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cmckeithen
Topic Author
Posts: 594
Joined: Sun Jul 20, 2003 9:31 am

747 Correct Engine Start-Up Order

Sat Mar 13, 2004 8:43 am

I would appreciate a 747 captain to answer this however if anyone else knows feel free to answer.

What is the correct start-up procedure for a 747?

I have seen during pushback engines 2&4 started before 1&3 while in others I have seen 1&2 then during taxi 3&4 started.

Thanks

[Edited 2004-03-13 00:43:35]
 
COAB767
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 9:05 am

Well I've never worked a 747 flight, but I've flown on them and I can tell you that they start engine 1 first then 2 and so on.
Continental Micronesia: "Fly With The Warmth Of Paradise"
 
Guest

RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 9:27 am

Dear Cmckeithen -
xxx
The normal start order is often 4-3-2-1...
Taxi on 2 engines would be on 1-4, the outboards, often when taxi-in to gate.
xxx
Sometimes, you start engines on the "opposite" side of the ramp activities...
Example, loading baggage (RH side) still, while almost ready, we could start 1-2...
We dont like to start before push back, because hard to push against engines that are operating.
xxx
If engine 4 has an inoperative generator, we then start 1 first.
We prefer to operate engine 1 and 4 first, because hydraulic systems 1 and 4 are related to brakes/steering.
(although brakes/steering could be operated with air driven pumps as well)...
xxx
Happy contrails  Smile
(s) Skipper




[Edited 2004-03-13 01:29:18]
 
cmckeithen
Topic Author
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 9:41 am

Thanks B747Skipper. I have often wondered how they started up a 747.
 
CX Flyboy
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 10:28 am

It depends on the airline. Different airlines do it differently, so don't take one answer as gospel. In Cathay we do it 4-1-2-3.
 
Thrust
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 11:29 am

I know this is completely irrelevant to the topic. All NWA and CO Express propliner start the starboard propeller, or engine no.2, first because passengers board from the port side of the aircraft. Then they start the left propeller, or engine no. 2 after boarding is complete, and the doors are closed. With twin jets, like the 767, I have noticed that normally I see the engine no. 1 started before engine no.2. Is it because cargo is loaded from the right side of the aircraft that the right engine is started up first? As for the 747, I am just going to ask why certain airlines do the different engine sequences. Does it really make a difference which engine is started first? I'm just wondering why these sequences are chosen.
Fly one thing; Fly it well
 
schweizair
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 12:29 pm

This is slightly off topic but when the 747 is at its designated flight level, are two engines shut down to save fuel? If so, is it engines 1 and 4 or 2 and 3? Or does that depend on the airline, where it's flying and the laws of the country it leaves?
 
An-225
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 12:34 pm

It all depends on the airline. At UAL we do 1-4-3-2. Lufthansa does 4-3, and then 2 and 1 are started at the same time (saw it at DEN). As for other companies, I also know that Air Canada does not accept any last minute bags, and it starts #2 engine first on its A-319/20/21 here at DEN.

Alex.
Money does not bring you happiness. But it's better to cry in your own private limo than on a cold bus stop.
 
Mr.BA
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 12:36 pm

I might not be 100% correct here but I believe it is illegal to shut down an engine that is fully operational. There is no reason to shut down an engine however high/low or light you are. It will not save fuel, in fact, the plane might not be able to maintain that cruise altitude. If an aircraft has 4 engines, it is designed to fly with 4 engines economically and safely.  Smile
Boeing747 万岁!
 
schweizair
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 12:41 pm

I disagree. The 777 is capable of flying with one engine off. Some Saab turboprops can actually take off with only one prop on. I would not be surprised if there may be a safety regulation that requires the 747 to be capable of flying if, say, one engine were hit by a bird and totally knocked out. After all, if the 747 comes spiraling out of the sky when only one engine blows, doesn't that kind of defeat the point of having four engines?
 
Mr.BA
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 1:02 pm

I agree, the B747 can even perform a safe descent from cruise to touchdown with only 2 engines. B747s have also taken off with only 3 engines without passengers (not allowed to have pax). Planes are capable of flying with an engine out.

I probably had mistaken what you meant earlier.

I was trying to say that pilots are not allowed to shut down fully operational engines to save fuel. It will no doubt save fuel but you cannot maintain that altitude or speed, and with the other 2 or 3 engines almost going at full blast if you attempt to maintain. It goes like.. 4 engines, you fly with 4 as it's designated to fly with 4 under normal operations. One engine out and diversion is most likely.

I apologise if I got you wrong.

[Edited 2004-03-13 05:05:53]

[Edited 2004-03-13 05:07:00]
Boeing747 万岁!
 
liamksa
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 2:10 pm

Perhaps a little misinformation running around here  Big grin The 777 is no different to any other airliner, in that it is required to perform with one engine inoperative (OEI). However no commercial operator is going to shutdown an engine inflight to save fuel (it won't), minimise wear or any other reason (a perfectly good engine that is).

I've heard of this method being used in military roles with P-3 Orions which spend a lot of time loiteing at low level. In this case shutting down 2 engines increases the aircraft's maximum endurance, allowing it to be on station for longer.

[Edited 2004-03-13 06:14:22]
 
AJ
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 2:49 pm

On Boeing 747-400s fitted with autostart two engines can be started simultaneously due to the higher bleed output of the new Pratt and Whitney APU that replaced the Classic's Garrett (AlliedSignal) unit.

On Qantas 744s the start sequence is 4 & 3, then 2 & 1. Autostart is limited to 5000' PA and 30 degrees celcius (from memory).
 
XFSUgimpLB41X
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 2:52 pm

In the 747-400 at NW, they start 3 and 4 at the same time..then 1 and 2 at the same time. The APU has enough juice to spin two at once.
Chicks dig winglets.
 
FredT
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 4:48 pm

Schweizair,
you will not take off on one engine in the Saab 340/2000. You can taxi on one engine, which is often done when approaching the ramp so #1 will be stopped when you come to a stop, enabling you to get rid of... er, deplane the pax directly.

Perhaps you have heard of the prop brake available as an option on the Saab 340 and that's the reason for the confusion? All that will do is enable you to use #2 as an APU on the ground without the prop spinning.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
Mr.BA
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 6:34 pm

To add to the original topic, I think SIA starts 1-2-3-4. From observation.
Boeing747 万岁!
 
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Starlionblue
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 10:44 pm

Schweizair said:
This is slightly off topic but when the 747 is at its designated flight level, are two engines shut down to save fuel? If so, is it engines 1 and 4 or 2 and 3? Or does that depend on the airline, where it's flying and the laws of the country it leaves?


While it is possible for a twin to fly on one, or a quad to fly on three, this would not be done. Drag increases from the windmilling engine (s). Drag increases from the induced yaw. Drag increases from holding the rudder out to one side. This would pretty soon eat up your fuel savings.

Also, the thrust required to keep the required speed&lift is the same regardless of the number of engines. Two engines at high thrust may well use more fuel than four at low.

Finally, any plane is designed to have thrust from a given number of engines. If you start messing with this, it will change flight characteristics, increasing drag and also wear on pylons, wing spars and so on. Sure, you can fly with engines out, but it is not optimal.

So I don't think regulations have much to do with it. As usual, it comes down to economics.


[Edited 2004-03-13 15:11:56]
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Guest

RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 10:57 pm

There is actually not any "start order" that the 747 has to follow.
xxx
Fact is, my airline uses Boeing publications, that is AOM Aircraft Operating Manuals, and the FCTM Flight Crew Training Manual "as is - out of the box"... and we follow the Boeing "recommended" procedures and check-lists, to the letter. The start order is the one that Boeing recommends.
xxx
Many large airlines, particularly in USA, have decided to publish their own manuals, their own check lists. They adapt procedures specifically to their own operations and requirements. It is perfectly acceptable as long as not contrary to the AFM Aircraft Flight Manual, and procedures are approved by the POI - (FAA Principal Operations Inspector) in charge of that airline. If Dodo Airlines wants to start the inboard engines first, OK, but that is not what is recommended by Boeing, the manufacturer.
xxx
My airline is just an airline, they do not claim to have designed the 747, nor is it a publishing company. Boeing publishes their AOM specific and tailored to our 747-287s, with some minor changes here and there, at our request, this because of our operations requirements. The start order we use, is known to the ramp staff, and we advise them of any changes if the start order needs to be different, for technical reasons, APU used or not used, generator problems, or push back concerns. As an example - if APU does not work (or APU generators failed), we often decide to use number 4 engine as source of power.
xxx
Happy contrails  Smile
(s) Skipper

P.S. What is that I read about cruising on 2 engines... Come on, guys...!



[Edited 2004-03-13 15:01:04]
 
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Starlionblue
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RE: 747 Correct Engine Start-Up Order

Sat Mar 13, 2004 11:12 pm

It also comes down to safety margins. I don't want to speak for the Skipper, but I imagine if his airline told him to shut down 2 engines during cruise in order to save fuel, he would tell them where to shove the other 2
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo

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