747 2 engine start

[413X3]

How often do 747 operators start 2 engines at a time? Just curious. Thanks David

[PLovett]

Just to add to the questions, I thought the 747 was capable of gang-starting all 4 if the need arises?

[bvcu]

747-400 has a much more powerful APU so dual engine start done by lots of operators to speed up departure.

[bigduke6]

On 747-400, normally start 2 engines at a time on every flight using autostart. For very hot days (say above 40C ish) or high elevation airports (NBO, MEX, etc), I would start the first 2 engines one at a time, then the last 2 together. And there is a Boeing bulletin about turning all packs off if the APU is older/high cycle to help out, but normally, you can leave one pack running.

As mentioned above, -400 has a better APU than the Classic, so 2 at a time is not a problem under most conditions. But after seeing slow starts or watching autostart cycle the fuel on and off under hot or high conditions, I now start the first 2 one at a time under those conditions (with all packs off), to help keep temperatures down and to get a quicker start. Then for the last 2 engines, you have the APU air plus the bleed air from the from 2 operating engines to help out.

Have been told you can start all 4 at once, but doubt it will really work. Autostart would attempt it, but as duct psi dropped, it would probably only start 3 at once, then get the 4th one running after one other engine had finished the start cycle and reduced bleed air requirements.

[spannersatcx]

CF6 and PW4000 do, RB211 don't do it as the 211 is triple spool the others are twin spool. That's the way it is where I am anyway.

[TopBunk]

Spanners

RB211 engines at BA are started 2 at a time!

Exceptions: above 2000ft amsl and/or 30degC when 1 at a time.

[Flight Detent]

a better system...

when I used to go to LAX, on departure we were always pushed back onto the taxiway prior to engine start...

that always put us under pressure to get the thing started and taxi for takeoff due to the high volume of taxiing traffic there always seemed to be...

so what we did was start the inboards, one at a time, and start taxiing (slowly) and start the outboards on the roll.

this had the advantage of being able to keep a pack running throughout the process, and still the Flight Engineer had everything sweet well in time for the takeoff checklist.

we were AP in leased QF -200s!

those were good days indeed...

then they got -400s and blew it!

Cheers...FD...

[spannersatcx]

Probably as we don't have autostart installed.

[B-HKD]

CF6 at LH, 4-3 together and then 2-1 together. (with autostart)

Ever hear the story of the Thai crew in paris?

They practiced on a sim with autostart, but ordered 744s without it. So one day at CDG they trashed all 4 engines together.

[Willit Run]

We start 1&4, and then 2&3. Packs off for all starts.
WE have auto start on all airplanes, but do our sim training in a box that doesn't have auto-start.

Its a big ole goofy world!

[boofhead]

When buying a Boeing you have to pay more to have a non-standard configuration. Possibly to have one without auto start would cost the airline 100s of thousands of dollars per airplane.

[B-HKD]

I doubt ordering a 744 without autostart cost more money than one with it.

This is the very reason that operators like CX (which have now retrofitted it on some RB211 744s) and SQ (PW4056) do not have it.

I read a post from a SQ 744 pilot a while back, and he said that it took them far longer than any other 744 operator to start up all 4 (when following their SOP) with manual start(saved the bean counters $$$) In fact he said that in frankfurt and london ATC were getting pretty annoyed about the whole thing.

Maybe somebody from/ex. SQ can tells us more about it?

So when it comes to autostart I am certain that you will pay more to have it then not to have it.

However there are some non-standard customer options that will cost you more.

For example:

QF ordered their RB211 744s without taxi lights, only with runway turnoff lights on the nose gear (just like many other operators did) however their last 3 744s with RB211s had them and so did their 6 744ERs, this because boeing decided that with taxi lights was the new standard and without them would cost extra $$$.

Or LH, which have all the light switches the other way around on their boeing fleet. Pull the switch and it's on, push it and its off. This cost extra $$$ too as it is non-standard.

The classic 747 had even more differences I hear.

And for this very reason no boeing type is the same until you enter the cockpit.

[charliecossie]

"however their last 3 744s with RB211s had them......... , this because boeing decided that with taxi lights was the new standard and without them would cost extra $$$."

Rubbish. Those aircraft were built for BA but went to QF instead. When they went into service with QF, they (QF) produced a differences training package for the engineers. Even the BA engineers at European stations had to do it.

[TopBunk]

Originally Posted by B-HKD

"however their last 3 744s with RB211s had them......... , this because boeing decided that with taxi lights was the new standard and without them would cost extra $$$."

Originally Posted by charliecossie

Rubbish. Those aircraft were built for BA but went to QF instead. When they went into service with QF, they (QF) produced a differences training package for the engineers. Even the BA engineers at European stations had to do it.

Fact: None of the BA B747-400's have taxi lights

[Dan Winterland]

Boeing tend to build aircraft as the customer wants.

In a previous life, we used to start 2 at a time (CF6s) at any alt or temp - with one pack running as well. We started 1 and 2 together if pushing back to the right (as viewed by the tug driver) and 3 and 4 together to the left. This is because the push would come to a halt if you tried to start the two engines on the outboard side of the turn. We would defeat the tug!

[B-HKD]

Rubbish. Those aircraft were built for BA but went to QF instead. When they went into service with QF, they (QF) produced a differences training package for the engineers. Even the BA engineers at European stations had to do it.

VH-OJS/T/U (Delivery 99'-00') All 3 B747-438 38 is boeing's QF customer code. 36 is BA. If they were ordered and built for BA then they would have been 36's. Example: United took 2-3 new Northwest built 744s and these kept the 51 customer code even though they never flew for NW.

Like TopBunk said,

None of the BA B747-400's have taxi lights

Now if you insist they were built for BA charliecossie, but somehow got the QF customer code

Then i can tell you this:

Taxi Lights became a standard in late 97' on the 744.

So please do tell me why would G-BYGG BA's last 744, (delivery 24.04.99) not have taxi lights, when a few months later VH-OJS (delivery 30.09.99) did have taxi lights, if it was indeed built for BA like you say....

The only reason you will see certain 744s built after 97' without taxi lights is because the customer paid extra to not have them. (pay a little more to not have them, save money with less bulbs to change in the long run)

Any difference the last three QF 744s have to the older 744s are purely improvements and new standard equipment added to the 744 line over the years.

QF ordered all 3 VH-OJS/T/U on: 23-Oct-1997 So none of these last 3 QF RR 744s were ever ordered or built for BA.

I have a feeling you are talking about VH-OEB/C/D also known as the ugly sisters. 1 is ex. Asiana. 2 are ex. Malaysian. (these two have recently been retired) they did indeed have some differences as they were all three CF6 and not built to QF specs. when QF had a all RR 744s. (before their ERs)

Next time check you facts before calling it rubbish

[parabellum]

Did ten years with SQ on the B744. Never had a problem with ATC starting 1,2,3 & 4 individually, especially if they let you start up to two engines on the push. Procedure can be accelerated a bit by initiating start on next engine when preceding one becomes self sustaining, EGT backing off, rather than waiting until fully stabilised. Even starting all four individually and letting each one stabilise you are talking less than five minutes and in my day both FRA and LHR would usually let you start on the push, surrounds permitting.

[B-HKD]

Thanks for clearing that up parabellum! Doesn't sound as bad as this SQ guy put it

On the B747-400 at SQ we have the most laborious engine start procedures ever designed I think. We could have had autostart but that was a cost cutting measure.

If you proceed as per the book you cannot start the next engine until the engine being started has infact fully stabilised. After many complaints from ATCs around the world because of the time taken its now normal to start the next engine as the engine being started reaches 50% N2, still too long.

There is nothing to prevent you starting 2 engines at the same time. The result is less bleed pressure to each engine resulting in a lower N2 when fuel is introduced. The P&W didn't like this at all, and many other things too.

I'm now on the B777 with a pair of beautiful Rollers and autostart and we are all done in about 3 minutes. Heaven.

[SMOC]

CX hasn't retrofitted any -400s with auto start, the only A/C with it are the new ERFs which came with it as standard and the ex SAA (RR) BCFs which also have Aux pumps on 1 & 4 as opposed to just #4.

CX have a fairly laborious 4 engine start procedure

#4 engine start
#1 engine start, #4 running at idle.
#2 engine start, #4, #1 running at idle.
#3 engine start, #4, #1 & #3 running at idle

Auto start.

#4 and #3 engine start.
#1 and #2 engine start, #4 & #3 running at idle.

So not having auto start costs CX effectively the price of 4 engines running at idle for every start or there about (6 vs 2). They have around 40 -400s without auto start.

Seeing they've had the 400 for over 20yrs I'd imagine the extra cost of the auto start system would have paid for itself many times over. CX is a penny wise pound foolish airline.

[charliecossie]

B-HKD:
I should scan the front page of the S,T,U differences training notes that Qantas used when they trained me on the differences between a standard QF 744 and the newly delivered, BA spec S, T and U. It was quite amusing being taught, by Qantas, how these new a/c differed from the their norm.
Bit I can't be bothered.
There's also a reason why these three went to QF instead of BA but I can't be bothered with that either.