PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Tech Log (https://www.pprune.org/tech-log-15/)
-   -   Are the MAXs now in 'Parc Ferme'..? (https://www.pprune.org/tech-log/620023-maxs-now-parc-ferme.html)

scifi 31st Mar 2019 18:21

Are the MAXs now in 'Parc Ferme'..?
 
I just wonder if the grounded aircraft are in Parc Ferme, where they cannot be worked on by engineers.
If,.as has been suggested in other threads, there is some common AoA data transmission error. Then it would be nice is the fault could be found in some of the other Maxs. as the only two aircraft we know had the fault are not intact now.

DaveReidUK 31st Mar 2019 18:30


Originally Posted by scifi (Post 10435155)
I just wonder if the grounded aircraft are in Parc Ferme, where they cannot be worked on by engineers.

What makes you think that?

They will be getting the same attention given to any aircraft that aren't going to fly again for a while.

Uplinker 1st Apr 2019 11:49

There are five Tui Max’s parked at Juliet 1 at Manchester, (making that intersection unavailable to traffic).

I would imagine that these aircraft can be worked on in the open to prepare them for short-term storage? Would they remove batteries, empty the fuel water drains and drain potable water? I am sure there is more to it than that. Maybe jack them onto blocks to prevent tyre flats?

They can change engines outside, (under a tent), so I would imagine they can work on Avionics and probes?

Flying Wild 1st Apr 2019 12:01

TUI Max aircraft at TFS have had wheel bogies wrapped in plastic along with normal probe/engine covers

scifi 1st Apr 2019 12:18

I was thinking that they would be a good source of information, and that an engineer could un-knowingly alter any evidence that would help pin-point the faults.
Were there not a few other aircraft that had similar captain side anomalies. These should be inspected by suitable FAA / CAA teams.

GordonR_Cape 1st Apr 2019 15:05


Originally Posted by scifi (Post 10435715)
I was thinking that they would be a good source of information, and that an engineer could un-knowingly alter any evidence that would help pin-point the faults.
Were there not a few other aircraft that had similar captain side anomalies. These should be inspected by suitable FAA / CAA teams.

I had that same thought, to test them every day until an AOA error occurs, but politics/liability/insurance would all get in the way.

scifi 9th Apr 2019 10:53

Lets be quite honest, that airframe was never designed for those engines, and no amount of software is going to solve that problem.
If Boeing want to use the LEAF engines then they need to design a new aircraft to suit them.

DaveReidUK 9th Apr 2019 13:30


Originally Posted by scifi (Post 10443204)
Lets be quite honest, that airframe was never designed for those engines, and no amount of software is going to solve that problem.

To be fair, it was never designed for the engines on the Classic or NG, either.

Exup 9th Apr 2019 14:20

Plenty of aircraft have been re-engined over the years not just the 737.

safetypee 9th Apr 2019 15:05

Exup, its not just re-engining, it’s repositioning, wt, cg, and lift from the extended nacelles - proportional to AoA.

At least none have been sent to Tucson so far.

tttoon 9th Apr 2019 15:09


Originally Posted by scifi (Post 10443204)
Lets be quite honest, that airframe was never designed for those engines, and no amount of software is going to solve that problem.
If Boeing want to use the LEAF engines then they need to design a new aircraft to suit them.

Can we get some arguments to support this statement?

pineteam 9th Apr 2019 16:13


Originally Posted by tttoon (Post 10443442)
Can we get some arguments to support this statement?

Just look at the size of the engines on the 737-200 vs 737-Max. The fact that they need to flatten the bottom part of the engine nacelle on the NG says a lot already.

DaveReidUK 9th Apr 2019 16:59


Originally Posted by pineteam (Post 10443480)
The fact that they need to flatten the bottom part of the engine nacelle on the NG says a lot already.

Even before the NG the nacelles were flattened, albeit not by quite so much, on the Classic.


krismiler 10th Apr 2019 00:00

The B737 fuselage design dates back to the 1950s, the later designed B767/757 are already obsolete and except for a few specialised variants, out of production. It should have been obvious to Boeing back in the 1980s that they needed a new airframe for their bread and butter narrowbody. Possibly they didn't see the new A320 as a threat and weren't willing to invest the money in a new design. Even at 30 years old the A320 is still a fantastic aircraft which is still able to be updated without mutating it into something the original designer wouldn't recognise. New sharklet wings and next generation engines have improved it's efficiency considerably, update the flight deck and there is no reason for it not to go on for another 20 years.

Boeing would need to spend billions on a new design which would be unlikely to offer significant improvements over the current A320 series, and the selling price would need to recoup the development costs. Margins at the economy end of the market aren't as much as at the higher widebody long haul end and it would take many years to get back into the black.

DaveReidUK 10th Apr 2019 06:49


Originally Posted by krismiler (Post 10443794)
Even at 30 years old the A320 is still a fantastic aircraft which is still able to be updated without mutating it into something the original designer wouldn't recognise. New sharklet wings and next generation engines have improved it's efficiency considerably, update the flight deck and there is no reason for it not to go on for another 20 years.

Boeing would need to spend billions on a new design which would be unlikely to offer significant improvements over the current A320 series

You can't have it both ways.

The A320 certainly has significant advantages over the 737, which is no surprise given that it came along 20 years later.

So what makes you think that an all-new aircraft 30 years further down the road than the A320 wouldn't be able to offer a corresponding leap over it in technology and capability ?

Cows getting bigger 10th Apr 2019 07:49

I'm not a tube driver so could someone please explain to me why the 757 was ditched, especially the -100 in favour of the 737? Was it due to the 'same type' argument that seems to pervade for the 737 Max? It seems to me that this was a good aircraft with plenty of space for bigger engines.

GordonR_Cape 10th Apr 2019 07:59


Originally Posted by Cows getting bigger (Post 10443946)
I'm not a tube driver so could someone please explain to me why the 757 was ditched, especially the -100 in favour of the 737? Was it due to the 'same type' argument that seems to pervade for the 737 Max? It seems to me that this was a good aircraft with plenty of space for bigger engines.

Someone stated that the cost-per-seat-mile of the B757 was almost twice as high as the B737. Simple economics, airlines stopped buying it, end of story. Fuel efficiency is king in the low-cost market, and safety is a secondary concern, as long as the aircraft is FAA approved, and has a long flight history, and passengers are willing to step on board.

Cows getting bigger 10th Apr 2019 08:40

You see, that's where I'm a bit confused. The only data I can find is that cost/seat mile for the latter 737s is in the region of 6-8 cents/mile; Boeing claim the Max is a 20% improvement on earlier models. The 757 appears to be about 7.5 cents/mile.

https://www.planestats.com/bhsn_2014sep

Wiki hits it from a different angle saying that a 737 Max has a Miles Per US Gallon of 102/seat with the 757-300 at 88 MPG.

For sure, the 757 appears to be more expensive but not in the order of twice as much. It would be an interesting theoretical exercise to number crunch a 757 with LEAF engines. :)

Bend alot 10th Apr 2019 09:39

Same TDC S269C and S269D

Nothing like a good engine change and pretty much all the air-frame - only thing similar is being able to continue to use the magnesium.

compressor stall 10th Apr 2019 10:26


Originally Posted by DaveReidUK (Post 10443908)
You can't have it both ways.

The A320 certainly has significant advantages over the 737, which is no surprise given that it came along 20 years later.

So what makes you think that an all-new aircraft 30 years further down the road than the A320 wouldn't be able to offer a corresponding leap over it in technology and capability ?

It's a good question.

If Boeing can design an aircraft that offers superior safety / fly by wire characteristics / ergonomics to the A320 family of aircraft, they'd be on a winner.

Unfortunately for them, I think that technology has largely plateaued since the A320 introduction. The only major change is in engine efficiency. The 787 and A350 are certainly incremental improvements, but largely offer a refinement (albeit larger) of the A320 FBW concept.

For Boeing, shrinking the 787 into a new 737 replacement would need to do a lot more than the A320 to be a best seller. Size aside, the 787 and the A320 are largely equals in terms of technology and safety. If the tech was there, Boeing would have it on show already in the 787.


All times are GMT. The time now is 22:05.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.