Is Boeing a Buy Here?

[NW-Bound]

From the cockpit voice recorder, it was reported that the captain of the Lion Air aircraft desperately looked up the flight manual at the last minute, but could not find anything about this poorly designed MCAS.

I think the aerospace business is following what the electronic consumer market has been doing. When is the last time you see a manual or much of any instruction that comes with your electronic gadget, or a software package?

Just fool around and learn how it works. It is OK for consumer products, which evolve so fast and have too many features to document, but not for something like a jetliner. With a car like Tesla, they just release new software without even telling their customers what the new features are, what the limitations are. Just try it to see if you like it. And if you die, it's your own fault.

I really think young engineers have a different attitude than we old timers had. We had more respect for safety and reliability. Young people are so used to just reboot something when it does not work right. You just don't do that with a commercial aircraft.

The above said, I don't think this is a software problem. The problem is with the design. I am sure they tested the software, and it did and still does exactly what they wanted it to do. But the design that they have really sucks, particularly the "feature" that keeps ratcheting up the MCAS authority by 2.5 degrees of stabilizer every time the pilot overrides it. Originally, they were allowing the MCAS to move the stabilizer 0.6 deg, and that was it. Then, they allowed it to move the stabilizer to the max!

 

[samclem]

From the cockpit voice recorder, it was reported that the captain of the Lion Air aircraft desperately looked up the flight manual at the last minute, but could not find anything about this poorly designed MCAS.
. . . .

Originally, they were allowing the MCAS to move the stabilizer 0.6 deg, and that was it. Then, they allowed it to move the stabilizer to the max!

The stabilizer can move to full up (aircraft nose down) for several reasons (as simple as a stuck contact in a switch) , not just MCAS/bad AoA data being fed to MCAS. In all cases of anomalous pitch trim behavior (including MCAS) the proper procedure is the same: Turn off the electric trim and use the manual trim wheel. It is a "memory" procedure (aka "BOLDFACE procedure") that pilots are required to know by memory--there should be no need to look up anything, or even to know about the existence of MCAS.
"Runaway trim" is not a novel thing, it is a condition that competent crews can handle. An MCAS failure/anomalous behavior manifests itself with symptoms similar to some conditions of runaway trim, and the proper procedures, executed in a timely manner, will work every time. There are indications the Lion Air crew >did< revert to manual trim for awhile, then inexplicably re-engaged electric trim.

I have a tremendous amount of empathy for both accident crews--Lion Air and Ethiopian Airlines. They were in a bad situation, facing something they had never seen before (esp the Ethiopian Airlines crew with the very high airspeed close to the ground). The resulting conditions on those flight decks must have been terrible. Everyone agrees (in retrospect) that crews should have received explicit training on the MCAS, and that the MCAS system needs revision. It will be better after the fix.

 

[NW-Bound]

A runaway trim by itself may be more easily detected. In this case, it was reported that the stick shaker was on to warn pilots of a "stall", and who knows what other misleading indicators. When there are many false indications, it is not easy to sort out what is really happening.

 

[samclem]

A runaway trim by itself may be more easily detected. In this case, it was reported that the stick shaker was on to warn pilots of a "stall", and who knows what other misleading indicators. When there are many false indications, it is not easy to sort out what is really happening.

Agreed., it is more complicated. Only one stick shaker was on, the yoke that was slaved to the bad AoA sensor (that's one way you can troubleshoot these things). But if you've pulled the nose up, used the electric trim to relieve the yoke pressure, and then there is an uncommanded nose down running of the trim (evident by the yoke pressures and the large striped trim wheel rapidly spinning at your knee), then turning off the electric trim and leaving it off would be the logical (and procedurally correct) response.

 

[Boho]

I wonder what it would cost to use big enough engines so planes could gain enough speed in these situations without diving. I'm not following everything though and I'm not sure whether the computer thought the plane wasn't diving or whether the computer wanted the plane to dive.

 

[REWahoo]

I wonder what it would cost to use big enough engines so planes could gain enough speed in these situations without diving.

You might want to stick to stock picking...

 

[Boho]

You might want to stick to stock picking...

Using the same intuition I use in stock picking, I bet planes sometimes dive to pick up speed to save fuel costs rather than because it's the safest way to gain speed.

 

[REWahoo]

Using the same intuition I use in stock picking...

Sometimes these set-ups are really hard to resist.

 

[NW-Bound]

Agreed., it is more complicated. Only one stick shaker was on, the yoke that was slaved to the bad AoA sensor (that's one way you can troubleshoot these things). But if you've pulled the nose up, used the electric trim to relieve the yoke pressure, and then there is an uncommanded nose down running of the trim (evident by the yoke pressures and the large striped trim wheel rapidly spinning at your knee), then turning off the electric trim and leaving it off would be the logical (and procedurally correct) response.

Unofficial sources say that the voice recordings indicated that the pilots were preoccupied with airspeed and altitude, and showed no signs of having noticed the run-away trim. Perhaps they spent all their time worried about the false stall warning. It was said that they discussed between themselves the "unreliable" airspeed and altitude readings that they were seeing.

Perhaps they were doomed by trusting the false stall warning, and dismissed the airspeed indicators and the altimeters.

 

[NW-Bound]

I wonder what it would cost to use big enough engines so planes could gain enough speed in these situations without diving. I'm not following everything though and I'm not sure whether the computer thought the plane wasn't diving or whether the computer wanted the plane to dive.

The 737 Max uses large engines, which have to be mounted quite a bit below the wings. Their thrust causes the plane to pitch up, which may cause the aircraft to get in a stall. Hence, they built the MCAS which will help pitch the aircraft nose down under certain conditions to help the pilots.

In these crashes, it was suspected that a bad angle-of-attack sensor (alpha vane) malfunctioned, and caused the computer to command continual pitch-down maneuvers, which the pilots failed to disable.

 

[samclem]

Unofficial sources say that the voice recordings indicated that the pilots were preoccupied with airspeed and altitude, and showed no signs of having noticed the run-away trim. Perhaps they spent all their time worried about the false stall warning. It was said that they discussed between themselves the "unreliable" airspeed and altitude readings that they were seeing.

Perhaps they were doomed by trusting the false stall warning, and dismissed the airspeed indicators and the altimeters.

Sorry, I don't know enough to comment on their actions. Normally, if a crew suspects a problem with their pitot-static readings (airspeed, altitude, rate of climb/VVI), the proper response is to use known pitch and power settings (pitch as determined by looking outside at the horizon, or using the artificial horizon(s) on the instrument panel) and then to work through the problem.


Not all crews are trained to the same level of proficiency, and not all companies hold to the same maintenance standards. The faulty AoA sensor on the Lion Air plane was written up and a previous crew flew an entire leg with the stick shaker on the day prior (which would be very distracting). The AoA sensor was not repaired properly. US carriers operate more 737 MAX airliners than any other country, there have been no accidents like this here. That is not an excuse for a poor design and we don't know that crew training/competency is a factor in either of these accidents. But achieving aviation safety requires a lot of things, aircraft design can't do it all.

 

[NW-Bound]

The NYT is reporting that the planes that crashed didn't have the latest safety updates because Boeing charges $$$ for them as an option. Many US airlines also don't pay for these because the FAA doesn't require them. I guess that's part of "light touch" regulation, but I can imagine lawyers making out that this isn't a good enough excuse.

Some excerpts from the above linked article.

Boeing’s optional safety features, in part, could have helped the pilots detect any erroneous readings. One of the optional upgrades, the angle of attack indicator, displays the readings of the two sensors. The other, called a disagree light, is activated if those sensors are at odds with one another.

Boeing will soon update the MCAS software, and will also make the disagree light standard on all new 737 Max planes...

The angle of attack indicator will remain an option that airlines can buy...

When it was rolled out, MCAS took readings from only one sensor on any given flight, leaving the system vulnerable to a single point of failure. One theory in the Lion Air crash is that MCAS was receiving faulty data from one of the sensors, prompting an unrecoverable nose dive.

In the software update that Boeing says is coming soon, MCAS will be modified to take readings from both sensors. If there is a meaningful disagreement between the readings, MCAS will be disabled.

 

[aja8888]

Safety features an OPTION??

With respect to this "optional" safety software on these multi million dollar planes, how could Boing even offer something like that as an option? They should have just thrown that into the huge price of the aircraft. Boing is starting to sound like Elon Musk is running the show here.

 

[NW-Bound]

I dunno. If the FAA said a feature was not necessary, then it would be an option to be charged extra.

There's always quite a lot of subjectiveness in the judgement of these things, not just in commercial aircraft, but in car manufacturing and house construction too.

... The faulty AoA sensor on the Lion Air plane was written up and a previous crew flew an entire leg with the stick shaker on the day prior (which would be very distracting). The AoA sensor was not repaired properly...

It has been a few decades since I worked on the development of an autoland autopilot for a commercial jet. I recall that there were items that were deemed critical, which had to be repaired before the aircraft could be flown again.

I don't recall who had the ultimate say about what is critical and what is not, the aircraft manufacturers, the FAA or the equivalent agency in a foreign country (such as the CAA for the British), or the airlines.

Apparently, someone decreed that the stick shaker staying on was not a critical failure. A lot of things will be learned later when the case was argued in court.

 

[CRLLS]

These 2 accidents are tragic. And I don't want to make light of the situation. In hindsight, it appears that it could have been avoided.

That being said, Coming from an engineering background, I'm fairly certain that somewhere along the way, the engineers designing the systems knew the consequences of single sensor failure, and how to address the situation, especially with there already being 2 sensors that could be used. I would like to be the fly on the wall in meetings where either the bean counters, the project managers, or general management overrode the engineers' suggestions to make it more safe.

Whether this is the case or not, I don't know. I have never worked in the aero industry. I do know that in general, some engineers' ideas are often overridden for "business concerns".

 

[SecondCor521]

Not all crews are trained to the same level of proficiency, and not all companies hold to the same maintenance standards. The faulty AoA sensor on the Lion Air plane was written up and a previous crew flew an entire leg with the stick shaker on the day prior (which would be very distracting). The AoA sensor was not repaired properly. US carriers operate more 737 MAX airliners than any other country, there have been no accidents like this here. That is not an excuse for a poor design and we don't know that crew training/competency is a factor in either of these accidents. But achieving aviation safety requires a lot of things, aircraft design can't do it all.

I realize it is conjecture on multiple aspects, but I would like your opinion: Do you think that a pilot from any of the US carriers who flew the 737 Max aircraft type would generally be capable of safely handling the situations that resulted in these two crashes?

 

[samclem]

I realize it is conjecture on multiple aspects, but I would like your opinion: Do you think that a pilot from any of the US carriers who flew the 737 Max aircraft type would generally be capable of safely handling the situations that resulted in these two crashes?

As you note, there are a lot of things that are still unknown about the circumstances that led to these crashes. But airlines with better training, higher crew experience requirements, and better maintenance have better safety records. I would have no hesitation to take a flight with my family on a 737 Max aircraft operated by a US carrier.

 

[NW-Bound]

... I would have no hesitation to take a flight with my family on a 737 Max aircraft operated by a US carrier.

Now that the hazard with failure of the alpha vane is well publicized and understood, any 737 pilot would know how to deal with it.

In my opinion, it is in fact ironic that, at this point, there's no need to ground the fleet anymore.

 

[triangle]

Using the same intuition I use in stock picking, I bet planes sometimes dive to pick up speed to save fuel costs rather than because it's the safest way to gain speed.

Using the same intuition I use in stock picking, I bet [-]planes[/-] stock prices sometimes dive [-]to pick up speed[/-] picking up value to save [-]fuel costs[/-] purchase price rather than because it's the safest way to [-]gain speed[/-] invest.

I am not sure this is what you meant but the exchange reminded me of the perils of trying to time stock purchases. Hopefully BA and the industry will learn from these two incidents.

 

[SecondCor521]

As you note, there are a lot of things that are still unknown about the circumstances that led to these crashes. But airlines with better training, higher crew experience requirements, and better maintenance have better safety records. I would have no hesitation to take a flight with my family on a 737 Max aircraft operated by a US carrier.

Thanks, that's what I think too.

 

[SecondCor521]

Using the same intuition I use in stock picking, I bet planes sometimes dive to pick up speed to save fuel costs rather than because it's the safest way to gain speed.

I'm fairly certain your intuition about planes is pretty much dead wrong.

Planes fly at high altitudes and at constant speed and at lower than max speed to save on fuel costs. I have never heard of diving to pick up speed to save on fuel costs.

Also, diving by itself is not the safest way to gain speed. Diving sometimes results in running into the ground, which is not safe. The safest way to gain speed that I know of is to add throttle and ensure a straight and level flight attitude.

The above is what I know based on about 50 hours of private pilot training. I may be wrong and would welcome correction by those who know more than me.

 

[Montecfo]

Garuda Airlines seeking to cancel $4.9B order for 49 planes, according to reports citing loss of customer confidence in the planes.

More shoes to drop I suspect

 

[BigNick]

Planes fly at high altitudes and at constant speed and at lower than max speed to save on fuel costs. I have never heard of diving to pick up speed to save on fuel costs.

"Diving to pick up speed to save on fuel costs" is utterly absurd.

In order to be able to dive, you have to be at a certain altitude. How did you get to that altitude? By burning fuel.

Also, once you've dived from 35,000 feet to 20,000 feet, where are you going to go for the rest of the flight? ATC will tell you to get back in your lane. Please climb. To do that you're going to have to burn fuel.

There are no free lunches with energy. A million joules will only get your 50-ton plane a certain distance no matter which angle you point it at.

 

[Freedom56]

Ralph Nader lost his Grand Niece on the Ethiopian flight:

https://www.wsj.com/articles/with-p...crash-ralph-nader-takes-on-boeing-11553120235

 

[ERD50]

Originally Posted by Boho View Post
Using the same intuition I use in stock picking, I bet planes sometimes dive to pick up speed to save fuel costs rather than because it's the safest way to gain speed.

I'm fairly certain your intuition about planes is pretty much dead wrong.

Planes fly at high altitudes and at constant speed and at lower than max speed to save on fuel costs. I have never heard of diving to pick up speed to save on fuel costs.

Also, diving by itself is not the safest way to gain speed. Diving sometimes results in running into the ground, which is not safe. The safest way to gain speed that I know of is to add throttle and ensure a straight and level flight attitude.

The above is what I know based on about 50 hours of private pilot training. I may be wrong and would welcome correction by those who know more than me.

Well, I have zero hours of pilot training, but I'll agree with SecondCor521 based on my basic knowledge of physics.

-ERD50