not illuminate, and the autostart sequence will not commence, until you select the fuel control switches to RUN.

For what it's worth, normal procedure at BA would be to select hydraulic demand pumps 1 and 4 to AUX, 2 and 3 to AUTO and turn all three packs off for the start -- the more air you have for the starter the less chance of start problems.

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Hi,

I just tried the BA B747 with Rolls Royce engines again:

IRS set to NAV; Hydraulic pumps SET; Fuel pumps ON; Ignition CONTINUOUS; APU ON; Pack 1 Normal; Packs 2 & 3 OFF; duct pressure: 30psi;

Start switch engine # 4: PULLED (does NOT illuminate); duct pressure rises to 51 & 50 psi; engine # 4 bleed valve ON; NO airflow to engine # 4; APU running; continuous ignition ON.

EPR for engine # 4 shows a value of 0.8 (see screenshots)

https://www.flickr.com/photos/141330124@N05/shares/7h7wio

Any help would be appreciated

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2 minutes ago, Juergen said:

 

Hi,

I just tried the BA B747 with Rolls Royce engines again:

IRS set to NAV; Hydraulic pumps SET; Fuel pumps ON; Ignition CONTINUOUS; APU ON; Pack 1 Normal; Packs 2 & 3 OFF; duct pressure: 30psi;

Start switch engine # 4: PULLED (does NOT illuminate); duct pressure rises to 51 & 50 psi; engine # 4 bleed valve ON; NO airflow to engine # 4; APU running; continuous ignition ON.

 

But have you placed the fuel control switch to RUN?

Why are you running Pack 1?

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Hi Guys,

I saw the post late (post from skelsey).

Set the hydraulic pumps 1 & 4 to AUX; 2 & 3 to AUTO; fuel pumps ON; Pack 1 to 3 OFF; FUEL CONTROL SWITCH TO ON and the engines STARTED.

Thanks, I am good to go - problem solved

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Hi Skelsey,

The pack situation I saw on a video, but can't remember why he had pack 1 set to normal. Your reason to set ALL packs to OFF makes absolute sense. I will change my procedure.

(same procedure for B737 NGX).

The blue is up again and thanks for help

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4 hours ago, Juergen said:

Start switch engine # 4: PULLED (does NOT illuminate); duct pressure rises to 51 & 50 psi; engine # 4 bleed valve ON; NO airflow to engine # 4; APU running; continuous ignition ON.

It seems there is an issue with the sim. Is anyone else seeing a duct pressure rise before the fuel cutoff switch is put to run? (Autostart switch ON).

 

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I did not have any of the 'Start' pull-switches illuminate and I did not see duct pressure before selecting the 'Run'

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2 hours ago, vc10man said:

I did not have any of the 'Start' pull-switches illuminate and I did not see duct pressure before selecting the 'Run'

 

Do you mean you didn't see duct pressure rising, Rick? Or did you just not look at the duct pressure?

Thanks.

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Anyone knows why Hydraulic 1 is set to AUX by BA SOP before engine start ?

 

Thanks

Michael Moe

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It's an air-driven pump, so using the Aux electric pump takes load off the bleed system and provides pressure to Hydraulic System 1 for steering and alternate brakes.

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23 minutes ago, skelsey said:

It's an air-driven pump, so using the Aux electric pump takes load off the bleed system and provides pressure to Hydraulic System 1 for steering and alternate brakes.

Thanks

Its not enough to set it to Auto then ? The APU would provide bleed air then to the system 1?

 

Thanks

Michael Moe 

 

 

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41 minutes ago, Michael Moe said:

Its not enough to set it to Auto then ? The APU would provide bleed air then to the system 1?

No -- in AUTO it will, as you say, run off the APU bleed air thus reducing the overall available duct pressure. The whole point of running the aux electric pump is to reduce the bleed demand on the APU during the start.

The more 'puff' you have available to turn the starter motor the faster the engine will turn over and the less chance there is of a hot/hung start.

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1 hour ago, skelsey said:

It's an air-driven pump, so using the Aux electric pump takes load off the bleed system and provides pressure to Hydraulic System 1 for steering and alternate brakes.

Thanks

So when you dont have an AUX option on the System 1 you just leave it at AUTO i guess.

Thanks Michael Moe

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On 18/04/2017 at 11:49 AM, Juergen said:

Hi,

I just tried the BA B747 with Rolls Royce engines again:

IRS set to NAV; Hydraulic pumps SET; Fuel pumps ON; Ignition CONTINUOUS; APU ON; Pack 1 Normal; Packs 2 & 3 OFF; duct pressure: 30psi;

Start switch engine # 4: PULLED (does NOT illuminate); duct pressure rises to 51 & 50 psi; engine # 4 bleed valve ON; NO airflow to engine # 4; APU running; continuous ignition ON.

EPR for engine # 4 shows a value of 0.8 (see screenshots)

https://www.flickr.com/photos/141330124@N05/shares/7h7wio

Any help would be appreciated

You should not be putting continuous ignition on. Ignition will be provided by the start system, whether autostart or manual.

Continuous ignition is primarily intended to prevent engine flameout, not for engine starting.

The difference between RR and GE start procedures in this case is due to the lack of  autostart in the DLH configuration. Without autostart the RR engine start would be very similar to GE apart from when the fuel is switched on. 

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14 hours ago, Qavion2 said:

 

Do you mean you didn't see duct pressure rising, Rick? Or did you just not look at the duct pressure?

Thanks.

Hi John, from your previous posts, I am aware that you are far more technically qualified that I am, so please forgive me if I do not know all the terms.

If you are referring to the NGT display, then no I did not see anything there, till I flicked that fuel cut-off switch to 'Run'. I'm in the KLM repaint at the moment en route to TNCM, so am not sure if it is a GE-engined version, but I'll come back with a screenshot later in the R-R version.

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18 minutes ago, vc10man said:

KLM repaint at the moment en route to TNCM, so am not sure if it is a GE-engined version

KLM would be a General Electric engine variant. You can also tell by looking at the EICAS since the General Electric variant is the only one of the three that doesn't use EPR.

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20 minutes ago, Captain Kevin said:

KLM would be a General Electric engine variant. You can also tell by looking at the EICAS since the General Electric variant is the only one of the three that doesn't use EPR.

Thanks Capt Kevin. Yep, can see it now.

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45 minutes ago, vc10man said:

Hi John, from your previous posts, I am aware that you are far more technically qualified that I am, so please forgive me if I do not know all the terms.

Hi, Rick, I was just trying to confirm that you were also seeing the duct pressure on the ECS Synoptic rising to 50psi (or so) with only the start switch pulled (with Autostart ON). If it doesn't rise, that's normal. If it does rise, we need to call an engineer :wink:

Cheers

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Just now, Qavion2 said:

 

Hi, Rick, I was just trying to confirm that you were also seeing the duct pressure on the ECS Synoptic rising to 50psi (or so) with only the start switch pulled (with Autostart ON). If it doesn't rise, that's normal. If it does rise, we need to call an engineer :wink:

Cheers

Hi John. Told you, you were the ace-of-the base, thanks for that clarification. Recalling from memory, I think I did not see anything in that EICAS synoptic(that's the term I was struggling to find) when I pulled Engine #4 start-switch until I threw that Run switch,

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26 minutes ago, vc10man said:

Thanks Capt Kevin. Yep, can see it now.

Yeah, best way to tell apart from looking physically at the engine from outside or looking at the ident page on the FMC, General Electric engines do not use EPR, so the upper EICAS will only display N1 and EGT. Rolls-Royce engines are triple-spool, so they're the only ones to have N3 on the lower EICAS. Pratt & Whitney engines....process of elimination at that point. Those have EPR, but no N3.

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