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Guest Popo

B747-400 RR Engines

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Guest Popo

Hi everyone,I am still new at operating B747-400. On two occasions I have tried to fly the B747-400 with the RR Engines and have failed to get the engines started when going through the procedured to start the engines. I follow the normal procedures of fuel control switch (run) and then engine start selector (pull) and nothing happens. Following the same procedures with the CG engines all works well.Is there a specific way to start the RR engines (British Airways variant)?Execuse me if I am raising something already touched on earlier in the forum.Cheers,Popo

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Very quick run through using Autostart on RR,GE,PW......... APU running and providing bleed air, check APU Bleed air on and 2 Packs off, Autostart On, Engine start lever to run then pull overhead start switch and watch EGT.Rob


Rob Prest

 

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Guest qq290677797

Normally, we don't use autostart to start the engine from cold and dark. Autostart is more often for restarting an engine which shut down by accident.

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Who's we?? Standard ops is to use Autostart if the aircraft is equipped. Also I'm bit confused by 'shut down by accident'---Re read your post, maybe you are talking about Con-ignition for protection against flameouts? I don't quite understand why you would think starting from cold and dark would make a difference?Rob


Rob Prest

 

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Popo,Within the PMDG sim there are few (if any?) differences in starting the different engine variants.When you say the start failed can you confirm exactly what did and didn't happen?Did the N2 (lower EICAS) increase?Did you get an indication of EGT increasing?Any cautions or warnings encountered?As for procedural matters, check that the APU is running, bleeds are ON, 2 packs are off (normally 2 and 3 but any pair is fine I believe)Look at the bottom of your upper EICAS screen and see what the 'Duct Pressure' readings are for each side too.let us know how you get on!


Mark Adeane - NZWN
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Hi,AFAIK there is no reason not to use autostart. It's just supposed to make it easier, that's all.If you pull the starters and they don't light up, check that the engine cutoff switches for those engines are not at CUTOFF. This got me yesterday! :(Best regards,Robin.

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Guest poschrob

Maybe a bit OT, but are the RW 744s with RR engines equipeed with autostart?Based on a couple of 744 cockpit videos I've seen the autostart option is only available on the GE equipeed variants (there wasn't even an autostart switch on overhead panel of the RR variants and the engine startup sequence went one by one - maybe an airline SOP question -, unlike the GE variants with two engines started the same time).I have no info on the PW variant.Rob

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I believe all variants have autostart but the configurations are different, I seem to recall someone telling me that one of the non-GE variants has an autostart button for each engine.For certainty's sake one of our real-worlders will have to jump in here. Qavion would be familiar with the RR and GE variants I suspect?


Mark Adeane - NZWN
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I guess no Autostart is optional (Autostart seems to be standard out of the factory... at least these days). Apart from a very long time ago, we've always had it on our Rollers.P&W were a little slow to bring out Autostart (it took them a few years to develop it for the 744), but now they have 4 individual switches for Autostart on the overhead panel.Cheers.Q> ЯнP.S. Check your engine bleed switches. These must be ON for starting engines on 744's.

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The second shot shows that the Korean aircraft has P&W engines ;)Cheers.Q> イアン

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Guest hangar744

yeah Q,it wasn't really clear in my previous post so I edited it. Now it is clear. First link RB211, second link PW4000.I agree with Qavion. I remember...a few years ago we had an old bird out of the desert. She had P&W without autostart. delcom

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The engines can be started using autostart, or manually. As far as I understand it (and I would like to be corrected if I am wrong) the autostart system controls the point at which fuel is delivered to the engine during the start process. I believe the system is also capable of automatically restarting engines in flight if there is a failure that causes the engine to stall, or ingestion of some kind causes a shutdown or engine stall. The autostart system in this case I believe will automatically try to restart the engine a number of times (circumstances permitting) not before finally giving up.To get the engines started on the 744 with the RB211, I always use the autostart system to control the delivery of the fuel to the engine when you get your 20% N2.. This is quite a normal procedure, I don't see a reason why you would not use this system for safety reasons. There is nothing stopping the pilot starting the engines taking the fuel cutoff switch to cutoff and therefore cutting any fuel flow to the engine and stopping the starting process. All it really means in simple terms.. rather than throwing the switch at 20%N2 to provide fuel flow, you throw it before pulling the starter switch and the system provides fuel automatically.. This in no way takes away responsibility for monitoring the start, and therefore the safety implications are the same.Starting for me goes like (assuming all proper prep): - APU ON and providing Bleed Air (check duct pressures) - Bleed Air ON for all four engines and ON for APU - Fuel pumps ON - Hydraulic Demand Pumps AUTO AUTO AUTO AUX (AUX for pushback purposes, no need if you're stationary, but I am in the habit) - Beacon - Park Brake - AUTOSTART ON (if OFF, the starting is slightly different)EICAS should show the following cautions ONLYENG SHUTDOWN 1, ENG SHUTDOWN 2, ENG SHUTDOWN 3, ENG SHUTDOWN 4Process for start: - Before start checks (configure packs etc) - Set lower EICAS to ENG display - Set fuel cutoff for ENG 1 to RUN (keep finger on switch) - Pull Starter for 1, verify illumination - Monitor duct pressure drop on upper EICAS (normal) - Monitor N2 increase on lower EICAS - At N2 = 20% monitor Fuel Flow (FF) increase (some call EGT here as engine EGT rises rapidly due to fuel burn?) - Monitor N1 and Exhaust Gas Temperature (EGT) - Verify the engine EGT peaks and does stabilise, if the engine continues to ramp up with no sign of stabilising throw cutoff switch to CUTOFF and abort the start before damaging the engine - Verify engine EGT and N1 stable - Good engine start confirmed - Take hand away from cutoff switch and repeat for next engine in your start sequence.For Manual I believe the difference is..AUTOSTART OFF - Before start checks (configure packs etc) - Set lower EICAS to ENG display - Pull Starter for 1, verify illumination - Monitor duct pressure drop on upper EICAS (normal) - Monitor N2 increase on lower EICAS - At N2 = 20% set fuel cutoff for ENG 1 to RUN (keep finger on switch) - Verify Fuel Flow (FF) increase (some call EGT here as engine EGT rises rapidly due to fuel burn?) - Monitor N1 and Exhaust Gas Temperature (EGT) - Verify the engine EGT peaks and does stabilise, if the engine continues to ramp up with no sign of stabilising throw cutoff switch to CUTOFF and abort the start before damaging the engine - Verify engine EGT and N1 stable - Good engine start confirmed - Take hand away from cutoff switch and repeat for next engine in your start sequence.The 744 APU can provide bleed air pressure to start two engines simultaneously by the way. Think that's right.. someone pipe up and correct me if I've made a glaring silly error here..CheersCraig


Craig Read, EGLL

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Yep your spot on Craig. Only thing is you cant (or shouldnt) perform a dual engine start with GE engines, not sure why? Rob


Rob Prest

 

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"I believe the system is also capable of automatically restarting engines in flight if there is a failure that causes the engine to stall, or ingestion of some kind causes a shutdown or engine stall. The autostart system in this case I believe will automatically try to restart the engine a number of times (circumstances permitting) not before finally giving up."
The Autostart system logic allows 2 attempts to start the engine on the ground (by itself). In the air, Autostart will attempt to start the engine indefinitely. Note: Autostart is initiated by the pilot.However, please don't confuse Autostart with "auto-ignition" and "auto-relight".The Auto Ignition system and it's sub-function "Autorelight" operate irrespective of the position of the AUTOSTART switch. These are automatic functions. On the RB211, the Auto-relight system detects abnormal deceleration of the engine after a flameout and starts firing the ignitors (this auto-relight feature is considered so reliable, it disables the other triggers for auto-ignition (such as the deployment of flaps and the activation of thermal anti-ice). Both ignitors on the engine are activated and the ignition is kept on until no flameout is detected .. plus 10 seconds. Autorelight will only stop working if the fuel levers are placed in cutoff, or the N3's drop below 35%.Then there are the CF6 and P&W systems..... other stories in themselves... I'll save those for another day ;) Try not to confuse the different types.
"To get the engines started on the 744 with the RB211, I always use the autostart system to control the delivery of the fuel to the engine when you get your 20% N2.. "
On the RB211, N3 is really the parameter which should be monitored (of course, the other rotors should be seen to be moving before initiating "fuel on" for a manual start). I think you've find it difficult to get the N2's to 20% using the starter motor ;)Cheers.Q>

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