Revelation wrote:PW100 wrote:It discusses a seemingly similar situation where a knowingly "broken processor" was used with no issues in Ariane 4, as the flight parameters would never reach the processor-software interaction limitations. The same set-up on Ariane 5 resulted in failure of first flight as flight parameters were significantly different, resulting in overload of the processor.
Perhaps, the same thing applies to the NG-MAX case. The processor limitations never showed up on the NG, but the extended software of the MAX might cause it to freeze up in certain scenarios.
All speculation of course, should we dismiss such scenario?
The only parallel I will draw is that Ariane 5's "broken processor" wasn't a broken processor in the sense that the fix was NOT to replace the processor but to fix the data conversion code.
I think we can talk of three different classes of fixes and the time to turn them around:
1) Software point fix: small number of months
2) Software redesign: large number of months
3) Hardware replacement: one year or more
The point I'm trying to make is that the most recent reports suggest that we are in case (2) i.e. software redesign (which was said to be started months ago anyway) and NOT in case (3) i.e. hardware replacement.
However, I agree with your suggestion that no scenario should be dismissed.
The reports we have are too conflicting and are written by people who are not computer professionals so figuring out exactly where things are is problematic.
The software redesign that was started 8 months ago is what caused this catastrophic failure. I'm not so sure solving this issue is a quick fix to that work.
A quick software point fix is what Boeing is stating, but everything from outsiders points to 2) or 3) (FAA specialists). If Boeings is still in denial it can cost them months to even a year of failed attempts.
I sure hope they have a plan B (more serious ground up software redesign) and a plan C (hardware redesign) in place and executing in parallel in case their optimism was just hopeful thinking.
At this point the 737 MAX rescue mission needs to have all of Boeings most brightest fully mobilised and engaged with all other projects in standby mode.
As for the ungrounding, it seems we are now looking at 20Q1(FAA)-20Q2(EASA)-20Q3(CAC) at best.
This makes me wonder how long Boeing will stay in denial and keep producion at 42 planes/m and 52 engines/m. I can see them willing to eat the cost of ordering excess engines from CFM just to prevent the opportunity for Airbus to jump into that gap and increase their 320 engine orders
Either way, the silver lining for Boeing will be they will be the first airplane manufacturer to break the 1000 deliveries a year milestone. I can see them deliver up to 1200 planes next year, a record Airbus probably wont be able to break for at least 10 years.