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tommy1808
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 7:27 pm

Polot wrote:
tommy1808 wrote:
StTim wrote:


There did seem to be a similar amount of test flying for the two programmes (neo and MAX) implying a similar level of change. What we are finding implies that there was more change on the MAX. What that should of meant for the test campaigns I will leave for others!


Wasn't it ~4000 hours/3 years for the neo vs less than 2000 hours/1.5 years for the max? The max reached 2000 hours about a month after being certified.

Best regards
Thomas

When certified the PW A320neo had 1,076 hrs with PWs https://www.airbus.com/newsroom/press-r ... ation.html

The CFMs apparently had ~360 hrs on top of that. https://www.mro-network.com/manufacturi ... tification

That 4,000 figure includes the A321neo and both engine options (in total the A320neo family should have more flight testing hours, since it has 2 engine choices rather than 1 which requires some duplicate flying for each engine type).



Ah.. thanks.

Best regards
Thomas
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estorilm
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 8:03 pm

Elshad wrote:
brons2 wrote:
What about the A320Neo? Certified as a derivative?

Granted, less change was required on A32x to add a larger engine, which goes back to the question of, has Boeing taken the 737 as far as it can go? A clean sheet design probably wouldn't have needed supplementary control systems to push the nose down under certain flight conditions.

Doesn’t the fact that the A320 / A320neo is already fly by wire make it easier to adapt?

There are some major differences here.. for starters, the perceived impact of the NEO changes on the aircraft can be very minimal, as engineers were able to put the engines (all axis) exactly where they needed to, to maintain optimal stability and handling.

Any other handling changes can be tweaked in FBW, even the reaction times and rates can probably be adjusted.

Finally, the aircraft already has highly advanced protection systems that would (without changing a single thing) already prevent the MAX-type behavior for which MCAS was created - although if there was a specific pitch-up type of behavior on the airframe, they'd obviously change the software with that in mind.

Very different set of circumstances.
 
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Revelation
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 8:10 pm

estorilm wrote:
Elshad wrote:
brons2 wrote:
What about the A320Neo? Certified as a derivative?

Granted, less change was required on A32x to add a larger engine, which goes back to the question of, has Boeing taken the 737 as far as it can go? A clean sheet design probably wouldn't have needed supplementary control systems to push the nose down under certain flight conditions.

Doesn’t the fact that the A320 / A320neo is already fly by wire make it easier to adapt?

There are some major differences here.. for starters, the perceived impact of the NEO changes on the aircraft can be very minimal, as engineers were able to put the engines (all axis) exactly where they needed to, to maintain optimal stability and handling.

Any other handling changes can be tweaked in FBW, even the reaction times and rates can probably be adjusted.

Finally, the aircraft already has highly advanced protection systems that would (without changing a single thing) already prevent the MAX-type behavior for which MCAS was created - although if there was a specific pitch-up type of behavior on the airframe, they'd obviously change the software with that in mind.

Very different set of circumstances.

Relevant to this thread, your A320neo arguments (FBW since day one, ability to place the engine where needed for optimal stability and handling) support the argument that 777x is a 777 derivative just like A320neo is a A320 derivative.
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CFRPwingALbody
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 8:35 pm

To be fair Boeing could use the 777 track record to speed the 777x certification when there is commonality. But for new elements they have to go trough the certification proces. I don't have insight into how similar the 777 vs 777x are. We do know that the 777x has different fuselage lengths, different wings, different engines and folding wing tip devices.
The folding wing tip devices are totally new for commercial aviation. I prefer very stringent certification criteria for this.
I don't have insight in how dangerous a unlocking of one of the wing tips is. I would like it to be proven that flight control can be maintained when a wing tip gets unlocked. If this can't be proven the probability of unlocking should be way below 1:1mln and that should also be proven. If boeing can't prove this AFAIK the 777X shouldn't receive flight certification. For ETOPS the 777X need to be able to fly with unlocked wingtip(s). That's one hack of a certification challenge, the best of luck to Boeing for accomplishing this.

For the A320NEO there were actually 8 versions to be certified: A320, A321, A319, A321ACF/LR with both engine options. This compares to four 737 types. The 777X has two types, as does the A330NEO. The A330NEO has new engines and new wings, thus that's a lot less changes than the 777X. The flight test program for the A330NEO involved >1400 hours for the A330-900 and 350hours for the A330-800 (still in progress). So less than 2000 flight test hours for the 777X would be very odd.
Airbus states that clean-sheet certification requires 2600 flight test hours.
So AFAIK there is very little advantage to be gained by grandfathering. Beter test properly than test to little and deliver a unsafe product. ... :ashamed: :fever:
 
WIederling
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 8:38 pm

DL717 wrote:
Like the A340-600?

.. That has afaik its very own certification.
Murphy is an optimist
 
Waterbomber2
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 8:40 pm

Revelation wrote:
estorilm wrote:
Elshad wrote:
Doesn’t the fact that the A320 / A320neo is already fly by wire make it easier to adapt?

There are some major differences here.. for starters, the perceived impact of the NEO changes on the aircraft can be very minimal, as engineers were able to put the engines (all axis) exactly where they needed to, to maintain optimal stability and handling.

Any other handling changes can be tweaked in FBW, even the reaction times and rates can probably be adjusted.

Finally, the aircraft already has highly advanced protection systems that would (without changing a single thing) already prevent the MAX-type behavior for which MCAS was created - although if there was a specific pitch-up type of behavior on the airframe, they'd obviously change the software with that in mind.

Very different set of circumstances.

Relevant to this thread, your A320neo arguments (FBW since day one, ability to place the engine where needed for optimal stability and handling) support the argument that 777x is a 777 derivative just like A320neo is a A320 derivative.


I don't agree.
I think that we should draw the line at a completely different wing.
A wing that was aluminium is replaced by a CFRP wing, so essentially different chassis or "airframe" as we call it.
Different airframe = complete new certification.

The fuselage would also need to go undergo its own cycles testing as it's not the same length, not the same door configurations, etc...

It's one thing to slap new engines on an airframe and certify the differences.
But between a B77W and B77X, all major components are different: the fuselage, wings, engines, cockpit, so essentially it's a different airframe so needs to be certified from scratch IMO.

I'm not sure there is anything left to grandfather.
Some subsystems such as airconditioning and landing gears could be considered, but then again, it must be considered if they are not affected by the other changes through a proper analysis.
 
CFRPwingALbody
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 8:48 pm

Another fact: it took Boeing 900 flight test hours to certify the 787-10. AFAIK that's for two engine types with several thrust ratings.
 
smartplane
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 8:58 pm

The rules are set, and then the OEM's operate tactically within them.

With the 8 and 9 adopting weights and engine thrusts below the heaviest / most powerful currently certified 777 iterations, which are ultimately certified back to the 772, in theory, Boeing should have had a simple certification process.

A theoretical 777-10 which would likely exceed current 777 certification weights will wait, so can be certified using the by then certified 779.

MAX issues have undoubtedly changed that, to the point it's not impossible MAX reviews could even 'ripple' back to the NG.

With the MAX, FAA and other authorities are going to want to make a point, and probably, with political encouragement, take a hard line to deficiencies.

The 777X must get caught in friendly and not so friendly fire, so the easy ride and rubber stamping Boeing expected, won't be the case.

FAA and EASA officials have already been meeting in neutral locations on the QT since January 2019, with phased removal / deletion of grandfathering top of the agenda.
 
nikeherc
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 9:04 pm

In case nobody noticed, there is a 779 static test airframe. It will undergo fatigue testing, both the fuse and the wings. Additionally, the wing will be subjected to the same maximum deflection test that the 787 was given. Thus the changes to the wings and fuselage will be thoroughly tested. The flight tests will examine all aspects of the flight window. This plane will be thoroughly tested before entry into service and this was already planned prior to the recent accidents.
DC6 to 777 and most things in between
 
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Polot
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 9:11 pm

WIederling wrote:
DL717 wrote:
Like the A340-600?

.. That has afaik its very own certification.

Nope, part of the same certificate as the A342/A343. It only took a little over a year to certify the -600.
Last edited by Polot on Mon Mar 18, 2019 9:14 pm, edited 1 time in total.
 
CFRPwingALbody
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 9:11 pm

smartplane wrote:
The rules are set, and then the OEM's operate tactically within them.

FAA and EASA officials have already been meeting in neutral locations on the QT since January 2019, with phased removal / deletion of grandfathering top of the agenda.


I'm relieved to read this.
Let the FAA & EASA also have a good look at the A320NEO and A330NEO to rule out Airbus overlooked implications of design changes.
Engine certification also is given far to easy, that's what the A320NEO PW GTF & 787 RR Trent 1000 have shown. (and A380 RR T900 & EA7000).
 
CFRPwingALbody
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 9:18 pm

Polot wrote:
WIederling wrote:
DL717 wrote:
Like the A340-600?

.. That has afaik its very own certification.

Nope, part of the same certificate as the A342/A343.

Wrong. The A340 is developed as two distinct plane families.
- The A342/A343 developed together with the A332/A333 (v1) (A330NEO is >v4), and
- the A345 / A346. Certification toke >1600 flight hours. [source]
And rightfully so because the -500&-600 used different wings, an additional center landing gear, different engines and different fuselage structures. That was very far from a simple stretch. Really a waist of development resources in hindsight. ETOPS restrictions were reduced a lot.
Last edited by CFRPwingALbody on Mon Mar 18, 2019 9:26 pm, edited 1 time in total.
 
OldAeroGuy
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 9:20 pm

nikeherc wrote:
In case nobody noticed, there is a 779 static test airframe. It will undergo fatigue testing, both the fuse and the wings. Additionally, the wing will be subjected to the same maximum deflection test that the 787 was given. Thus the changes to the wings and fuselage will be thoroughly tested. The flight tests will examine all aspects of the flight window. This plane will be thoroughly tested before entry into service and this was already planned prior to the recent accidents.


Exactly.

Too many people on A.net are getting the certification basis (the rules for certification compliance) confused with the testing and analysis required to demonstrate certification compliance.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
CFRPwingALbody
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 9:28 pm

OldAeroGuy wrote:
Too many people on A.net are getting the certification basis (the rules for certification compliance) confused with the testing and analysis required to demonstrate certification compliance.

Please educate me!
Do you mean that the same rules for certification compliance are set for the legacy and the derivative, for example the 777 & 777X. But that in any case compliance with the certification rules set has to be proven with tests?
Last edited by CFRPwingALbody on Mon Mar 18, 2019 9:32 pm, edited 1 time in total.
 
smartplane
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 9:29 pm

nikeherc wrote:
In case nobody noticed, there is a 779 static test airframe. It will undergo fatigue testing, both the fuse and the wings. Additionally, the wing will be subjected to the same maximum deflection test that the 787 was given. Thus the changes to the wings and fuselage will be thoroughly tested. The flight tests will examine all aspects of the flight window. This plane will be thoroughly tested before entry into service and this was already planned prior to the recent accidents.

It's not that some testing is performed.

The issue / concern, is the testing that isn't performed, or the degree of actual testing, because grandfathering rules are invoked.

If you can start with the 772, and invoke pre-existing 747 and 707 certification for partial grandfathering, then take 772 certification and use grandfathering to take weights from 545K to 766K, are there risks?

Proponents will argue look how safe the 777 has been. Grandfathering works. The cynic in me says, with every layer of grandfathering does the 'luck' factor increase? When is it time to start with a clean sheet? Would the 777X be a safer and better aircraft if it was a clean sheet?
 
CFRPwingALbody
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 9:45 pm

I think we are getting to an interesting point. How much different is a derivative from a clean sheet!?
I would say that the 777X is actually a clean sheet design. because even the fuselage changed from AL to Al-Li. How much of a derivative is the 777X from the 777 and how much in new?
AFAIK the A342/3 => A345/6 was less of a change than to the 777 => 777X.
AFAIK a stretch like the 787-10 from the 787-9 is a whole different ballgame that the former developments.
The same can be sad about the A320shark=>A320NEO compared to the 737NG=>737Max they aren't comparable.
I would say the A320NEO and A330NEO program's can't be compared either, because the scope is different (re-engine vs re-engine & re-wing).

The A321ACF/LR is follow-on development from the A321NEO. But should it have been flight certified as clean sheet.
To be honest I think most likely it should have been. That's another example of grandfathering possibly going to far.
Last edited by CFRPwingALbody on Mon Mar 18, 2019 9:50 pm, edited 1 time in total.
 
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Polot
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 9:46 pm

CFRPwingALbody wrote:
Polot wrote:
WIederling wrote:
.. That has afaik its very own certification.

Nope, part of the same certificate as the A342/A343.

Wrong. The A340 is developed as two distinct plane families.
- The A342/A343 developed together with the A332/A333 (v1) (A330NEO is >v4), and
- the A345 / A346. Certification toke >1600 flight hours. [source]
And rightfully so because the -500&-600 used different wings, an additional center landing gear, different engines and different fuselage structures. That was very far from a simple stretch. Really a waist of development resources in hindsight. ETOPS restrictions were reduced a lot.

Yes, as part of A340 certificate: https://www.easa.europa.eu/documents/ty ... -downloads

It was not certified as a brand new clean sheet aircraft. All grandfathered aircraft/derivatives need flight testing/certification. Whether that is the 737NG, A340NG, 77W/L, A320neo, 737 Max, A330neo, or the 777X.
 
nikeherc
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 9:50 pm

smartplane wrote:
nikeherc wrote:
In case nobody noticed, there is a 779 static test airframe. It will undergo fatigue testing, both the fuse and the wings. Additionally, the wing will be subjected to the same maximum deflection test that the 787 was given. Thus the changes to the wings and fuselage will be thoroughly tested. The flight tests will examine all aspects of the flight window. This plane will be thoroughly tested before entry into service and this was already planned prior to the recent accidents.

It's not that some testing is performed.

The issue / concern, is the testing that isn't performed, or the degree of actual testing, because grandfathering rules are invoked.

If you can start with the 772, and invoke pre-existing 747 and 707 certification for partial grandfathering, then take 772 certification and use grandfathering to take weights from 545K to 766K, are there risks?

Proponents will argue look how safe the 777 has been. Grandfathering works. The cynic in me says, with every layer of grandfathering does the 'luck' factor increase? When is it time to start with a clean sheet? Would the 777X be a safer and better aircraft if it was a clean sheet?



Do you know which grandfathering rules are being invoked? Do you know what is and isn’t being tested? Do you really think that the 772 relied on grandfathering from the 707 and 747?

If the fuselage and wings are being tested like a new design, the entire flight envelope is tested and all new systems and software are tested, what is being left out?
DC6 to 777 and most things in between
 
CFRPwingALbody
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 10:00 pm

nikeherc wrote:
If the fuselage and wings are being tested like a new design, the entire flight envelope is tested and all new systems and software are tested, what is being left out?


Possibly minute changes to the legacy systems to prevent obsolescence of components, that turn out to have a significant impact. The electronics from early 2000's aren't comparable and possibly compatible with today's electronics. Though aviation grade equipment evolves slower, it still evolves.
 
smartplane
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 10:06 pm

nikeherc wrote:
smartplane wrote:
It's not that some testing is performed.

The issue / concern, is the testing that isn't performed, or the degree of actual testing, because grandfathering rules are invoked.

If you can start with the 772, and invoke pre-existing 747 and 707 certification for partial grandfathering, then take 772 certification and use grandfathering to take weights from 545K to 766K, are there risks?

Proponents will argue look how safe the 777 has been. Grandfathering works. The cynic in me says, with every layer of grandfathering does the 'luck' factor increase? When is it time to start with a clean sheet? Would the 777X be a safer and better aircraft if it was a clean sheet?



Do you know which grandfathering rules are being invoked? Do you know what is and isn’t being tested? Do you really think that the 772 relied on grandfathering from the 707 and 747?

If the fuselage and wings are being tested like a new design, the entire flight envelope is tested and all new systems and software are tested, what is being left out?

So to clarify, you are confirming Boeing hasn't requested / isn't negotiating any grandfathering for the 779 vis a vis earlier 777 models and 787? Boeing and the FAA are treating the 779 as a 'clean sheet'.
 
frmrCapCadet
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 10:20 pm

I don't know how 'grandfathering' could be entirely limited. There will always be new and better ways of building planes, and not all of those new things will be able to be incorporated into new models of older planes. I can see limitations. Likely the 737 would be in direct aim. But would anyone be sure the 320 would not have also run afoul of this? It is not exactly a spring chicken.
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OldAeroGuy
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 10:21 pm

CFRPwingALbody wrote:
OldAeroGuy wrote:
Too many people on A.net are getting the certification basis (the rules for certification compliance) confused with the testing and analysis required to demonstrate certification compliance.

Please educate me!
Do you mean that the same rules for certification compliance are set for the legacy and the derivative, for example the 777 & 777X. But that in any case compliance with the certification rules set has to be proven with tests?


Depends if there has been a change and/or the nature of the change. That's why AC 21.101 is titled "Establishing the Certification Basis of Changed Aeronautical Products"

For instance, if the nose gear hasn't been changed, then a change to the wing won't necessarily drive compliance rules or require testing of the nose gear.

A material substitution in an unaltered section of the fuselage may/may not require testing if there has been a well established method of showing compliance for new materials.

The wing change from aluminum to GRP may not mean a change to wing structural strength compliance rules but testing will be required. The same change to GRP may mean a change in lightning strike rules and compliance.

The whole certification basis discussion is more complicated than a simple chart. It's important to understand that saying the certification basis is unchanged doesn't mean that it hasn't been updated in significant and substantial areas and that testing is waved
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
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ikolkyo
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 10:22 pm

It's hilarious that because the MAX is having issues that any other airplane certified under similar circumstances is automatically suspect. Plus I urge some of you to actually learn what grandfathering actually is because some of you are just spewing crap.
 
nikeherc
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 10:53 pm

smartplane wrote:
nikeherc wrote:
smartplane wrote:
It's not that some testing is performed.

The issue / concern, is the testing that isn't performed, or the degree of actual testing, because grandfathering rules are invoked.

If you can start with the 772, and invoke pre-existing 747 and 707 certification for partial grandfathering, then take 772 certification and use grandfathering to take weights from 545K to 766K, are there risks?

Proponents will argue look how safe the 777 has been. Grandfathering works. The cynic in me says, with every layer of grandfathering does the 'luck' factor increase? When is it time to start with a clean sheet? Would the 777X be a safer and better aircraft if it was a clean sheet?



Do you know which grandfathering rules are being invoked? Do you know what is and isn’t being tested? Do you really think that the 772 relied on grandfathering from the 707 and 747?

If the fuselage and wings are being tested like a new design, the entire flight envelope is tested and all new systems and software are tested, what is being left out?

So to clarify, you are confirming Boeing hasn't requested / isn't negotiating any grandfathering for the 779 vis a vis earlier 777 models and 787? Boeing and the FAA are treating the 779 as a 'clean sheet'.


No I am saying anything new or different will be thoroughly tested. Anything that hasn’t changed will be tested in so far as it could be affected by anything new or different. The fuselage is new, the wing is new, the engine is new, the cockpit is new, they will all be thoroughly tested. Perhaps the lavs and galleys won’t be recertified, but only if they are not new.
DC6 to 777 and most things in between
 
OldAeroGuy
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Mon Mar 18, 2019 11:30 pm

smartplane wrote:
The issue / concern, is the testing that isn't performed, or the degree of actual testing, because grandfathering rules are invoked.

If you can start with the 772, and invoke pre-existing 747 and 707 certification for partial grandfathering, then take 772 certification and use grandfathering to take weights from 545K to 766K, are there risks?


Can you name anything from the 707 or 747 that is "grandfathered" onto the 777?

The only possibility I see is the magnetic compass and I doubt that's true.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
Weatherwatcher1
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 12:25 am

Can someone please explain what grandfathering is?

Looking through AC 21.101, I don’t see that term. Is grandfathering an invented slang term for amended type certificate or supplemental type certificate?

I always thought commonality was a good thing and that while major/minor determinations can be challenging the certification basis for changes is a very robust process.

keesje wrote:
Aircraft manufacturers prefer grandfathering of existing STC's (also e.g. A346)


How do you grandfather an STC? What does that even mean? Is a grandfathered STC the same as an amended STC?
 
planecane
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 12:30 am

Waterbomber2 wrote:
par13del wrote:
keesje wrote:
I think many feel safety assurance & independence for certifying bodies go hand in hand. There's 300 body bags and we must be open to safety process enhancements.

Yeah, so if they are not government employee's who is going to go through the financials of the private company, their shareholders, political affiliations, social leanings etc etc etc.
Simple solution, either use what you have now or have them become government employees.


If financial limitations of the FAA are what is forcing them to delegate to Boeing, there is an easy solution and that is to do what every government agency does for any type of certification.
Boeing have to pay their certifying engineers anyway, so why not have the FAA do this in-house and charge Boeing for every resource used in the certification process? Why shouldnthe taxpayer foot the billnfor what an individual company wants to get done?

If you take an exam at the DMV, you have to pay the examination fee, why should it be any different for certifying aircraft?

Same thing if you want to apply for a patent, etc...


I think though that the real reason of delegating is different. There are simply just so many things involved that to get an airplane flying, you need to cut a lot of corners and the government don't want to be caught cutting corners.
This was my experience in aircraft maintenance. We received audits but the purpose was not safety, it was merely to give the impression of oversight so thay id something happens, the government can say that they did their part.
They never checked us while performing maintenance and mostly did only paperwork checks.
If I would be an inspector tasked to do a real audit, I would probably lay out enough findings within the first hour, to close down every MRO in the world.


I have experience in the cell phone industry and FCC testing works the same way. The manufacturer does the tests and submits reports. Before you jump to the lives at risk in aviation argument, part of the cell phone FCC certification is the radiation levels absorbed by the brain.
 
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Revelation
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 12:35 am

OldAeroGuy wrote:
Can you name anything from the 707 or 747 that is "grandfathered" onto the 777?

The only possibility I see is the magnetic compass and I doubt that's true.

Will EASA have a second look & check for short cuts / efficiency's in the certification process should A321XLR have the Caravelle's magnetic compass?

Apart from safety considerations, are there economical drivers that conflict?
Last edited by Revelation on Tue Mar 19, 2019 12:43 am, edited 2 times in total.
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own
 
BoeingGuy
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 12:35 am

CFRPwingALbody wrote:
OldAeroGuy wrote:
Too many people on A.net are getting the certification basis (the rules for certification compliance) confused with the testing and analysis required to demonstrate certification compliance.

Please educate me!
Do you mean that the same rules for certification compliance are set for the legacy and the derivative, for example the 777 & 777X. But that in any case compliance with the certification rules set has to be proven with tests?


I’ve explained how it works in one of the threads. The 777X has to step up to new certication basis for a lot of regulations.
 
GalaxyFlyer
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 12:38 am

People posting all kinds of gibberish without any knowledge of the subject. An amended (NOT “grandfathered”) certificate is different from an STC. An amendment to the original TC is based on the original TC, not some plane you built 50 years ago. Each component in the amendment will be related to the specific section in Part 25, the current amendment that goes with that section will likely be used as the basis of the certification.

There’s lots more to this process than the media is portraying.

GF
 
EChid
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 1:26 am

texl1649 wrote:
In any case, Asseline (the pilot, a Frenchman of course), certainly felt there was blame/fault/fraud in the systems/investigation (and it's interesting the French authorities are also involved in the ET crash, given that France is something like 3 percent of the worlds' GDP).

The reason for this was widely publicized. Ethiopia originally asked Germany to perform the analysis (many countries had offered assistance), apparently wanting to select based on perceived neutrality and proximity. Germany said they did not have sufficient technology to read the recorders, but the US, Canada, UK, France, and Australia did. France was the next closest country, and BEA is well-respected. This is not an international conspiracy against Boeing/the FAA.
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Waterbomber2
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 7:03 am

CFRPwingALbody wrote:
smartplane wrote:
The rules are set, and then the OEM's operate tactically within them.

FAA and EASA officials have already been meeting in neutral locations on the QT since January 2019, with phased removal / deletion of grandfathering top of the agenda.


I'm relieved to read this.
Let the FAA & EASA also have a good look at the A320NEO and A330NEO to rule out Airbus overlooked implications of design changes.
Engine certification also is given far to easy, that's what the A320NEO PW GTF & 787 RR Trent 1000 have shown. (and A380 RR T900 & EA7000).


I must agree with this. How the PW GTF for the neo ever got certified, let alone with ETOPS is beyond me.

Engines should undergo similar testing regimes as airframes, simulating cycles and hours over at least a half life, before being certified.
In a world where twins have become the norm, engine reliability is not a performance indicator but a true safety concern.

OEM's and regulators should not rely on stellar safety records as basis to become complacent.

I also think that it's inadequate for regulators to accept certifying airframes on the basis of multiple airframes achieving milestones, while the fleet leader test frame may not even reach 500 flight hours before a type certificate is delivered.
An option would be to deliver "frozen" type certificates that are unfrozen if the type can prove 5000 flight hours without a siginificant accident or reliability issue while in operation, on a single airframe.
 
rbavfan
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 7:55 am

texl1649 wrote:
I suppose the real issue is what could impact safety in a derivative. Derivatives would tend to benefit from the experience/safety of their predecessor models, most of the time, hence the underlying rationale of grandfathering. All of the majors/minors/carriers have benefited from the cost and safety benefit savings of derivative model engineering.

The real risk happens when there is an all new model, which is why there have been so few over the past 30 years. A320, A330, 787, 777, and a couple of failed quads. (Unless you want to argue for Embraer/BBD).

As AF296 crash at Habsheim showed, along with the MAX crashes the past few months, new flight control software can create real risks when it disempowers pilots (with respect to elevator control in all 3 instances). Was the A320 somehow safer though because it wasn't back then a derivative? No.

I think this question/thread is really a very thinly veiled attempt to pile on Boeing as there have been a couple recent tragedies. I also think the 737, despite being a 50 year old design, has had an exemplary safety (and reliability) record, and isn't fatally flawed due to some mistakes made in the newest software. If it had been crashing/much less safe than newer competitors over a period of years an argument might be made otherwise.


The A330 was NOT a new model. It was a stretched, re-winged, re-engined A300.
 
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 8:09 am

keesje wrote:
OldAeroGuy wrote:
GEUltraFan9XGTF wrote:

Just some light bedtime reading there.


If you don't understand what this document says, you don't understand "grandfathering" and its limitations.


The big question remains if following the rules (Chapter 3), the 777X ended up being allowed to be certified under the 77W certification basis, what happened ?
- Changes are minor (if so for the 777X, anything is apparently minor) ?
- Some one at the FAA wasn't paying attention ?
- Some one at the FAA was actually someone at Boeing & had different goals ?
- The Latest Requirements Contribute nothing Materially to the Level of Safety?

Using this 1996 flowchart roughly modelling the process; how did the 777X end up in the right lower corner instead of the left lower corner ?

Image

I thing is the wings, tail, engines, dimensions & cockpit changed we should have a new TC.
Otherwise the 757 was a 737 really?


No otherwise the 727/737/757 were 707's. They all have the same fuselage/door design dating back to 1957.
 
rbavfan
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 8:18 am

brons2 wrote:
Polot wrote:
it’s a lack of proper oversight issue.


Agreed, and sad to see it hasn't changed that much in 45 years, remember the DC-10 cargo door?


And interesting how much MDC management is now running Boeing.
 
1989worstyear
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 8:27 am

estorilm wrote:
Elshad wrote:
brons2 wrote:
What about the A320Neo? Certified as a derivative?

Granted, less change was required on A32x to add a larger engine, which goes back to the question of, has Boeing taken the 737 as far as it can go? A clean sheet design probably wouldn't have needed supplementary control systems to push the nose down under certain flight conditions.

Doesn’t the fact that the A320 / A320neo is already fly by wire make it easier to adapt?

There are some major differences here.. for starters, the perceived impact of the NEO changes on the aircraft can be very minimal, as engineers were able to put the engines (all axis) exactly where they needed to, to maintain optimal stability and handling.

Any other handling changes can be tweaked in FBW, even the reaction times and rates can probably be adjusted.

Finally, the aircraft already has highly advanced protection systems that would (without changing a single thing) already prevent the MAX-type behavior for which MCAS was created - although if there was a specific pitch-up type of behavior on the airframe, they'd obviously change the software with that in mind.

Very different set of circumstances.


How is something from 31 years ago "highly advanced"? :?

You make it sound like we're in 1988 and Airbus does not have decades of experience with the envelope protections.
Stuck at age 15 thanks to the certification date of the A320-200 and my parents' decision to postpone having a kid by 3 years. At least there's Dignitas...
 
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 8:32 am

waly777 wrote:
oldannyboy wrote:
I think people need to grow out of this FAA-only bubble kind of mentality.
Thank god there are other certifying bodies who are not only better funded and more technically apt, but to a large degree far more independent than the FAA. Cue the UK CAA and EASA.
I trust that these bodies will both give Boeing and the FAA a run for their money in the 777/8-9 certification, and should they sniff any of the crap that has lead to having to deal with these 300 body bags they will kick up a royal stink.


And yet the 787 and 737 max were both certified by the UK CAA and EASA? so what does that say about their supposedly better funding and technical abilities?


Oh yes agree on this. They should stop piggy-backing on the stupid FAA.
Back in the day the CAA actually did a very good, largely independent job. They actually managed to make manufacturers change their designs. Coming to think of it, back in the day the expression 'piggy backing' probably didn't even exist...
 
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CARST
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 8:35 am

keesje wrote:
Otherwise the 757 was a 737 really?


How should we know that now, like 35 years later...

But I would guess the 757 could have been certified as some form of 737NEO. But Boeing decided to develop this "long-range 737" as a dual-project with the 767 and give airlines the option to fly both planes side-by-side with a single cockpit layout. And I think you don't want to tell me that they could have certified the 767 as a 737 derivative, too...
 
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 8:37 am

smartplane wrote:
nikeherc wrote:
smartplane wrote:
It's not that some testing is performed.

The issue / concern, is the testing that isn't performed, or the degree of actual testing, because grandfathering rules are invoked.

If you can start with the 772, and invoke pre-existing 747 and 707 certification for partial grandfathering, then take 772 certification and use grandfathering to take weights from 545K to 766K, are there risks?

Proponents will argue look how safe the 777 has been. Grandfathering works. The cynic in me says, with every layer of grandfathering does the 'luck' factor increase? When is it time to start with a clean sheet? Would the 777X be a safer and better aircraft if it was a clean sheet?



Do you know which grandfathering rules are being invoked? Do you know what is and isn’t being tested? Do you really think that the 772 relied on grandfathering from the 707 and 747?

If the fuselage and wings are being tested like a new design, the entire flight envelope is tested and all new systems and software are tested, what is being left out?

So to clarify, you are confirming Boeing hasn't requested / isn't negotiating any grandfathering for the 779 vis a vis earlier 777 models and 787? Boeing and the FAA are treating the 779 as a 'clean sheet'.


They did. https://www.wsj.com/articles/boeing-777x-clears-hurdle-with-faa-1398916634

(I see a lot of diverision, dismissing, probably by members that had to reboot last week when their sources of truth where changing their minds and even corrected, top down. Lets stay on topic. )

I think using the the 77W as certification base for the for 777-9, and the using the 777-200 as certification base for the 77W means you are creating an new aircraft not using the latest certification standards. That saves times and money. That is why Boeing does it in the first place.

The discussion is if we should allow corporations to certify new aircraft (new wings, tails, cockpit, engines, systems, landing gear, dimensions, fuselage, materials) using old certification standard using older, different aircraft as reference.

Apparently authorities are changing their minds too and will work to curtail grandfathering certification data, requirements and using really far fetched certification bases. So we seem to be moving in the right direction on by-passing new certification standards.

smartplane wrote:
The rules are set, and then the OEM's operate tactically within them.

FAA and EASA officials have already been meeting in neutral locations on the QT since January 2019, with phased removal / deletion of grandfathering top of the agenda.


Over the years, the FAA / EASA have implemented new and tougher design requirements, but a derivative gets many of the designs grandfathered in. I think the 777X is an extreme example of a new aircraft benefiting from a barely acceptable grandfathering process. I think independent people should ask the FAA where they draw the line, and what factors in for them.
"Never mistake motion for action." Ernest Hemingway
 
Bricktop
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 9:49 am

Funny how the big picture attack on the B777X has shifted from “It’s a warmed over pile of old junk” to “it’s a brand new plane that needs recertification from the ground up”.

Never try to please your enemy, because your enemy is never pleased.
 
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 10:47 am

oldannyboy wrote:
They should stop piggy-backing on the stupid FAA.
Back in the day the CAA actually did a very good, largely independent job. They actually managed to make manufacturers change their designs. Coming to think of it, back in the day the expression 'piggy backing' probably didn't even exist...


EASA does not hang on funding but on treaty conditions.
There is this "mutual acceptance of certification" between EASA and FAA thingy around.
Though the FAA seems to quite often renege on "strange" grounds ( that make more sense in a competitive than in a safety environment.)
Murphy is an optimist
 
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 10:49 am

FrenchPotatoEye wrote:
Who cares as long as it's tested properly and certified with full safety.
It's a quality control process. As we can see, assessing yourself is open to process failure.
 
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 10:51 am

par13del wrote:
keesje wrote:
Taking a step back, maybe there are enough people with the right skills, but they do not report to the right, independent employer.

No, take a step back and accept that these are human beings who have lives and need jobs. If you want the government to have these employees on staff, then go right ahead and raise taxes on the people so that they can offer a competitive wage and benefit package.
The price per person would be minimal. It just put a levy on each air ticket. At a guess 5¢ per ticket would work.
 
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 11:01 am

Initially, grandfathering was extremely narrow from the perspective of airworthiness authorities, intended to prevent new requirements and regulations automatically applying retrospectively to aircraft and engines already in service. But OEM's successfully broadened the concept to new models which are 'closely' based on current and previous models.

And grandfathering is far more comprehensive than specific aircraft and engines. For instance regulations and exemptions are grandfathered too. Even scaling is grandfathered.

OEM's treat more like a legal precedent.

Previously, OEM's had teams working to justify grandfathering, and the FAA/CAA teams, equal in expertise or greater, to challenge.

Now OEM's largely self-regulate. If airworthiness authority staff become successfully obstructive, they are head hunted by an OEM.

Unless the FAA and EASA receive additional funding, recruit impartial industry experts, and create more in-house training, development and progression opportunities, after the talk fest, will much change?
Last edited by smartplane on Tue Mar 19, 2019 11:03 am, edited 1 time in total.
 
oldannyboy
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 11:01 am

WIederling wrote:
oldannyboy wrote:
They should stop piggy-backing on the stupid FAA.
Back in the day the CAA actually did a very good, largely independent job. They actually managed to make manufacturers change their designs. Coming to think of it, back in the day the expression 'piggy backing' probably didn't even exist...


EASA does not hang on funding but on treaty conditions.
There is this "mutual acceptance of certification" between EASA and FAA thingy around.
Though the FAA seems to quite often renege on "strange" grounds ( that make more sense in a competitive than in a safety environment.)


That's precisely one of the things that is pi**ing me off more... blindly piggy backing on the FAA.
 
sxf24
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 11:22 am

oldannyboy wrote:
WIederling wrote:
oldannyboy wrote:
They should stop piggy-backing on the stupid FAA.
Back in the day the CAA actually did a very good, largely independent job. They actually managed to make manufacturers change their designs. Coming to think of it, back in the day the expression 'piggy backing' probably didn't even exist...


EASA does not hang on funding but on treaty conditions.
There is this "mutual acceptance of certification" between EASA and FAA thingy around.
Though the FAA seems to quite often renege on "strange" grounds ( that make more sense in a competitive than in a safety environment.)


That's precisely one of the things that is pi**ing me off more... blindly piggy backing on the FAA.


And the FAA “blindly piggy backed” of EASA for certification of Airbus aircraft. I do suspect it will now change on both sides.
 
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 11:51 am

sxf24 wrote:
And the FAA “blindly piggy backed” of EASA for certification of Airbus aircraft. I do suspect it will now change on both sides.


This is not true. Even if EASA and FAA certify a new aircraft at the same time, often they are not the same end product.

Where I work we have the luxury of our local regulars acceptance of both EASA and FAA TCDS when importing aircraft. We have in the past imported aircraft from the US on an EASA certification basis as that provided a competitive advantage.

This does not only apply to large aircraft, something like a Cessna Caravan under EASA will be certified for an extra passenger over the FAA one.

EASA and the FAA do not blindly rubber stamp each other’s work. Take for example the 737NG, the FAA certified that without STS, however EASA would not certify the 737NG without it.

I fully expect the special conditions placed on the 77X to be slightly different between EASA and the FAA. Boeing will build the aircraft to meet both TCDS requirements.
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 12:03 pm

smartplane wrote:
Initially, grandfathering was extremely narrow from the perspective of airworthiness authorities, intended to prevent new requirements and regulations automatically applying retrospectively to aircraft and engines already in service. But OEM's successfully broadened the concept to new models which are 'closely' based on current and previous models.

And grandfathering is far more comprehensive than specific aircraft and engines. For instance regulations and exemptions are grandfathered too. Even scaling is grandfathered.

OEM's treat more like a legal precedent.

Previously, OEM's had teams working to justify grandfathering, and the FAA/CAA teams, equal in expertise or greater, to challenge.

Now OEM's largely self-regulate. If airworthiness authority staff become successfully obstructive, they are head hunted by an OEM.

Unless the FAA and EASA receive additional funding, recruit impartial industry experts, and create more in-house training, development and progression opportunities, after the talk fest, will much change?


I guess as a society we should rewind a bit here. Make sure airworthiness regulators are well paid, trained prestige jobs for experienced, senior engineering people, that have full political back up & credibility to be very independent, inflexible and sustained uncooperative and raise the red flag on anyone when they need to. I'm no commie, but some responsibilities are better not left open for commercial aviation. You need a strong government on safety.

If airworthiness authority staff become successfully obstructive, they are head hunted by an OEM.

look mammy I'm a VP now :sorry:
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 12:08 pm

keesje wrote:
smartplane wrote:
Initially, grandfathering was extremely narrow from the perspective of airworthiness authorities, intended to prevent new requirements and regulations automatically applying retrospectively to aircraft and engines already in service. But OEM's successfully broadened the concept to new models which are 'closely' based on current and previous models.

And grandfathering is far more comprehensive than specific aircraft and engines. For instance regulations and exemptions are grandfathered too. Even scaling is grandfathered.

OEM's treat more like a legal precedent.

Previously, OEM's had teams working to justify grandfathering, and the FAA/CAA teams, equal in expertise or greater, to challenge.

Now OEM's largely self-regulate. If airworthiness authority staff become successfully obstructive, they are head hunted by an OEM.

Unless the FAA and EASA receive additional funding, recruit impartial industry experts, and create more in-house training, development and progression opportunities, after the talk fest, will much change?


I guess as a society we should rewind a bit here. Make sure airworthiness regulators are well paid, trained prestige jobs for experienced, senior engineering people, that have full political back up & credibility to be very independent, inflexible and sustained uncooperative and raise the red flag on anyone when they need to. I'm no commie, but some responsibilities are better not left open for commercial aviation. You need a strong government on safety.

If airworthiness authority staff become successfully obstructive, they are head hunted by an OEM.

look mammy I'm a VP now :sorry:

And your senior experienced engineering people are going to be completely lost looking at code/software. As would probably most senior software engineers out there (trying to decipher other people’s coding and how it all works is very hard!).
 
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Re: Boeing 777-8/-9 Grandfathering Certification, 777X or 7X7?

Tue Mar 19, 2019 12:46 pm

keesje wrote:
I think using the the 77W as certification base for the for 777-9, and the using the 777-200 as certification base for the 77W means you are creating an new aircraft not using the latest certification standards.

Yet we have:

BoeingGuy wrote:
Yep, and the 777X has to comply with a lot of new requirements and more current certication amendments than did the 777-300ER. A couple of examples are having to step up to amendment 131 of CFR 25.1322 and comply with the totally new CFR 25.1302.

So we do have a new aircraft using the latest certification standards.

BoeingGuy wrote:
I’ve explained how it works in one of the threads. The 777X has to step up to new certication basis for a lot of regulations.

:checkmark:

keesje wrote:
I think the 777X is an extreme example of a new aircraft benefiting from a barely acceptable grandfathering process.

Yet you've posted so many photoshopped A322 proposals our heads spin, and those concepts if ever enacted would all be examples of "new aircraft benefiting from a barely acceptable grandfathering process" just as A340-500/600 benefited from having a basis of certification in A340-200/300, and discussing these cases are avoided because of, what, recency bias???

There's a stench of a vulgar "kick them when they're down" mentality at play here, IMHO.

WIederling wrote:
Eye is on 777(X) because that is the next big thing coming up and the process is unknown/open.

Or we seek to differentiate two different certification agencies that are more similar than different, and who largely act in concert with each other.

If we believe many posters here, Airbus is working on an A322 with an all new CFRP wing as we speak, and the resulting aircraft will be similar in scope of change to 777x.

I can imagine there are some people at Airbus looking on with similar levels of interest as there are at Boeing.
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