Preliminary report on Lion Air crash released - Boeing 737 MAX involved was "unfit to fly"

[Brooksie359]

3 hours ago, Sakkura said:

 

 

The pilots requested clearance to return to the airport three minutes into the flight.

And they didn't get it? If someone didn't let them return then they should be held responsible. If a plane is malfunctioning they need to be able to land for safety reasons. 

[D13H4RD]

6 minutes ago, Blasteque said:

Most aircraft have an "alternative control laws" flight control mode that disables some, if not most or all, automatic systems.  Doing this can be more dangerous than simply trying to fix the one problem that is in front of you.  Most modern flight crews would struggle with handling a modern airliner completely in manual mode, especially if it's set to a condition other than level cruise.

I think that's what happened to AF447 and AA8501. The computers were set to alternate mode (AF's went into it from the temporary inconsistencies in airspeed from the frozen pitot tubes whilst AA went into it from the captain's ill-advised procedure to deal with a malfunctioning rudder unit). The aircraft would act differently from usual as a result.

8 minutes ago, Blasteque said:

The auto-trim system is there for reason: the 737-MAX's increased length allows the aircraft to enter a stall condition it can not recover from more easily than the standard length 737.  It's not something you want to turn off unless you're absolutely certain the system is wrong.

There's also another reason for that: the CFM LEAP-X engines themselves. Specifically how they are placed and such.

 

4 minutes ago, Brooksie359 said:

And they didn't get it? If someone didn't let them return then they should be held responsible. If a plane is malfunctioning they need to be able to land for safety reasons. 

I'm pretty sure priority is given to any aircraft that is in need of urgent attention, such as an emergency. However, AFAIK, the crew never declared a Mayday, which would've given them absolute priority for communications and landing.

[Brooksie359]

3 minutes ago, D13H4RD said:

I think that's what happened to AF447 and AA8501. The computers were set to alternate mode (AF's went into it from the temporary inconsistencies in airspeed from the frozen pitot tubes whilst AA went into it from the captain's ill-advised procedure to deal with a malfunctioning rudder unit). The aircraft would act differently from usual as a result.

There's also another reason for that: the CFM LEAP-X engines themselves. Specifically how they are placed and such.

 

I'm pretty sure priority is given to any aircraft that is in need of urgent attention, such as an emergency. However, AFAIK, the crew never declared a Mayday, which would've given them absolute priority for communications and landing.

No being able to know you altitude and speed is a huge issue. They should have been clear for landing. 

[D13H4RD]

4 minutes ago, Brooksie359 said:

No being able to know you altitude and speed is a huge issue. They should have been clear for landing. 

They might have, but we're speculating at this point. They have not yet released ATC transcripts.

 

Once they took off however, turning back to the airport would be difficult, not when you have to deal with a computer that's gone haywire, the constant alarms, the ominous sound of the stick shaker and add that with unreliable airspeed and altitude information and you have one heck of a difficult time. Triply so if it's over dark waters, because then you have no reference point.

 

Another problem is that asking ATC for altitude info may not always be accurate, especially if the plane's transponder gets its altitude information from the failed sensors that relay altitude information to the altimeter alongside the transponder. That's precisely what happened to Aeroperu 603, where the altimeter and ATC told them that they were at 9700 feet, when they were actually <30 feet above the ocean.

[Blasteque]

1 minute ago, D13H4RD said:

Another problem is that asking ATC for altitude info may not always be accurate, especially if the plane's transponder gets its altitude information from the failed sensors that relay altitude information to the altimeter alongside the transponder. That's precisely what happened to Aeroperu 603, where the altimeter and ATC told them that they were at 9700 feet, when they were actually <30 feet above the ocean.

To add to this:

There tends to be a mistaken impression by the layman that ATC radar (or any radar) can give high accuracy information in three dimensions.  This cannot be assumed.  Most radar systems have much higher precision in the horizontal plane than in the vertical plane.  Spinning antenna style systems may have less than a dozen vertical scan bands; this makes altitude readings crazy imprecise, but good enough to allow you to plan and coordinate traffic (because the traffic themselves have altimeters).  Fixed antenna phased array systems have done away with those restrictions (or at least have to potential to do so), but they're expensive and so are not found everywhere. 

 

(There are exceptions, of course.  The USN developed fairly precise 3D airsearch radar using conventional parabolic mirror radar technology a long time ago.  Likewise, early phased arrays systems, like APG-63, still had limited vertical scanning.)

[D13H4RD]

I think this one question's on everyone's minds.

 

How and why did maintenance personnel give PK-LQP a clean bill of health before it departed on its ill-fated journey

[Yun4xGaming]

7 hours ago, D13H4RD said:

D13H4RD's opinion

The report gives me more questions than answers. Specifically the following;

• Why didn't the airline ground the aircraft until the program was sorted out and confirmed as such?
• What were the major differences between the aircraft's second last flight and its ill-fated one?
• Were all Lion Air crews properly trained on the 737 MAX's new features?
• Why did Lion Air maintenance personnel clear the aircraft for its final flight?

So many questions, and it looks like those will be answered in the coming months. Looking a bit like improper maintenance may have played a pretty key role in this aviation catastrophe.

1. A single Faulty AOA Vane is not a reason to Ground a Fleet of a plane, Planes have this thing called MEL "Minimum Equipment List" whic specifies what is required on the Absoloute Minimum. Planes can be dispatched with alot of Stuff Inoperative and its still Fine

2. There is no Difference, Both flights had the exact same Fault(AOA Vane showing Indications whic are too High). The difference being 1 Crew managed to Cope with the Fault and the other one failed to follow the Stabilizer Trim Runaway Checklist

3. They all had to atleast be Trained for a Stabilizer Runaway Event whic is more dangerous than MCAS Thinking the planes Stalling

4. Because they've Flushed the Pitot Tubes, did additional Tests and they turned out fine so they cleared it again.

7 hours ago, VegetableStu said:

to be in the position of the pilot crew where the decision must be made between calling it a basic joke and landing it only to make passengers angry and having the small chance of finding out it's one step missing on the takeoff crew's part (it isn't; see OP), or continue the flight and hope something somewhere buffs that out...

If there is Something wrong you Divert, it doesnt matter if your Passengers are going to be Pissed. Atleast thats the way it is with most Western Airlines (EasyJet,Lufthansa,Ryanair,KLM etc.). No Pilot can get Fired for Pre-Cautiously Diverting.

7 hours ago, Taf the Ghost said:

If flight speed & altitude weren't working, they should have called an emergency very quickly and headed back to the airfield, though that might have still ended up in a land-based crash as well.

 

A faulty sensor causing the stick to automatically pitch into a nose-down move is a useful safety feature, but there's no way to shut it off? Either the problem is more complex than the first run of analysis, or that's a massive big issue. 

The Captains ALT and SPD indications weren't working on the Previous flight so they Switched the Captains PFD to source its info from the Right hand Pitot-Static port and they continued the Failure and wrote it up after landing. Oh and you can land a Plane with 2 Things only btw. Pitch+Power, the plane wouldnt have "ended up in aland-based crash" thats completly wrong. The QRH gives you Pitch and Thrust Values for a Given weight whic you can use to land your Plane if you had No Speed and Altittude indication on all 3 Displays.

The "Stick"(btw. it's called a Yoke not a stick, there is no such thing as a Stick in a 737) doesn't bring the plane in a nosedive, the Pilots can ALWAYS counter it. and Yes there are 3 Ways to Counterract it really Simply. 1st way, use your Rocker Switches on the yoke to Trim Nose Up (against the Nose Down input from MCAS) whic will also inhibit any Trim Operation wether that is from MCAS or from the STS(Speed Trim System) for 5 Seconds before they start working again, 2. Way is to use the Stabilizer Cutout Switches witch the Crew on the Previous flight have correctly Done. and the 3. Way whic is also the easist is to Just Grab your Trimwheel. The Trimwheel is Mechanically Connected to the Gearbox of the THS via a Steel Cable. If you hold the Trimwheel with your Hand(Whic doesn't require a Hulk to do) No electrical triminput will be able to Override it. That should also be your First thought if the Trim is doing something its not supposed to and you cant figure it out, just Grab it.

7 hours ago, D13H4RD said:

There is a way to shut it off, but it's not found in the flight manual, apparently.

 

It is however, found in an emergency checklist used for situations like this. That is apparently what the previous crew may have used, hence why they were able to continue.

What isn't found in the Manual is the Description of the MCAS System whic was operating. and what the Other Crew found and did was the NNC(Non-normal Checklist) of the QRH(Quick Reference Handbook) was the Stabilizer Trim Runaway Checklist, and EVERY Commercial Plane carries a Flight manual(called FCOM in most cases) And a QRH onboard.

7 hours ago, Taf the Ghost said:

One has to wonder why this plane wasn't grounded until that issue was addressed. "Plane randomly wants to dive into the ground" is pretty high on the "needs to be fixed" list of problems.

The Issue was written up by the FlightCrew on the Previous flight whic was Unreliable Airspeed and Alttitude. Maintenance have done the AMM Tasks and it was working fine again. However no AOA Fault was Reported hence MX didn't fix it. How should they fix something theyre not aware of? and the plane doesnt "Randomly" dive into the Ground, it happens for a Particular Reason. Stall a 737Max with no assistance from the SMYD,EFS and MCAS and then you'll be glad systems like these Exist.

7 hours ago, VegetableStu said:

TBH/IMO the previous crew should have brought it up o_o or at least somehow brief the next one

They Have, they made a Tech Log Entry and MX Looked at it, but no one knew the Problem was with the AOA Vane, everyone suspected a Malfuction with the ADR(Air Data Reference) Systems.

7 hours ago, D13H4RD said:

That was actually their plan. They radioed ATC asking for permission to return to the airport.

 

Given the circumstances (a rogue computerized system that's repeatedly forcing the plane's nose down unless you find the checklist which tells you how to disable the feature alongside a dark sky with unreliable airspeed and altitude information unless you rely on backup), it's a pretty big hill. Reminds me of Aeroperu 603.

You don't have to Find a Checklist, theres this thing whic we like to call Airmanship. Every Pilot needs to know all Memory Items of the Top off the Head. Unrealiable Airspeed? 4° Nose Up and 74% N1. Trim Runaway? Grasp and Hold the TrimWheel. Aeroperu 603? 2 Completly diffrent accidents whic dont even Resemble eachother. The Instruments on this flight were working(On the Previous flight the Captains Instruments were Showing unreliable Indications whic was looked at by MX before the Accident Flight)

7 hours ago, RejZoR said:

I watch Air Crash Investigations regularly and in like 75% of cases, crashes happen because of some idiot carelessly "fixing" the aircrafts. In most cases because information isn't transferred properly between staff during shift changes and because maintenance staff doesn't follow proper procedures.

 

The other problem are airlines understaffing and pressuring airliners to fly asap because grounded planes are doing loss, causing maintenance staff to rush the maintenance and doing it poorly.

Really, your basing your opinion on ACI whic is a complete overdamatization of the Smallest Thing? Have you ever worked as a Aeronautical  Engineer or do you know anyone that is one? No one "Carelessly" Fixes planes these Days. You have to exactly follow the AMM Tasks and get the Task signed off, you cant just go to a plane and do something and call it a job done, Goodluck with that. What is your Claim of Understaffing and pressure based on? Do you have any Graphs, Data or Anything at all to back that claim up, or just ACI?

7 hours ago, D13H4RD said:

The reason why is because it's still really early days. Plus, we can really only speculate what might have been in the crew's minds until investigators find the CVR and gather what they can out of it.

 

Aircraft catastrophes are very rarely only caused by one thing. Rather, it's a chain link of different causes that add up to disaster. Like we can say a crash is caused by pilot error, but what exactly led the crew to make that fatal mistake?

2 Crews Faced with the Same Situation, 1 Crew were able to Handle the Issue, the other weren't. Go Figure.

7 hours ago, Trixanity said:

That's what can make flights so scary: human error can quickly result in hundreds of deaths .

 

Especially these maintenance issues and whether or not the aircraft is allowed to remain grounded or land shortly after take-off.

 

I'm quite sure that money and time is a huge issue in every regard: costs money for a plane to be grounded and it takes time (therefore money) to meticulously go through everything on a plane so skipping or overlooking something due to constraints is possible and then we get to the crew noticing something and calling it in but having to take logistics of the airport, the dissatisfaction of everyone with a delayed/grounded flight etc and it seems like sometimes the call is just to try to work around any issue because in most cases it's probably a minor issue that can be fixed later.

 

I can't imagine how many times these things happen and are usually okay so it becomes standard procedure to the point where the grey area between OK and not OK is so small that it's hard to see when you should stop everything or carry on.

A Single Human error doesnt cause a Crash, its a Chain of errors and also down to the Skill of a Person. I'm sorry to say but so many People are Pilots because they have the money when in reality they shouldn't even be allowed to touch something. Every Plane is objected to Multiple Maintenace Checks like C/D-Checks where its Torn appart and Every Inch is inspected. Those inspections dont happen randomly, They happen after xxxx Hours and Every airline keeps track of that. so a Plane going in for Maintenance Checks does not Cause a delay at all cause it's planned. 99% of the Cases theres always a Backup plane that can be flown in from somewhere or it's standing around at the airport to replace the "Faulty" one its not as big of a deal as you make it out to be. And no plane get's grounded for "minor" issue, if there is one, it's written up in the Tech Log and fixed on the next annual Check. it doesnt cause a delay and there is no reason to not tell of something thats faulty. I can tell you that The major western airlines dont Skimp their Maintenance, there is almost no Grey area, If you see that something is Broken you consult the AMM and to the Task in there, no matter what.

7 hours ago, D13H4RD said:

And that's the difficult part. It's easy to say they could've grounded the plane, but in reality, it's way harder because these airlines want to make money, and they will generally try to keep planes flying even if they have an issue that is deemed minor.

Again this is so wrong. The Previous Crew wasn't aware of the MCAS system, they had however Unreliable SPD and ALT on the Cpt. Side, so they thought the Trim Runaway was because of that whic they have Reported to Maintenance. Maintenance Flushed the ADM's (Air Data Modules) and the Cpt. Pitot Tube, did Tests whic Worked Ok and they cleared the Plane. No one was even suspecting a faulty AOA Vane.

7 hours ago, RejZoR said:

I think the main problem is so many systems depending on each other and pilots are forced to know all of them and how they behave it's in the end not a safety feature anymore, it's a problem in the end.

 

Example here being system placing airplane into dive to eliminate a non existing stall event and then pilots trying to counter it.

I'm sorry but it doesnt Take a genius to look Realize that you need to Pull back more and More to maintain the Pitch attitude, give it some NU Trim to ease of the Yoke Forces only to feel the Nose wanting to go down again. You'd look down on the Trimwheel and see it Run away from you(Whic btw. on the 737 is Loud). Whic is what the Crew on the Previous Flight managed to do.

7 hours ago, D13H4RD said:

Sort of like Qantas Flight 72

Except that the Upsets in QF72 happened within Seconds and caused Abrupt sharp movements. Because of a Faulty AOA sensor

7 hours ago, williamcll said:

TL;DR Human error?

Liekly, but theres more to it than Just shifting the blame to the Pilots.

6 hours ago, Blasteque said:

More info can be found here:

http://aviationweek.com/commercial-aviation/lion-air-crash-report-details-automatic-trim-issues

 

Previous to the prior flight there were faults detected that prompted a AOA sensor replacement. 

 

During the prior flight the flight crew encountered basically the same problem; that crew addressed the issue by switching off the auto-trim (which is new to the MAX and is not in the rest of the 737 line; if you were only familiar with legacy 737s it could be surprise, but it should have been covered in type orientation).

 

That crew then reported the issue in the maintenance log.

 

Maintenance then performed several servicing tasks (did not replace anything).  The system passed their test procedure to their satisfaction.

 

Next flight the crew struggled again.  As has been mentioned, the auto-trim cut-off is not in the flight manual, but it is in an emergency procedure.  This crew either didn't have the time (they had just taken off) or didn't fully realize the situation they were in.  The CVR will hopefully give more insight when it is found.

There is no "Auto-Trim" on a 737, you have MCAS(Only on the MAX) and the STS(Speed Trim System). Also this Cut off Switch as you've been Refering to (Proper name is: Stabilizer Trim Cutout Switches, of whic there are Always 2, one for the Main Electrical Channel and one for the Autopilot Channel) has been in the 737 since the Very first 737, if you were only fammiliar with legacy 737s then you would Exactly know where your 2 Cutout switches are. Wherever you got that Info From, its complete BS. The Stabilizer Cutout Switches and their Function are also Mentioned in the FCOM(Flight Crew Operating Manual) Whic every pilot will atleast have seen when they do their TypeRating. They had the Time, the crew before them Managed to stop the Runaway. 

[YaBoiWill]

8 hours ago, Taf the Ghost said:

no way to shut it off

Boeing says that there is a method detailed in the manual, which should have been in the cockpit. 

Either the crew weren't trained properly on the new max, or they just didn't know what was going on

[Yun4xGaming]

5 hours ago, ARikozuM said:

Shouldn't there be a "big red button" that says turn off autonomy? A safety feature isn't a safety feature if there's no way to override it easily.

There is a very easy way to Override it, Grasp and Hold the Trimwheel.

4 hours ago, Blasteque said:

Most aircraft have an "alternative control laws" flight control mode that disables some, if not most or all, automatic systems.  Doing this can be more dangerous than simply trying to fix the one problem that is in front of you.  Most modern flight crews would struggle with handling a modern airliner completely in manual mode, especially if it's set to a condition other than level cruise.

 

Furthermore, in this situation the problem was (likely) caused by an erroneous sensor.  Turning off the auto-trim makes the auto-control nose down inputs go away, but it doesn't fix the problem: one side of the cockpit reports an AOA problem, the other doesn't.  In level condition you can review your airspeed, altimeter, and artificial horizon and realize which AOA indicator is wrong.  In climbing condition this is more difficult to do.

 

The auto-trim system is there for reason: the 737-MAX's increased length allows the aircraft to enter a stall condition it can not recover from more easily than the standard length 737.  It's not something you want to turn off unless you're absolutely certain the system is wrong.

Every Pilot that does a TR atleast on the 320 Fammily needs to be able to Fly the plane undery any Conditions in Alternate and Direct Law. Heck the Airbus Test Pilots have done landings on the A320 in Mechanical Revision Mode using only the THS and Rudder and they did it Fine. Refer to above with "Auto-Trim", it doesnt exist on the 737. Putting the Stabilizer Trim Cutout Switches to cutout DOES solve your Problem infront of you because MCAS wont be annoying you and trying to Trim Nose down. It doesn't matter if youre in Level,Climb or Descend. AFAIK the Lion Air 737 MAX's dont have the AOA indicators Options on the PFD(Almost no airline has the Option) So they couldn't have ever known whic AOA Sensor was faulty. The 737MAX's length that has been increased doesnt allow the plane to enter a stall Condition, Every flying object can Stall. the System is there to Help because in the past theres been Near Stall Incidents with the 73NG.

4 hours ago, D13H4RD said:

They might have, but we're speculating at this point. They have not yet released ATC transcripts.

 

Once they took off however, turning back to the airport would be difficult, not when you have to deal with a computer that's gone haywire, the constant alarms, the ominous sound of the stick shaker and add that with unreliable airspeed and altitude information and you have one heck of a difficult time. Triply so if it's over dark waters, because then you have no reference point.

 

Another problem is that asking ATC for altitude info may not always be accurate, especially if the plane's transponder gets its altitude information from the failed sensors that relay altitude information to the altimeter alongside the transponder. That's precisely what happened to Aeroperu 603, where the altimeter and ATC told them that they were at 9700 feet, when they were actually <30 feet above the ocean.

Once they would have gotten Rid of MCAS they could've returned just Fine. I'm not saying its a difficult situation but it would've been Doable. They'd have the Stick shaker going on and from reading the Preliminary Report all their Instruments were fine. and even if they weren't. Back to the Basics, Pitch+Power

[Blasteque]

3 minutes ago, Yun4xGaming said:

 

There is no "Auto-Trim" on a 737, you have MCAS(Only on the MAX) and the STS(Speed Trim System). Also this Cut off Switch as you've been Refering to (Proper name is: Stabilizer Trim Cutout Switches, of whic there are Always 2, one for the Main Electrical Channel and one for the Autopilot Channel) has been in the 737 since the Very first 737, if you were only fammiliar with legacy 737s then you would Exactly know where your 2 Cutout switches are. Wherever you got that Info From, its complete BS. The Stabilizer Cutout Switches and their Function are also Mentioned in the FCOM(Flight Crew Operating Manual) Whic every pilot will atleast have seen when they do their TypeRating. They had the Time, the crew before them Managed to stop the Runaway. 

Thanks for all the corrections.  I'm not familiar with the 737 at all, that was just based upon what I read on Aviation Week. 

The pilot “moved the STAB TRIM switches to CUT OUT and the SIC continued the flight with manual trim without auto-pilot until the end of the flight.” Boeing introduced an automatic trim system known as the Maneuvering Characteristics Automation System on the 737 MAX." 

In my head I blurred all that together!

[Yun4xGaming]

2 minutes ago, Blasteque said:

Thanks for all the corrections.  I'm not familiar with the 737 at all, that was just based upon what I read on Aviation Week. 

The pilot “moved the STAB TRIM switches to CUT OUT and the SIC continued the flight with manual trim without auto-pilot until the end of the flight.” Boeing introduced an automatic trim system known as the Maneuvering Characteristics Automation System on the 737 MAX." 

In my head I blurred all that together!

Yes thats refering to the Previous Flight where the Crew did Mange to figure out that they were having a Trim runaway and did the Correct thing.

This is what the Crew on the Previous flight did whic is Also Part of the Memory Items. (Memory Items= Things that you NEED to know off your Memory without Looking at a Checklist)

[Trik'Stari]

And people call me crazy for refusing to fly.

 

I have flown before, about 4 times, it's not bad. It's quite fun actually.

 

But as I've gotten older and lost friends and family to various things, it's made me realize how quickly death can come for you. I will never fly again. I'll drive or take a frigging boat.

 

I don't care about the statistics. If you look at it it in the right way, a car crash is more survivable than a plane crash, even a ship wrecking incident is probably more survivable. Careening into the ocean at 391 knots? You're not surviving that, ever. I've already survived a head on collision at 45mph. No thanks.

 

 

And yet, I'd board a colony ship to mars, tomorrow, if given the chance.

[Yun4xGaming]

34 minutes ago, Trik'Stari said:

And people call me crazy for refusing to fly.

 

I have flown before, about 4 times, it's not bad. It's quite fun actually.

 

But as I've gotten older and lost friends and family to various things, it's made me realize how quickly death can come for you. I will never fly again. I'll drive or take a frigging boat.

 

I don't care about the statistics. If you look at it it in the right way, a car crash is more survivable than a plane crash, even a ship wrecking incident is probably more survivable. Careening into the ocean at 391 knots? You're not surviving that, ever. I've already survived a head on collision at 45mph. No thanks.

 

 

And yet, I'd board a colony ship to mars, tomorrow, if given the chance.

Thats cause you are Crazy, listen to yourself. You refuse to Fly yet you would board a colony ship to mars? lol

[Trik'Stari]

1 minute ago, Yun4xGaming said:

Thats cause you are Crazy, listen to yourself. You refuse to Fly yet you would board a colony ship to mars? lol

My cost/benefit analysis is simply different from yours lol

[D13H4RD]

6 hours ago, Yun4xGaming said:

Except that the Upsets in QF72 happened within Seconds and caused Abrupt sharp movements. Because of a Faulty AOA sensor

QF72's sudden uncommanded dives were caused by a malfunctioning ADIRU IIRC. 

 

About the AOA sensor, didn't mean "ground the entire fleet". Just PK-LQP. Then again, who knows what actually happened when the aircraft spent the night. They probably did not suspect the AOA sensors had to be checked potentially because that may not be suspected. 

 

Just asking, do you work in the aeronautical industry? Or just a deep aviation enthusiast? Because you seem to know way more about the 737 MAX and aircraft in general than many of us at this point. It's something that either deep enthusiasts or those who've worked in the aeronautical industry either as an engineer or as a pilot for a long while know of deeply. Either that or it's something that's pretty basic and I missed them. 

[D13H4RD]

Here's something. 

 

Boeing recently issued a statement regarding Flight 610 after the NTSC released their preliminary findings. 

Spoiler

The report explains that the maintenance logs for the accident aircraft recorded problems related to airspeed and altitude on each of the four flights that occurred over the three days prior to Flight 610. The logs indicate that various maintenance procedures were performed, but issues related to airspeed and altitude continued on each successive flight. The logs indicate that, among other procedures, on Oct. 27, two days prior to the incident flight, one of the airplane’s Angle of Attack (AOA) sensors was replaced.

 

On Oct. 28, before the flight immediately prior to Flight 610, the pilot in command and the maintenance engineer discussed the maintenance that had been performed on the aircraft. The engineer informed the pilot that the AOA sensor had been replaced and tested. The report does not include records as to the installation or calibration of the new sensor, nor does the report indicate whether the sensor was new or refurbished. Although the report states that the pilot was satisfied by the information relayed by the engineer that the AOA sensor had been replaced and tested, on the subsequent flight the pilots again experienced problems with erroneous airspeed data, and also experienced automatic nose down trim.

 

The report states that the flight crew of the Oct. 28 flight turned off the stabilizer trim switches within minutes of experiencing the automatic nose down trim, and continued with manual trim through the end of the flight. The report further notes that the pilot performed three non-normal checklist procedures, including the runaway stabilizer non-normal checklist, which is a memory item prescribed by the 737 MAX Flight Crew Operations Manual, and reaffirmed in Boeing Flight Crew Operations Manual Bulletin TBC-19 and FAA Emergency Airworthiness Directive (AD) Number 2018-23-51, as the appropriate procedure to address unintended horizontal stabilizer movement, regardless of source. 

 

The report indicates that the remainder of the Oct. 28 flight was uneventful and that the flight continued to its destination. The report also states that, after landing, the pilot reported some of the experienced issues both on the aircraft maintenance log and to engineering. The report states that the pilot ran the runaway stabilizer non-normal check list, but it does not state that he communicated that fact in the maintenance documentation following that flight.

 

The following day, Oct. 29, shortly after taking off, the pilots experienced issues with altitude and airspeed data that the pilots had previously experienced on the earlier flights, due to erroneous AOA data. Data from the flight data recorder summarized in the report also makes clear that, as on the previous flight, the airplane experienced automatic nose down trim. In response, the flight crew repeatedly commanded nose up trim. This sequence repeated for the remainder of the flight, during which the flight crew was able to maintain control of the airplane for approximately ten minutes. Unlike as is stated with respect to the prior flight, the report does not state whether the pilots performed the runaway stabilizer procedure or cut out the stabilizer trim switches.

However, what I really highly recommend everyone read is the actual report from the NTSC as linked below. It's a 12MB PDF file that contains detailed information alongside maintenance logs and checklists plus documentation and airworthiness directive letters sent out. It is far more clearer and detailed that the OP itself, so much so that I will likely update it with information from the document itself (as it should've been). 

NTSC Preliminary Report

[JupiteL]

There's little to do with Boeing. The faults were at the control station when people decided it was fit to fly when the engine made faulty noises. Bad engine is normal, forcing it to fly is another thing.

[NeuesTestament]

20 hours ago, ARikozuM said:

Shouldn't there be a "big red button" that says turn off autonomy? A safety feature isn't a safety feature if there's no way to override it easily.

Fly by wire can be turned off with a button on the joystick in some Airbus planes as far as I know. But switching to complete manual flight in an instead is also not without risks, especialls if the plane is already in a rather unfortunate position.

[NeuesTestament]

12 hours ago, Yun4xGaming said:

Thats cause you are Crazy, listen to yourself. You refuse to Fly yet you would board a colony ship to mars? lol

If somebody says stuff like "I don't care about statistics", it is usually not worth it to interact with them. That's basically them saying "I have made up my mind" and nothing you say will change that.

[Yun4xGaming]

11 hours ago, D13H4RD said:

QF72's sudden uncommanded dives were caused by a malfunctioning ADIRU IIRC. 

 

About the AOA sensor, didn't mean "ground the entire fleet". Just PK-LQP. Then again, who knows what actually happened when the aircraft spent the night. They probably did not suspect the AOA sensors had to be checked potentially because that may not be suspected. 

 

Just asking, do you work in the aeronautical industry? Or just a deep aviation enthusiast? Because you seem to know way more about the 737 MAX and aircraft in general than many of us at this point. It's something that either deep enthusiasts or those who've worked in the aeronautical industry either as an engineer or as a pilot for a long while know of deeply. Either that or it's something that's pretty basic and I missed them. 

One of the AOA sensors was sending out wrong Information to the ADIRU's whic then commanded those Nose Down Inputs on QF72, you can check out the Final report. Heres the thing with Grounding the plane, as a Mechanic if you get a Report from a pilot about something thats wrong you'll Fix it and Conduct tests according to the AMM Tasks. If the Tests are statisfactory then you'll release the plane again. PK-LQP was "Only" having issues on the last 4 flights. 4Flights is a normal rotation for a Crew, usually Pilots do around 4-6Flights a day. Alteast in Europe. now those 4 issue flights have also been in the timespan of over 3 days, so thats really not that Much. And the Pilots were Satisfied with what the Mechanics have done so there really wasnt a reason to Ground the Plane.

Regarding your last question, Hoping to get an ATPL in a Few Years and Currently working on my PPL so yes

 

3 hours ago, JupiteL said:

There's little to do with Boeing. The faults were at the control station when people decided it was fit to fly when the engine made faulty noises. Bad engine is normal, forcing it to fly is another thing.

Where'd you get that Info from? The engines ran fine.

1 hour ago, NeuesTestament said:

Fly by wire can be turned off with a button on the joystick in some Airbus planes as far as I know. But switching to complete manual flight in an instead is also not without risks, especialls if the plane is already in a rather unfortunate position.

Negative, that Red Button on the "Joystick"(Proper Term is Sidestick) is to disconnect the Autopilot OR to take over Priority from the Other Persons sidestick for example if they were flying badly or doing something they shouldn't do in manual flight you can Hold down the AP Disconnect button(The Red one on the Sidestick) and you'll Takeover control from the other Sidestick until you release the button(Unless you hold it for Longer than 40 Seconds) OR the Other persons who'm you've taken Priority from Presses down His AP Disconnect button. It's also associated with a Aural annunciation and Visual Warnings on the Glareshield. The only way to Go from Normal Law to Alternate Law in the 320 manually is to either turn off both of the FAC(Flight Augmentation Computer) or Turn off 2 of the 3 ADR's. Otherwise you can't go into Alternate Law  without having Certain System Failures like Double Hydraulic Failure, Multiple Faulty Sensors, Unusual Attiude etc.

[79wjd]

16 hours ago, Trik'Stari said:

And people call me crazy for refusing to fly.

 

I have flown before, about 4 times, it's not bad. It's quite fun actually.

 

But as I've gotten older and lost friends and family to various things, it's made me realize how quickly death can come for you. I will never fly again. I'll drive or take a frigging boat.

 

I don't care about the statistics. If you look at it it in the right way, a car crash is more survivable than a plane crash, even a ship wrecking incident is probably more survivable. Careening into the ocean at 391 knots? You're not surviving that, ever. I've already survived a head on collision at 45mph. No thanks.

 

 

And yet, I'd board a colony ship to mars, tomorrow, if given the chance.

You can't just choose to ignore some statistics while embracing others. Yes, you're absolutely far more likely to die in a plane accident than a car/boat accident. But the odds of getting in an accident in the first place are so massively skewed that flying is still far safer than driving.

[D13H4RD]

2 hours ago, Yun4xGaming said:

Regarding your last question, Hoping to get an ATPL in a Few Years and Currently working on my PPL so yes

That's pretty awesome. 

 

Hope you'll make it to that ATPL license, and most importantly, hope you enjoy it along the way. 

 

Maybe someday, you'll be part of the flight crew on one of my future flights. XD

 

(Always found pilots rather fascinating) 

[Yun4xGaming]

1 hour ago, D13H4RD said:

That's pretty awesome. 

 

Hope you'll make it to that ATPL license, and most importantly, hope you enjoy it along the way. 

 

Maybe someday, you'll be part of the flight crew on one of my future flights. XD

 

(Always found pilots rather fascinating) 

It's gonna be a long way but i believe it'll Payout, this has been my dream since i've been able to breathe, If you are my Pax one day say Hi

[D13H4RD]

41 minutes ago, Yun4xGaming said:

It's gonna be a long way but i believe it'll Payout, this has been my dream since i've been able to breathe, If you are my Pax one day say Hi

Will do.

 

Have to admit, I'm a little jealous. XD