Boeing Systemic Problems Continue

[boeingboy]

Maybe YOU are the armchair wannabe , Please answer the below information Boeing boy

I'm sorry - what exactly do you wish me to answer??

Any stab trim issue in a 737 is dealt with using the same procedure - you throw both cutoff switches. Period.

As for MCAS - you cannot "shut it off" it is a subroutine program burried into the flight control software in the aircraft. Maybe you should pay a little more attention to the discussions happening around this subject. MCAS "stall" prevention is over-ridden by using the thumb switches. That part of the system worked flawlessly every time in all 3 cases. You quoted a bunch of statements - So I really don't know what you want to know.

[boeingboy]

Boeing made a choice to have critical flight control software be affected by a single AoA sensor. It was a choice to save money and it backfired. They were shown to have cheated the system and now they are facing the consequences.

That's not entirely accurate. They didn't do this deliberately. It's easy to see how this happened when the system changed bit by bit over the entire development time of the airplane.

It still in no way excuses them - and they need some sort of new check and balance system when things get changed to some degree late in the development program for any aircraft.

[florch]

In retrospect, perhaps there should be dual input. I suppose its easy to second guess engineers and test pilots after these accidents and say "I told you so". Engineering and design involves choices and compromises based upon cost, ease of implementation, weight, complexity, etc.

Boeing made a mistake with the NG when they used a single source of radar altimetry which turned out to be the cause of the Turkish accident at Schipol. Now it is a dual installation - I suppose they assumed how could two pilots (in the Turkish case, three) could possibly not notice the throttles going to idle hundreds and thousands of feet in the air, let alone not notice the speed decay to the stall.

Airbus never contemplated someone flying into a thunderstorm in the ITCZ where the rate of ice accretion exceeding the heating capabilities of the probes. Nor did they anticipate a situation where one pilot is pulling back and the other pushing forward on the joystick (AF 447) with the aircraft getting into a deep stall.

ATR never anticipated pilots shutting down the wrong engine shortly after take-off (Taipei).

And finally, Boeing never thought that professional airline pilots type rated on the B737 could not hand fly the aircraft - i.e. manually trim the aircraft with the thumb switch (thus shutting off MCAS), pulling the power levers out of take-off power to at least a climb or cruise setting so they were not racing around at Vne and trying to use the manual trim wheel. Boeing never thought that professional airline pilots type rated on the B737 could not recognize an unreliable airspeed condition let alone do the (very) simple drill. Boeing never thought that professional airline pilots type rated on the B737 could not, after 26 trim runaways, not turn of the stab trim using the cut-out switches.

Use your imagination and think of the wildest, most ridiculous situation of pilot incompetence and now design an aircraft that will be crash proof. Good luck doing that with a cost and weight that would allow the aircraft to fly.

+1. This is an awesome post.

[TFTMB heavy]

Didn’t they have a third pilot on the jumpseat and he’s the one that suggested they flip the trim cutoff switches? They also didn’t snag the defect if IRC.

Also, I read on here that Boeing still hasn’t submitted the full software package for the MCAS fix and that pilots still pooched it in the sim during testing for the fix.

There is no mention in the Indonesian report of a jumpseater telling them to turn off the stab trim on the incident flight.

Don't believe everything you read on here; my guess that everything has been redesigned, tested and submitted by now as there is huge pressure to get it done.

There was a third pilot on the flight deck on the day before the accident and that is mentioned in the report. What were his actions exactly I do not recall but I do recall he assisted the two pilots operating the flight. My original wasn't clear as it suggested a third pilot was present during the accident.

You're only guessing about the MCAS fix having been submitted so I will follow your advice and not believe everything I read on here.

[L39Guy]

I think that since they have been testing the fix on pilots in the engineering simulator one can conclude that there is a fix.

I think that one can safely assume that this is the #1 priority at Boeing.

[Curiousflyer]

I think that since they have been testing the fix on pilots in the engineering simulator one can conclude that there is a fix.

I think that one can safely assume that this is the #1 priority at Boeing.

A proposed fix. It’s not a fix until it’s approved by regulators.

I imagine there have been many proposed fixes in the last year.

Will dual sensor on MCAS even change anything?

[2R]

The original reasoning for the MCAS was due to longitudinal instability in some flight regimes .
The software fix does not address an aerodynamic issue that the other 737 models do not have .
The sooner they fire everyone involved in the cover up and deceit the sooner they can get back the Trust of the travelling pax. Without an aerodynamic fix that particular model of 737 will not fly.

Boeing is making the same errors of crisis mismanagement that Pan Am made after Lockerbie.
They need to get ahead of this crisis before they end up in the same dustbin of history as Pan Am .

[C-GGGQ]

The original reasoning for the MCAS was due to longitudinal instability in some flight regimes .
The software fix does not address an aerodynamic issue that the other 737 models do not have .

It's not unstable. It flies fine. It just doesn't fly EXACTLY like older 737's meaning that without MCAS it would not be eligible to be considered same type. MCAS was purely to make the plane feel the same to the pilots so new training wasn't needed and airlines could operate it with the same type rating.

[Curiousflyer]

The original reasoning for the MCAS was due to longitudinal instability in some flight regimes .
The software fix does not address an aerodynamic issue that the other 737 models do not have .

It's not unstable. It flies fine. It just doesn't fly EXACTLY like older 737's meaning that without MCAS it would not be eligible to be considered same type. MCAS was purely to make the plane feel the same to the pilots so new training wasn't needed and airlines could operate it with the same type rating.

Keep in mind that is according to Boeing and the data regarding how the 737Max flies without MCAS has been kept secret from the public and regulators. Ie the Transport Canada email leak

[L39Guy]

I think that since they have been testing the fix on pilots in the engineering simulator one can conclude that there is a fix.

I think that one can safely assume that this is the #1 priority at Boeing.

A proposed fix. It’s not a fix until it’s approved by regulators.

I imagine there have been many proposed fixes in the last year.

Will dual sensor on MCAS even change anything?

A proposed fix. It’s not a fix until it’s approved by regulators. Ok, what's your point?

I imagine there have been many proposed fixes in the last year. Probably, but what's your point?

Will dual sensor on MCAS even change anything? Of course it will. Some sort of confirmation via other means (sensors) would nullify an erroneous sensor causing MCAS to activate. In addition to this, the rate of trim input is reduced and there is only one MCAS cycle to a lower, total nose down trim value.

[L39Guy]

The original reasoning for the MCAS was due to longitudinal instability in some flight regimes .
The software fix does not address an aerodynamic issue that the other 737 models do not have .
The sooner they fire everyone involved in the cover up and deceit the sooner they can get back the Trust of the travelling pax. Without an aerodynamic fix that particular model of 737 will not fly.

Boeing is making the same errors of crisis mismanagement that Pan Am made after Lockerbie.
They need to get ahead of this crisis before they end up in the same dustbin of history as Pan Am .

To be perfectly correct, the MAX was dynamically neutral at rear C of G, low weights at a high alpha (angle of attack, i.e. near the stall). The certification requirement is for a positive stability, in other words the nose of the aircraft falling naturally away from a stall angle of attack. MCAS introduced an artificial nose down "kicker" that other aircraft also have via a different means.

"Fixes" to address other aerodynamic issues on other airplanes is nothing new. Have a look at a Beech 1900D sometime with all of the strakes, etc. hanging off that aircraft. The Q400 the same, the C130H models and up too.

Even the venerable B747-800 has an aerodynamic band-aid that pilots are not aware of - it has an aileron flutter problem and there is software running in the background to address this. And, to the best of my knowledge, the -800 pilots were not made of aware of this in their flight manuals.

I know some pilots are offended that they were not told of the existence of MCAS, although it would not have changed things one iota. MCAS behaves identically to a stab trim runaway and should have been treated as such. The Ethiopean pilots knew about MCAS after the Lion Air accident; did that change the outcome? Not one iota.

[L39Guy]

Keep in mind that is according to Boeing and the data regarding how the 737Max flies without MCAS has been kept secret from the public and regulators. Ie the Transport Canada email leak

Kept secret from the public? Do you really think the public cares nor is capable of understanding any of the minutae of aerodynamics? That's a ridiculous comment. Did you know that Boeing has "kept secret" the B747-800 flutter issue and its fix from the public? Are you calling for the grounding of the B747-800 too?

Kept secret from the regulators? If I recall the Lion Air accident report correctly, that statement is not true either. Boeing might have not advised the FAA of some changes to the MCAS system but the regulator of the host country knew about MCAS.

[2R]

How many non-miltary aircraft have MCAS fitted ?
What you expect from an unstable fighter approaching coffin corner in a fur ball ,in an aircraft that has ejection seats is not the aerodynamic fix that has been approved for use on ANY civilian aircraft.
The secrecy, deceit and misinformation is something we have not seen since the Ford Pinto .

[L39Guy]

You mean, how many non-military aircraft have a "stick-pusher" like device to provide positive, aerodynamic stability? Plenty. I believe, and stand to be corrected, that they Piper Cheyenne has such as device. Others do too, they just not called MCAS and they work using different sensors, logic and mechanisms to introduce positive stability at high angles of attack.

Secrecy, deceit, misinformation? Yup, that's all stuff from the popular media (G & M, NY Times, Washington Post), etc. and it makes for great copy. The reality is that there are plenty of devices, software changes, modifications, etc. made in the background that manufacturers (engineers, test pilots, etc) make to aircraft without a line pilot's knowledge in order to keep an aircraft within the certification rules. The presence of strakes on the aircraft I noted earlier are a few examples, the B747-800 flutter solution, the stick-pushers found on many aircraft are all examples.

For your convenience, here is the report from the Indonesian accident. Read it, you'll learn a lot (https://www.flightradar24.com/blog/wp-c ... Report.pdf).

[Ki-ll]

To be perfectly correct, the MAX was dynamically neutral at rear C of G, low weights at a high alpha (angle of attack, i.e. near the stall). The certification requirement is for a positive stability, in other words the nose of the aircraft falling naturally away from a stall angle of attack. MCAS introduced an artificial nose down "kicker" that other aircraft also have via a different means.

Why was a simple “nudger” in elevator circuit not enough? Why was it necessary to drive the whole stabilizer MCAS-style?

[boeingboy]

Why was a simple “nudger” in elevator circuit not enough? Why was it necessary to drive the whole stabilizer MCAS-style?

They needed the control authority the stabilizer has over the elevator due to the envelope it works in. Low speed and high angle of attack. The actual stall system is a separate system as it was in the 737 NG and classics using - in part - the STS and EFS.

[Curiousflyer]

I think that since they have been testing the fix on pilots in the engineering simulator one can conclude that there is a fix.

I think that one can safely assume that this is the #1 priority at Boeing.

A proposed fix. It’s not a fix until it’s approved by regulators.

I imagine there have been many proposed fixes in the last year.

Will dual sensor on MCAS even change anything?

A proposed fix. It’s not a fix until it’s approved by regulators. Ok, what's your point?

I imagine there have been many proposed fixes in the last year. Probably, but what's your point?

Will dual sensor on MCAS even change anything? Of course it will. Some sort of confirmation via other means (sensors) would nullify an erroneous sensor causing MCAS to activate. In addition to this, the rate of trim input is reduced and there is only one MCAS cycle to a lower, total nose down trim value.

How exactly does this work then? MCAS is required flight control system for certification of the aircraft to fly. But it’s going to disable itself if both AoA sensors don’t agree? How then is the aircraft still certified to fly?

[Curiousflyer]

Keep in mind that is according to Boeing and the data regarding how the 737Max flies without MCAS has been kept secret from the public and regulators. Ie the Transport Canada email leak

Kept secret from the public? Do you really think the public cares nor is capable of understanding any of the minutae of aerodynamics? That's a ridiculous comment. Did you know that Boeing has "kept secret" the B747-800 flutter issue and its fix from the public? Are you calling for the grounding of the B747-800 too?

Kept secret from the regulators? If I recall the Lion Air accident report correctly, that statement is not true either. Boeing might have not advised the FAA of some changes to the MCAS system but the regulator of the host country knew about MCAS.

You completely misread my post.
No one has seen the data on how the 737 Max flies without MCAS. I’m merely suggesting that their is no proofthat the airplane won’t flip upside down without out MCAS installed.
The Transport Canada email leak suggests that they don’t have he data on how the MAX flies without MCAS.
“I put together a little presentation which I believe illustrates the problem and how an easy fix would be to have Boeing implement what they keep trying to tell us. The MCAS fixes makes the MAX an NG.”
https://theaircurrent.com/aviation-safe ... m-737-max/

Will the plane flip upside down without MCAS? I doubt it, but it has to be proven exactly how it fly which at this point in time it doesn’t appear that information has been released to regulators.

[ahramin]

How exactly does this work then? MCAS is required flight control system for certification of the aircraft to fly. But it’s going to disable itself if both AoA sensors don’t agree? How then is the aircraft still certified to fly?

It works the same way as every other system on the airplane. Once the takeoff roll is commenced, there is no requirement for the aircraft to remain certified. Even on a plane without MCAS, an aircraft with a u/s AOA probe is no longer certified to fly. That doesn't mean you stop the plane on the side of the airway and call for a tug.

[Raymond Hall]

Today, from the British newspaper, The Telgraph:

Boeing surrenders crown of world’s biggest plane maker to Airbus after 737 Max crisis

Airbus has trounced Boeing to become the world’s biggest aircraft maker as the US aerospace giant continues to grapple with the fallout from the grounding of its 737 Max jet.

The European company delivered 863 planes in 2019, against just 345 deliveries by its American rival.

Shares in Airbus rose almost 4pc after the figures were released. They were ahead of the 860 shipments the firm had forecast in October when it trimmed projections because of production problems.

It is the first time since 2011 that Airbus has overtaken its US competitor.

Deliveries by Boeing more than halved from the previous year’s 704 following a safety scandal over the 737 Max..

The company has taken orders for about 5,000 of the bestselling jets, 400 of which have been turned out from its production line in Seattle since the model launched in 2017.

Because of the grounding Boeing is unable to deliver the 737 Max to customers, resulting in them piling up around the plant - with photos showing dozens stored in a staff car park.

The majority of Boeing's deliveries in 2019 were larger, wide-body models as a result. Other planes made by the firm include the 747 Jumbo used for long-haul flights around the world.

Boeing has taken an almost $10bn (£7.6bn) hit relating to costs from the grounding, including compensation payments to airlines that have been unable to take delivery of the aircraft. Its shares have fallen by about a quarter.

https://www.telegraph.co.uk/business/20 ... rbus-737/