737 Max

[Julien]

Interesting article

 

https://www.bbc.co.uk/news/extra/jDOe2y9Tbo/boeing-737-max?fbclid=IwAR1dUOr-wthWDUChw5AuNwtktk4KHRDoqtE63_anHy8eoo2Y-_mGy6igltI

[Dave Swindell]

1 hour ago, Sabrejet said:

737-8 rings a bell.

737 Max is the fourth generation 737, form 2017 onwwards

737-8 is third generation 737 introduced in 1997

[Sabrejet]

2 hours ago, Dave Swindell said:

737 Max is the fourth generation 737, form 2017 onwwards

737-8 is third generation 737 introduced in 1997

 

 

USA Today:

 

An announcement that Boeing had sold new jetliners was getting notice for another reason: a possible name change of the aerospace giant's most troubled plane.

Boeing said Wednesday that a Polish airline, Enter Air, had ordered a pair of its 737 Max jetliners, which have been grounded ever since they figured in two crashes.

More: Boeing sold 1 plane last month amid pandemic, Max grounding

Only the announcement didn't identify the planes as Maxes. Instead, they were called the 737-8, perhaps signalling that Boeing may want a new name to combat the plane's image problems.

Boeing officials didn't say a name change is official, noting that the Max name appeared elsewhere in the same announcement. The Max name showed up in referring to Enter Air's fleet -- with the  new planes, it will have 10 of the Max aircraft. Testing is going on around changes in the plane to get it flying again.

 

[Sabrejet]

Ah it was BBC News, 15 July 2019: "Boeing ditches 737 Max name on new Ryanair plane" - 737-8200 was painted on an a/c which had the previous day been painted "737-MAX".

 

https://www.bbc.co.uk/news/business-48995509

[EwenS]

2 hours ago, Dave Swindell said:

737 Max is the fourth generation 737, form 2017 onwwards

737-8 is third generation 737 introduced in 1997

 

 

Not quite

737 first generation - 737-100, -200

737 second generation renamed Classic when the NG came along - 737-300, -400, -500

737NG (New Generation) - 737-600, -700, -700ER, -800, -900, -900ER

737 MAX - 737 MAX 7, MAX 8, MAX 9, MAX 10

 

As noted the MAX might yet get a new name, at least for some airlines.

 

 

[wellsprop]

I'm not entirely sure how Boeing have managed to get it re-certified. 

 

My understanding is that FAA 14 CFR Part 25 requires an aircraft to have positive longitudinal stability. I assume that the stability augmentation section allows them to get around this by proving the software keeps the aircraft stable.

 

Having a dynamically unstable aircraft isn't inherently dangerous if it is controlled and understood. That said, the senior avionics lecturer from the uni I went to (he's always on BBC news whenever there's an article about planes) has said that there's no way a new design with those pitch characteristics would get certification. And judging by his CV and the aircraft systems he has developed, I have no reason to doubt what he says. 

[John B (Sc)]

I think part of the explanation to 'wellsprop' 's puzzlement may be that the 737 is an old design, so the later rules don't all apply. This is an oddity which Boeing in particular has used to their advantage a lot. I believe EASA was pushing for this to be changed but it all takes time, quid pro quos will be demanded and Boeing has  lot of clout.

 

This is not the first problem the 737 has had. Some may recall the rudder hard over problems of the Nineties. Two fatal accidents  and some incidents  which resulted in changes being required -  & the type continued insrevice.  Boeing tried to deflect blame then too;  actually I'm not sure they ever admitted there was a design oversight.

 

Once upon a time Boeing was run by people - enthusiastic engineers - who wanted to build darn good aeroplanes, now it is run by people who mostly want to make money.

Edited November 19, 2020 by John B (Sc)

[The Tomohawk Kid]

23 hours ago, Sabrejet said:

Believe it or not there are still airline industry execs saying that we will be "back to normal" by the end of 2021! They are either stupid or in denial.

 

Which ones? The quotes I have seen, airlines are stating they are not envisaging getting back to anything approaching 2019 level before 2024/5 at the earliest.

 

Tommo.

[Sabrejet]

1 hour ago, The Tomohawk Kid said:

 

Which ones? The quotes I have seen, airlines are stating they are not envisaging getting back to anything approaching 2019 level before 2024/5 at the earliest.

 

Tommo.

 

Manufacturers rather than airlines.

[John B (Sc)]

Thinking further on wellsprop's comment - surely when first designed, way back in the ?Seventies?, the 737 must have had positive longitudinal stability built in mechanically.  'Relaxed' stability aeroplanes - with computer controlled unstable systems, didn't exist.  So this must be a later development, much later. I seem to recall the 7373 series went through quite a major set of stretch processes, having started out as the small brother of the 707, with the same fuselage diameter. 

 

I suspect the relaxed stability design element must be a very late change, perhaps made as tails were shrunk to improve efficiency - or at least tails were not increased to cope with increased loads and moment arms in a simple mechanical fashion.   Hmm - I'm with that lecturer of yours!

 

I don't mind low stability in pitch or roll in a soaring sailplane - it makes it light and responsive.  Zero longitudinal stability can easily result in a PIO and risk of overstress unless carefully handled; some all flying tail sailplanes are 'challenging' in wave rotor turbulence and can be exciting to frightening if a trim failure occurs. That's fine if we choose to accept that for efficiency when soaring, but not good for an airliner.

[wellsprop]

On 20/11/2020 at 18:46, John B (Sc) said:

Thinking further on wellsprop's comment - surely when first designed, way back in the ?Seventies?, the 737 must have had positive longitudinal stability built in mechanically.  'Relaxed' stability aeroplanes - with computer controlled unstable systems, didn't exist.  So this must be a later development, much later. I seem to recall the 7373 series went through quite a major set of stretch processes, having started out as the small brother of the 707, with the same fuselage diameter. 

Good question.

 

The 737 was designed in the 60's and all 737 variants are longitudinally stable (up until the Max).

 

The 737 was designed at a time when engines were turbojets (long skinny tubes), this led to the 737 having short undercarriage. Since the 1960's engine technology has vastly improved and turbofans are now the standard powerplants. Turbofan efficiency increases as the diameter of the fan increases (more efficiency = less fuel = more money for airlines).

 

The 737-600/700/800/900 are powered by the CFM-56 turbofan, which has a very noticeable flat bottom to the engine cowl - this is due to ground clearance issues.

 

 

The 737 Max was re-engined with CFM LEAP (seriously good engine, managed another 10% efficiency improvement), this engine has an even larger fan diameter than the CFM-56, the only way this engine could be fitted to the 737 Max is by moving the engine forward and up. This means when the aircraft is at a high pitch angle, high thrust setting and low speed, the elevators do not have enough control authority to decrease the pitch therefore preventing stall.

 

This is a very big problem, because standard stall recovery (& prevention) is add power and push the nose down. The pilots were not told/trained about these differences.

 

For more info, go to about 9 minutes here.

 

What makes me most sad is that Boeing allowed this to happen and knowingly passed off "major" changes as "minor" changes. There are regulations that define what change is "major" and what is "minor" - this is more or less standard across the world. The changes Boeing made were clearly "major".

 

As a (junior) aerospace engineer in a leading aerospace company, I make these sorts of changes. I have made mistakes, however, they immediately got picked up by a senior engineer who checks everything I do. Once a change is complete, it has to be signed off by a senior engineer, the team leader, the departmental manager, all other engineering departments, the aircraft chief engineer and the head of engineering (this is more or less the same across aerospace companies). All these checks are in place to pick up and rectify mistakes, it works VERY well an makes the aerospace industry very safe.

 

Engineers at Boeing knowingly allowed changes to be passed with the wrong classification (they were probably told to by senior management). I have complete confidence that any of my engineering colleagues would never knowingly allow an unsafe change to be made. When I joined the company, the engineering manager made it extremely clear that everything we do must be correct and safe as our business relies on our reputation to survive. Boeing's business doesn't rely on it's reputation (as much) - as one of the USA's most important businesses, Boeing has preferential treatment from the US government. I believe that senior managers at Boeing were well aware of this and, as such, they were happy to take risks in order to compete with the A320 series (that is now outselling the 737). The FAA should have picked up on this (here in the UK, other aerospace companies "check our homework" to make sure that we are complying with EASA rules), however, the FAA allowed Boeing too much autonomy and things were missed.

 

I realise this is a bit of a monster post, but it's not a simple subject. When rules aren't followed in the aerospace industry, people die. What makes it worst is the rules weren't just "not followed" they were blatantly ignored.

[NoSG0]

Cat among the pigeons?

 

Interestingly, according to post 271, Reuters is saying that EASA will also look at lifting the grounding in January?

 

Yet post 272 quoting Times of India says EASA thinks more needs to be done. 

 

https://www.airliners.net/forum/viewtopic.php?f=3&t=1437865&sid=1be548c9aa216e312b906997c3fc63d5&start=250#p22522447

 

Dominic Gates:

https://twitter.com/dominicgates

 

FAA chief conceded original certification missed the flaws in MCAS Cites "fragmented communication between the flight test and operational sides within Boeing and between Boeing & the FAA” "Measures in place to make sure it does not happen again”

 

So I wonder if they are getting special dispensation for the affected FAR's?

 

I would like to say a lot more, but, I would get banned and the thread will go down hill. 

 

[John B (Sc)]

Thanks for that excellent explanation, wellsprop.

I had forgotten about the potential major pitch up problem on overshoot/ landing go around; I have a feeling that was a part of the cause of  a night overshoot, loss of control & reference followed  by a steep descent accident in Russia not long ago, I think that was a Boeing 737.

 

I entirely agree that for engineers to deliberately underplay the significance of changes is clearly wrong and quite unprofessional. Very sad, as you say. Quite how they justify that to themselves, I don't know - either for their own consciences or in the event of legal enquiry,

 

 

Edited November 24, 2020 by John B (Sc)

[wellsprop]

1 hour ago, John B (Sc) said:

Quite how they justify that to themselves, I don't know - either for their own consciences or in the event of legal enquiry,

 

 

 

Who needs a conscience with a pay cheque like this (am I too cynical?).

https://www.nytimes.com/2020/01/10/business/boeing-dennis-muilenburg-severance.html#:~:text=Boeing said Mr.,Mr.

[NoSG0]

No, not to cynical at all I am sorry to say.

 

So looks like the EASA wants further improvements down the road.

 

https://twitter.com/dominicgates/status/1331297475815116801

 

The article is behind a paywall.  Maybe there are some other bits out there as what the EASA wants.  I did manage to see that there is a 28 day consult?

Edited November 24, 2020 by NoSG0
Typo

[Alan P]

On 11/24/2020 at 10:26 PM, NoSG0 said:

No, not to cynical at all I am sorry to say.

 

So looks like the EASA wants further improvements down the road.

 

https://twitter.com/dominicgates/status/1331297475815116801

 

The article is behind a paywall.  Maybe there are some other bits out there as what the EASA wants.  I did manage to see that there is a 28 day consult?

Here’s the gist of what EASA said in their press release, it is a step in the right direction:

 

Quote

EASA’s review of the 737 MAX began with the MCAS but went far beyond,” Ky said. “We took a decision early on to review the entire flight control system and gradually broadened our assessment to include all aspects of design which could influence how the flight controls operated. This led, for example, to a deeper study of the wiring installation, which resulted in a change that is now also mandated in the Proposed Airworthiness Directive. We also pushed the aircraft to its limits during flight tests, assessed the behaviour of the aircraft in failure scenarios, and could confirm that the aircraft is stable and has no tendency to pitch-up even without the MCAS.”

 

Human factor analysis was another focus area – to ensure that the pilots were provided with the right alerts in the cockpit if a problem arose, along with the procedures and training needed to know how to respond. A fundamental problem of the original MCAS is that many pilots did not even know it was there. In the accident version of the aircraft, there was no caution light to make a pilot aware that the AoA sensor was faulty, making it almost impossible to determine the root cause of the problem.

 

That is why EASA now proposes that the changes to the aircraft design which will be required by the final Airworthiness Directive will be accompanied by a mandatory training programme for pilots, including flight simulator training, to ensure that the pilots are familiar with all aspects of the flight control system of the 737 MAX and will react appropriately to typical failure scenarios. 

 

[John B (Sc)]

Thank you Alan P. (Hope you are indeed back to piloting!)

 

The description you append sounds like the sort of testing I'd expect from a competent certification authority taking its responsibilities seriously - DP Davies would approve! . Sad that the FAA no longer give me that confidence. 

[Max Headroom]

Ryanair has just ordered more at a hefty discount

 

https://www.theguardian.com/business/2020/dec/03/ryanair-orders-boeing-737-max-jets

 

Apparently taking up slots cancelled by others.

 

Trevor

 

[SAT69]

On 11/19/2020 at 5:13 PM, John B (Sc) said:

 

Once upon a time Boeing was run by people - enthusiastic engineers - who wanted to build darn good aeroplanes, now it is run by people who mostly want to make money.

I can remember a time when Boeing was a lot more friendly, and generous. Mind you this is many years ago (1960 or thereabouts) and my grandfather wrote and asked for some pictures and information about their airplanes, for me. What he got back was a rather big package filled with some 20 or more printed sheets; pictures on the front and information on the back ... and it was free! You want a picture of a Boeing airplane from the company now and you have to pay for it.

[Circloy]

On 04/12/2020 at 02:49, SAT69 said:

I can remember a time when B...... was a lot more friendly, and generous. Mind you this is many years ago (1960 or thereabouts) and my grandfather wrote and asked for some pictures and information about their airplanes, for me. What he got back was a rather big package filled with some 20 or more printed sheets; pictures on the front and information on the back ... and it was free! You want a picture of a B...... airplane from the company now and you have to pay for it.

Did you pay the licence fee for using their name?

[SAT69]

1 hour ago, Circloy said:

Did you pay the licence fee for using their name?

Oops! No. Reckon I'll be hearing from their lawyers shortly. It's the simple stuff that'll getcha.

[Skodadriver]

On 12/3/2020 at 9:42 PM, Max Headroom said:

Ryanair has just ordered more at a hefty discount

 

https://www.theguardian.com/business/2020/dec/03/ryanair-orders-boeing-737-max-jets

 

Apparently taking up slots cancelled by others.

 

Trevor

 

Many years ago I vowed never to fly on Ryanair as long as Michael O'Leary is in charge. Looks like I'll be standing by my vow even after Mr O'Leary's departure. I'm not a nervous flyer by any means but I will never, ever fly on a 737 Max. I'm sure others will disagree but the Max is and always will be a lash-up. It looks wrong (at least to my eyes) and even if the MCAS issue is resolved I can't stop myself wondering what other undiscovered nasties are lurking beneath the surface. 

[Alan P]

On 12/1/2020 at 3:57 PM, John B (Sc) said:

Thank you Alan P. (Hope you are indeed back to piloting!)

 

The description you append sounds like the sort of testing I'd expect from a competent certification authority taking its responsibilities seriously - DP Davies would approve! . Sad that the FAA no longer give me that confidence. 

Thanks John, I'm very much back in aviation, on the training side. EASA isn't all good, but at least they give the impression they're trying to help. I've passed many queries up the line and found the response from the different European aviation authorities to be both receptive and positive. 

[John B (Sc)]

On 12/9/2020 at 5:04 PM, Alan P said:

Thanks John, I'm very much back in aviation, on the training side. EASA isn't all good, but at least they give the impression they're trying to help. I've passed many queries up the line and found the response from the different European aviation authorities to be both receptive and positive. 

That's nice to hear. I imagine there is quite a bit to do on the training side just now, given how many folk will be out of currency or just needing some rust removed !  

I do wonder how the CAA is going to manage as we leave EASA; they seem to have taken on some good people, but it is many years since the CAA had to run the whole show themselves, so to speak.  Not easy to recreate that capability quickly; there will be struggles.

(And down at the private end, even more so since airline ops and commercial activities will naturally take priority. I have a foot in several camps here - my lady is a commercial pilot but we are also private pilot owners and involved with gliding as well.)

 

[Julien]

On 08/12/2020 at 22:56, Skodadriver said:

Many years ago I vowed never to fly on Ryanair as long as Michael O'Leary is in charge. Looks like I'll be standing by my vow even after Mr O'Leary's departure. I'm not a nervous flyer by any means but I will never, ever fly on a 737 Max. I'm sure others will disagree but the Max is and always will be a lash-up. It looks wrong (at least to my eyes) and even if the MCAS issue is resolved I can't stop myself wondering what other undiscovered nasties are lurking beneath the surface. 

I had the displeasure of flying Ryan Air once, never again. Like you their use of the Max gives me another reason to avoid them.