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Offline blackkite

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Re: Boeing 737 MAX family
« Reply #1 on: December 09, 2011, 07:28:47 am »
Hi! I post Boeing's official 737 series drawings for comparison, reference and entertainment. ;D

Offline blackkite

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Re: Boeing 737 MAX family
« Reply #2 on: December 09, 2011, 07:32:32 am »
Next drawings. Enjoy.
 
  • 737 MAX 7 – Replacement for the 737-700 and 737-700ER
  • 737 MAX 8 – Replacement for the 737-800
  • 737 MAX 9 – Replacement for the 737-900ER
http://en.wikipedia.org/wiki/Boeing_737_MAX
 
http://www.newairplane.com/737/737Max/
« Last Edit: December 09, 2011, 07:40:08 am by blackkite »

Offline Grey Havoc

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Re: Boeing 737 MAX family
« Reply #3 on: December 09, 2011, 11:00:29 am »
Via the Drudge Report:

Quote
The National Labor Relations Board has dropped its controversial case against airline manufacturer Boeing, which had become a lightning rod for conservatives.

The labor board argued for much of the past year that Boeing decided to locate a new plant to build its new 787 Dreamliner jets in South Carolina, a right-to-work state, in retaliation for strikes by unionized workers at its existing facilities in Washington state.

But the panel appeared to bow to political pressure Friday, saying that a deal the company reached this month with the International Association of Machinists to build a different type of airliner, the 737 Max, in Washington satisfied its concerns.

http://thehill.com/blogs/transportation-report/labor-employment/198399-labor-board-withdraws-boeing-complaint
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Offline Sundog

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Re: Boeing 737 MAX family
« Reply #4 on: May 02, 2012, 11:18:17 am »

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Offline Skyblazer

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Re: Boeing 737 MAX family
« Reply #6 on: May 03, 2012, 01:54:07 am »
Extended 737?!?

Lo, the Boeing 707 is reborn!!! (with winglets, and only two engines)

Offline Triton

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Re: Boeing 737 MAX family
« Reply #7 on: November 19, 2012, 10:28:02 am »
Final concept rendering of Boeing 737 MAX 8 and 737 MAX 9?

Source:
http://www.bangaloreaviation.com/

Offline fightingirish

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Re: Boeing 737 MAX family
« Reply #8 on: November 19, 2012, 12:12:06 pm »
Yes, the chin bump and longer retraction mechanism has been eliminated. The engine location has been moved slightly forward for better ground clearance. Other aerodynamic parts and the cockpit have also been refined.

Sources:
Aviation Week Magazine - November 19th, 2012, page 39
Aviation Week - Boeing Looks To Future Technology Needs In MAX Design
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Re: Boeing 737 MAX family
« Reply #10 on: November 26, 2012, 02:35:59 pm »
Quote
Get an insider's peek into Boeing's Transonic Wind Tunnel testing lab, where technicians hover around a small scale replica of the Boeing 737 MAX. They're conducting tests on the MAX's new Advanced Technology winglet. The results of these high-accuracy tests will tell if the new winglet measures up to its desired effect.


Offline Triton

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Re: Boeing 737 MAX family
« Reply #11 on: November 26, 2012, 02:37:47 pm »
Quote
Boeing has unveiled the super-efficient winglet design which will be incorporated into the 737 MAX design and production system plans. Check it out in this new video with animation of the 737 MAX. Find out more at www.newairplane.com/737max


Offline Triton

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Re: Boeing 737 MAX family
« Reply #12 on: November 17, 2013, 02:12:16 pm »

Offline Triton

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Re: Boeing 737 MAX family
« Reply #13 on: July 14, 2014, 12:07:36 pm »
Boeing Launches Higher Capacity 737 MAX Variant
Jul 14, 2014 Guy Norris | ShowNews

Source:
http://aviationweek.com/farnborough-2014/boeing-launches-higher-capacity-737-max-variant

Quote
Farnborough -- Boeing is to offer a higher capacity variant of the 737-8, a member of the new MAX family, to further improve seat-mile operating economics and increase competitiveness against the Airbus A320neo.

The minor model derivative will incorporate the mid-fuselage extra passenger exit door of the higher capacity 215-seat 737-9 to satisfy regulatory safety emergency evacuation requirements. The modification will give the new sub-model seating for up to 200, or around 11 more than the standard configuration of the 737-8. “It will have 5% better operating costs for a little less than a 1% dip on trip costs,” says Boeing Commercial Airplanes Vice Chairman and CEO, Ray Conner.

The variant, which at least for the moment is dubbed the 737-8MAX (to differentiate it from the original 737-MAX8 designation) will “take advantage of the extra 88 inches of space in the cabin,” says Conner referring to the longer internal dimensions of the 737-800/MAX -8 cabin compared to the A320. The decision was taken to offer the derivative at this relatively late stage in the MAX program because “we got a lot more comfortable with where we are, and as performance has continued to improve over the course of year. It was a matter of comfort and whether the customer base showed interest,” Conner adds.

The variant will become available after the three main 737 MAX models, the –7, -8 and -9, are developed and certificated. The current schedule calls for the 737-8 to be certified first in 2017, the -9 in 2018 and the -7 in 2019. The A320neo currently has 2,843 firm orders versus the 2,099 for the MAX.

Offline Steve Pace

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Re: Boeing 737 MAX family
« Reply #14 on: December 08, 2015, 05:25:07 pm »
The first Boeing 737-8 MAX rolled out today (12/8/2015). -SP
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Offline Moose

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Re: Boeing 737 MAX family
« Reply #15 on: December 08, 2015, 07:31:19 pm »
Great looking aircraft, unfortunate that the merely re-engined NEO is still well ahead on orders.

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Re: Boeing 737 MAX family
« Reply #16 on: December 09, 2015, 04:06:19 am »
Interesting that the serrated nacelle is back.  I would have thought that the solution adopted for the 777x could be applied on all follow-on aircraft.  I remember reading the oversized windows on the 787 were made possible by the carbon fiber construction.  I guess aluminum can work too.

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Re: Boeing 737 MAX family
« Reply #17 on: December 09, 2015, 09:59:01 am »
Very satisfactory that NEO, a thorough update of an already much more advanced aircraft, has such a lead in orders.

Offline fightingirish

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Re: Boeing 737 MAX family
« Reply #18 on: January 24, 2016, 11:34:26 am »
Slán,
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Offline Kiltonge

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Re: Boeing 737 MAX family
« Reply #19 on: January 24, 2016, 12:39:56 pm »
How history might have been different had Boeing not been so resistant to redesigning the 737's wing for the -300.  They increased the chord with a new slat, added a tip extension and called it a day.    Was it just a case of saving time and money or were they really that confident in their product?

Edit: I found this in Flight's archive, regarding the -300 wing 4.4% chord extension:

Quote
The modification is a clever way of altering airflow over the wing, particularly the
top surface, so that it approaches that an aft-loaded or supercritical section. The
result is a 4 per cent improvement in aerodynamic efficiency, equivalent to an
increase in cruise Mach number of 0-02 and a fuel saving of 1.5 - 3 per cent ranges
of 200-1,500 n.m.

15 years later they had to bite the bullet and created the wonderful 737NG wing, which finally matched or exceeded the A320's wing.  Had they done that back in the early 1980s the A320 would have had a much tougher fight against the -400 as a 727-replacement, and perhaps we would have more innovative successors than midlly warmed-over re-engining projects.

« Last Edit: January 24, 2016, 12:52:08 pm by Kiltonge »

Online fredymac

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Re: Boeing 737 MAX family
« Reply #20 on: February 02, 2016, 08:58:32 am »

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Re: Boeing 737 MAX family
« Reply #21 on: July 12, 2016, 09:15:33 am »

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Re: Boeing 737 MAX family
« Reply #22 on: July 27, 2016, 06:42:20 am »
Don't know if they are changing the routine from Farnborough.


Offline flateric

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Re: Boeing 737 MAX family
« Reply #23 on: November 22, 2016, 01:32:15 pm »
...
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stealth, more than a few of them truly technically ignorant and proud of it." Sherm Mullin, Skunk Works

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Re: Boeing 737 MAX family
« Reply #26 on: March 08, 2017, 03:54:36 am »



Offline bobbymike

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Offline Grey Havoc

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Re: Boeing 737 MAX family
« Reply #28 on: June 17, 2017, 05:51:13 am »
Boeing intensifies small jet battle with Airbus (ft.com, registration may be required)

Article on the new 737 Max 10, intended to enter service around 2020.
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Offline Foo Fighter

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Re: Boeing 737 MAX family
« Reply #30 on: March 13, 2019, 08:09:54 am »
There seems to be something wrong with their '*&oody airplanes'.  Doing nothing will hardly improve trust levels.

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Re: Boeing 737 MAX family
« Reply #31 on: March 13, 2019, 12:32:39 pm »
"Thank you for summing that up."

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Offline Grey Havoc

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Offline Triton

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Re: Boeing 737 MAX family
« Reply #33 on: March 13, 2019, 06:06:28 pm »
"Ethiopian Airlines crash: What is the MCAS system on the Boeing 737 Max 8?"
March 12, 2019 by Chris Lefko

Source:
https://phys.org/news/2019-03-ethiopian-airlines-mcas-boeing-max.html#jCp

Offline Grey Havoc

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Re: Boeing 737 MAX family
« Reply #34 on: March 14, 2019, 12:03:05 pm »
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Offline lastdingo

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Re: Boeing 737 MAX family
« Reply #36 on: March 14, 2019, 02:35:50 pm »
I don't understand why they gave the high authority autopilot an algorithm to push the nose down at all.
Every pilot knows that you either need to increase thrust A LOT or pitch the nose down when there's an acoustic stall warning.
Thrust isn't much of an option in airliners because of poor thrust:weight ratio, so pilots would pitch down unless they totally lost orientation and violate basic rules of flying.

Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #37 on: March 14, 2019, 04:26:24 pm »
Stick pusher have been around for 70 years...

Airbus don't require a stick pusher;  the ctr law are simply impaired, what means that whatever you ask it won't allow.

Boeing are direct ctrl plane: hands on stick and not a push buttons (think Thrustmaster and Playstation).
Today with the massification of flights (and flight hours obviously) we face a lot of various surfacing problems that seems to tackle the sane logic of 100th old Boeing: long hours pilots deemed senior flyer that have been conditioned by aitbus "relaxed" authority (you delegate your inputs to the ctrl software) and young pilot with hours on console that start any critical reflexion only after having pressed 100 time repeatedly on a push button.  Those are conflicting worlds and I fear that mixing both would lead us only to disaster like that.

Boeing should assume their philosophy of flight (the sane one IMOHO - especially with all the unforeseen problems with global warming - think flows mechanics for example) and sponsor their own accredited flight syllabus.

yes, you get it, you'll be a Boeing/Embraer/[today] Bombardier qualified pilot or a... button pusher.

On a thread on Keypub, I even put frwd that flight interfaces (ctrl law, avionic, cockpit disposition) would have to be commune cross platform and across airframer. It obviously lead us to delegating a lot of flight responsibility to the ground team via datalink.
« Last Edit: March 14, 2019, 04:35:38 pm by TomcatViP »

Offline Grey Havoc

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Offline Grey Havoc

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Re: Boeing 737 MAX family
« Reply #39 on: March 16, 2019, 05:31:13 am »
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Offline draganm

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Re: Boeing 737 MAX family
« Reply #40 on: March 16, 2019, 08:46:26 am »
any comments on this whopper of a statement?

Quote
MCAS was introduced by Boeing on the 737 Max 8 because its heavier, more fuel-efficient engines changed the aerodynamic qualities of the workhorse aircraft and can cause the plane's nose to pitch up in certain conditions during manual flight.

Angle of attack sensors on the aircraft tell the MCAS to automatically point the nose of the plane down if it is in danger of going into a stall. This is done through horizontal stabilizers on the plane's tail which are activated by the aircraft's flight control computer.
Read more at: https://phys.org/news/2019-03-ethiopian-airlines-mcas-boeing-max.html#jCp
to me that says" Boeing stuck engines on their 737 platform  that were too large and aerodynamically inappropriate for the  aircraft, made it inherently unstable and dangerous to operate, then tried to address the problem with a software band-aid" . Really would like ot hear what any aero Engineers here would have to say about that
     This is mind blowing. We flew with Southwest in December and i remember asking the the flight attendant " is this a max 8?", he said no, it was a -700. On the way back though, by the time we sat down and i pulled out the brochure, we were indeed on a max 8. Talk about bad luck, they only have 34 of them out of a fleet of 500.  Needless to say the flight was uneventful but the fact that 189 people died, and then another 159 3 months later for the same problem is really horrible. Shows the power of Corporations today, that the US government was the last to act, only after the entire rest of the world had grounded them
         

Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #41 on: March 16, 2019, 11:52:43 am »
Fuel efficient -> more payload or more fuel -> more mass -> more alpha (AoA) (especially during climb to cruise alt).
Swept wings are inherently unstable nose high. For 70 years man have flown aircraft fitted with a stick pusher. The only difference here is that its a digital/software system implemented in the FBW rules. You obviously have to know a bit about aviation to understand its action during flight. But, hey, Airline Pilots are said to be such guys...

Last but not least, the pitot feed might be the one faulting the FBW.
 
 
« Last Edit: March 16, 2019, 12:03:47 pm by TomcatViP »

Offline Archibald

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Re: Boeing 737 MAX family
« Reply #42 on: March 16, 2019, 12:16:28 pm »
Quote
a safety feature on the Boeing aircraft was repeatedly trying to put the plane into a dive as a result of a malfunction.

the suspect mugshot has been published



https://www.youtube.com/watch?reload=9&v=WMhYl74vw2c
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Offline Hobbes

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Re: Boeing 737 MAX family
« Reply #43 on: March 16, 2019, 12:29:50 pm »

 to me that says" Boeing stuck engines on their 737 platform  that were too large and aerodynamically inappropriate for the  aircraft, made it inherently unstable and dangerous to operate, then tried to address the problem with a software band-aid" .
       

None of those are problematic. Thousands of unstable aircraft have been operated since the 1970s without incident. Where it went wrong is that the pilots didn't realize the MCAS was influencing the airplane's attitude due to insufficient training on that system.

Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #44 on: March 16, 2019, 01:12:38 pm »
deleted
« Last Edit: March 16, 2019, 02:48:01 pm by TomcatViP »

Offline galgot

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Re: Boeing 737 MAX family
« Reply #45 on: March 16, 2019, 01:13:43 pm »
From what I’ve read here and there,
the pilot wasn’t meant to be more trained about the MCAS as flying the MAX doesn’t need an extra type rating from previous 737 types, that was a selling argument. Rating a pilot to an extra type cost money to the airlines…
Problem , new engines and MCAS changes a lot the way the plane fly in certain conditions, that would certainly requires extra type rating.
« Last Edit: March 16, 2019, 01:17:35 pm by galgot »

Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #46 on: March 16, 2019, 02:46:54 pm »
Non MAX 737 had a stick pusher.

Offline galgot

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Re: Boeing 737 MAX family
« Reply #47 on: March 16, 2019, 02:59:58 pm »
But it's not the MCAS. btw, MCAS apparently doesn't "push the stick", it unrolls trim to nose down.
good vid :
https://www.youtube.com/watch?time_continue=651&v=TlinocVHpzk

Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #48 on: March 16, 2019, 03:08:10 pm »
The angle of attack is also used to control an Automatic trim action during manual flight to gradually relieve the pilot of any constant stick forces. This action is not described in the 737NG FCOM and might be the reason why the bulletin is restricted to the 737 MAX type, which has implemented this to increase longitudinal stability for this type.

Any such Automatic trim action which doesn’t makes sense has the feel of a runaway pitch trim which is a very common emergency simulator training scenario. In isolation, this should be easy to spot and the correct action (Cut out the trim as described below) could be taken in relative calmness. I’m inclined to think the JT610 crew had to handle a more difficult and stressing false Stall warning and recovery situation, which is the same between the 737NG and the 737 MAX.

The Stall warning and recovery functions are:

Above a preset AOA, a stall warning audio voice says: “Stall, Stall, Stall” and the Pilots control yoke on the side with the high AOA start shaking as an additional physical warning
If the AOA does not decrease after the triggered Stick Shaker but stays at a high angle, the system then creates a stronger control Yoke force through the Elevator Feel & Centering unit by applying a nose down stick force for the present Yoke position.
As an additional measure, the Flight Control Computer starts a stabilizer trim nose down movement using the Autopilot trim channel. The trim action lasts 10 seconds. The Pilot’s can counteract the trim by using their trim buttons, it overrides the Stall system trim.
If the AOA persists, the Pitch trim nose down will trigger again after a certain time lapse. If the PIlots have counter trimmed, the system waits 5 seconds until it repeats the trim nose down for 10 seconds.
If the crew suspects an Automatic trim action or Stall warning to be false, the Operating Procedure is to switch off the Nose down trim action by disengaging both trim channels of the Pitch trim system and trimming the stabilizer manually by the wheel. These switches are placed on the central pedestal, Figure 4.

Figure 4. Control stand Switch to Cut Out the AUTO PILOT’s STAB TRIM function (No 6) and the PIlot’s trim channel (No 5). No 4 are the Pilot’s trim buttons operating the MAIN ELECTrical trim (No 5) in normal operation. Source: 737NG FCOM.
It’s this action that Boeing’s message conveys, reminding the 737 operators this is the procedure for suspected false stall actions caused by a false AOA reading.



See also here: https://www.flightglobal.com/news/articles/atlas-767-crash-probe-strives-to-comprehend-pitch-up-456702/
(regarding similar nose pitch down and accelerated dive down on the crashed Atlas's 767).
« Last Edit: March 16, 2019, 03:26:43 pm by TomcatViP »

Offline galgot

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Re: Boeing 737 MAX family
« Reply #49 on: March 16, 2019, 03:34:46 pm »
Very interesting thanks. This at the end in particular :
"It’s by now clear it’s not a simple fact of them stalling the aircraft due to one side airspeed readings being unreliable. They had more to fight, so far is understood. But exactly what, we don’t know and therefore we don’t speculate further."

The MCAS was indeed introduced with the MAX :
 http://www.b737.org.uk/mcas.htm
"MCAS was introduced to counteract the pitch up effect of the LEAP-1B engines at high AoA. The engines were both larger and relocated slightly up and forward from the previous NG CFM56-7 engines to accomodate their larger diameter. This new location and size of the nacelle causes it to produce lift at high AoA; as the nacelle is ahead of the CofG this causes a pitch-up effect which could in turn further increase the AoA and send the aircraft closer towards the stall. MCAS was therefore introduced to give an automatic nose down stabilizer input during steep turns with elevated load factors (high AoA) and during flaps up flight at airspeeds approaching stall."

Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #50 on: March 16, 2019, 05:02:29 pm »
Quote
This website and the 737 Technical Guide have no connection to the Boeing Company.

And on the front page of teh same website:



« Last Edit: March 16, 2019, 05:13:14 pm by TomcatViP »

Offline galgot

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Re: Boeing 737 MAX family
« Reply #51 on: March 16, 2019, 05:22:00 pm »
Ok... And ?

Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #52 on: March 16, 2019, 05:45:18 pm »
rotation speed is extremely low and capped. Moreover system "operates only at extreme high speed pitch up condition" (doc2 - the one paragraph before last one).

Then I will ask you: does that fits climb to cruise conditions?

Offline galgot

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Re: Boeing 737 MAX family
« Reply #53 on: March 16, 2019, 06:17:09 pm »
rotation speed is extremely low and capped. Moreover system "operates only at extreme high speed pitch up condition" (doc2 - the one paragraph before last one).

Then I will ask you: does that fits climb to cruise conditions?

Well...if you say so. I was just pointing that the MCAS system was introduced with the MAX version, due to the new engines apparently. And that it maybe would have required a more throughout training (specific type rating) for that version.

As for your question, did the Ethiopian plane even had time to be in cruise condition, the crash occured , what, 6 or 8 mn after takeoff ?



Offline TomS

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Re: Boeing 737 MAX family
« Reply #54 on: March 16, 2019, 07:07:02 pm »
It didn't.  Which is problematic because MCAS is inactive while flaps are deployed, and they definitely should have been deployed at that point.

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Re: Boeing 737 MAX family
« Reply #55 on: March 17, 2019, 03:19:35 am »
Which raises the question, did Boeing put in a hardware interlock or similar to ensure it wouldn't activate while the flaps were in operation?
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Offline draganm

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Re: Boeing 737 MAX family
« Reply #57 on: March 17, 2019, 11:24:05 am »
so they knew they had an airplane with very different flight characteristics, actually in comparing the pictures it doesn't even look like the same aircraft, yet gave no additional training to pilots who were trained on standard 737's? Seems extremely negligent, even before the 1st crash
 737-700

max8




Offline mboeller

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Re: Boeing 737 MAX family
« Reply #58 on: March 17, 2019, 01:00:27 pm »
I have just read this Seattle times article about the crashes:

https://www.seattletimes.com/business/boeing-aerospace/failed-certification-faa-missed-safety-issues-in-the-737-max-system-implicated-in-the-lion-air-crash/

I think this article gives a very good summary about the subject.

Offline kcran567

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Re: Boeing 737 MAX family
« Reply #59 on: March 18, 2019, 12:00:28 am »
Here is a very good synopsis of a pilot familiar with the 737 MAX and it's mcas
Problems and how he had a nose down situation and disabled the autopilot.
Very interesting to read this . I'm tremendously saddened for Lion and Ethiopian air and all
Souls lost. Also, I live near Phoenix Sky Harbor airport and used to see many many
737s always flying around the clock departing and returning. Air traffic is 1/10th what is
Normal, and very quiet. Like a ghost town. And the planes are taking off and landing in
at very high altitude approaches than normal...am seeing very few and only older 737s. The traffic impact is much more than what is reported.


1) From November 2018, after the Lion Air crash. ASRS summary: “B737MAX Captain reported an autopilot anomaly in which led to an undesired brief nose down situation.”

ACN: 1597380

Time / Day

Date : 201811

Place

Locale Reference.ATC Facility : ZZZ.TRACON
State Reference : US
Altitude.MSL.Single Value : 2000

Environment

Weather Elements / Visibility : Rain
Weather Elements / Visibility : Snow

Aircraft

Reference : X
ATC / Advisory.TRACON : ZZZ
Aircraft Operator : Air Carrier
Make Model Name : B737-800
Crew Size.Number Of Crew : 2
Operating Under FAR Part : Part 121
Flight Plan : IFR
Mission : Passenger
Nav In Use : FMS Or FMC
Flight Phase : Climb
Airspace.Class B : ZZZ

Component

Aircraft Component : Autoflight System
Aircraft Reference : X
Problem : Malfunctioning

Person

Reference : 1
Location Of Person.Aircraft : X
Location In Aircraft : Flight Deck
Reporter Organization : Air Carrier
Function.Flight Crew : Captain
Function.Flight Crew : Pilot Flying
Qualification.Flight Crew : Instrument
Qualification.Flight Crew : Air Transport Pilot (ATP)
Qualification.Flight Crew : Multiengine
Experience.Flight Crew.Last 90 Days : 626
ASRS Report Number.Accession Number : 1597380
Human Factors : Human-Machine Interface
Human Factors : Confusion

Events

Anomaly.Aircraft Equipment Problem : Less Severe
Detector.Automation : Aircraft Other Automation
Detector.Person : Flight Crew
When Detected : In-flight
Result.Flight Crew : FLC Overrode Automation
Result.Flight Crew : Overcame Equipment Problem
Result.Aircraft : Equipment Problem Dissipated

Assessments

Contributing Factors / Situations : Aircraft
Contributing Factors / Situations : Human Factors
Primary Problem : Aircraft

Narrative: 1

It was day three of six for me and day three with very good FO (First Officer). Well rested, great rapport and above average Crew coordination. Knew we had a MAX. It was my leg, normal Ops Brief, plus I briefed our concerns with the MAX issues, bulletin, MCAS, stab trim cutout response etc. I mentioned I would engage autopilot sooner than usual (I generally hand fly to at least above 10,000 ft.) to remove the possible MCAS threat.

Weather was about 1000 OVC drizzle, temperature dropping and an occasional snow flake. I double checked with an additional personal walkaround just prior to push; a few drops of water on the aircraft but clean aircraft, no deice required. Strong crosswind and I asked Tug Driver to push a little more tail east so as not to have slow/hung start gusts 30+.

Wind and mechanical turbulence was noted. Careful engine warm times, normal flaps 5 takeoff in strong (appeared almost direct) crosswind. Departure was normal. Takeoff and climb in light to moderate turbulence. After flaps 1 to "up" and above clean "MASI up speed" with LNAV engaged I looked at and engaged A Autopilot. As I was returning to my PFD (Primary Flight Display) PM (Pilot Monitoring) called "DESCENDING" followed by almost an immediate: "DONT SINK DONT SINK!"

I immediately disconnected AP (Autopilot) (it WAS engaged as we got full horn etc.) and resumed climb. Now, I would generally assume it was my automation error, i.e., aircraft was trying to acquire a miss-commanded speed/no autothrottles, crossing restriction etc., but frankly neither of us could find an inappropriate setup error (not to say there wasn't one).

With the concerns with the MAX 8 nose down stuff, we both thought it appropriate to bring it to your attention. We discussed issue at length over the course of the return to ZZZ. Best guess from me is airspeed fluctuation due to mechanical shear/frontal passage that overwhelmed automation temporarily or something incorrectly setup in MCP (Mode Control Panel). PM's callout on "descending" was particularly quick and welcome as I was just coming back to my display after looking away. System and procedures coupled with CRM (Resource Management) trapped and mitigated issue.

Synopsis

B737MAX Captain reported an autopilot anomaly in which led to an undesired brief nose down situation
« Last Edit: March 18, 2019, 12:11:53 am by kcran567 »

Offline ADVANCEDBOY

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Re: Boeing 737 MAX family
« Reply #60 on: March 18, 2019, 12:37:45 am »
If I understand it correctly, the horizontal stabilizer jackscrew  was in a  nose down position  for the leading edge of the stabilizer while it should be the opposite. I don`t know if it was a software problem or a mechanical failure, but this is what came to my mind. 737, being a  60 + year old design was probably not well suited for very massively extended fuselage versions. As  stabilizers  got further and further away from the main wing, the load exerted to  rear stabilizers grew. I wonder if that jackscrew was updated   for increased loads or they used the same design from 60ies.
I am, just totally guessing here. Besides, in February another Boeing crashed- 767-300 cargo aircraft.
 Now I can see Boeing is desperate to regain falling market value by advancing  forward with 797. 
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Offline Grey Havoc

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Offline lastdingo

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Re: Boeing 737 MAX family
« Reply #62 on: March 18, 2019, 05:23:37 am »
https://www.seattletimes.com/business/boeing-aerospace/failed-certification-faa-missed-safety-issues-in-the-737-max-system-implicated-in-the-lion-air-crash/

Boeing largely self-certified instead of a proper certification process.

Quote
The FAA, citing lack of funding and resources, has over the years delegated increasing authority to Boeing to take on more of the work of certifying the safety of its own airplanes.

Early on in certification of the 737 MAX, the FAA safety engineering team divided up the technical assessments that would be delegated to Boeing versus those they considered more critical and would be retained within the FAA.

But several FAA technical experts said in interviews that as certification proceeded, managers prodded them to speed the process. Development of the MAX was lagging nine months behind the rival Airbus A320neo. Time was of the essence for Boeing.

A former FAA safety engineer who was directly involved in certifying the MAX said that halfway through the certification process, “we were asked by management to re-evaluate what would be delegated. Management thought we had retained too much at the FAA.”

“There was constant pressure to re-evaluate our initial decisions,” the former engineer said. “And even after we had reassessed it … there was continued discussion by management about delegating even more items down to the Boeing Company.”

Even the work that was retained, such as reviewing technical documents provided by Boeing, was sometimes curtailed.

“There wasn’t a complete and proper review of the documents,” the former engineer added. “Review was rushed to reach certain certification dates.”

When time was too short for FAA technical staff to complete a review, sometimes managers either signed off on the documents themselves or delegated their review back to Boeing.

“The FAA managers, not the agency technical experts, have final authority on delegation,” the engineer said.


That's a classic case of business managers going too far, overriding engineers where the engineers have a superior point in the discussion.

Offline kcran567

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Re: Boeing 737 MAX family
« Reply #63 on: March 18, 2019, 10:28:57 am »
I agree AdvancedBoy and others, how could Boeing make the aircraft much longer, change the engine location and a much more powerful engine, change the wing, and still call it a "737" max without an all new certification? Apparently Boeing didn't even have the flight manuals updated with the new procedures to get control back.



pics from from NYT:

Offline Foo Fighter

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Re: Boeing 737 MAX family
« Reply #64 on: March 18, 2019, 10:47:35 am »
I would not like to be a Boeing senior executive, this sort of thing could take them all the way down.

Offline kcran567

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Re: Boeing 737 MAX family
« Reply #65 on: March 18, 2019, 12:06:50 pm »
One last video, this is good story on the Lion air crash very similar to the Ethiopian crash.
The report talks about faulty Angle Of Attack sensors, among other issues.
A few days before the Lion air crash a flight crew was able to land safely after
turning off the stabilizer electrical switch after another nose down faulty mcas error.
Other pilot crews didn't know to do this apparently. Lack of proper training and the
737 max prone to this malfunction.

« Last Edit: March 18, 2019, 12:09:20 pm by kcran567 »

Offline Triton

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Re: Boeing 737 MAX family
« Reply #66 on: March 18, 2019, 02:10:23 pm »
"Boeing faces a 'very, very serious' criminal probe — Here's what to expect"
Alexis Keenan
Reporter
Yahoo Finance March 18, 2019

Source:
https://www.yahoo.com/lifestyle/boeing-justice-department-crash-202330994.html

Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #67 on: March 18, 2019, 02:19:11 pm »
Stupidity won't make a case in court.

Once again the MCAS is just a sophisticated simple system that couldn't have brought the plane down by itself. The feed of information was erroneous on Lion air's flight and we have similitude here to assess that we could well be in the same case.
Ppl should relax. There is nothing in the Seattle time to justify from wrong doing etc...

At the end, it will stand in history how you can have an FBI inquiry after the last presidential election while staying mumble with the amount of false logic regarding hard to understand technological matters filling the press today.
« Last Edit: March 18, 2019, 02:28:13 pm by TomcatViP »

Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #68 on: March 18, 2019, 02:23:41 pm »
Quote
I agree AdvancedBoy and others, how could Boeing make the aircraft much longer, change the engine location and a much more powerful engine, change the wing, and still call it a "737" max without an all new certification?

A321?

Oh.. Wait. It's not exactly the same.

Dear Boeing, how stupid you are when you could have called this new product: the semi-MAX

 ::)
« Last Edit: March 18, 2019, 02:25:45 pm by TomcatViP »

Offline Triton

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Re: Boeing 737 MAX family
« Reply #69 on: March 18, 2019, 04:09:50 pm »

Offline Triton

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Re: Boeing 737 MAX family
« Reply #70 on: March 18, 2019, 07:56:17 pm »
"Boeing Shows 'What Not To Do' In 737 MAX Crisis Communications, Says Expert"
by Michael Goldstein
03/18/2019

Source:
https://www.forbes.com/sites/michaelgoldstein/2019/03/18/boeing-shows-what-not-to-do-in-737-max-crisis-communications-says-expert/#1c47120e40a7

Offline Grey Havoc

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Offline Grey Havoc

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Offline Grey Havoc

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Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #74 on: Yesterday at 12:04:38 pm »
Quote
“They’re critical, and cost almost nothing for the airlines to install,” said Bjorn Fehrm, an analyst at the aviation consultancy Leeham. “Boeing charges for them because it can. But they’re vital for safety.”
Source: https://pressfrom.info/us/news/us/-257796-doomed-boeing-jets-lacked-2-safety-features-that-company-sold-only-as-extras.html

To me this is another sign that Boeing is still thinking they are selling planes to people that knows about flight: it's a redundant safety feature with basic commune flight rules. Now that they have understood the discrepancy that exists b/w their understanding of the business and that of the industry today, I would suggests them top add to their catalog: a white scarf, retro designed google and "seatpants" that their public (PIC mainly) understand what they do for a living: flying.... 
« Last Edit: Yesterday at 12:14:50 pm by TomcatViP »

Offline mboeller

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Re: Boeing 737 MAX family
« Reply #75 on: Today at 04:26:33 am »
article about another aspect:

https://leehamnews.com/2019/03/22/bjorns-corner-the-ethiopian-airlines-flight-302-crash-part-2/

As far as I understand it:
"blowback". Both crews tried to escape the stall-warning from MCAS and overspeed at low attitude. Therefore the elevators lost efficiency and that in the end doomed the aircrafts.

Offline TomcatViP

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Re: Boeing 737 MAX family
« Reply #76 on: Today at 10:12:44 am »
VMO is higher than 300knots. And Bjorn refers to ground speed. It's difficult to assess a speed excursion just by the say of it. A blownback issue with the tailplane inside the normal operational envelope would trigger to many false flag for such to go unnoticed until today.

I don't bit it. I am sorry but the blownback is more in the hands of those that want to see any malfunction to suits their early theories.  I would like experts in the press to focus more on the AoA indicator. The circumstances surrounding the swap of this unit in LionAir and the apparent casual decision to continue into the flight on both occasions despite a very early warning of a safety system failure is disconcerting by itself to fill thousands of inked pages. Just imagine the panic inside the cabin with such hard noseover inputs. How can any crew makes for the screams and protest that would have occurred?  And where are then the concerned journalists that would have had the competencies to discuss this (by being simple passenger themselves) instead of embracing weird sophisticated theories?
« Last Edit: Today at 10:22:45 am by TomcatViP »