Boeing 737 (MAX) news

Join this forum to discuss the latest news that happened in the world of commercial aviation.

Moderator: Latest news team

Post Reply
jan_olieslagers
Posts: 3001
Joined: 24 Jun 2006, 08:34
Location: Vl.Brabant
Contact:

Re: Boeing 737 (MAX) news

Post by jan_olieslagers » 20 May 2019, 17:21

I do not want you mentioning my employer
Why then did you make it clear who that is? Not that I care, either way, but you have no ground for whining.

Passenger
Posts: 6277
Joined: 06 Dec 2010, 20:54

Re: Boeing 737 (MAX) news

Post by Passenger » 20 May 2019, 17:34

sean1982 wrote:
20 May 2019, 16:51
...your analogy doesnt make sense either as every airline first and foremost wants to operate safely, no matter what type they fly or have on order
Sure. Just like the Ethiopian crew. They were also 100% sure it was safe.

User avatar
luchtzak
Posts: 11318
Joined: 18 Sep 2002, 00:00
Location: Hofstade, Zemst - Belgium
Contact:

Re: Boeing 737 (MAX) news

Post by luchtzak » 20 May 2019, 17:49

sean1982 wrote:
20 May 2019, 16:51

Secondly, have I not said before I do not want you mentioning my employer? Wasn't that clear enough?
Text removed.

Passenger: please respect personal details.

Passenger
Posts: 6277
Joined: 06 Dec 2010, 20:54

Re: Boeing 737 (MAX) news

Post by Passenger » 20 May 2019, 21:59

luchtzak wrote:
20 May 2019, 17:49
sean1982 wrote:
20 May 2019, 16:51
Secondly, have I not said before I do not want you mentioning my employer? Wasn't that clear enough?
Text removed.
Passenger: please respect personal details.
Sorry webmaster - but I didn't mention name or function. And actually it was relevant. It proofs why some people insist and persist that the 737 MAX is safe.

Actual damage so far: 1 billion USD (1 miljard). And that's going to increase a lot more because Boeing has choosen for salami communication (= a quote from travel news editor Jan Peeters, travel360.be, 6th May): bad news is released in slices, and only when there is no possibility anymore to hide it.

Latest example: Boeing admits errors in the flight simulator software:
https://www.afp.com/en/news/15/boeing-a ... oc-1gm9761

737MAX
Posts: 243
Joined: 29 Aug 2017, 08:46

Re: Boeing 737 (MAX) news

Post by 737MAX » 20 May 2019, 22:31

As always, you have your idea of things and you will *never* be open to extra information (which doesn't necessarily contradicts your opinion, by the way).

Why are you member of a forum if you only want to talk to yourself?

lucas
Posts: 98
Joined: 01 Feb 2017, 15:06

Re: Boeing 737 (MAX) news

Post by lucas » 20 May 2019, 23:24

Come-on guys, is it really that hard to do what a forum is meant for? Listen to each others opinion and respect it. That's the only way to have a constructive debate. You don't have to share somebody's ideas to respect them.

User avatar
luchtzak
Posts: 11318
Joined: 18 Sep 2002, 00:00
Location: Hofstade, Zemst - Belgium
Contact:

Re: Boeing 737 (MAX) news

Post by luchtzak » 22 May 2019, 09:04

Boeing 737 MAX parking lot, crowded.

User avatar
sn26567
Posts: 35473
Joined: 13 Feb 2003, 00:00
Location: Rosières/Rozieren, Belgium
Contact:

Re: Boeing 737 (MAX) news

Post by sn26567 » 22 May 2019, 18:50

We could fill a dictionary with the requests to Boeing for compensation for the grounding of the 737 MAX airline fleets. Here are the latest ones:

TURKISH AIRLINES expects compensation from Boeing for losses over the grounding of 12 737 Max aircraft, the chairman of Turkey's flagship carrier was quoted as saying, adding that he would meet Boeing's chief executive on Friday.

China's three biggest airlines have filed claims seeking compensation from Boeing over the grounding and delayed delivery of 737 MAX 8 aircraft following two deadly crashes, Chinese state media reported on Wednesday. The reports in various state-run media that China Southern Airlines, China Eastern Airlines, and Air China would seek payouts from the American aerospace giant come against the backdrop of an escalating US-China trade war.
André
ex Sabena #26567

pilot_gent
Posts: 36
Joined: 21 Jul 2015, 22:38

Re: Boeing 737 (MAX) news

Post by pilot_gent » 22 May 2019, 21:28

The reason why people don't want to fly the MAX anymore is quite easy, social media and so claimed experts sprouting their opinions. In the days without social media there wouldn't have been such a hype around this. I'm, btw, not claiming these deads are not a tragedy, they are.

A lot of opinions of people, some more correct than others. I'll give my own :D Like with every crash, several causes. Like with most crashes, pilot error plays a big role.

"There was nothing more the pilots could have done" (quote Ethiopian):
- Fact: they did not once touch the throttles. Forces became uncontrollable due to the high speed.
- Fact: they re-engaged the trim system (not recommended). Due to the re-engaging, the faulty system put the nose even more down.
- Fact: they did not perform the items for unreliable airspeed.

"The MCAS is a fix for an unstable aircraft, it should have never flown".:
I understand this might be difficult to understand for the public, this is however common practice in aviation. The Fokker 100 has a stick pusher, it pushes the nose down when AOA gets too high. Sound familiar? Have a look at what MCAS does.

The crash has in my opinion 3 main causes:
- Faulty AOA sensor --> fix it or replace it.
- MCAS functioning on faulty sensor --> build in extra check (software).
- Pilots unable to fly an aircraft without autopilot --> the disease of commercial aviation, won't be fixed soon unfortunately.

Would the crash have happened if the pilots knew how to fly? Probably not.

Would the crash have happened if MCAS didn't activate? I'm not sure. It would have still been unreliable airspeed + pilots not able to fly. Just look at Air France how well that played out...

Bracebrace
Posts: 192
Joined: 04 Apr 2006, 00:00

Re: Boeing 737 (MAX) news

Post by Bracebrace » 23 May 2019, 03:11

pilot_gent wrote:
22 May 2019, 21:28
- Fact: they did not once touch the throttles. Forces became uncontrollable due to the high speed.
Can you explain this "fact"?

pilot_gent
Posts: 36
Joined: 21 Jul 2015, 22:38

Re: Boeing 737 (MAX) news

Post by pilot_gent » 23 May 2019, 08:41

Bracebrace wrote:
23 May 2019, 03:11
Can you explain this "fact"?
Sure.

- The aircraft took off with takeoff thrust (almost full thrust).
- The thrust setting remained there till the crash.
- The force of the stabilizer (the surface controlled by MCAS) is proportional to the airspeed

meaning: an input by MCAS might have been recoverable by pulling the yoke at low speed, but not at high speed due to the increased force.

This is not just my analysisis, Flight Global:

"Proper response to an overspeed would be to retard the thrust levers and adjust pitch attitude. The crew was trying to raise the nose, yet thrust remained at 94% N1. Retarding the thrust levers and extending the speed brakes would have slowed the aircraft, and may have allowed the descent to be arrested by the elevator alone.

737MAX
Posts: 243
Joined: 29 Aug 2017, 08:46

Re: Boeing 737 (MAX) news

Post by 737MAX » 23 May 2019, 09:05

You are right, pilot_gent. They had the behavior of pilots who never fly the damn plane.

No need to explain why the plane will end up on the ground if you level-off with 94% thrust all the way...

I can imagine they were confused and so on, like discussed earlier, but no, they haven’t done « everything they could ».

Bracebrace
Posts: 192
Joined: 04 Apr 2006, 00:00

Re: Boeing 737 (MAX) news

Post by Bracebrace » 23 May 2019, 09:29

pilot_gent wrote:
23 May 2019, 08:41
- The force of the stabilizer (the surface controlled by MCAS) is proportional to the airspeed

meaning: an input by MCAS might have been recoverable by pulling the yoke at low speed, but not at high speed due to the increased force.

This is not just my analysisis, Flight Global:

"Proper response to an overspeed would be to retard the thrust levers and adjust pitch attitude. The crew was trying to raise the nose, yet thrust remained at 94% N1. Retarding the thrust levers and extending the speed brakes would have slowed the aircraft, and may have allowed the descent to be arrested by the elevator alone.
I am still not getting the explanation. An aircraft uses aerodynamic forces to steer. The elevator is hydraulic driven, they didn't have a hydraulic failure. Elevator was moveable. More airspeed means more controllability and an increased natural tendency of the aircraft to pitch up. Reducing thrust creates the opposite: it gives a slight nose-down. Opposite.

If you are referring to manual trim, as the MCAS trims down, the manual trim becomes harder (to impossible) to move the further away you move from the in-trim speed. Manual trim forces depend mainly on "out-of-trim" condition. As it provides a trim-down, the in-trim speed becomes higher and you need to dive down to gain speed (clearly described in the 737 FCTM, aerodynamic offloading).

In short: if the MCAS activates you need speed to correct the situation. If you/they do know all in detail, then I would like to know what the final "in-trim speed" was when the MCAS activation was stopped in reference to their actual speed.

BTW: the article is very clear. The wording is "may". They don't know. They guess.

pilot_gent
Posts: 36
Joined: 21 Jul 2015, 22:38

Re: Boeing 737 (MAX) news

Post by pilot_gent » 23 May 2019, 11:46

Bracebrace wrote:
23 May 2019, 09:29
I am still not getting the explanation. An aircraft uses aerodynamic forces to steer. The elevator is hydraulic driven, they didn't have a hydraulic failure. Elevator was moveable. More airspeed means more controllability and an increased natural tendency of the aircraft to pitch up. Reducing thrust creates the opposite: it gives a slight nose-down. Opposite.

If you are referring to manual trim, as the MCAS trims down, the manual trim becomes harder (to impossible) to move the further away you move from the in-trim speed. Manual trim forces depend mainly on "out-of-trim" condition. As it provides a trim-down, the in-trim speed becomes higher and you need to dive down to gain speed (clearly described in the 737 FCTM, aerodynamic offloading).

In short: if the MCAS activates you need speed to correct the situation. If you/they do know all in detail, then I would like to know what the final "in-trim speed" was when the MCAS activation was stopped in reference to their actual speed.

BTW: the article is very clear. The wording is "may". They don't know. They guess.
Just to be clear, I'm talking about aerodynamic forces, not force experienced by pulling a yoke. Wether the elevator is hydraulic or cable or whatever is thus irrelevant (for this discussion). I'm also not talking about the thrust pitching moment as that effect is negligible compared to stab trim movement.

- Each time the stabilizer moves a change in pitching moment occurs.
- At low speed a certain amount of change will trigger a pitching moment, the same amount of change will cause a larger pitching moment at high speed.
- the final blow of MCAS at >340 kts put the aircraft in a nose down moment, unable to arrest with elevator alone (while before they were).

Anyway, this is all secondary. If you drive a car and the car goes too fast you remove your foot from the pedal. You would expect a fully qualified flight crew to do the same with an aircraft going in overspeed.

Bracebrace
Posts: 192
Joined: 04 Apr 2006, 00:00

Re: Boeing 737 (MAX) news

Post by Bracebrace » 23 May 2019, 11:58

pilot_gent wrote:
23 May 2019, 11:46
- At low speed a certain amount of change will trigger a pitching moment, the same amount of change will cause a larger pitching moment at high speed.
- the final blow of MCAS at >340 kts put the aircraft in a nose down moment, unable to arrest with elevator alone (while before they were).

Anyway, this is all secondary. If you drive a car and the car goes too fast you remove your foot from the pedal. You would expect a fully qualified flight crew to do the same with an aircraft going in overspeed.
Not really, it's about the in-trim speed. As said before, in order to move the stabilizer, the forces depend on the difference between the in-trim speed and the actual speed. The lower the difference, the lower the forces. So in order to be able to move the stabilizer - trimmed for a high-speed, you need to go for that speed. If that speed is an overspeed, you need to go into overspeed or you will not be able to recover. Reducing speed will only reduce effectiveness. You need the speed. Aerodynamic offloading with a jammed stabilizer as explained in the FCTM (which Boeing asks you to do in the stab trim runaway checklist)
Last edited by Bracebrace on 23 May 2019, 12:50, edited 1 time in total.

User avatar
sn26567
Posts: 35473
Joined: 13 Feb 2003, 00:00
Location: Rosières/Rozieren, Belgium
Contact:

Re: Boeing 737 (MAX) news

Post by sn26567 » 23 May 2019, 12:22

Boeing is being sued by French widow who filed a lawsuit against the manufacturer for US$276 million in damages over the crash in Ethiopia of a B737 MAX 8, which killed all 157 people on board — including her husband.
André
ex Sabena #26567

pilot_gent
Posts: 36
Joined: 21 Jul 2015, 22:38

Re: Boeing 737 (MAX) news

Post by pilot_gent » 23 May 2019, 13:24

Bracebrace wrote:
23 May 2019, 11:58
pilot_gent wrote:
23 May 2019, 11:46
- At low speed a certain amount of change will trigger a pitching moment, the same amount of change will cause a larger pitching moment at high speed.
- the final blow of MCAS at >340 kts put the aircraft in a nose down moment, unable to arrest with elevator alone (while before they were).

Anyway, this is all secondary. If you drive a car and the car goes too fast you remove your foot from the pedal. You would expect a fully qualified flight crew to do the same with an aircraft going in overspeed.
Not really, it's about the in-trim speed. As said before, in order to move the stabilizer, the forces depend on the difference between the in-trim speed and the actual speed. The lower the difference, the lower the forces. So in order to be able to move the stabilizer - trimmed for a high-speed, you need to go for that speed. If that speed is an overspeed, you need to go into overspeed or you will not be able to recover. Reducing speed will only reduce effectiveness. You need the speed. Aerodynamic offloading with a jammed stabilizer as explained in the FCTM (which Boeing asks you to do in the stab trim runaway checklist)
Since you are still talking about a different thing than I am I'll give it a rest (i never referred to trimming manually).

Bracebrace
Posts: 192
Joined: 04 Apr 2006, 00:00

Re: Boeing 737 (MAX) news

Post by Bracebrace » 23 May 2019, 19:14

No, Boeing does. It is a stabilizer trim runaway. The procedure the Ethiopian guys followed.

737MAX
Posts: 243
Joined: 29 Aug 2017, 08:46

Re: Boeing 737 (MAX) news

Post by 737MAX » 23 May 2019, 19:41

Before Boeing’s MAX return to service: we need answers and transparency
https://www.eurocockpit.be/news/boeings ... v4ZBB_ggIs

User avatar
luchtzak
Posts: 11318
Joined: 18 Sep 2002, 00:00
Location: Hofstade, Zemst - Belgium
Contact:

Re: Boeing 737 (MAX) news

Post by luchtzak » 25 May 2019, 06:01


Post Reply