Mayam13, is there a point you wish to make, as I don't understand the relationship to my post and your photo?

https://cimg0.ibsrv.net/gimg/pprune....cd9b15bdaf.jpg
Yes ..I have points, pardon me for not attaching my comments .
1. Both Lion Air and Ethiopian aeroplane pilots were not exposed to max simulators during their watered down 'difference' training
2. I admit one airline did acquire a simulator two months before crash.
3. The second photo I attached, gives EASA requirements, before re-certification. It asks for 70 test points in simulator.
4. The elaborate wiring re-routing suggests, the EMC-EMI checks integrity,is in question. It could be one of the delegated checks to Boeing engineers by FAA.
5. What about B 737 NG, does this aeroplane also require wiring changes?will Boeing clarify?
6. My point is that, Boeing underplayed simulator training for customer airlines .

Fine, obviously lots of comments regarding this have been made over the past year or so no need for me to add comment. I was only advising on available MAX sims outside of the USA.

There are 3 MAX sims in the UK at Gatwick. 2 at Boeing Flight Training and one just round the corner at L3. I have trained/checked on both Boeing sims, while the L3 sim is still, I believe, to be certified.

Interesting facts here by Juan on the latest with the Max.

737 Max retrun to service / synthetic airpseed
 

This article seems well written and well informed. The interesting (at least to me) element is the simmering tensions between the FAA and EASA, the application of the ISSA process to the Max, and the idea that the Max may return to service and then have synthetic airpseed retrofitted later. Lots in here to disagree on!

https://theaircurrent.com/aviation-s...r-jets-return/

Correct me if I am reading this wrongly , but I deduct the following :
FAA could alone allow the return to service by September . so for US domestic use only.
EASA will need to perform its own re-certification process to allow it in EASA land, and that will take an extra few months.
Adding Synthetic airspeed could take 2 years and adding a 3rd mechanical AoA is really not feasible , and yet one of the two is required later by EASA ?
Yes lots to disagree on !

It's either synthetic airspeed or harware third vane,
Synthetic airspeed incorporates a modelled third vane so to speak.

I am reading some speculation about a possible "deal" between the lines to add the synthetic airspeed some time down the road. How feasible that is from a regulatory point of view ... I find it doubtful.

Wouldn't that require another major software change later on to integrate the "third" vane into the systems and protections?

Assuming the synthetic airspeed is only a software update, that can be done on the aircraft quickly and easily - a few hours, including any functional checks/validation. Such software changes are fairly routinely done on an overnight.
Flight critical software updates are not real common, but are not exactly rare either - once every year or two being fairly typical. The main reason they are not more common is that the validation and certification of flight critical (i.e. DAL A) software is very time consuming and expensive. What tends to happen is less important changes/updates go on a sort of wish list. Then, when something important comes down (or sometimes if the wish list gets long enough) that justifies a change, they decide which of the wish list items should also be included.

A few hours?!?!?! This requires the programming of cascading sets of Kalman filters...the first set of calculations has to normalize the pitot/static differences due to the local flow effects of the respective locations. Since the MAX pitot are fixed, and AoA are free to rotate, the effects must be compensate for in the sideslip flow. (MAX does not have sideslip indicators.)
Since the MAX only has 2 ADIRU's, the computing power is already used up.
The second set of Kalman filters will balance the differences, and the third set of filter will provide the synthetic resultant.

Who expects this many levels of filter to provide an accurate resultant, especially given the software issue that BA currently has???

They should have simply added another AOA sensor to the tail, and either hard wired it in...What about replacing the 2 pitots with the combi pitot AoA??? now instead of 2 AoA, they would have 4, and how difficult would that wiring have been???

In regards to Ian W’s post: Can you link to the expert assessments that this virus “will just stop”? I’ve never heard any such thing. And what’s with the term “hypochondriac' flights” after an accounting of hundreds of thousands of deaths worldwide between January and June just this year? We all hope for the best but this post is by Ian W doesn’t contain any factual or attributable information. The issue of restarting Max 8 production likely has rationale that Boeing, as a business, is justifying. Not the non-fact that Covid-19 will just stop.

Surely a synthetic airspeed system would be more than a simple software upgrade ? The sources used to calculate it would need to be tied in to some form of computer with the ability to reject an erroneous input, calculate a value and then display it. This is more likely to require a major upgrade of the system, possibly a hardware change as well.

I'm pretty certain tdracer was referring to the time involved in installing an update, not the time required to do the software writing.

My educated guess is that they are going to use the flight control computers - which already receive data from several other systems (ADIRU, GPS, etc.) - to calculate a synthetic airspeed when the normal ones either disagree or are judged to be unreliable. So it would be a basic s/w update to the flight control computers.
If they can't do it all in s/w and need some sort of hardware update, all bets are off. But updating the flight control computer s/w is a long established process once the new software is certified.

It's fair to say, I think, that implementing synthetic airspeed is a far greater effort - development resource wise as well as computational resource wise - then validating two AOA readings against each other.
Given the time it took them (or better takes them, 'cause their are still not done) and the problems they encountered when implementing the later gives a pretty clear idea of a lower limit time and trouble wise synthetic airspeed is going to take. Do not forget that the synthetic airspeed information has yet to be included in other systems, their diagnostic routines, mode switching, warnings, etc.
Personally I would expect either upgraded hardware or maybe even another box (e.g. 3rd air data unit), which might be a more effective solution, becoming neccessary. Kalman filters are efficient but have tight real time requirements. From what we have learnt about that FCU ... difficult.

Was the latter ever a realistic option ?

With caveat that we do not have full details of the MCAS modification, it is difficult to connect what has been been disclosed with the reported certification differences - #48.

Cross monitoring two vanes shuts down MCAS, preventing a hazardous condition. This should enable the aircraft to be flown safely to complete the flight - with care. Three vanes would be better and could enable a higher level of safety.

AoA error post mod, apparently, also shuts down both ADCs and FGCs (?) (pressure error correction - UAS, no airspeed, and other system effects), this also degrades or removes stall warning (continuous stick shake); again three vanes would help.

MCAS mods could be acceptable in isolation, but the consequences of loss of AoA on a safe recovery might not (stby airspeed / alt, manual trim, no stall warning, autoslat, feel), i.e. technical mods meet CS 25, but the operational consequences would not meet CS 25.1301/1309; thus focus on JOEB, ISSA.
There could be technical agreement enabling return to service, operational modification could be deferred (exposure time / magnitude risk), but proposed action would have to be agreed before return to service.

A further puzzle is reference to Synthetic Airspeed. It could be a valuable aid with loss of ADC function, alleviating consequential concerns, but current SA designs appear to rely on AoA, the loss of which caused the loss of ADC in the first place !!!
Can inertial data alone replace AoA aspects used in SA (787), would it be sufficiently accurate for continued flight, approach, and landing, or to restore lost functions.

Airbus views the temporary use of BUSS for the management and recovery of ADC malfunction (AirbusWIN, flt ops support); what is the Boeing view re 787 - procedure detail?

Ironic that while the aviation community is threatened in its existence, the Corona pandemic will turn out to be the saviour of Boeing.
(If) they are going to get away with a software uodate😡 Nobody cares at the moment..

I was actually wondering if the situation wasn't a good opportuinity to can the entire project. It would be much cheaper now.

With a backlog of over 4000 orders how can it possibly be cheaper to can it? there are tens of airliners that have gone from design to production and sold much less than a tenth of that. 4000 orders is in the region of 200billion, how is that ever going to get canned? even if they had to do a clean sheet design that sort of cash will still make it way more than viable.

AND yes for the last couple of months we do have a pandemic going on but these are projects with a horizon of decades. Several Booms and Busts are unavoidable and expected.

Many of the customers having a perspective of survival in the current situation might be happy to defer their orders for a 737 replacement or happily accept cancelation without penalty.
I guess I am not a follower of the "V-shaped" recovery theory.

With the current situation in the South China Sea, the Chinese government are unlikely to approve any solution Boeing come up with, particularly as the aircraft already in China aren't needed anyway due to the reduction in air traffic.

A downturn of 1 - 2 years would suit COMAC very well as it gives them time to catch up with the C919 program and be ready once airlines start buying again, possibly grabbing a few orders which would have gone to Boeing because their aircraft wasn't ready earlier.

Bit of the topic, did Boeing ever develop any combi or freighter variants of the Max?

Nope........

I don't think Boeing has built a narrow-body freighter or combi since the mid 1980s ...

There are military versions of the 737NG with a big cargo door used in combi coniguration. USN is one operator.

Ah yes, I'd forgotten about the C-40A (based on the -700C). Seventeen built for the USN, plus five more -700Cs in total with Aramco, TAAG Angola and Air Algerie.

Thanks for answering my question, case closed.

FYI, yes the 737-700C has a big cargo door, but the "C" in 737-700C stands for "convertible," not "combi." I believe the FAA approval allows the airplane to be operated in either all passenger or all cargo configurations. I don't believe it is FAA approved for "combi," or partial passenger and partial cargo on the main deck, operation. See the FAA TCDS for TC A16WE on page 47, available on rgl.faa.gov.

The military utilization is not necessarily limited by the FAA approval, though, so it's possible a military service somewhere has a combi configuration. However, in general these days the US military is having the FAA approve all basic configurations of airplanes that are also civil products, so I doubt the US military is using a combi configuration.

The Navy (which operates 17 out of the 22 -700Cs built) seems to think they can be configured as combis:

https://www.navy.mil/navydata/fact_d...0&tid=600&ct=1

Duck
After the Helderberg disaster, the regulations governing "Combi" aircraft were significantly changed. While out of my area of expertise, those who are in the know have told me it would be close to impossible to certify a new Combi style aircraft to the updated regulations.
All the Combi's currently in operation where certified prior to the regulations being updated in response to the Helderberg.
As DR notes, military operations do not need to comply with commercial certification restrictions.

The notion that all, or most, or even 20% of those orders will remain on the books is, in my view, optimistic. Most of the companies that have placed orders are no longer forecasting the same future and / or planning the same expansion, or even fleet replacement, as they were pre-Covid. And many are simply no longer in a financial position to pursue the orders.

If successfully certified, the MAX will be around for anywhere between 20 and 30 years, I think. For that long a period, we'll likely witness at least two or three complete boom-and-bust cycles, with all their associated effects. The fact that many airlines won't take their deliveries in the next 2 years doesn't mean that they won't in the subsequent 20 years either. The existing aircraft will not last forever, the pressure to lower costs will not go anywhere and aviation will not remain forever in a state of global crisis.

Either way, any deliveries for now are a far cry away. FAA certification this fall might easily mean that EASA certification will not happen before 2021. And who knows what life will look like by then.

The situation post 9/11 was not much different - aircraft were being parked by the hundreds (if not thousands), airlines were in no position to take delivery of new aircraft and had no money to pay for them. Yet nearly every order that Boeing and Airbus had on the books on the first of September, 2001 was eventually delivered. Most months to years later than the original schedule, but aside from a few operators that went bankrupt and disappeared, the aircraft on the books were delivered.

I recognize I'm continuing a major thread drift, but this information may be of interest to some:

TD - It wouldn't be impossible - just more costly. The main deck cargo compartments on the various combi jet transports produced in past decades were Class B compartments as defined in 14 CFR 25.857 at the time. Class B compartments are required to have fire /smoke detection, but are not required to have built in fire extinguishing/suppression. The change in the definition of a Class B cargo compartments in the rule effective in 2016 went from one where the crew had to have adequate access to enter the compartment and fight a fire to now requiring the crew to be able to effectively fight any fire in the compartment with a handheld fire extinguisher from one access location without entering the compartment. This has the effect of severely limiting the size of compartments that can meet the Class B definition relative to the old definition. "Combi" large main deck cargo compartments on passenger airplanes as previously designed typically were much too large to meet that new requirement, forcing any such compartment on a new airplane to be classified as a Class C cargo compartment like the lower deck compartments, which requires an extinguishing (suppression) system.

So it's not impossible to obtain a type certificate for a combi today, but it's apparently not cost effective to design, certificate, build, and operate a combi compared to running cargo separately on all-cargo airplanes that have less costly fire safety requirements, as evidenced by combis not being proposed in recent years.

Changes were required by AD after the 1987 South African Airways 747-200 Combi accident prior to this rule change, but this 2016 change was one of the eventual part 25 changes that resulted from that accident. The FAA lessons learned library has an extensive section on this accident and the various actions that resulted. Here's a link to it:

https://lessonslearned.faa.gov/ll_ma...abID=1&LLID=33

Well, if 80% or more of the orders get cancelled, and the industry is slow to pick up, that would be a good opportunity to launch a new clean sheet model to replace the Max.

Using what funding, exactly?
Boeing is borrowing money in the tens of $billions just to stay in business, while Airbus is apparently going to be getting billions in bailout funding from the EU.
It'll be a tad difficult to come up with another ten or twenty billion dollars to launch a new clean sheet design when they're struggling to remain solvent...