Boeing Max.

This forum has been developed to discuss aviation related topics.

Moderators: lilfssister, North Shore, ahramin, sky's the limit, sepia, Sulako, I WAS Birddog

User avatar
confusedalot
Rank 8
Rank 8
Posts: 917
Joined: Fri Jul 03, 2009 9:08 pm
Location: location, location, is what matters

Re: Boeing Max.

Post by confusedalot »

With all respect to all, yer all missing the point. And the point is.....you still need to know how to fly a plane. These machines are now so dummy proof that pretty much any driver can operate them. Good, bad, does not matter, if you have a quarter of a brain of the average human, you can't get hurt. YET, they still crash.

Reminds me of the toyota incident where the lady had a gas pedal runaway but could not figure out that all she needed to do was push on the brakes. She was smart enough to call her husband though while all of this was going on, telling him how terrified she was.......go figure......So all toyotas have a convoluted kill system now.
Flew the ng only, not the max, but pretty much the same plane. Did max sim though.
You could kill the whole system with a flick of a switch, but that was not done. That includes the mcas. But then......you need to fly the plane.
Sure, there was an engineering lapse/mistake. How far do we need to go?
Remember air france who could not figure a out a deep stall in an airbus and flat stalled into the south atlantic?
And of course there is the media, they conviently forget to tell the whole story for a quick and lucrative story.

Cheers.
---------- ADS -----------
 
Attempting to understand the world. I have not succeeded.

veni, vidi,...... vici non fecit.

:?
User avatar
pilotbzh
Rank 7
Rank 7
Posts: 595
Joined: Sat Jan 15, 2005 7:33 am
Location: yyz

Re: Boeing Max.

Post by pilotbzh »

GoinVertical wrote: Wed Sep 04, 2019 4:58 pm
pilotbzh wrote: Wed Sep 04, 2019 4:09 pm
lostaviator wrote: Wed Sep 04, 2019 3:45 pm Once you get yourself into the situation of having that much nose down trim, at such a low altitude, you are done.

The manual trim wheel won’t move with the opposing forces applied. The only way to trim is to release all force and let the nose fall. If you don’t have a few thousand feet, it’s all over.
Not true, first pull hard to bring the nose up respecting the stall warning, then release pressure to manually trim nose up, no need to loose altitude.... as long as you control the speed, it won't work if you let the speed go 350+Kts
What if the stab is trimmed so nose - down that full up elevator only gives you level flight or just slightly better?

With full nose down trim, you still have full authority on the elevators to pull that nose up but the force required to do so increases with speed. The trim only adjust the horizontal stab... and juste like railing a fish you don’t have to give back any line as you lower the rod to rail or descent at all to manually re-trim a mis-trim situation, but speed control is crucial...
---------- ADS -----------
 
lostaviator
Rank 5
Rank 5
Posts: 334
Joined: Fri Jul 20, 2012 12:42 pm

Re: Boeing Max.

Post by lostaviator »

pilotbzh wrote: Wed Sep 04, 2019 7:19 pm
GoinVertical wrote: Wed Sep 04, 2019 4:58 pm
pilotbzh wrote: Wed Sep 04, 2019 4:09 pm

Not true, first pull hard to bring the nose up respecting the stall warning, then release pressure to manually trim nose up, no need to loose altitude.... as long as you control the speed, it won't work if you let the speed go 350+Kts
What if the stab is trimmed so nose - down that full up elevator only gives you level flight or just slightly better?

With full nose down trim, you still have full authority on the elevators to pull that nose up but the force required to do so increases with speed. The trim only adjust the horizontal stab... and juste like railing a fish you don’t have to give back any line as you lower the rod to rail or descent at all to manually re-trim a mis-trim situation, but speed control is crucial...
I don’t want to start an argument, but where did you get that information? Every conversation I’ve had with training pilots has been that the elevator can JUST keep the plane level with full nose down trim.

The shortage of max sims, and... the fact that Boeing doesn’t even know how the max handles, makes this a hard discussion to find real answers too.
---------- ADS -----------
 
User avatar
pilotbzh
Rank 7
Rank 7
Posts: 595
Joined: Sat Jan 15, 2005 7:33 am
Location: yyz

Re: Boeing Max.

Post by pilotbzh »

Did it in the max Sim.... Have 14000h TT just 400h on Max...
---------- ADS -----------
 
J31
Rank (9)
Rank (9)
Posts: 1077
Joined: Thu Feb 26, 2004 7:21 am

Re: Boeing Max.

Post by J31 »

The sim will only simulate what is programmed. Boeing provided the parameters to the sim manufactures and originally never included the MCAS programming. Many of the world regulators have little faith in the simulator programming to accurately portray the extreme corners of the MAX flight flight envelope.

I know from experience that the manual trim forces in the simulator do not accurately represent the Boeing 737-200. The aircraft took much more strength to manually turn the trim wheel in flight.

I would not put a lot of faith in a MAX sim to accurately simulate the ability to climb with full nose down trim at this point in time.

Boeing is going to have to prove both in the sim and the aircraft that the trim forces do not need super strength or split second reaction to keep the MAX from becoming a lawn dart.
---------- ADS -----------
 
iflyforpie
Top Poster
Top Poster
Posts: 8064
Joined: Tue Apr 15, 2008 12:25 pm
Location: Winterfell...

Re: Boeing Max.

Post by iflyforpie »

The stab doesn’t just trim the stabilizer. It also trims the elevators via the feel and centering unit and the PCUs. So nose down, you have to overcome a lot more spring pressure than when it’s neutral... and have to deflect the elevator much more relative the to neutral set by the feel and centering unit to counter what the stab is doing. Add some speed in there and now you’re fighting hydraulic pressure from the feel system as well.
---------- ADS -----------
 
Geez did I say that....? Or just think it....?
User avatar
Flying Low
Rank 8
Rank 8
Posts: 926
Joined: Sun Feb 15, 2004 7:22 pm
Location: Northern Ontario...why change now?

Re: Boeing Max.

Post by Flying Low »

Boeing is going to have to prove both in the sim and the aircraft that the trim forces do not need super strength or split second reaction to keep the MAX from becoming a lawn dart.
Well....the Lion Air crew flew the airplane for around 9 minutes using the electric trim repeatedly and the Ethiopian crew flew for 6 minutes using brute force. Even if you say it's 3 minutes to get the flaps up (when the MCAS kicks in) that's 6 and 3 minutes respectively for each crew flying with the MCAS forcing the nose down. I think we can fairly say split second reaction time is not necessary and considering the electric trim works neither is super human strength. Please don't get me wrong...I'm not excusing Boeing from a badly designed system...I still do not understand how either crew lost the airplane.
---------- ADS -----------
 
"The ability to ditch an airplane in the Hudson does not qualify a pilot for a pay raise. The ability to get the pilots, with this ability, to work for 30% or 40% pay cuts qualifies those in management for millions in bonuses."
mixturerich
Rank 5
Rank 5
Posts: 314
Joined: Mon Apr 13, 2015 7:04 pm

Re: Boeing Max.

Post by mixturerich »

Flying Low wrote: Thu Sep 05, 2019 10:28 pm ...I still do not understand how either crew lost the airplane.
What are you implying? That they were incompetent??
---------- ADS -----------
 
tbaylx
Rank 8
Rank 8
Posts: 804
Joined: Fri Jun 25, 2004 6:30 pm

Re: Boeing Max.

Post by tbaylx »

mixturerich wrote: Fri Sep 06, 2019 1:38 am
Flying Low wrote: Thu Sep 05, 2019 10:28 pm ...I still do not understand how either crew lost the airplane.
What are you implying? That they were incompetent??
Assuming that the regulatory body maintained ICAO standards and that the crew passed their PPC's then the crew wasn't incompetent. That still leaves a lot of room between marginal and . Yeager however.

They were presented with a challenging situation outside of their training and weren't able to handle it. That doesn't mean they were incompetent, but they weren't up to the task of recovering a flyable aircraft outside the realm of their training. To say that crew response didn't have a part in it is as ignorant as saying Boeing MCAS design had no part in it. Both were contributing factors to varying degrees.

The point is that Boeing can't send an aircraft out with a non normal that X% of the worlds pilots are unable to recover from. Even if that's a small percentage it will lead to a hull loss every so often, which is obviously unacceptable.
---------- ADS -----------
 
co-joe
Rank 11
Rank 11
Posts: 3671
Joined: Mon Feb 16, 2004 2:33 am
Location: YYC 230 degree radial at about 10 DME

Re: Boeing Max.

Post by co-joe »

mixturerich wrote: Fri Sep 06, 2019 1:38 am
Flying Low wrote: Thu Sep 05, 2019 10:28 pm ...I still do not understand how either crew lost the airplane.
What are you implying? That they were incompetent??
The thought certainly has crossed a few minds. An guy who "flew 8000 hours in 6 years", and a 200 hour FO? Not saying it outright, but questions of experience have to factor in to the discussion.
---------- ADS -----------
 
User avatar
Flying Low
Rank 8
Rank 8
Posts: 926
Joined: Sun Feb 15, 2004 7:22 pm
Location: Northern Ontario...why change now?

Re: Boeing Max.

Post by Flying Low »

I'm not implying anything. I don't know why they did what they did. I do fly the 737NG and have flown the MAX before it was grounded.

The first crew actually did a decent job of flying the plane. The flight data shows a corresponding manual electric trim nose up after each MCAS triggered nose down trim. I just checked my numbers and that airplane was in the air for 13 minutes so they were successfully dealing with this for longer than I initially thought. Control was only lost after the Captain handed control to the FO so he could look through the QRH. I don't understand why the Captain didn't call for the Runaway Stabilizer checklist or memory items.

Image

The second crew did manage to get to the trim cutoff switches but never pulled back the thrust. It stayed at 94%. By the time the cutoff switches were used they were at Vmo. The other curious thing I just noticed is that when the flap handle is moved from the flap 5 position the airplane looks to be close to 250 knots (although it's hard to tell on such a small graph).

Image

Our checklist instructions in the QRH state, "While every attempt is made to supply needed non-normal checklists, it is not possible to develop checklists for all conceivable situations."

I don't understand how a crew does not make the jump to the Runaway Stabilizer non-normal checklist in this case as the only significant difference is that they had an intermittent runaway stabilizer.
---------- ADS -----------
 
"The ability to ditch an airplane in the Hudson does not qualify a pilot for a pay raise. The ability to get the pilots, with this ability, to work for 30% or 40% pay cuts qualifies those in management for millions in bonuses."
boeingboy
Rank (9)
Rank (9)
Posts: 1245
Joined: Wed Mar 03, 2004 2:57 pm
Location: West coast

Re: Boeing Max.

Post by boeingboy »

I've mentioned this many times before in previous posts....but for all the fighting the 2 crews did - they were both able to continue their climb and/or maintain altitude. Now the stick may have been in their laps or they had their feet on the dash - but they were still able to maintain control. So switch the damn thing off.

As pilots we are all taught from our first flight that you trim the airplane for level hands off flight. Why these crews did not do that is beyond me. Lion air did it - but never shut it off. ET did it - but not long enough. We all know MCAS will trim faster than the manual trim will - so why were they only trimming half as much? The ET crew did shut it off then turned it back on - I suspect this is because the nose was still very heavy so they switched it on to trim up - which is what the data shows. However they did not trim nearly long enough and then did not turn it off again, allowing the system to trim it down. Even with the heavy nose - the whole time the trim was shut off the ET crew managed to climb about 8000 feet. The aircraft was controllable and recoverable - the crews must share the blame in these accidents.
---------- ADS -----------
 
User avatar
ToolShed
Rank 2
Rank 2
Posts: 54
Joined: Mon Jan 10, 2011 10:58 am
Location: LINNG

Re: Boeing Max.

Post by ToolShed »

Arm chairing at its best.
---------- ADS -----------
 
C.W.E.
Rank (9)
Rank (9)
Posts: 1262
Joined: Mon Dec 18, 2017 2:22 pm

Re: Boeing Max.

Post by C.W.E. »

Boeing has been a great builder of airplanes and will in the end recover from this situation they are in.

However the cost will be staggering.

It will be interesting to see what happens in their corporate structure because the share holders will be very concerned.
---------- ADS -----------
 
mixturerich
Rank 5
Rank 5
Posts: 314
Joined: Mon Apr 13, 2015 7:04 pm

Re: Boeing Max.

Post by mixturerich »

In all honesty, the first questions I asked myself after the dual Max crashes were, what were their experiences levels, what kind of training did they do, and what was the company culture like? This sh*t is important. It literally was as simple as pulling the electric trim circuit breaker to solve the problem. Huge can of worms but we’re lucky to have pretty top notch training environments in North America, plus in Canada we have the bush - makes you really think outside the box.

That being said, Boeing cut some corners and now they’re paying for it. Perhaps it’s a blessing in disguise - huge wake up call, don’t do it again.
---------- ADS -----------
 
User avatar
Flying Low
Rank 8
Rank 8
Posts: 926
Joined: Sun Feb 15, 2004 7:22 pm
Location: Northern Ontario...why change now?

Re: Boeing Max.

Post by Flying Low »

It will be interesting to see what happens in their corporate structure because the share holders will be very concerned.
Yes...they are concerned now. They didn't seem very concerned as Boeing gradually switched from an engineering company to one that was focused on unlocking shareholder value. This is typical of short term investor outlook. Get the money now, quickly rather than concentrate on creating a superior product and letting value increase over time.
---------- ADS -----------
 
"The ability to ditch an airplane in the Hudson does not qualify a pilot for a pay raise. The ability to get the pilots, with this ability, to work for 30% or 40% pay cuts qualifies those in management for millions in bonuses."
Jet Jockey
Rank 5
Rank 5
Posts: 316
Joined: Sun Sep 22, 2013 8:42 am
Location: CYUL

Bad news for Boeing and its MAX...

Post by Jet Jockey »

Europe's aviation safety watchdog will not accept a US verdict on whether Boeing's troubled 737 Max is safe.

Instead, the European Aviation Safety Agency (Easa) will run its own tests on the plane before approving a return to commercial flights.

Hope Canada does the same thing.

https://www.bbc.com/news/business-49591363
---------- ADS -----------
 
Last edited by Jet Jockey on Sat Sep 07, 2019 7:07 am, edited 1 time in total.
AZ382
Rank 1
Rank 1
Posts: 16
Joined: Tue Jan 05, 2010 3:33 am

Re: Boeing Max.

Post by AZ382 »

boeingboy wrote: Fri Sep 06, 2019 4:37 pm I've mentioned this many times before in previous posts....but for all the fighting the 2 crews did - they were both able to continue their climb and/or maintain altitude. Now the stick may have been in their laps or they had their feet on the dash - but they were still able to maintain control. So switch the damn thing off.

As pilots we are all taught from our first flight that you trim the airplane for level hands off flight. Why these crews did not do that is beyond me. Lion air did it - but never shut it off. ET did it - but not long enough. We all know MCAS will trim faster than the manual trim will - so why were they only trimming half as much? The ET crew did shut it off then turned it back on - I suspect this is because the nose was still very heavy so they switched it on to trim up - which is what the data shows. However they did not trim nearly long enough and then did not turn it off again, allowing the system to trim it down. Even with the heavy nose - the whole time the trim was shut off the ET crew managed to climb about 8000 feet. The aircraft was controllable and recoverable - the crews must share the blame in these accidents.
The airport is at 7625ft. The ET crew got a bit above 8000ft, they never climbed more than 1000ft from the ground.
---------- ADS -----------
 
boeingboy
Rank (9)
Rank (9)
Posts: 1245
Joined: Wed Mar 03, 2004 2:57 pm
Location: West coast

Re: Boeing Max.

Post by boeingboy »

The airport is at 7625ft. The ET crew got a bit above 8000ft, they never climbed more than 1000ft from the ground.
Umm - not quite - at 1000ft AGL the L autopilot was engaged, the flaps retracted and pitch trim position decreased.

Look at the FDR data- They reached about 9000 AGL and were airborne for roughly 6 min.
---------- ADS -----------
 
imcool
Rank 1
Rank 1
Posts: 23
Joined: Mon Aug 26, 2019 7:43 pm

Re: Bad news for Boeing and its MAX...

Post by imcool »

Jet Jockey wrote: Sat Sep 07, 2019 6:37 am Europe's aviation safety watchdog will not accept a US verdict on whether Boeing's troubled 737 Max is safe.

Instead, the European Aviation Safety Agency (Easa) will run its own tests on the plane before approving a return to commercial flights.

Hope Canada does the same thing.

https://www.bbc.com/news/business-49591363
Great initiative by Europe.
---------- ADS -----------
 
Post Reply

Return to “General Comments”