morrisond
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So how New is the 777X?

Sun Feb 23, 2020 1:33 pm

Its this really a new Airplane in an old wrapper kind of like the A330 vs A300-600?

Various articles I have read over the years indicate the following has changed:

New Wing (some reports say it is no heavier than old)
New Wingbox
New Gear
New Engines (some articles say lighter - some say about the same - some say slightly heavier)
Extended Tail (I would assume all new)
New Fuselage Ribs (at least in the topside no idea about the lower lobe)
New stringers due to extended length
New Skin Panels (obviously - different lengths/stresses)
New 787 Based Interior (lighter and probably an evolution from 787)
New 787 Based Cockpit and avionics
New Larger Windows (heavier)
More 787 systems like smooth ride

What has stayed the same:

Bleed air system
Doors? Passenger/ Emergency/ Cargo? (But didn't they drop one Emergency Exit saving weight?)

Is this literally a new aircraft and all the remains is the shape of the nose and the outer mold line of the fuselage cross section?

When Boeing saw how good the A351 was going to be would it not have made sense to throw more resources at the 777X to make it as efficient as possible.

Does starting with the 777W as a base for OEW weight calculations seems not the right way to go given that it is basically an all new 10W 787 with one vey large wing?

Please - let us try and not make it an 777X vs A350 discussion.

I'm really trying to get to the bottom of this and figure out what is leftover from 777W.

What did they keep and not touch with redesign that has significant mass that they would not have applied 787 lessons too?
 
KFLLCFII
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Re: So how New is the 777X?

Sun Feb 23, 2020 1:43 pm

morrisond wrote:
I'm really trying to get to the bottom of this and figure out what is leftover from 777W.


The FAA, EASA, and all other regulating bodies will be doing the same.
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TFawkes
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Re: So how New is the 777X?

Sun Feb 23, 2020 1:49 pm

The cross section is the same. The material for the fuselage is the same aluminum as the 77W. The 777-8 is essentially the same size as the 777-300ER, whereas the -9 is effectively a stretch.

The cargo loading system is the same too.
 
StTim
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Re: So how New is the 777X?

Sun Feb 23, 2020 2:32 pm

As they can build it on the same production line (last I heard) then I suspect most of the frame is very similar or just minor tweaks. Materials, fixings, stress paths etc are the same.

Interesting morrisond - if your view is correct then it will be a significantly longer test campaign that Boeing were saying.
 
B757Forever
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Re: So how New is the 777X?

Sun Feb 23, 2020 2:57 pm

The 777X new wing is CFRP instead of aluminum like the earlier 777 aircraft. At one point in the design I had heard the fuselage was going to be lithium-aluminum. Is that still the case?
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reidar76
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Re: So how New is the 777X?

Sun Feb 23, 2020 3:11 pm

It still has the 767 nose.
 
Okcflyer
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Re: So how New is the 777X?

Sun Feb 23, 2020 3:35 pm

I haven’t yet read anything official that the empennage is new. I would expect it’s essentially the same with just a couple of tweaks. Due to the 777 being a longer design than the old 772, the horizontal stab could be smaller (longer moment arm).

At first glance, one would think the vertical stab could be reduced in size as well since the GE9X produce almost 15k less take off thrust each. However, they’re now further from the centerline (further out on the wing) which requires a larger tail itself.

In conclusion, I expect the tail is very minimum change. Perhaps a small tweak to trailing edges or tips to maximize efficiency otherwise the same. You can see they kept the same complicated screw driver tip tail cone as well that everything else new doesn’t use.

Outside of the wing and wing box, I don’t think much of the structural system changed. Ribs were slightly re-profiled in a small part, along with the larger windows and 6k altitude, requires rebalancing the members thickness to accommodate new load. Rebalancing is a well understood process that happens almost every IGW variant that comes about.

Doors, floor beams, would all be minimal change.

Subsystems architecture carried over. Hydraulics, electrics, pneumatics should be minimal change.

Radome, cockpit structure, etc all carry.

All of these areas alone save tons of design and certification time and risk, not to mention manufacturing risk and cost.
 
United857
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Re: So how New is the 777X?

Sun Feb 23, 2020 3:47 pm

From a structural integrity standpoint, the 777X is very different from the original 777. Pretty much the only thing major items that have remained the same is the outer fuselage diameter and the horizontal stabilizer.

In order to get an extra 4 inches of cabin width to accommodate 18-inch wide seats 10 abreast, the fuselage ribs had to be reprofiled to be significantly shorter. From a load-bearing perspective, this completely changes the way the fuselage behaves under load, even though the outer diameter is the same, and thus in my opinion should not be considered the "same" fuselage. In addition, the fuselage skin is now made from aluminum lithium to save weight, instead of simply aluminum, which again changes the overall load-bearing properties.

The wing is also now made from CFRP, which has drastically different load-bearing properties from aluminum and is pretty much all new to the 777. What makes this rewing more significant than previous rewings on other aircraft programs (think 747-400 -> 747-8 and 737 Classic -> 737 NG) is that in those other cases, the basic planform of the wing remained the same even though the airfoil was reprofiled from conventional to supercritical (the 737NG also received wingtip extensions between the ailerons and winglets, but when comparing the planforms of the wing, the inboard side of ailerons begin in exactly the same place as the original 737-100 and the engine pylons are still located the same distance from centerline, which means the overall planform of the wing did not change). In the case of the 777X, the entire planform was changed in addition to a new airfoil profile, with the engine pylons now 34 feet 11 inches from centerline instead of 31 feet 6.5 inches and the ailerons located at different points along the wingspan. Although the wing leveraged the design used on the 787, the new 777X wing really shares nothing in common with the original 777.

Regarding the empennage, vertical stabilizer is a new design copied from the 787, while the horizontal stabilizer has received tip extensions to increase area. I suspect the change in the vertical stabilizer is to compensate for the fact that the 777X engines are further from centerline. Although the engines produce 105k thrust instead of 115k, the increased moment arm of the engines may have had a larger impact.

In term of length, the 777-8 is approximately halfway between the old 777-200 and 777-300 series, at 229 feet in length (the 777-200 was 209 feet and the 777-300 was 242 feet). The 777-9 is a stretch, at almost 252 feet in length.
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TFawkes
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Re: So how New is the 777X?

Sun Feb 23, 2020 4:11 pm

United857 wrote:
In order to get an extra 4 inches of cabin width to accommodate 18-inch wide seats 10 abreast, the fuselage ribs had to be reprofiled to be significantly shorter. From a load-bearing perspective, this completely changes the way the fuselage behaves under load, even though the outer diameter is the same, and thus in my opinion should not be considered the "same" fuselage. In addition, the fuselage skin is now made from aluminum lithium to save weight, instead of simply aluminum, which again changes the overall load-bearing properties.

Do you have a source on the Al-Li fuselage? AFAIK that was only ever speculated, not confirmed
 
mjoelnir
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Re: So how New is the 777X?

Sun Feb 23, 2020 4:14 pm

AFAIK the aluminium lithium skin on the fuselage did not happen for the 777X.

AFAIK the thing some posters here call ribs, are actually called frames. Longitudinal there are the stringers. AFAIK ribs are in the wing attached to the main spar(s) giving the wing the form.

Did they really change the wing box?
 
TFawkes
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Re: So how New is the 777X?

Sun Feb 23, 2020 4:26 pm

mjoelnir wrote:
AFAIK the aluminium lithium skin on the fuselage did not happen for the 777X.

AFAIK the thing some posters here call ribs, are actually called frames. Longitudinal there are the stringers. AFAIK ribs are in the wing attached to the main spar(s) giving the wing the form.

Did they really change the wing box?

Wing box definitely changed. Just examine the underside of a 777-300 vs. the 777-9. Not surprising given they had to join composite to Aluminum.
 
VSMUT
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Re: So how New is the 777X?

Sun Feb 23, 2020 4:31 pm

TFawkes wrote:
The cross section is the same. The material for the fuselage is the same aluminum as the 77W. The 777-8 is essentially the same size as the 777-300ER, whereas the -9 is effectively a stretch.

The cargo loading system is the same too.


The 777-8 is a full 4 meters shorter than the -300ER.
 
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ikolkyo
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Re: So how New is the 777X?

Sun Feb 23, 2020 4:34 pm

It’s more of a new aircraft than the A320neo, A330neo and MAX. But not so new that it’s literally a new aircraft hiding underneath. I consider the 777X very similar to the 737 classic to 737NG transition
 
cedarjet
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Re: So how New is the 777X?

Sun Feb 23, 2020 5:23 pm

I am stunned by how few have been sold. In this day and age we’re used to seeing new types go into service with 1,000 preorders, but this bird is at just 309.

Is it jitters because of Boeing’s shortcomings (as an aside, January 2020 was the first month since the 1950s Boeing haven’t booked a single order for a jet airliner), not quite right for the market, lots of young 777-300ERs too young to need replacing...?
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mjoelnir
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Re: So how New is the 777X?

Sun Feb 23, 2020 5:27 pm

TFawkes wrote:
mjoelnir wrote:
AFAIK the aluminium lithium skin on the fuselage did not happen for the 777X.

AFAIK the thing some posters here call ribs, are actually called frames. Longitudinal there are the stringers. AFAIK ribs are in the wing attached to the main spar(s) giving the wing the form.

Did they really change the wing box?

Wing box definitely changed. Just examine the underside of a 777-300 vs. the 777-9. Not surprising given they had to join composite to Aluminum.


That is actually no proof. Most of that look comes from the fairings and they are considerable changed from the 777-200/300.
 
JohanTally
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Re: So how New is the 777X?

Sun Feb 23, 2020 5:47 pm

cedarjet wrote:
I am stunned by how few have been sold. In this day and age we’re used to seeing new types go into service with 1,000 preorders, but this bird is at just 309.

Is it jitters because of Boeing’s shortcomings (as an aside, January 2020 was the first month since the 1950s Boeing haven’t booked a single order for a jet airliner), not quite right for the market, lots of young 777-300ERs too young to need replacing...?


Name one widebody program that went into service with 1,000 preorders? At the planned build rate it represents 5-7 years of production and this is before the first delivery. Widebody demand is currently down especially for the largest models but as long as the ME3 market doesn't completely crash the backlog is healthy.
 
United857
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Re: So how New is the 777X?

Sun Feb 23, 2020 6:24 pm

ikolkyo wrote:
It’s more of a new aircraft than the A320neo, A330neo and MAX. But not so new that it’s literally a new aircraft hiding underneath. I consider the 777X very similar to the 737 classic to 737NG transition

I personally consider the 777 to 777X to be even more of a change than the 737 Classic to 737NG. This primarily because if you look at the wing planform between the classic and NG, the two are pretty much identical, which is revealed by the fact that the engine pylons and flaps/ailerons remain the exact same distance from the centerline of the aircraft, although the airfoil was changed from conventional to supercritical. True, the wing was extended to a span of 112 feet without winglets, but all of that came outboard of the aileron.
You can see this in this diagram: http://i4.photobucket.com/albums/y120/Aeroweanie/Overlay.jpg
From Boeing's airport planning document on pages 28-41, you can see than the engine pylons remain at exactly 15ft 10in from centerline on the 737-100 all the way up to the 737-900: https://www.boeing.com/resources/boeingdotcom/commercial/airports/acaps/737.pdf

For the 777X, the engine pylons are about 35 ft from centerline instead of 31.5 ft, and the flaps/ailerons also bear no connection in placement to the original 777. The relocation of these major components highlights the fact that the underlying planform of the wing has been changed, and thus is an even greater modification than from the 737 Classic to 737NG.
Compare pages 2-3 to 2-5 from here (200LR/300ER/777F): https://www.boeing.com/resources/boeingdotcom/commercial/airports/acaps/777_2lr3er.pdf
With page 2-4 from here (777-9): https://www.boeing.com/resources/boeingdotcom/commercial/airports/acaps/777-9_RevA.pdf
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VSMUT
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Re: So how New is the 777X?

Sun Feb 23, 2020 7:24 pm

cedarjet wrote:
I am stunned by how few have been sold. In this day and age we’re used to seeing new types go into service with 1,000 preorders, but this bird is at just 309.

Is it jitters because of Boeing’s shortcomings (as an aside, January 2020 was the first month since the 1950s Boeing haven’t booked a single order for a jet airliner), not quite right for the market, lots of young 777-300ERs too young to need replacing...?


Because it was a poorly thought out attempt at competing with the A350-1000, an aircraft Boeing consistently underestimated at the time. To remain competitive they increased the size, so the CASK could be lowered to that of the A350. Unfortunately that also brought it well into VLA territory, and as well all know, the A380 and 747-8 didn't exactly sell in meaningful numbers either.

It didn't really help either that Emirates in particular pushed for it to have ultra-long-range performance. In the end it got too heavy because of that, and the A350 still ended up superseding it in that metric.

Remember, this is an aircraft pushed out by the same management that was behind the 737MAX. Rational long term thinking wasn't their strong side.
 
ILNFlyer
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Re: So how New is the 777X?

Sun Feb 23, 2020 7:36 pm

JohanTally wrote:
cedarjet wrote:
I am stunned by how few have been sold. In this day and age we’re used to seeing new types go into service with 1,000 preorders, but this bird is at just 309.

Is it jitters because of Boeing’s shortcomings (as an aside, January 2020 was the first month since the 1950s Boeing haven’t booked a single order for a jet airliner), not quite right for the market, lots of young 777-300ERs too young to need replacing...?


Name one widebody program that went into service with 1,000 preorders? At the planned build rate it represents 5-7 years of production and this is before the first delivery. Widebody demand is currently down especially for the largest models but as long as the ME3 market doesn't completely crash the backlog is healthy.


I believe the 787 had about 860 orders prior to first delivery.
 
Opus99
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Re: So how New is the 777X?

Sun Feb 23, 2020 7:41 pm

ILNFlyer wrote:
JohanTally wrote:
cedarjet wrote:
I am stunned by how few have been sold. In this day and age we’re used to seeing new types go into service with 1,000 preorders, but this bird is at just 309.

Is it jitters because of Boeing’s shortcomings (as an aside, January 2020 was the first month since the 1950s Boeing haven’t booked a single order for a jet airliner), not quite right for the market, lots of young 777-300ERs too young to need replacing...?


Name one widebody program that went into service with 1,000 preorders? At the planned build rate it represents 5-7 years of production and this is before the first delivery. Widebody demand is currently down especially for the largest models but as long as the ME3 market doesn't completely crash the backlog is healthy.


I believe the 787 had about 860 orders prior to first delivery.

the 77W had way less than 309 before EIS and thats the best selling 777.
 
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reidar76
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Re: So how New is the 777X?

Sun Feb 23, 2020 7:47 pm

I hope Boeing is not getting away with limited testing and certification process for the 777X. This bird is changed in so many ways it must be certified as a new aircraft, and not as a variant of the 777 classic. It needs it own type certificate. I hope FAA and EASA don't let Boeing take any MAX shortcuts this time around.
 
Opus99
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Re: So how New is the 777X?

Sun Feb 23, 2020 7:55 pm

reidar76 wrote:
I hope Boeing is not getting away with limited testing and certification process for the 777X. This bird is changed in so many ways it must be certified as a new aircraft, and not as a variant of the 777 classic. It needs it own type certificate. I hope FAA and EASA don't let Boeing take any MAX shortcuts this time around.

The certification bodies are very aware of the changes in the 777X and they’ve said that it really depends on a lot of things. They can’t say for sure that certification will go one way or another
 
tomcat
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Re: So how New is the 777X?

Sun Feb 23, 2020 8:08 pm

mjoelnir wrote:
TFawkes wrote:
mjoelnir wrote:
AFAIK the aluminium lithium skin on the fuselage did not happen for the 777X.

AFAIK the thing some posters here call ribs, are actually called frames. Longitudinal there are the stringers. AFAIK ribs are in the wing attached to the main spar(s) giving the wing the form.

Did they really change the wing box?

Wing box definitely changed. Just examine the underside of a 777-300 vs. the 777-9. Not surprising given they had to join composite to Aluminum.


That is actually no proof. Most of that look comes from the fairings and they are considerable changed from the 777-200/300.


At the very least, the interfaces of the center wing box (ie the side of body rib) with the outer wing box must have been modified for the following reasons:
- the sweep angle of the outer wingbox has been modified. This is affecting the interfaces between the side of body rib with the front and rear spars and outer wingbox skins stringers
- due to the material change of the outer wingbox from aluminum to CFRP, the spars and skins gages have been modified which is again affecting the side of body rib design.

Besides these trivial changes, I understand that the 777x comes with a new airfoil. This has a direct impact on the center wingbox design.

Then the changes of sweep angle, of the wing planform and of the wing stiffness are affecting the interface loads between the outer wingbox and the center wingbox. This must have required to at least revisit the sizing of center wingbox even if its layout hasn't been modified.
 
JayinKitsap
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Re: So how New is the 777X?

Sun Feb 23, 2020 8:26 pm

Well the changes are sufficient enough to do complete stress and fatigue frames for the model. In particular the lowered cabin altitude changes the entire structure, which had to be tested anyway with the sculpted ribs to gain added inside width.

It doesn't appear that the regulatory agencies are giving Boeing any kind of slack these days, it probably will go thru a certification process harder than a clean sheet would have 5 years ago.
 
TFawkes
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Re: So how New is the 777X?

Sun Feb 23, 2020 9:20 pm

reidar76 wrote:
I hope Boeing is not getting away with limited testing and certification process for the 777X. This bird is changed in so many ways it must be certified as a new aircraft, and not as a variant of the 777 classic. It needs it own type certificate. I hope FAA and EASA don't let Boeing take any MAX shortcuts this time around.

Grandfathering certification isn't exactly trivial. The wing is a scaled 787 wing, well-proven that went through the max bend test just fine. The fuselage is largely unchanged from the 77W even with the sculpting. They'll allow what's reasonable.

Honestly the flight test campaign is going far too slowly. Every time a test is successful the bird should be back up in the air right after refueling. It's not like we lack the computational power to crunch the recorded data in real time. There's a 2 Petaflop mini supercomputer onboard the test frame anyway, and you can easily enough rent time at Lawrence Livermore or Oak Ridge Labs if you want to crunch big data quickly if you'd prefer to just beam all the data down to Terra Firma immediately for safe keeping and secondary validation.
 
Opus99
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Re: So how New is the 777X?

Sun Feb 23, 2020 9:24 pm

TFawkes wrote:
reidar76 wrote:
I hope Boeing is not getting away with limited testing and certification process for the 777X. This bird is changed in so many ways it must be certified as a new aircraft, and not as a variant of the 777 classic. It needs it own type certificate. I hope FAA and EASA don't let Boeing take any MAX shortcuts this time around.

Grandfathering certification isn't exactly trivial. The wing is a scaled 787 wing, well-proven that went through the max bend test just fine. The fuselage is largely unchanged from the 77W even with the sculpting. They'll allow what's reasonable.

Honestly the flight test campaign is going far too slowly. Every time a test is successful the bird should be back up in the air right after refueling. It's not like we lack the computational power to crunch the recorded data in real time. There's a 2 Petaflop mini supercomputer onboard the test frame anyway, and you can easily enough rent time at Lawrence Livermore or Oak Ridge Labs if you want to crunch big data quickly if you'd prefer to just beam all the data down to Terra Firma immediately for safe keeping and secondary validation.

Slowly? I don’t quite agree given how spaced out 350 test campaign was initially. This aircraft has flown almost every single day since the first flight. With just the one they’ve done over 66 hours and 22 flights

There was also a weekend when it flew on both Saturday and Sunday
 
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ElroyJetson
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Re: So how New is the 777X?

Mon Feb 24, 2020 1:10 am

As I recall Boeing claimed the composite panels on the wing would save about 5,000 lbs of weight. Still, the overall wing is much bigger so I do not know if there is a net weight savings versus the 77W.
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william
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Re: So how New is the 777X?

Mon Feb 24, 2020 1:25 am

VSMUT wrote:
cedarjet wrote:
I am stunned by how few have been sold. In this day and age we’re used to seeing new types go into service with 1,000 preorders, but this bird is at just 309.

Is it jitters because of Boeing’s shortcomings (as an aside, January 2020 was the first month since the 1950s Boeing haven’t booked a single order for a jet airliner), not quite right for the market, lots of young 777-300ERs too young to need replacing...?


Because it was a poorly thought out attempt at competing with the A350-1000, an aircraft Boeing consistently underestimated at the time. To remain competitive they increased the size, so the CASK could be lowered to that of the A350. Unfortunately that also brought it well into VLA territory, and as well all know, the A380 and 747-8 didn't exactly sell in meaningful numbers either.

It didn't really help either that Emirates in particular pushed for it to have ultra-long-range performance. In the end it got too heavy because of that, and the A350 still ended up superseding it in that metric.

Remember, this is an aircraft pushed out by the same management that was behind the 737MAX. Rational long term thinking wasn't their strong side.


Truth be told this market is not big enough for two new programs to pay for R&D and be profitable. Airbus brought a product that ate the 777-300 launch and no way did it make sense to design from the ground up a new VLA. Especially seeing the A380 orders at the time and the 787 eating into replacement sales. The A350 is a great aircraft, and in hindsight, Boeing's answer should had been a rewinged 787-11 and the let the 777 soldier on as a freighter.

Especially seeing how the ME3 airlines are not the long term gold mine of orders that Airbus and Boeing thought they were.
 
morrisond
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Re: So how New is the 777X?

Mon Feb 24, 2020 1:42 am

Here is an article I found on it.

It says its substantially heavier - but that may be with the wheel bays included in terms of the part Subaru delivers to Boeing is substantially heavier - however it does say it carries substantially more payload.

https://www.flightglobal.com/systems-an ... 38.article
 
RogerMurdock
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Re: So how New is the 777X?

Mon Feb 24, 2020 1:53 am

Okcflyer wrote:
You can see they kept the same complicated screw driver tip tail cone as well that everything else new doesn’t use.


A220 has one like that, no?
 
JohanTally
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Re: So how New is the 777X?

Mon Feb 24, 2020 1:56 am

VSMUT wrote:
cedarjet wrote:
I am stunned by how few have been sold. In this day and age we’re used to seeing new types go into service with 1,000 preorders, but this bird is at just 309.

Is it jitters because of Boeing’s shortcomings (as an aside, January 2020 was the first month since the 1950s Boeing haven’t booked a single order for a jet airliner), not quite right for the market, lots of young 777-300ERs too young to need replacing...?


Because it was a poorly thought out attempt at competing with the A350-1000, an aircraft Boeing consistently underestimated at the time. To remain competitive they increased the size, so the CASK could be lowered to that of the A350. Unfortunately that also brought it well into VLA territory, and as well all know, the A380 and 747-8 didn't exactly sell in meaningful numbers either.

It didn't really help either that Emirates in particular pushed for it to have ultra-long-range performance. In the end it got too heavy because of that, and the A350 still ended up superseding it in that metric.

Remember, this is an aircraft pushed out by the same management that was behind the 737MAX. Rational long term thinking wasn't their strong side.


The A35K has been in service for 2 full years but has only garnered 176 orders total so to act like it is in a league of it's own is pretentious. We could also talk about the Airbus management team that keeps popping up in the news for corruption and being hit with billions of dollars in fines with more potentially on the horizon. A and B intentionally don't overlap models so the 777X program will have it's part of the market as with the A350 program.
 
Elementalism
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Re: So how New is the 777X?

Mon Feb 24, 2020 3:01 am

The 747-8 and A380 died in part because nobody wants to run 4 engines anymore. There is a segment of the market for VLA. 777x will fill it. Over its lifetime to the tune of around 1200-1500 deliveries would be my guess.
 
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kitplane01
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Re: So how New is the 777X?

Mon Feb 24, 2020 3:54 am

The 777X vertical tail is now composite. Maybe lots did change ?!?!?

https://www.seattletimes.com/business/b ... -777x-jet/
 
Insertnamehere
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Re: So how New is the 777X?

Mon Feb 24, 2020 4:34 am

TFawkes wrote:
reidar76 wrote:
I hope Boeing is not getting away with limited testing and certification process for the 777X. This bird is changed in so many ways it must be certified as a new aircraft, and not as a variant of the 777 classic. It needs it own type certificate. I hope FAA and EASA don't let Boeing take any MAX shortcuts this time around.

Grandfathering certification isn't exactly trivial. The wing is a scaled 787 wing, well-proven that went through the max bend test just fine. The fuselage is largely unchanged from the 77W even with the sculpting. They'll allow what's reasonable.

Honestly the flight test campaign is going far too slowly. Every time a test is successful the bird should be back up in the air right after refueling. It's not like we lack the computational power to crunch the recorded data in real time. There's a 2 Petaflop mini supercomputer onboard the test frame anyway, and you can easily enough rent time at Lawrence Livermore or Oak Ridge Labs if you want to crunch big data quickly if you'd prefer to just beam all the data down to Terra Firma immediately for safe keeping and secondary validation.


With the number of data points being collected I'm sure, the boys back in Boeing want to be going through this with a fine-tooth comb considering the debacle they're in over their last iterative aircraft. Furthermore, with these large datasets, you're not able to quickly crunch these numbers and engineers wanting data visualization, it's going to take some time especially in a large multinational which has meetings for meetings.
 
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Revelation
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Re: So how New is the 777X?

Mon Feb 24, 2020 5:30 am

StTim wrote:
Interesting morrisond - if your view is correct then it will be a significantly longer test campaign that Boeing were saying.

That would be true if you assume morrisond knows more about the testing than Boeing does, which I think he would admit is not true.
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morrisond
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Re: So how New is the 777X?

Mon Feb 24, 2020 12:27 pm

Revelation wrote:
StTim wrote:
Interesting morrisond - if your view is correct then it will be a significantly longer test campaign that Boeing were saying.

That would be true if you assume morrisond knows more about the testing than Boeing does, which I think he would admit is not true.


Correct - I have no clue how long it will take but as has also been stated Boeing has no real clear idea how long it will take either. I don't believe there is a public schedule right now - just "Hope" of a certain schedule.

Who knows how long it will take. I assume a few months longer than normal but I doubt that extends into a year or longer.

Flight testing is flight testing - you can only stall an aircraft so many times before it is unproductive. Certain manoeuvres have to be performed maybe a few more for a clean sheet. It's the paperwork that can take longer.

If they do certify as a clean sheet I think the last clean sheet (A350) was 14.5 months from first flight to type certification with EIS 4 months later using 5 test airframes (I think the same as 777x).

So I expect if they are forced to complete a clean sheet flight test program it should be done by summer next year and EIS possibly before the end of 2021.
 
TTailedTiger
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Joined: Sun Aug 26, 2018 5:19 am

Re: So how New is the 777X?

Mon Feb 24, 2020 12:38 pm

william wrote:
VSMUT wrote:
cedarjet wrote:
I am stunned by how few have been sold. In this day and age we’re used to seeing new types go into service with 1,000 preorders, but this bird is at just 309.

Is it jitters because of Boeing’s shortcomings (as an aside, January 2020 was the first month since the 1950s Boeing haven’t booked a single order for a jet airliner), not quite right for the market, lots of young 777-300ERs too young to need replacing...?


Because it was a poorly thought out attempt at competing with the A350-1000, an aircraft Boeing consistently underestimated at the time. To remain competitive they increased the size, so the CASK could be lowered to that of the A350. Unfortunately that also brought it well into VLA territory, and as well all know, the A380 and 747-8 didn't exactly sell in meaningful numbers either.

It didn't really help either that Emirates in particular pushed for it to have ultra-long-range performance. In the end it got too heavy because of that, and the A350 still ended up superseding it in that metric.

Remember, this is an aircraft pushed out by the same management that was behind the 737MAX. Rational long term thinking wasn't their strong side.


Truth be told this market is not big enough for two new programs to pay for R&D and be profitable. Airbus brought a product that ate the 777-300 launch and no way did it make sense to design from the ground up a new VLA. Especially seeing the A380 orders at the time and the 787 eating into replacement sales. The A350 is a great aircraft, and in hindsight, Boeing's answer should had been a rewinged 787-11 and the let the 777 soldier on as a freighter.

Especially seeing how the ME3 airlines are not the long term gold mine of orders that Airbus and Boeing thought they were.


Good grief at the history revision. Both AA and UA canceled/constantly deferred their A350 orders for the 77W. That's not quite "eating the 777-300's lunch". That's a lot of nerve to say such a thing when we saw how Airbus reacted to the 787 launch...
 
TFawkes
Posts: 66
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Re: So how New is the 777X?

Mon Feb 24, 2020 1:51 pm

Insertnamehere wrote:
TFawkes wrote:
reidar76 wrote:
I hope Boeing is not getting away with limited testing and certification process for the 777X. This bird is changed in so many ways it must be certified as a new aircraft, and not as a variant of the 777 classic. It needs it own type certificate. I hope FAA and EASA don't let Boeing take any MAX shortcuts this time around.

Grandfathering certification isn't exactly trivial. The wing is a scaled 787 wing, well-proven that went through the max bend test just fine. The fuselage is largely unchanged from the 77W even with the sculpting. They'll allow what's reasonable.

Honestly the flight test campaign is going far too slowly. Every time a test is successful the bird should be back up in the air right after refueling. It's not like we lack the computational power to crunch the recorded data in real time. There's a 2 Petaflop mini supercomputer onboard the test frame anyway, and you can easily enough rent time at Lawrence Livermore or Oak Ridge Labs if you want to crunch big data quickly if you'd prefer to just beam all the data down to Terra Firma immediately for safe keeping and secondary validation.


With the number of data points being collected I'm sure, the boys back in Boeing want to be going through this with a fine-tooth comb considering the debacle they're in over their last iterative aircraft. Furthermore, with these large datasets, you're not able to quickly crunch these numbers and engineers wanting data visualization, it's going to take some time especially in a large multinational which has meetings for meetings.

There's not THAT much data. It's nothing like the informatics coming out of Google and Facebook. It's a few terabytes per flight. That's nothing.

The campaign is too slow for what can easily be done faster if the engineers are let loose and management gets out of the way.
 
TFawkes
Posts: 66
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Re: So how New is the 777X?

Mon Feb 24, 2020 1:54 pm

morrisond wrote:
Revelation wrote:
StTim wrote:
Interesting morrisond - if your view is correct then it will be a significantly longer test campaign that Boeing were saying.

That would be true if you assume morrisond knows more about the testing than Boeing does, which I think he would admit is not true.


Correct - I have no clue how long it will take but as has also been stated Boeing has no real clear idea how long it will take either. I don't believe there is a public schedule right now - just "Hope" of a certain schedule.

Who knows how long it will take. I assume a few months longer than normal but I doubt that extends into a year or longer.

Flight testing is flight testing - you can only stall an aircraft so many times before it is unproductive. Certain manoeuvres have to be performed maybe a few more for a clean sheet. It's the paperwork that can take longer.

If they do certify as a clean sheet I think the last clean sheet (A350) was 14.5 months from first flight to type certification with EIS 4 months later using 5 test airframes (I think the same as 777x).

So I expect if they are forced to complete a clean sheet flight test program it should be done by summer next year and EIS possibly before the end of 2021.

The A350 had to have fixes implemented partway through flight testing, so it's not representative. The 777-200 would be the last clean sheet of note, and that was just 10 months with 4 frames.
 
morrisond
Topic Author
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Re: So how New is the 777X?

Mon Feb 24, 2020 2:03 pm

TFawkes wrote:
morrisond wrote:
Revelation wrote:
That would be true if you assume morrisond knows more about the testing than Boeing does, which I think he would admit is not true.


Correct - I have no clue how long it will take but as has also been stated Boeing has no real clear idea how long it will take either. I don't believe there is a public schedule right now - just "Hope" of a certain schedule.

Who knows how long it will take. I assume a few months longer than normal but I doubt that extends into a year or longer.

Flight testing is flight testing - you can only stall an aircraft so many times before it is unproductive. Certain manoeuvres have to be performed maybe a few more for a clean sheet. It's the paperwork that can take longer.

If they do certify as a clean sheet I think the last clean sheet (A350) was 14.5 months from first flight to type certification with EIS 4 months later using 5 test airframes (I think the same as 777x).

So I expect if they are forced to complete a clean sheet flight test program it should be done by summer next year and EIS possibly before the end of 2021.

The A350 had to have fixes implemented partway through flight testing, so it's not representative. The 777-200 would be the last clean sheet of note, and that was just 10 months with 4 frames.


Thanks - that's a good Data point - assuming 777X goes smooth it could be done sooner - a few bumps more like A350.
 
StTim
Posts: 3610
Joined: Thu Aug 08, 2013 7:39 am

Re: So how New is the 777X?

Mon Feb 24, 2020 7:16 pm

TFawkes wrote:
morrisond wrote:
Revelation wrote:
That would be true if you assume morrisond knows more about the testing than Boeing does, which I think he would admit is not true.


Correct - I have no clue how long it will take but as has also been stated Boeing has no real clear idea how long it will take either. I don't believe there is a public schedule right now - just "Hope" of a certain schedule.

Who knows how long it will take. I assume a few months longer than normal but I doubt that extends into a year or longer.

Flight testing is flight testing - you can only stall an aircraft so many times before it is unproductive. Certain manoeuvres have to be performed maybe a few more for a clean sheet. It's the paperwork that can take longer.

If they do certify as a clean sheet I think the last clean sheet (A350) was 14.5 months from first flight to type certification with EIS 4 months later using 5 test airframes (I think the same as 777x).

So I expect if they are forced to complete a clean sheet flight test program it should be done by summer next year and EIS possibly before the end of 2021.

The A350 had to have fixes implemented partway through flight testing, so it's not representative. The 777-200 would be the last clean sheet of note, and that was just 10 months with 4 frames.


I followed the A350 testing closely. Yesthey had to incorporate changes but they did keep pretty close to the initial time schedule.

To think that the 777X won't have to incorporate changes during testing is clutching at straws. The MAX kept to their schedule but had to incorporate changes to MCAS. I think it is fair to say these were rushed. I do not want the same to happen on the 777X on the altar of an unrealistic timeframe.
 
Austin787
Posts: 399
Joined: Fri Jun 17, 2016 11:39 pm

Re: So how New is the 777X?

Mon Feb 24, 2020 9:02 pm

What I'd like to know is:
How the changes affect the plane's handling
Software additions or changes
Whether Boeing is clearly communicating all changes
Whether Boeing would offer simulator training
Thoroughness in testing

Boeing cannot afford the 777X becoming the 777MAX
 
TFawkes
Posts: 66
Joined: Wed Feb 19, 2020 2:51 pm

Re: So how New is the 777X?

Tue Feb 25, 2020 1:52 pm

StTim wrote:
TFawkes wrote:
morrisond wrote:

Correct - I have no clue how long it will take but as has also been stated Boeing has no real clear idea how long it will take either. I don't believe there is a public schedule right now - just "Hope" of a certain schedule.

Who knows how long it will take. I assume a few months longer than normal but I doubt that extends into a year or longer.

Flight testing is flight testing - you can only stall an aircraft so many times before it is unproductive. Certain manoeuvres have to be performed maybe a few more for a clean sheet. It's the paperwork that can take longer.

If they do certify as a clean sheet I think the last clean sheet (A350) was 14.5 months from first flight to type certification with EIS 4 months later using 5 test airframes (I think the same as 777x).

So I expect if they are forced to complete a clean sheet flight test program it should be done by summer next year and EIS possibly before the end of 2021.

The A350 had to have fixes implemented partway through flight testing, so it's not representative. The 777-200 would be the last clean sheet of note, and that was just 10 months with 4 frames.


I followed the A350 testing closely. Yesthey had to incorporate changes but they did keep pretty close to the initial time schedule.

To think that the 777X won't have to incorporate changes during testing is clutching at straws. The MAX kept to their schedule but had to incorporate changes to MCAS. I think it is fair to say these were rushed. I do not want the same to happen on the 777X on the altar of an unrealistic timeframe.

What makes a 10-month timeframe unrealistic? If the frame was engineered and built right the first time, the testing doesn't serve any purpose other than making the testers feel good. Why not mandate 4-year flight testing timelines?
Why is it invalid for Boeing to provide quantitative analysis that makes physical testing of the same conditions superfluous?
 
StTim
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Joined: Thu Aug 08, 2013 7:39 am

Re: So how New is the 777X?

Tue Feb 25, 2020 1:59 pm

TFawkes wrote:
StTim wrote:
TFawkes wrote:
The A350 had to have fixes implemented partway through flight testing, so it's not representative. The 777-200 would be the last clean sheet of note, and that was just 10 months with 4 frames.


I followed the A350 testing closely. Yesthey had to incorporate changes but they did keep pretty close to the initial time schedule.

To think that the 777X won't have to incorporate changes during testing is clutching at straws. The MAX kept to their schedule but had to incorporate changes to MCAS. I think it is fair to say these were rushed. I do not want the same to happen on the 777X on the altar of an unrealistic timeframe.

What makes a 10-month timeframe unrealistic? If the frame was engineered and built right the first time, the testing doesn't serve any purpose other than making the testers feel good. Why not mandate 4-year flight testing timelines?
Why is it invalid for Boeing to provide quantitative analysis that makes physical testing of the same conditions superfluous?


At present I would say that there is a huge question mark over the ability of Boeing to correctly analyse and test boundary conditions in flight systems. Until they can build trust again I would want each one rigourously tested - not signed off by some engineer under huge pressure from management to keep to time and budget.

As a corollary has Boeing shown an ability to engineer and build something right first time over the last frames they have developed?

MAX - No!
787 - No
747-8 - No
KC-46 - No

Not a good track record.

Airbus isn't much better but I would say that the A350 (the incarnation they finally built) is about the best in most current engineering timeframes.
 
TFawkes
Posts: 66
Joined: Wed Feb 19, 2020 2:51 pm

Re: So how New is the 777X?

Tue Feb 25, 2020 2:05 pm

StTim wrote:
TFawkes wrote:
StTim wrote:

I followed the A350 testing closely. Yesthey had to incorporate changes but they did keep pretty close to the initial time schedule.

To think that the 777X won't have to incorporate changes during testing is clutching at straws. The MAX kept to their schedule but had to incorporate changes to MCAS. I think it is fair to say these were rushed. I do not want the same to happen on the 777X on the altar of an unrealistic timeframe.

What makes a 10-month timeframe unrealistic? If the frame was engineered and built right the first time, the testing doesn't serve any purpose other than making the testers feel good. Why not mandate 4-year flight testing timelines?
Why is it invalid for Boeing to provide quantitative analysis that makes physical testing of the same conditions superfluous?


At present I would say that there is a huge question mark over the ability of Boeing to correctly analyse and test boundary conditions in flight systems. Until they can build trust again I would want each one rigourously tested - not signed off by some engineer under huge pressure from management to keep to time and budget.

As a corollary has Boeing shown an ability to engineer and build something right first time over the last frames they have developed?

MAX - No!
787 - No
747-8 - No
KC-46 - No

Not a good track record.

Airbus isn't much better but I would say that the A350 (the incarnation they finally built) is about the best in most current engineering timeframes.

Your trust and feelings on the matter are immaterial. Can you look at the math and prove it's faulty? Can you look at the materials and manufacturing processes behind the base parameters of the math and prove they don't meet spec? If not, you don't get a seat at the table to say they can't do their jobs well.

That's the big difference between academia and commercial operations in the public view. Your opinion has no validity in academia if you can't prove its soundness. There are long-established techniques of proof used for this, techniques Boeing engineers and mathematicians know like the back of their hand.

Trust is a meaningless construct in the substance of engineering. You either did it right or didn't, and if you did it right, the testing is pointless. And the testing will always be incomplete regardless because of unknown unknowns.

Uh, the A350 has had plenty of In-Flight engine shutdowns because of bad construction on the cockpit interfaces to not resist liquid spills.

The A350 had various structural problems discovered during ground and flight testing. If anything, the A330 was their last relatively seamless clean sheet.
 
dtw2hyd
Posts: 7880
Joined: Wed Jan 09, 2013 12:11 pm

Re: So how New is the 777X?

Tue Feb 25, 2020 2:09 pm

Would a derated GE90-115B relatively have the same efficiency as a GE9X? Knowing the track record of new engines, development costs, never-ending issues, what is the advantage with GE9X? Why not go with a proven power source.
 
TFawkes
Posts: 66
Joined: Wed Feb 19, 2020 2:51 pm

Re: So how New is the 777X?

Tue Feb 25, 2020 2:13 pm

dtw2hyd wrote:
Would a derated GE90-115B have relatively same efficiency of a GE9X? Knowing the track record of new engines, development costs, never ending issues, what is the advantage of GE9X? Why not go with a proven power source.

No. The GE9X is already 11% more fuel efficient, so to de-rate the GE90-115B would only widen that gap. You want your engine operating as close to redline conditions as possible for best efficiency under the Sterling Cycle.

Using tailor-made engines for the workload is always best for fuel efficiency, but the business case isn't always trivial to close. In other words, why not put a derated GE90-115B on the 737 MAX?

The GE9X is a GEnx derivative with Ceramic Matrix Composites integrated into the hot sections and in rotating turbine parts. Its development isn't nearly as expensive as accounting standards make it appear.

Eventually when GE begins work on a geared fan variant, that will raise some expensive questions for the engineers for sure.
 
StTim
Posts: 3610
Joined: Thu Aug 08, 2013 7:39 am

Re: So how New is the 777X?

Tue Feb 25, 2020 2:17 pm

TFawkes wrote:
StTim wrote:
TFawkes wrote:
What makes a 10-month timeframe unrealistic? If the frame was engineered and built right the first time, the testing doesn't serve any purpose other than making the testers feel good. Why not mandate 4-year flight testing timelines?
Why is it invalid for Boeing to provide quantitative analysis that makes physical testing of the same conditions superfluous?


At present I would say that there is a huge question mark over the ability of Boeing to correctly analyse and test boundary conditions in flight systems. Until they can build trust again I would want each one rigourously tested - not signed off by some engineer under huge pressure from management to keep to time and budget.

As a corollary has Boeing shown an ability to engineer and build something right first time over the last frames they have developed?

MAX - No!
787 - No
747-8 - No
KC-46 - No

Not a good track record.

Airbus isn't much better but I would say that the A350 (the incarnation they finally built) is about the best in most current engineering timeframes.

Your trust and feelings on the matter are immaterial. Can you look at the math and prove it's faulty? Can you look at the materials and manufacturing processes behind the base parameters of the math and prove they don't meet spec? If not, you don't get a seat at the table to say they can't do their jobs well.

That's the big difference between academia and commercial operations in the public view. Your opinion has no validity in academia if you can't prove its soundness. There are long-established techniques of proof used for this, techniques Boeing engineers and mathematicians know like the back of their hand.

Trust is a meaningless construct in the substance of engineering. You either did it right or didn't, and if you did it right, the testing is pointless. And the testing will always be incomplete regardless because of unknown unknowns.

Uh, the A350 has had plenty of In-Flight engine shutdowns because of bad construction on the cockpit interfaces to not resist liquid spills.

The A350 had various structural problems discovered during ground and flight testing. If anything, the A330 was their last relatively seamless clean sheet.



To do the maths you have to understand the input conditions. Boeing did not get this right on the MAX. Why should we trust them to do so again?

The whole point of testing is to catch snafu's not railroad them through.

So if I accept the A330 as the last relatively seamless frame then perhaps it is more the current engineers than the companies.
 
TFawkes
Posts: 66
Joined: Wed Feb 19, 2020 2:51 pm

Re: So how New is the 777X?

Tue Feb 25, 2020 2:39 pm

StTim wrote:
TFawkes wrote:
StTim wrote:

At present I would say that there is a huge question mark over the ability of Boeing to correctly analyse and test boundary conditions in flight systems. Until they can build trust again I would want each one rigourously tested - not signed off by some engineer under huge pressure from management to keep to time and budget.

As a corollary has Boeing shown an ability to engineer and build something right first time over the last frames they have developed?

MAX - No!
787 - No
747-8 - No
KC-46 - No

Not a good track record.

Airbus isn't much better but I would say that the A350 (the incarnation they finally built) is about the best in most current engineering timeframes.

Your trust and feelings on the matter are immaterial. Can you look at the math and prove it's faulty? Can you look at the materials and manufacturing processes behind the base parameters of the math and prove they don't meet spec? If not, you don't get a seat at the table to say they can't do their jobs well.

That's the big difference between academia and commercial operations in the public view. Your opinion has no validity in academia if you can't prove its soundness. There are long-established techniques of proof used for this, techniques Boeing engineers and mathematicians know like the back of their hand.

Trust is a meaningless construct in the substance of engineering. You either did it right or didn't, and if you did it right, the testing is pointless. And the testing will always be incomplete regardless because of unknown unknowns.

Uh, the A350 has had plenty of In-Flight engine shutdowns because of bad construction on the cockpit interfaces to not resist liquid spills.

The A350 had various structural problems discovered during ground and flight testing. If anything, the A330 was their last relatively seamless clean sheet.


To do the maths you have to understand the input conditions. Boeing did not get this right on the MAX. Why should we trust them to do so again?

The whole point of testing is to catch snafu's not railroad them through.

So if I accept the A330 as the last relatively seamless frame then perhaps it is more the current engineers than the companies.

One team of Boeing got it wrong. But beyond that, your trust is immaterial and irrelevant. Can you prove the math is faulty, yes or no? If not, you have no valid input to give on the quality of their work wrt a certification campaign.

Testing is always incomplete. You only test for the cases and conditions you know to test for. Only for incredibly small systems can you test for absolutely everything. This is, in fact, why safety-critical hardware and software are mathematically verified. Testing is unreliable. A closed proof is not.

This is why the algorithms and data structures of the Rust standard library are undergoing a verification campaign with the ACM and WHO so it can be used in all sorts of safety-critical applications rather than require developers to constantly reinvent the wheel.

It's not about trust. It's about correctness. As much as that is against human nature, you can't be objective unless you admit the testing doesn't verify anything. The thing being tested was either right to begin with or it wasn't, and the correctness can be proven if you're diligent enough. With the computing power we have today, and conditional solvers made through Answer-Set Prolog and other niche languages, you'd be shocked at just what can and already has been automated away. No one tests the schedulers at the biggest trade ports in the world. The schedule producers are already mathematically proven to be both correct and optimal, so sudden drastic changes to schedules aren't questioned anymore. Eventually this will be applied to all kinds of manufacturing and engineering disciplines, whether the public likes it or not.
 
morrisond
Topic Author
Posts: 2469
Joined: Thu Jan 07, 2010 12:22 am

Re: So how New is the 777X?

Tue Feb 25, 2020 2:49 pm

So why did Boeing put the engines farther apart on the 777X? I believe this necessitated the bigger tail. Was this due to the wider wingspan? Or was it an Aero advantage or some other reason.

With the same MTOW all things being equal would they not have been smarter to put them in the same place so the tail was smaller (and could have been smaller than 777W) due to lower thrust and longer fuselage length?

Or was it because they are really planning for a much longer 85M -10 and they needed the wider gear/engines for stability and ground handling issues?

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