Boeing To Make Door Modification On 737 MAX

817Dreamliiner · Mon May 27, 2013 2:35 pm

Read this from an Article on Aspire Aviation:

Quote:
It is on course to reach the firm configuration in mid-2013. Intriguingly, Aspire Aviation can exclusively reveal that Boeing is looking to feature a door modification on the 737 MAX 8 which will add around 9 seats to the aircraft’s capacity of seating 162 passengers in a 2-class configuration. The door modification is likely to be a standard feature across all MAX variants, Aspire Aviation‘s sources at Chicago-based Boeing say.

As a result, the 737 MAX 8 will likely seat 171 passengers while the MAX 7 and MAX 9 will accommodate 135 and 189 passengers in a 2-class configuration, respectively. Though the 737 MAX 9, capable of carrying 215 and 226 passengers in a single-class layout before and after the door modification, is unlikely to match the A321neo’s high-capacity 236-seat option enabled by the addition of an overwing exit, deactivation of door 2 and a push back in the location of door 3, as well as adopting the SpaceFlex aft-cabin configuration. Airbus claims this high-capacity configuration will reduce seat-mile costs by 5% alone.

The door modification, the same sources say, will enable the 737 MAX 8 to meet its 13% fuel burn per seat reduction target while increasing its payload/range performance with a “negligible” impact on the aircraft’s manufacturer’s empty weight (MEW).

Its interesting, but what Im failing to understand is what kind of modification to the door will allow them to add 9 more seats unto the aircraft? Or does the article mean to say door configuration??

Source: http://www.aspireaviation.com/2013/0...s-all-fronts/#.UaNg7TUFb6U.twitter

[Edited 2013-05-27 07:40:11]

PHX787 · Mon May 27, 2013 2:45 pm

Quoting 817Dreamliiner (Thread starter):
Its interesting, but what Im failing to understand is what kind of modification to the door will allow them to add 9 more seats unto the aircraft? Or does the article mean to say door configuration??

Depending on where they position the door, and the shape of the fuselage, that's what determines how many more seats they can squeeze in. Are they completely redesigning the fuselage cross-section with the MAX?

travelavnut · Mon May 27, 2013 2:46 pm

Quoting 817Dreamliiner (Thread starter):
but what I failing to understand is what kind of modification to the door will allow them to add 9 more seats unto the aircraft?

That would be 1,5 rows worth of seats.

I am also having a hard time visualizing that...

Stitch · Mon May 27, 2013 2:59 pm

Maybe they are increasing the door size?

The 737 family currently uses Type I doors at the front and back per aviation-safety.net and per FAA FAR 25.807, each door is certified for 45 passengers per exit.

The Type C door, which is the same height but wider (minimum of 30 inches vs. the 24 inches of the Type I), is certified for 55 passengers per exit.

So if Boeing replaced Door 1L with a Type C door, that would increase the Evacuation Limit by 10 people. And since it is the same height as a Type I door, just wider, clearance should not be an issue.

[Edited 2013-05-27 08:00:48]

N821NW · Mon May 27, 2013 3:06 pm

Quoting Stitch (Reply 3):
Maybe they are increasing the door size?

Could you tell me how having a BIGGER would make MORE passengers fit? I have a hard time understanding that one...

And if they decide to shrink the door then we will have issues if there is a need for a emergency evacuation, considering how obese American's (and to a lesser extent Canadian's) are getting I can already visualize people getting stuck in the door and having to be pushed by other passengers...heck just imagine Rob Ford trying to get out of a current Boeing B737NG over-wing exit.

N62NA · Mon May 27, 2013 3:15 pm

Quoting N821NW (Reply 4):
Could you tell me how having a BIGGER would make MORE passengers fit? I have a hard time understanding that one...

Yeah, I'm a bit confused about this as well!

catdaddy63 · Mon May 27, 2013 3:17 pm

WN has commented in the past that the entryway to the aircraft is a boarding bottleneck. Making the L1 door wider, thus enlarging the pathway might be something they pressed for.

Stitch · Mon May 27, 2013 3:24 pm

Quoting N821NW (Reply 4):
Could you tell me how having a BIGGER would make MORE passengers fit? I have a hard time understanding that one...

Quoting N821NW (Reply 4):
Yeah, I'm a bit confused about this as well!

Larger doors allow a higher evacuation limit. So assuming the 737 MAX is not "cabin floor area limited" and the seating capacity is capped by the EL, increasing the door size to raise the evacuation limit would allow more seats to be fitted.

The 737-900 had the same EL as the 737-800 because it had the same number and type of exits. So even though it had more cabin floor area than a 737-800, they could not use it. The 737-900ER added two additional exit doors which raised the EL and allowed that extra space to be utilized to seat more passengers.

And Airbus is also considering modifying the location of exit doors, as well as adding additional exit doors, to the A321-200neo to raise the EL from the current 220 to 236.

All that being said, neither the 737-800 nor the 737-8 are at their ELs in a two-class configuration...

So maybe they are pushing Door 2L / Door 2R farther back to extend the cabin floor length which would allow an additional row to be added without as deep a cut in seat pitch (plus removing / moving a toilet to free up a half row)?

[Edited 2013-05-27 09:22:55]

Clydenairways · Mon May 27, 2013 3:27 pm

So a 739 MAX with a maximum of 226 seats. It will be interesting to see this door modification that will enable this. It's hard to visualize this without more details.

Stitch · Mon May 27, 2013 3:29 pm

Quoting clydenairways (Reply 8):
It will be interesting to see this door modification that will enable this. It's hard to visualize this without more details.

Think of the current 737NG door, just six inches wider.

Clydenairways · Mon May 27, 2013 3:33 pm

Quoting Stitch (Reply 9):
Think of the current 737NG door, just six inches wider.

Ok. But where do the additional seats go then? Take another toilet/galley out?

Stitch · Mon May 27, 2013 3:40 pm

Quoting clydenairways (Reply 10):
Ok. But where do the additional seats go then? Take another toilet/galley out?

As we are talking 1.5 rows, I would expect that it would be a combination of removing a toilet, tightening the seat pitch and using slimmer seat backs.

In a Boeing OEM configuration, the 737-800 is 160 in two classes (12F at 36 inch pitch and 148Y at 32 inch pitch). To get to 162, I am assuming the MAX will have six seats in the Overwing Exit Row as opposed to the 4 in the 737-800.

So remove the toilet and tighten the seat pitch, that would give 12F and 159Y for 171 total.

N821NW · Mon May 27, 2013 3:46 pm

Sorry but I really can't see Boeing making a bigger door...

817Dreamliiner · Mon May 27, 2013 3:58 pm

Quoting Stitch (Reply 9):

Quoting Stitch (Reply 11):

Interesting, never actually thought of it that way.

rj777 · Mon May 27, 2013 4:02 pm

Are there any current airplanes that use type C doors?

speedygonzales · Mon May 27, 2013 4:03 pm

I'm guessing moving the front doors forward and/or the rear doors backwards, and possibly adopting the flat rear bulkhead from the 900ER on all models.

garpd · Mon May 27, 2013 4:04 pm

Perhaps they are increasing the size of the R1 and R2 doors? Both of which are smaller than their L1 ans L2 counterparts if I am not mistaken

scarebus03 · Mon May 27, 2013 4:15 pm

so the B707-300 fuselage is going back into production

Stitch · Mon May 27, 2013 4:15 pm

Quoting rj777 (Reply 14):
Are there any current airplanes that use type C doors?

The A321 uses them per A321 Type C Exit / Door 2L (by Ditzyboy Jun 7 2009 in Tech Ops)

817Dreamliiner · Mon May 27, 2013 4:21 pm

Quoting speedygonzales (Reply 15):
I'm guessing moving the front doors forward and/or the rear doors backwards

Im not sure if the doors can be moved any further than they already are:

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Photo © Christopher Melaisi

Quoting speedygonzales (Reply 15):
and possibly adopting the flat rear bulkhead from the 900ER on all models.

Isnt this being done already or am I mistaken?

Quoting garpd (Reply 16):
Perhaps they are increasing the size of the R1 and R2 doors? Both of which are smaller than their L1 ans L2 counterparts if I am not mistaken

Are they? I always thought they were the same size?

Stitch · Mon May 27, 2013 4:25 pm

Quoting garpd (Reply 16):
Perhaps they are increasing the size of the R1 and R2 doors? Both of which are smaller than their L1 ans L2 counterparts if I am not mistaken.

Quoting 817Dreamliiner (Reply 19):
Are they? I always thought they were the same size?

Per the ACAP, the Type I doors used on 1L and 2L measure 0.86m x 1.83m while those used for 1R and 2R measure 0.76m x 1.65m.

N821NW · Mon May 27, 2013 4:25 pm

Quoting 817Dreamliiner (Reply 19):
Are they? I always thought they were the same size?

From what I know almost all R doors on Boeing planes are smaller then the L doors.

817Dreamliiner · Mon May 27, 2013 4:29 pm

Quoting Stitch (Reply 20):
Per the ACAP, the Type I doors used on 1L and 2L measure 0.86m x 1.83m while those used for 1R and 2R measure 0.76m x 1.65m.

Quoting N821NW (Reply 21):
From what I know almost all R doors on Boeing planes are smaller then the L doors.

Hmmm, well, you learn something new everyday

by738 · Mon May 27, 2013 4:44 pm

Interesting on current 738 the front LH and rear LH are also different sizes (inches)
1 Main Fwd LH 1 Type I 864W x 1829H (34 x 72),
2 Main Aft LH 1 Type I 762W x 1829H (30 x 72),
3 Service (Fwd, RH, Aft, RH) 1+1 Type I 762W x 1651H (30 x 65 - both)
4 Overwing/Emergency left 2 Type III 508W x 914H (20 x 36)
5 Overwing/Emergency right 2 Type III 508W x 914H (20 x 36)

garpd · Mon May 27, 2013 4:47 pm

Quoting scarebus03 (Reply 17):
so the B707-300 fuselage is going back into production

If it ain't broken, don't fix it.

ODwyerPW · Mon May 27, 2013 4:50 pm

I'm wondering what this does for the 737-7Max max single class capacity? Are we finally looking at a true 149pax -7 with decent seat pitch (WN config)?

Was door reconfiguration a factor in WN becoming a launch customer for the -7?

leo467 · Mon May 27, 2013 4:57 pm

Interesting idea. I can clearly see that the exit door is a limiting factor with a new generation of seats which have slimmer cushions and save a couple of inches in valuable floor space. So the 8 Max is aiming towards the famous 199 Pax configuration always wanted by Ryanair???

On a side note - can anybody explain why a 737-800 has an Exit Limit of 189 Pax and a A320 of 180 Pax, but the A320 has larger doors (at least on the right hand side of the aircraft, but I would assume this does not matter?!).

BlueShamu330s · Mon May 27, 2013 5:14 pm

Adding extra seats to achieve CASM guarantees; how old school.

There was I expecting high tech, ground breaking innovations and new propulsion technology...

Rgds

hiflyeras · Mon May 27, 2013 5:20 pm

Quoting Stitch (Reply 11):
To get to 162, I am assuming the MAX will have six seats in the Overwing Exit Row as opposed to the 4 in the 737-800.

I think you're thinking of the 737-700. The -800 has a full six abreast at the overwings.

Quoting 817Dreamliiner (Reply 19):
Im not sure if the doors can be moved any further than they already are:

Agreed. Moving the front doors forward would encroach on an already tight flight deck and electrical panels built into the wall. With the tapering of the aft fuselage, the rear doors can't really be moved much further back than they already are. They're already quite 'stubby'...low height clearance as it is.

I thing this might all come down to a wider main cabin door L1 to allow for faster egress in an evacuation, thus allowing the limit to be raised slightly. But it also means airlines will have to reduce seat pitch to 29-30" which they might be hesitant to do without the fear of alienating customers.

ssteve · Mon May 27, 2013 5:47 pm

Quoting Blueshamu330s (Reply 27):
Adding extra seats to achieve CASM guarantees; how old school.

There was I expecting high tech, ground breaking innovations and new propulsion technology...

They shouldn't do it because it's not cool enough?

Incidentally, one of the technology features requested by flight attendants is a door that's easier to open, because the existing door is grandfathered in. They may not be changing the door that matters, though... that's not clear to me, and of course it's all just informed speculation at this point.

Stitch · Mon May 27, 2013 6:03 pm

Quoting Stitch (Reply 11):
To get to 162, I am assuming the MAX will have six seats in the Overwing Exit Row as opposed to the 4 in the 737-800.

Quoting HiFlyerAS (Reply 28):
I think you're thinking of the 737-700. The -800 has a full six abreast at the overwings.

While that is true for most, if not all, airline operators of the type, Section 2.4.13 of the Boeing 737 Family ACAP shows a row of 6 seats at the forward overwing exit and a row of 4 seats in the aft overwing exit for a Mixed Class configuration of First Class and Economy Class seating.

1337Delta764 · Mon May 27, 2013 6:10 pm

Since Boeing is modifying the doors, why not add a slide raft option? The 737NG is the only current Boeing or Airbus aircraft that does not offer them (they are at least optional on the A32x).

hiflyeras · Mon May 27, 2013 6:50 pm

Quoting Stitch (Reply 30):
While that is true for most, if not all, airline operators of the type, Section 2.4.13 of the Boeing 737 Family ACAP shows a row of 6 seats at the forward overwing exit and a row of 4 seats in the aft overwing exit for a Mixed Class configuration of First Class and Economy Class seating.

You're probably right...it's likely carrier-option. If there is more legroom they can have six seats but with a tighter space they need to leave out the window seat and can only have two seats per side instead of three.

BA777 · Mon May 27, 2013 7:30 pm

So Ryanair could get the capacity up to 198...?

speedygonzales · Mon May 27, 2013 7:40 pm

Quoting 817Dreamliiner (Reply 19):
Quoting speedygonzales (Reply 15):
I'm guessing moving the front doors forward and/or the rear doors backwards

Im not sure if the doors can be moved any further than they already are:

It will be tight, but we're only talking 1m or so for 9 more seats.

The Aspire Aviation article doesn't have much details, but the reason I'm leaning towards moving the doors is that they mention incrasing the standard two class capacity from 162 to 171, which points to lengthening the cabin, not increasing the 189 seat exit limit. If it could be achieved by using slimmer seats or rearranging the cabin layout, there's no need to change the doors or wait for the MAX. The max limit is only mentioned for the -9, but it's not clear if the 226 number came from Boeing, or if Aspire got it themselves by adding 9 to 215.

Anyway, whatever the door modification ends up being, the need to change the doors to increase capacity is IMO an admission by Boeing that the NEO has a solid lead on the MAX.

Quoting 817Dreamliiner (Reply 19):

Quoting speedygonzales (Reply 15):
and possibly adopting the flat rear bulkhead from the 900ER on all models.

Isnt this being done already or am I mistaken?

Boeing's ACAPS document only show the flat bulkhead on the drawings of the 900ER, but they might have changed it for the 700 and 800 without updating the documentation,

Viscount724 · Mon May 27, 2013 10:01 pm

Quoting Stitch (Reply 30):
Quoting Stitch (Reply 11):
To get to 162, I am assuming the MAX will have six seats in the Overwing Exit Row as opposed to the 4 in the 737-800.
Quoting HiFlyerAS (Reply 28):
I think you're thinking of the 737-700. The -800 has a full six abreast at the overwings.

While that is true for most, if not all, airline operators of the type, Section 2.4.13 of the Boeing 737 Family ACAP shows a row of 6 seats at the forward overwing exit and a row of 4 seats in the aft overwing exit for a Mixed Class configuration of First Class and Economy Class seating.

KLM 737-700/800/900s all have 3-3 seating at the overwing exits (with a few inches more seat pitch).

DocLightning · Mon May 27, 2013 10:06 pm

Quoting PHX787 (Reply 1):
Are they completely redesigning the fuselage cross-section with the MAX?

A complete redesign of the cross-section would be too much of a deviation to be still considered a 737 for regulatory purposes. They would have to certify it as an entirely new type and come up with all the procedures for pilots to ensure a common type rating and etc. etc. etc. The cross-section cannot change.

Viscount724 · Mon May 27, 2013 10:12 pm

Quoting DocLightning (Reply 36):
Quoting PHX787 (Reply 1):
Are they completely redesigning the fuselage cross-section with the MAX?

A complete redesign of the cross-section would be too much of a deviation to be still considered a 737 for regulatory purposes. They would have to certify it as an entirely new type and come up with all the procedures for pilots to ensure a common type rating and etc. etc. etc. The cross-section cannot change.

If not mistaken the 757 and 767 have a common pilot type rating but they certainly don't have the same cross-section.

garpd · Mon May 27, 2013 10:18 pm

Quoting Blueshamu330s (Reply 27):
Adding extra seats to achieve CASM guarantees; how old school.

There was I expecting high tech, ground breaking innovations and new propulsion technology...

Rgds

Your sarcasm aside, there is nothing wrong with eeking out more efficiencies from an established design. If a relatively minor change to the doors allows for more seats in the same fuselage, it wouldn't make sense not to take advantage of that.

Perhaps this just goes to show how well the 707/737 fuselage was designed, that even after 50 years it's still as adaptable and efficient as it was when the first ones rolled of the production line.

Few fuselages have stayed in production over so many models for so long.

lightsaber · Mon May 27, 2013 11:18 pm

Quoting 817Dreamliiner (Reply 19):
Quoting speedygonzales (Reply 15):
and possibly adopting the flat rear bulkhead from the 900ER on all models.

Isnt this being done already or am I mistaken?

Is it? I would think the MAX would standardize on the 900ER bulkhead, but that is a detail I do not know...

What is the answer?

Quoting speedygonzales (Reply 34):
but the reason I'm leaning towards moving the doors is that they mention incrasing the standard two class capacity from 162 to 171, which points to lengthening the cabin, not increasing the 189 seat exit limit.

Interesting find. Although 3 of those seats would be from the bulkhead move...

Lightsaber

Jetmarc · Mon May 27, 2013 11:44 pm

What I don't understand is how does a wider door make a difference?? Unless being wider allows for a dual lane escape slide. Can somebody explain to me... is it because people can apparently move through it faster as if easier to round the corner? The MD80 had a max seating of 172 even with that little dinky R1 service door/hatch! I too wonder if its more about configuration than modification. Perhaps they'll make the 737MAX more like the A321 and ditch the OWWEs for 900ER style hatches forward and aft of the wings.

etops1 · Tue May 28, 2013 12:16 am

Can they please change the slide arming mechanism on the door ? That girt bar has got to go .

fpetrutiu · Tue May 28, 2013 12:18 am

Quoting BA777 (Reply 33):
So Ryanair could get the capacity up to 198...?

thank God it's not up to RyanAir... Then we'll see a 550 pax 737...

0newair0 · Tue May 28, 2013 1:34 am

Quoting fpetrutiu (Reply 42):
Then we'll see a 550 pax 737...

...All standing and holding on to overhead hand straps that will retract if their coin slots aren't continuously fed.

mffoda · Tue May 28, 2013 2:49 am

Quoting fpetrutiu (Reply 42):
Quoting BA777 (Reply 33):
So Ryanair could get the capacity up to 198...?

thank God it's not up to RyanAir... Then we'll see a 550 pax 737...

On the other hand.... It definitely throws a wrench into the per seat cost argument when the OEM's used different numbers in their ads... Particularity, since Boeing using 162 seats in their assumptions for the 737-8 and Airbus used 157 seats in their assumptions... When comparing to the 150 seat A320neo's... I wonder how the new numbers add up with 171 seats for the 737-8??

Maybe ferpe can give us some insight...

planemaker · Tue May 28, 2013 4:05 am

Quoting mffoda (Reply 44):
On the other hand.... It definitely throws a wrench into the per seat cost argument when the OEM's used different numbers in their ads... Particularity, since Boeing using 162 seats in their assumptions for the 737-8 and Airbus used 157 seats in their assumptions... When comparing to the 150 seat A320neo's... I wonder how the new numbers add up with 171 seats for the 737-8??

It is a bit of joke, really, this game they play... not only seat numbers but distance as well - whatever makes them look better. However, other than on sites like this, the "propaganda" is pretty pointless since airlines run the true numbers through their own network and in their own configurations. Furthermore, the COC & CASM is only part of the purchasing decision.

Stitch · Tue May 28, 2013 4:32 am

Quoting planemaker (Reply 45):
It is a bit of joke, really, this game they play... not only seat numbers but distance as well - whatever makes them look better.

Both OEMs partake of this game - Airbus is playing with door distances, number of doors, seat pitch and seat design to fit 236 seats into an A321-200neo.

goosebayguy · Tue May 28, 2013 5:36 am

Its a fair point that many people these days are slightly larger. I'm wondering when it was decided that 45 or 55 people could evacuate these doors and if people's increased girths these days actually reduces the number able to evacuate. Anyone know what year these rules were introduced?

ggflyboy · Tue May 28, 2013 5:40 am

Quoting Stitch (Reply 3):
The Type C door, which is the same height but wider (minimum of 30 inches vs. the 24 inches of the Type I), is certified for 55 passengers per exit.

I think this is the real joke. What bizzarro study proved that increasing the door width by 6 inches means an extra 10 passengers can get out in an emergency?? At this point, there's no hard science and we're just playing games, especially if the modification is only made to 1L. Isn't there also a certification requirement to assume that half the exits might be blocked? What if "half the exits" means that the wider doors are inop? But I guess the OEM gets to choose which exits are blocked when they certify... Airbus had one entire side blocked for the A380 certification.

And another thought... 1L is located close to the low-density first class area, so this modification would not proportionally help the extra 9 people stuffed into the back.

Maybe this is cynical comment, but in an accident the 73 tends to break apart somewhere just forward (or aft) of the wing box anyway, so it might make this a moot point... lots of people just get out through the split. Think Turkish, Lion Air, etc.

Btw, somewhat unrelated: took a ride in my first 757-300 today--- second row from the back. Just like sitting in the back of the bus! Felt like I was one with the rudder. Anyway, this might be informing my opinion here on seating density and exit configuration.

ssteve · Tue May 28, 2013 5:45 am

Quoting ggflyboy (Reply 48):
I think this is the real joke. What bizzarro study proved that increasing the door width by 6 inches means an extra 10 passengers can get out in an emergency??

On the other hand, what makes you think an increase in the width of the door by 25% wouldn't mean an 10% increase in passengers escaping? (In my own opinion, 24" would seem like a bottleneck...)

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