View Full Version : 741/742 differences?

21st May 2002, 14:46
Something thats been puzzling me for awhile now.

How to differentiate between the 747-100 and -200 series?

Is there an easy way to distinguish them apart externally?


21st May 2002, 15:32
747-100 only has a couple of windows on the upper deck. It was envitioed this would be a lounge. When the airlines decided to put Pax seats up there, extra windows were added on the -200.

21st May 2002, 15:36
Many operators have added additional windows to
their -100 upper decks (and some were built this way) - so no go on this one (already thought of that!)

Additionally some -200's were built with 3 UD windows as I recall.

Any other takers?

gas path
21st May 2002, 20:12
Not that you'd notice from a distance but, the wheels and brakes were bigger.

Flight Detent
22nd May 2002, 12:26
Wot a good question!!
As already mentioned, the upper deck number of windows is not an accurate way to tell the difference.
Also, as already mentioned, the brakes, wheels and tyres are a smaller size, but way to hard to pick from a distance.
So, what's left,
The -100 does not have the wingtip navigation lights mounted at the tip of the leading edge, they are mounted actually about one third chord back along the outboard tip.
The -100 has it's white tail lights mounted at the outboard tips of each horizontal stab, whereas the -200 (and -300) has them mounted in the centre.
That's all I can think of for now!

Dead Leg...Dead ?
22nd May 2002, 12:38
... the difference is about 100..

22nd May 2002, 13:37
Okay so the cosmetic differences are few and far between - but what else ? Surely boeing didnt make a whole number change from -100 to -200 for a few windows or light fittings ?

22nd May 2002, 15:31
An extra 40,000 pounds of fuel, upped the operating weights meaning heavy duty wheels and brakes and bigger gear - a freighter variant and a myriad of operational mods also contributed to calling it the Mk2 version. Unless your -200 has -7Q or -7R4 engines with the associated pylon fairing changes, most of these changes are not going to be noticeable from a terminal window.

22nd May 2002, 15:59
Sorry but even the nav light position is not conclusive either, I know some 200's that have mid cord nav lights and some 100's that had the tail nav lights moved as well.;)

23rd May 2002, 13:02
so.. we are back to the begining again :)
It's a tough shot for sure!

27th May 2002, 11:32
On the inside I've heard that the 741 had one AP, while the 742 had two?

27th May 2002, 12:16
Nah, they're all got at least two autopilots.
The only way to pick for sure from the outside is the smaller brakes, and that's rather hard to do.
Easier in the cockpit, as the flap speed placard has a lower set of numbers on eg, eg, the Flap 1 speed on the -200 is 275kts, on the -100 it's 265kts.

basil fawlty
29th May 2002, 20:07
There are a number of differences between -100 & 200 a/c, but they are externally very similar!
1. Higher fuel capacity due to larger CWT and extra reserve tanks for 2&3 main tanks. approx 20T extra.
2. Two APU generators on the -200
3. half pack setting on the -200
4. Bigger/stronger landing gear due to increased weights, also bigger wheels and brake packs to cope with higher speeds
5. Higher flap limit speeds
6.2 stages of flap load relief on the -200

and loads more stuff!
BTW, any 747 can have 2 or 3 autopilots not dependant on series.

29th May 2002, 21:05
basil, sorry but not all true,
-100 can have 2 apu gens (BA only had one for weight saving)
not all -200 have 1/2 pack settings, in fact 75% of the ones I work don't.
Don't the 100 and 200 have 17in wheels whereas the 300 has 19in wheels.
askop, minimun 2 a/p some have 3.

The only way I can tell if it is a -100 or -200 is if it is painted on the side.

As you can see from the interesting posts on here there doesn't seem to be many visual differences that could conclusively differentiate the 100 from the 200.

I can state for sure that the a/c I did today was a -400 (or can I really be sure!!) :cool:

basil fawlty
29th May 2002, 22:21
yes, of course there are differences even between a/c of the same series, hence customer suffixes and manufacturer effectivity codes. i was just listing a few differences that came to mind from my personal experience of the 747. its very rare to find two aircraft that are alike.
btw, another one i just thought of is auto fuel heat. i don't think the early a/c had that?

29th May 2002, 22:36
AFAIK, the main difference between the 100 and 200 is one of max gross weight, and the associated structural changes. A lot of the other changes mentioned in other posts are more in the nature of incremental improvements/changes to equipment fit that are normal in any production run -- and which are often retrofitted to earlier aircraft as well.

These days, the changes that resulted in the 200 might have only resulted in it being called 100ER, but that's today.

But of course today, they'd never have a -100 to begin with. They'd start at least at 200. And the baseline model would already be an ER. So if the 747 was a new model, what we know as the 100 would probably be the 200ER, and what we know as the 200 would be the 200ERX or some such.

29th May 2002, 23:08
...but of course, they ain't.

basil fawlty
30th May 2002, 18:17

The ER suffix is applied to twin engined Boeing aircraft that are fitted with the appropriate equipment so they can undertake EROPs flights, engines of proven reliability (0.05 shutdowns/1000hrs for 120 min EROPs and 0.02 shutdowns/1000hrs for 180 min EROPs), 4th source of main bus electrical power etc. etc. It is not used on 4 engined aircraft as it is not relevent. The 777 was ETOPs equiped from day one, so there is no need to differentiate it from other aircraft with an ER suffix. The longer range, higher weight version of the -200 is therefore called -200IGW (increased gross weight) and the stretched version becomes the 300 series of course. Just thought I'd add that before somebody asks the obvious question!.......

30th May 2002, 18:39

except that Boeing has dropped the "IGW" designation in favor of the good old "ER". They now well 777-200ERs, not 200IGWs.

And as further rebuttal, consider the 767-400ER. By your logic, since the model is equipped for long-range ops from the start, there would be no need for the 'ER' designator. But not only does it have one, it's actually part of the official designation, as inscribed on the manufacturer's plate (all other 767 models are officially designated 767-200 or 767-300, with no 'ER' , even if they are 'ER' models; the 'ER' here is a marketing name, not an official designation).

Anyway, the basic point is; DON'T LOOK FOR LOGIC IN AIRLINER DESIGNATIONS. They are as much as product of fads and marketing spin as they are of engineering. When the manufacturers think a new designation will help sell the airplane, they'll apply it. When they think stressing commonality will help sell the airplane, they'll keep the old designation, perhaps with a modifier.

The 747-300 is really very little different from a 747-200 except for the stretched upper deck, but it gets a new model number. But later, the 747-400F omits the stretched upper deck but keeps the -400 model number of the basic 747-400. Why does the addition of a stretched upper deck rate a new model number, but not its deletion?

The 747-200 is basically a 747-100 with higher weights (and a few other incremental improvements), but it rates a new model number. Today, an increase in weights at best rates an 'ER' (or, for a short time, an 'IGW').

Don't look for logic, or at least don't look for a consistency of logic over time.

basil fawlty
30th May 2002, 22:13
spagliola, or may i call you spag:D

i was merely responding to the fact that a 747 would never have an ER varient because it only applies to twins thats all. a 747-200ER would never happen if it were a new aircraft today which is what you intimated in your post.

whatever you say goes with the rest as far as i'm concerned, i don't have the time to argue the toss over such a small point.

i've worked on every 747 varient going in one capacity or another over the last 13 years so please don't teach your granny to suck eggs on this one!

all the best.

30th May 2002, 22:35
i was merely responding to the fact that a 747 would never have an ER varient because it only applies to twins thats all.

Ooops, somebody forgot to tell that to Boeing. See for example this press release from earlier this month:

First Boeing 747-400ER Comes Together in Everett Factory (http://www.boeing.com/news/releases/2002/photorelease/q2/pr_020507g.html)

Relax, when one is talking airliner designators, there's really no consistent, long-term logic. What might have been true at one point (such as 'ER only applies to twins') will cease to be true as soon as the manufacturer decides otherwise. And then become true again at some future time, when the mood so strikes them. So one just has to laugh about it.