737 MAX Update blancolirio 4/29/19 youtube

Youtube blancolirio ^ | 4/29/19 | Juan Brown

[FtrPilot]

mad_as_he$$...thanks for posting the following link. The link contains a lot of relevant information and should be mandatory reading before making any comments on the Ethopian 737 MAX accident. The link includes the B737 Max 8 Runaway Stabilizer Checklist.

Read Me Please

Based upon the timeline not sure the crew even had time to save the aircraft in Ethiopia.

I strongly disagree. The pilots violated the 3 basic rules for any aircraft emergency

1. Maintain Aircraft Control

2. Analyze the Situation, Take Proper Action

3. Land as soon as practicable

IMHO, the pilots' biggest mistake is they left the power levers (throttles) at close to takeoff power. Step 6 of the Runaway Stabilizer Checklist is Stabilizer...Trim manually. The pilots should have known that trimming manually is impossible when airspeed is above 250 KIAS. If they had slowed down below 250 KIAS and left the stab trim cut out switches at Cut Out, they could have trimmed the aircraft manually, and landed safely.

The pilots were unable to trim manually and elected to re-engage the stab trim switches to enable the yoke trim switches. Unfortunately, this re-engaged MCAS which overrode the yoke trim switches, putting the aircraft in a dive which the pilots did not recover from.

Basic airmanship...the pilots did not perform a high speed dive recovery procedure. Throttles-idle, roll wings level, pull maximum G allowable.

WhoisAlanGreenspan?

The outrage is the Ethiopian pilots followed Boeing's MCAS sensor failure procedure by exercising a runaway stabilizer trim recovery, but it didn't work.

I don't disagree with this statement, however, there are contributing factors:

Boeing disabled the AOA disagree warning...therefore, the pilots were unable to determine the aircraft malfunction. Boeing also made AOA gauge displays as an option. If the AOA gages were displayed, and the pilots got the AOA disagree warning, and Boeing had published checklist procedures for this malfunction, the pilots should have been able to safely land the aircraft.

The runaway stabilizer trim recovery procedure did not work because the airspeed was too high for the pilots to manually trim the stabilier. Basic airmanship would dictate the pilots should have slowed down. The checklist should have instructed the pilots to fly at 250 KIAS or slower.

Note 1: Boeing has made significant changes to the MCAS software and are currently flight testing the upgrades. IMHO, these changes would have prevented both 737 MAX accidents.

Note 2: I have referenced 250 KIAS as the maximum speed that pilots can manually trim the aircraft. I am not type rated in the 737 and don't know the exact airspeed where manual trim is achievable. If anyone knows the actual airspeed, please post...thanks.

[fireman15]

I am not type rated in the 737 and don't know the exact airspeed where manual trim is achievable. If anyone knows the actual airspeed, please post...thanks.

You make some very good points in your post.

However, when the stab trim switches are placed in the manual position the trim wheel controls the position of the stabilizer trim... it does this regardless of the airspeed of the 737. I looked at the link you provided and there is nothing at that location to indicate that the plane has to be slowed down to use the manual trim wheel.

The two “stab trim” cutout switches have separate purposes. The one on the left labeled “MAIN ELECT” cuts all of the power to the system, the switch on the right labeled “AUTO PILOT” disconnects the automatic trim from the autopilot and allows the trim jack to be moved up and down manually with the electric motor assisting.

There is no speed limit at which the manual trim can be used, but if there were excessive aerodynamic forces on the trim jack, it would be much easier to use the manual trim with the assistance of the electric motor

If you can find any information that disputes this I would love to hear it so I can correct my brother and neighbors who are long time Captains on 737 aircraft and the primary sources of my information.

[mad_as_he$$]

Guess we will have to wait for the NTSB report. It will be interesting to see what they say and if it is in conflict with the Ethiopian accident teams report.

[mad_as_he$$]

Every aircraft accident has more than one cause (it seems). I agree that the crew violated some very basic principles of aircraft control and I am just a guy with a single engine ticket. One thing I know from my business (not related to flying), which has complex control systems, is that once an operator becomes confused or disoriented the recovery/action time is significantly longer than “normal”. If this flight crew wound up fighting each other then all bets are off.

I am waiting for the input from a family friend who has a long career flying 737’s in the US. He is very conservative in his comments and is very concerned about these incidents. His last comment to me was “What else is Boeing not telling us?”

As a side I watched the Air Disasters show last night on the 777 crash at SFO. The upshot was the guy flying the plane had a few thousand hours on a 320 and had NEVER made a non-instrument landing in a 777. Two senior captains managed to confuse the 777 control system to where it disabled the auto-throttle feature.

[fireman15]

once an operator becomes confused or disoriented the recovery/action time is significantly longer than “normal”.

My wife and I both loved roller coasters and had season passes to Magic Mountain, Disneyland and Universal Studios in the early 1990s So we used to fly our airplane from the Seattle area to LA a couple times a month to take advantage of those passes. One time my wife and I were flying back from LA, and we ended up going through some very nasty weather starting in Northern California. At one point we were flying about 500 feet over I-5, we had been getting bounced around till our eyeballs could hardly see straight, it was very dark and it was raining so hard that the visibility was very bad. This finally broke my wife; she started crying, and yelling that she would rather be giving birth again and she was convinced we were going to die...

It hit home at that point that it is a combination of factors that takes a small plane down in bad weather. Every weather report I got and was getting was over the radio was completely inaccurate. The plane was a handful because of the turbulence. I was trying to keep an eye on the GPS, and looking at charts to get ATIS and airport frequencies and keep from running into something solid. She was having a fit and then we started running low on gas. So I thought that we would just land somewhere, get some gas, take a rest and maybe spend the night.

The runway we were based at was surrounded by trees but had these little 20 watt bulbs that came on at dusk and gave just enough light to land safely. So we came to the first airport that I thought that we would land at, but all the lights were off, so another 20 miles further and there was another airport and all its lights were off too. Then I remembered that you had to turn the lights on at these little unattended airports by flicking the transmitter 5 times on the airport frequency. I forgot that because of all the crap going inside and outside the plane. If we had been really low on fuel it could have been a tragic mistake.

Anyway, we landed at the third airport and got some gas and my wife calmed down and it stopped raining so we decided to keep on going. But within half an hour we were back in the same type of messy weather... it was like it followed us all the way from Northern California. When we landed at our airport there was thunder and lightning and about a 20 knot crosswind, we had to do a go around. Then as we were getting out of the plane at our hangar some guy drove up with his high beams on blinding us.

I thought it was the sheriff checking to see who would be landing in such awful weather at our little Podunk airport, and to see if we needed any help. But it was some drunk guy in a 4 wheel drive pickup. And he yelled, “How much money do you have to have to fly an airplane like that?” I was in no mood and was ready to tear his face off, so I just said, “Get the hell out of here!!!” It think that his plan was to rob us but he sensed the homicidal tone in my voice and yelled some obscenities and left.

[WhoisAlanGreenspan?]

Here's some helpful info;

The actual preliminary accident report. From page 11.
At 05:40:35, the First-Officer called out “stab trim cut-out” two times. Captain agreed and FirstOfficer confirmed stab trim cut-out. http://www.ecaa.gov.et/documents/20435/0/Preliminary+Report+B737-800MAX+%2C%28ET-AVJ%29.pdf/4c65422d-5e4f-4689-9c58-d7af1ee17f3e

Then we have a 16 minute video detailing Runaway Stab Trim Procedures from Boeing. If you too impatient skip forward to 14:20 where he explains how manual trim was impossible at that speed. Runaway Stab Trim

[FtrPilot]

I read in another account that the pilots turned the switches off but that it was difficult to use the trim “wheels off at high speed” so they switched them back on....

There is only one stabilizer trim wheel

The picture below shows that the 737 MAX has 2 stabilizer trim wheels.

the speed that you are traveling at has no effect on its operation and it moves the trim position rapidly and effectively

This is only true if horizontal trim is controlled by an elevator trim tab. See picture below:

In the 737, and pretty much all current airliners, pitch trim is controlled by movement of the leading edge of the horizontal stabilizer. See picture below:

The further the leading edge of the horizontal stab is away from neutral, the higher the aerodynamic force on the horizontal stab...and manual trim becomes more difficult. Compound that with high airspeed and there could be a situation where the pilots cannot manually change pitch trim. Please refer to the following video starting at time stamp 14:20. (Entire video is worth watching...thanks to WhoisAlanGreenspan? for posting the URL.

Runaway Stab Trim

[WhoisAlanGreenspan?]

If you have some way to prove the following statements are true, please do. Otherwise your BS is showing.

The two “stab trim” cutout switches have separate purposes. The one on the left labeled “MAIN ELECT” cuts all of the power to the system, the switch on the right labeled “AUTO PILOT” disconnects the automatic trim from the autopilot and allows the trim jack to be moved up and down manually with the electric motor assisting.

There is no speed limit at which the manual trim can be used, but if there were excessive aerodynamic forces on the trim jack, it would be much easier to use the manual trim with the assistance of the electric motor

[fireman15]

The picture below shows that the 737 MAX has 2 stabilizer trim wheels.

It is the same control with hand holds on both sides so both pilots can reach and move it. But you are correct.

Although there appear to be no tables in the manuals... you are correct that the airspeed and/or aerodynamic forces may have to be reduced in order to move the trim wheels without the assistance of the electric motor on this type of stabilizer... so I stand corrected.

[FtrPilot]

Although there appear to be no tables in the manuals...

The following link discusses the Ethiopian accident:

www.reuters.com/article...

Here's a quote from the article:

"At speeds up to 250 knots (288 mph) pilots can stabilize trim with the manual wheel. But when the speed rises towards 300 knots and higher, the wheel becomes impossible to turn as air rushing over control surfaces makes them harder to move..."

I believe the article is worth reading. It mentions the runaway trim checklist and the unreliable airspeed checklist. What I find interesting is that the unreliable airspeed checklist calls for auto-throttle off as well as setting engine thrust to 75%. Perhaps, if the runaway trim checklist also called for setting engine thrust to 75%, the pilots could have saved the aircraft & all souls on board.

IMHO, pilot error will be the root cause. However, I believe Boeing will take a hit for training & flight manual.

[fireman15]

Good article; I hadn’t seen it previously.

[fireman15]

Read the article that FtrPilot linked to in post #50. It does a more complete job of explaining the mechanics of this tragedy than I have seen previously, and in some ways more complete than what was described to me by the 737 pilots that I know. Even a stubborn old coot like myself was able to learn a thing or two from it.

[mad_as_he$$]

Yikes! Some days it might be more prudent to just go back to bed, of course by the time you know that it is to late!

[FtrPilot]

Here's the link again:

www.reuters.com/article...

The article does include a lot of information not found anyplace else...definitely worth reading (and re-reading).

As a pilot, some of the paragraphs make me want to scream...

FTA: "The proper response to MCAS emergencies, Leeham Co analyst Bjorn Fehrm said, is to correct the dangerous nose-down 'trim' using electronic thumb switches, then turn off MCAS and trim manually with the wheel."

The pilots did not know this because they weren't trained on MCAS. The flight manual does not contain any information on "MCAS emergencies".

FTA: "The plane’s engines were at 94 percent thrust on take-off and remained there for the rest of the flight."

AAAAARRRRRGGGGGGG...

IMHO, this 'pilot error' will be listed as a root cause of the accident. This is basic airmanship (lack thereof). Item 1 for any malfunction is: "Maintain Aircraft Control".

Even a stubborn old coot like myself was able to learn a thing or two...

This applies to a most us, and is one of the reasons that I blog on Free Republic. I try to keep an open mind and listen to what other Freepers have to say.

[fireman15]

I didn’t tell you how the day began... While I was working as a firefighter I frequently got 4 day stretches off. With our one fuel stop it took us about 8 hours to fly down to LA most of the time, but it was usually much less stressful than driving and we would often stop at little out of the way places along the route and the flights were always fun for me.

We usually flew into Santa Paula airport and used the folding tandem bicycle that we put behind the rear seat of the plane to ride to our favorite inexpensive motel that was about 20 miles away. Then we would rent a car from there for a couple days and go to the amusement parks and restaurants that we liked to visit. Santa Paula was a great little airport and we met a lot of celebrities who kept there planes at the airport. It is the airport John Denver made his last flight from.

My wife was a dead ringer for Sally Field at the time, so celebrities would spot her from afar and come up and introduce themselves. They were usually people at the fringe of celebrity, like the old guy who did cartoon voices like Baby Huey and a bunch of other characters. It was sometimes a little bizarre but very fun and interesting, and one of the reasons we liked making it our destination.

But that trip we both ate something that made us feel ill and it was really hot, so we decided to cut the trip short and just go home. After our free brunch we laid around at the motel until checkout time and got off to a late start. And then it took us longer than normal to ride our bike back to the airport because of how we were feeling and it was already getting much warmer than usual.

So we didn’t take off in the plane until a little after 1:00 p.m. which under good conditions would get us back to our home airport about 9:00 p.m.. The first thing that happened was that our fuel pressure dropped while we were climbing out, because the heat combined with the proportion of car gas we still had in the tank we started with caused a little vapor lock in the lines. The fuel pressure guage went down to zero and we lost a couple hundred RPM.

My other tank had almost all 100 “low lead” aviation fuel in it so switching tanks and turning the electric fuel pump off and on fixed it, but it made us a little uneasy for a moment or two. I had meant to start off with this tank for more safety in warm weather but of course forgot. The plane has both a mechanical and electric fuel pump - the electric is supplemental. The two combined sometimes agitate warm fuel, especially cheaper but more volatile car gas enough to cause it to vaporize in the lines. This was the first time we experienced enough of a drop in fuel pressure to affect our power output. This got my wife a little agitated but once we got up to the cool smooth air at around 10,000 feet everything was fine.

We normally only made one fuel stop about 100 miles North of San Francisco at Yolo County Airport where they sold the cheapest car gas on our route. It was an interesting place. At that time it was the “Skydiving capitol of the West Coast”. On the stop on our way down they were having a nudist sky diving event. When my wife went to use the restroom she noticed that all of the other women around the facility had matching brown skin suits on, then she realized the skin suits were their actual skin. I of course noticed the attire of the other people as well, but didn’t find it as shocking as my wife did.

Things didn’t go bad until after we left Yolo County. About the time we got to our cruising altitude of around 10,000 feet there were clouds starting to form below us and as we were getting over the mountains in Northern California there were thick clouds above us as well. Then the two layers started getting closer together. And that is when it started getting stormy and nasty. It was dark by that time and I can’t tell you how relieved I was when we were able to spot the lights at Grants Pass quite a few miles away because that meant that there was nothing solid between us, and the lower level of clouds was gone there.

But as we descended and got closer to the mountains we were hitting some harsh turbulence and the lights ahead of us started going in and out of view as scuddy clouds and heavy rain came between us and the lights. And as we continued on our descent we started running though those nasty little clouds and heavy rain showers and they would completely obscure our view out of the plane with big rocks an unknown distance below. It was very unnerving as we got bounced around and hit strong updrafts and downdrafts without being able to see anything outside the airplane.

For me it was a big relief when we finally got down to the straight stretch of I-5 that led back to Seattle, but my wife was worn to a frazzle by that time. And the choppy air was different but bad over the freeway because of the nature of the system coming in. So that is the reason my poor wife finally reached her breaking point.

[fireman15]

I try to keep an open mind and listen to what other Freepers have to say.

I have tried to avoid most of the conversations on this subject because most of the non-aviators have formed very harsh opinions based on faulty and sensationalized MSM reporting. My opinion has been formed mostly from speaking with people who fly or flew 737s for a living. My own knowledge of 737s is very limited.

The flight manual does not contain any information on “MCAS emergencies”.

I am not sure that is not an accurate statement; the manual includes information on how to deal with a malfunctioning automatic stabilizer trim system, and how to use the stabilizer trim manually. Pilots are also trained to deal with a malfunctioning automatic trim. That would appear to be the same thing. Where are you making the differentiation between automatic trim emergencies and MCAS emergencies?

[fireman15]

Apologies

Never Mind!

My neighbor three doors down is a retired airline pilot, and now attorney, his wife is an airline pilot, his daughter is an airline pilot, and his son is an airline pilot. He has flown basically every Boeing airliner from the 727 on, along with many variants of the 737. He said that they all had basically the same automatic trim system and he told me some funny stories about how if you didn't like the pilot flying the plane after you... you could pull out the little handle on either of the trim wheels that made it easier to use manually and position it so that when they checked the trim in their preflight it would whack them on the knee and it "hurt like a bugger".

When I talked to him a month or two ago he like almost every other 737 jockey I talked with thought that the crash was most likely completely the fault of the pilots. Today when I asked him about it... he said that he had been following it very closely and that it appeared that Boeing not only changed the way their automatic trim behaved on this plane, but also some of the actual mechanical parts in the system and this information was not passed on properly.

He went into much greater detail than anything I have read here or anywhere else. He said that the coverage was mostly nonsensical but that Boeing and people in the FAA had some real problems and explaining to do. I asked him about "criminal negligence" and he said that it could not be ruled out at this point... and that there could be people going to jail over this one. So my apologies to everyone here.

[Capt. Tom]

The lawyers may be able to convince a bunch of people who don’t know crap about airplanes to give them a bunch of money.

That's the bottom line, isn't it.

When a jury is picked, ignorance of a major event is what qualifies them to sit in judgement. - Tom

[fireman15]

In 1999 a guy bought an RV6 home built airplane from another party at the Arlington Air Show. Almost immediately after buying it the new owner took it up for a “test flight” and pointed it almost straight up while using full throttle. The plane obliged for a couple thousand feet before losing airspeed, stalling and auguring almost straight in.

It took approximately 6 minutes for emergency crews to reach the fiery crash site. Afterward, attorneys for the guy's family claimed if they had arrived sooner that he could have been saved. Even though any reasonable person should be able to deduct that flying almost straight into the ground at high speed would result in instant death, the same as if you drove a car into solid concrete at 100 mph. Any pilot could tell you that the “accident” was 100% the guys own fault.

But all that was left of the body was basically ashes so it really couldn't be proved that he died on impact. And “witnesses” with vivid imaginations said that they saw someone moving around in the fire. So the jury awarded the guys family $10.5 million dollars saying that the airshow should have been paying to have firefighters on the field during the show.

https://www.heraldnet.com/news/10-5-million-jury-verdict-in-death-of-pilot/

[CondoleezzaProtege]

Thank you for this thoughtful response, and keep us posted if your pilot friend has any other helpful insight to share. I have committed this whole Boeing ordeal to prayer. Not just due to my own concerns as a frequent passenger, but because I really want the best of America up and running again in true ‘MAGA’ fashion... Corruption must be uprooted at every level.

God bless you.

🙏 🇺🇸