17 minutes ago, Bobsk8 said:

So you are claiming that all three crews, ( the two that died and the one that was saved by the extra pilot riding in the jump seat) where incompetent and not that that the Max was an accident waiting to happen. You won't convince me of that. 

I’m saying the one Ethiopian crew had the new procedure and what the minister said makes me think they still went off reservation and turned the trim back on after turning it off. Turning it back on made it more difficult for them to save the plane, even though it may very well have been unsavable already because of their altitude and how much the trim had been allowed to runaway with.

The max was indeed an accident waiting to happen when they programmed in a stick pusher masquerading as a flight control logic without the fault detections and inhibits that a proper stick pusher would have.

Edited April 4, 20197 yr by KevinAu

6 minutes ago, w6kd said:

So how many hours of turbine time have you logged?  Your opinions have been among the most cynically critical in this thread, and I'm going to go out on a limb and guess that you don't have either an aerospace engineering degree or a turbine type rating in hand to base your snark on.  So if you're going to attack others for their lack of bona fides as a basis for having an opinion here, start first by gazing into the nearest mirror.

Let's assume that the MCAS is the problem here.  An MCAS problem causes a runaway trim, which is a known emergency condition covered by a critical memory item.  Regardless of how or even if the system's new features were taught in the training centers, one need not know the cause of the runaway to recognize that it has occurred, and then properly and promptly correct it with the critical action procedure if properly trained.  The corrective action as it exists today solves the problem regardless of cause because it completely depowers the trim motors.

 

 

About 16000.

And I completely agree with your second paragraph, it’s exactly what I have said here earlier.

Edit, sorry thought you meant that at me.

Edited April 4, 20197 yr by KevinAu

I found this on the PPrune forums, just posted:

http://www.ecaa.gov.et/documents/20435/0/Preliminary+Report+B737-800MAX+%2C(ET-AVJ).pdf/4c65422d-5e4f-4689-9c58-d7af1ee17f3e

Quote

Narrative of the flight from the preliminary report:

1 FACTUAL INFORMATION

1.1 HISTORY OF FLIGHT

On March 10, 2019, at about 05:44 UTC (All times listed is Universal Coordinated Time (UTC), as recorded on the FDR.), Ethiopian Airlines flight 302, a Boeing 737-8 (MAX), Ethiopian registration ET-AVJ, crashed near Ejere, Ethiopia, shortly after takeoff from Addis Ababa Bole International Airport (HAAB), Ethiopia. The flight was a regularly scheduled international passenger flight from Addis Ababa to Jomo Kenyatta International Airport (HKJK), Nairobi, Kenya. There were 157 passengers and crew on board. All were fatally injured, and the Aircraft was destroyed.

The following is based on the preliminary analysis of the DFDR, CVR and ATC communications. As the investigation continues, revisions and changes may occur before the final report is published.

At 05:37:34, ATC issued take off clearance to ET-302 and to contact radar on 119.7 MHz.

Takeoff roll began from runway 07R at a field elevation of 2333.5 m at approximately 05:38, with a flap setting of 5 degrees and a stabilizer setting of 5.6 units. The takeoff roll appeared normal, including normal values of left and right angle-of-attack (AOA). During takeoff roll, the engines stabilized at about 94% N1, which matched the N1 Reference recorded on the DFDR. From this point for most of the flight, the N1 Reference remained about 94% and the throttles did not move. The N1 target indicated non data pattern 220 seconds before the end of recording. According to the CVR data and the control column forces recorded in DFDR, captain was the pilot flying.

At 05:38:44, shortly after liftoff, the left and right recorded AOA values deviated. Left AOA decreased to 11.1° then increased to 35.7° while value of right AOA indicated 14.94°. Then after, the left AOA value reached 74.5° in ¾ seconds while the right AOA reached a maximum value of 15.3°. At this time, the left stick shaker activated and remained active until near the end of the recording. Also, the airspeed, altitude and flight director pitch bar values from the left side noted deviating from the corresponding right side values. The left side values were lower than the right side values until near the end of the recording.

At 05:38:43 and about 50 ft radio altitude, the flight director roll mode changed to LNAV.

At 05:38:46 and about 200 ft radio altitude, the Master Caution parameter changed state. The First Officer called out Master Caution Anti-Ice on CVR. Four seconds later, the recorded Left AOA Heat parameter changed state.

At 05:38:58 and about 400 ft radio altitude, the flight director pitch mode changed to VNAV SPEED and Captain called out “Command” (standard call out for autopilot engagement) and an autopilot warning is recorded.

At 05:39:00, Captain called out “Command”.

At 05:39:01 and about 630 ft radio altitude, a second autopilot warning is recorded.

At 05:39:06, the Captain advised the First-Officer to contact radar and First Officer reported SHALA 2A departure crossing 8400 ft and climbing FL 320.

Between liftoff and 1000 ft above ground level (AGL), the pitch trim position moved between 4.9 and 5.9 units in response to manual electric trim inputs. At 1000 ft AGL, the pitch trim position was at 5.6 units.

At 05:39:22 and about 1,000 feet the left autopilot (AP) was engaged (it disengaged about 33 seconds later), the flaps were retracted and the pitch trim position decreased to 4.6 units.

Six seconds after the autopilot engagement, there were small amplitude roll oscillations accompanied by lateral acceleration, rudder oscillations and slight heading changes. These oscillations continued also after the autopilot was disengaged.

At 05:39:29, radar controller identified ET-302 and instructed to climb FL 340 and when able right turns direct to RUDOL and the First-Officer acknowledged.

At 05:39:42, Level Change mode was engaged. The selected altitude was 32000 ft. Shortly after the mode change, the selected airspeed was set to 238 kt.

At 05:39:45, Captain requested flaps up and First-Officer acknowledged. One second later, flap handle moved from 5 to 0 degrees and flaps retraction began.

At 05:39:50, the selected heading started to change from 072 to 197 degrees and at the same time the Captain asked the First-Officer to request to maintain runway heading.

At 05:39:55, Autopilot disengaged,

At 05:39:57, the Captain advised again the First-Officer to request to maintain runway heading and that they are having flight control problems.

At 05:40:00 shortly after the autopilot disengaged, the FDR recorded an automatic aircraft nose down (AND) activated for 9.0 seconds and pitch trim moved from 4.60 to 2.1 units. The climb was arrested and the aircraft descended slightly.

At 05:40:03 Ground Proximity Warning System (GPWS) “DON’T SINK” alerts occurred.

At 05:40:05, the First-Officer reported to ATC that they were unable to maintain SHALA 1A and requested runway heading which was approved by ATC.

At 05:40:06, left and right flap position reached a recorded value of 0.019 degrees which remained until the end of the recording.

The column moved aft and a positive climb was re-established during the automatic AND motion.

At 05:40:12, approximately three seconds after AND stabilizer motion ends, electric trim (from pilot activated switches on the yoke) in the Aircraft nose up (ANU) direction is recorded on the DFDR and the stabilizer moved in the ANU direction to 2.4 units. The Aircraft pitch attitude remained about the same as the back pressure on the column increased.

At 05:40:20, approximately five seconds after the end of the ANU stabilizer motion, a second instance of automatic AND stabilizer trim occurred and the stabilizer moved down and reached 0.4 units.

From 05:40:23 to 05:40:31, three Ground Proximity Warning System (GPWS) “DON’T SINK” alerts occurred.

At 05:40:27, the Captain advised the First-Officer to trim up with him.

At 05:40:28 Manual electric trim in the ANU direction was recorded and the stabilizer reversed moving in the ANU direction and then the trim reached 2.3 units.

At 05:40:35, the First-Officer called out “stab trim cut-out” two times. Captain agreed and FirstOfficer confirmed stab trim cut-out.

At 05:40:41, approximately five seconds after the end of the ANU stabilizer motion, a third instance of AND automatic trim command occurred without any corresponding motion of the stabilizer, which is consistent with the stabilizer trim cutout switches were in the ‘’cutout’’ position

At 05:40:44, the Captain called out three times “Pull-up” and the First-Officer acknowledged.

At 05:40:50, the Captain instructed the First Officer to advise ATC that they would like to maintain 14,000 ft and they have flight control problem.

At 05:40:56, the First-Officer requested ATC to maintain 14,000 ft and reported that they are having flight control problem. ATC approved.

From 05:40:42 to 05:43:11 (about two and a half minutes), the stabilizer position gradually moved in the AND direction from 2.3 units to 2.1 units. During this time, aft force was applied to the control columns which remained aft of neutral position. The left indicated airspeed increased from approximately 305 kt to approximately 340 kt (VMO). The right indicated airspeed was approximately 20-25 kt higher than the left.

The data indicates that aft force was applied to both columns simultaneously several times throughout the remainder of the recording.

At 05:41:20, the right overspeed clacker was recorded on CVR. It remained active until the end of the recording.

At 05:41:21, the selected altitude was changed from 32000 ft to 14000 ft.

At 05:41:30, the Captain requested the First-Officer to pitch up with him and the First-Officer acknowledged.

At 05:41:32, the left overspeed warning activated and was active intermittently until the end of the recording.

At 05:41:46, the Captain asked the First-Officer if the trim is functional. The First-Officer has replied that the trim was not working and asked if he could try it manually. The Captain told him to try. At 05:41:54, the First-Officer replied that it is not working.

At 05:42:10, the Captain asked and the First-Officer requested radar control a vector to return and ATC approved.

At 05:42:30, ATC instructed ET-302 to turn right heading 260 degrees and the First-Officer acknowledged.

At 05:42:43, the selected heading was changed to 262 degrees.

At 05:42:51, the First-Officer mentioned Master Caution Anti-Ice. The Master Caution is recorded on DFDR.

At 05:42:54, both pilots called out “left alpha vane”.

At 05:43:04, the Captain asked the First Officer to pitch up together and said that pitch is not enough.

At 05:43:11, about 32 seconds before the end of the recording, at approximately 13,4002 ft, two momentary manual electric trim inputs are recorded in the ANU direction. The stabilizer moved in the ANU direction from 2.1 units to 2.3 units.

At 05:43:20, approximately five seconds after the last manual electric trim input, an AND automatic trim command occurred and the stabilizer moved in the AND direction from 2.3 to 1.0 unit in approximately 5 seconds. The aircraft began pitching nose down. Additional simultaneous aft column force was applied, but the nose down pitch continues, eventually reaching 40° nose down. The stabilizer position varied between 1.1 and 0.8 units for the remainder of the recording.

The left Indicated Airspeed increased, eventually reaching approximately 458 kts and the right Indicated Airspeed reached 500 kts at the end of the recording. The last recorded pressure altitude was 5,419 ft on the left and 8,399 ft on the right.

To pilots here, 05:43:11 does it means they turned on again the automatic trim??

They also seem to forgot to reduce the power?

Regards,
Simbol

Edited April 4, 20197 yr by simbol

https://aviation.stackexchange.com/questions/2317/how-does-an-alpha-aoa-vane-work

Playing the devil's "avocado" here, but why two defective ones in an old LOW but reliable technology, regardless of all the shortcomings in the design of the MCAS? Maybe before following the money first, let's follow the two Angle-of-Attack sensors histories. How come they got bad so quickly in these two brand new a/c's.

Cheers,

   

3 hours ago, simbol said:

To pilots here, 05:43:11 does it means they turned on again the automatic trim??

They also seem to forgot to reduce the power?

Manual electric trim = trim switches on the yoke, which are inoperative with stab trim cutout so yes, apparently they switched it back on, probably, like Kevin said above, in the hopes it would help them to trim ANU when it only exacerbated the situation because MCAS was enabled to kick in again (which means they did follow procedures but then abandoned them by turning it back on). However, at that point, judging by the Captain's remark that pitch up force was not enough and their difficulties to trim manually, it seems even without that last MCAS input they were not going to make it.

The thrust levers stayed in one position throughout the flight, as outlined in the report, so yes, they didn't adjust thrust. Adding thrust helps to move the nose up but obviously also increases speed.

 

3 hours ago, mabe54 said:

Playing the devil's "avocado" here, but why two defective ones in an old LOW but reliable technology, regardless of all the shortcomings in the design of the MCAS? Maybe before following the money first, let's follow the two Angle-of-Attack sensors histories. How come they got bad so quickly in these two brand new a/c's.

It was only the left AoA vane which was faulty. The right one provided correct data. You can see this by the abnormal readings on the Captain's side (like an extreme nose up attitude) and by the fact that only the Captain's stick shaker activated (on the affected side). In the case of the Lion Air accident, it was also one faulty AoA vane. I'm not sure if the AoA vane being faulty in both cases suggests a problem with AoA vanes on the MAX, but it is remarkable that the Lion Air maintenance was not able to correct the issue and the aircraft went back into the air in an unairworthy state (with the AoA vane still faulty).

Edit: Just read Kevin's reply below so it seems there was no issue with the AoA vane other than being hit by a bird.

Edited April 4, 20197 yr by threegreen

3 hours ago, mabe54 said:

https://aviation.stackexchange.com/questions/2317/how-does-an-alpha-aoa-vane-work

Playing the devil's "avocado" here, but why two defective ones in an old LOW but reliable technology, regardless of all the shortcomings in the design of the MCAS? Maybe before following the money first, let's follow the two Angle-of-Attack sensors histories. How come they got bad so quickly in these two brand new a/c's.

Cheers,

   

Ethiopean reportedly hit a bird at takeoff on the vane.

28 minutes ago, KevinAu said:

Ethiopian reportedly hit a bird at takeoff on the vane.

That will do it.

It reminded me of the famous line from Casablanca:  Of all the gin joints in all the towns in all the world she walks into mine.

Cheers,

7 hours ago, KevinAu said:

And if they turned the trim back on, then they were clearly not following the procedure, despite what the minister says. Because the procedure clearly says ‘stay in the cutout position for the remainder of the flight’. And yes, like I said earlier, they may not have been able to or felt like they would have been able to, hand spin the wheel enough, in time. So, if they did flip the trim back on again for whatever reason, then they’re off the reservation and you cannot say they followed ‘all’ procedures. Unfortunately, some days, you realize too late, you should have just stayed in bed.

Damned if you do, damned if you don't.

It's not clear that they did return the switches to normal (the report is explicit that the cutout switches were placed to cutout, but it does not state anywhere that they were subsequently returned to NORM -- that is an inference that some people have made based on the recorded electric trim inputs, but we don't actually even know for certain whether those were commanded by the crew and not, say, some sort of electrical transient. They certainly don't seem congruous with what the crew was trying to achieve -- surely you'd be holding the trim switches down, not just giving them a small blip in that situation -- indeed earlier in the flight the trim inputs were much longer).

If they didn't, and flew the aircraft in to the ground unable to control the pitch or move the trim wheel by hand (as inferred from the FO's comments), almost certainly aware that the trim issue was very likely to be MCAS (where the electric trim switches would have an effect) and not a true uncontrollable stab runaway per se -- there'd be people on forums decrying them as SOP monkeys unable to think outside the box.

If they did attempt to regain some control of the pitch trim by returning the switches to NORM, they get hammered for not following the SOP.

As I say, damned if you do, damned if you don't. Equally dead, however.

7 hours ago, simbol said:

I found this on the PPrune forums, just posted:

http://www.ecaa.gov.et/documents/20435/0/Preliminary+Report+B737-800MAX+%2C(ET-AVJ).pdf/4c65422d-5e4f-4689-9c58-d7af1ee17f3e

To pilots here, 05:43:11 does it means they turned on again the automatic trim??

They also seem to forgot to reduce the power?

Regards,
Simbol

My bet is that they did turn the trim system back on, even though that is not explicitly said so in this report. If the stab is too far out of trim, the airloads can prevent the manual trim wheel from moving. But by turning it back on, but not making a more definite nose up input, it allowed the mcas run to for that one last time that put them into terminal dive. I will speculate that it was probably the fo who flipped it back on when the wheel didn’t work for him, but didn’t make it clear that he had done so to the captain. The small nose up input may have been the fo trying it out on his yoke switch. But since the capt didn’t know he had that switch back, he never made a more definite nose up command. Again, I speculate.

7 hours ago, w6kd said:

The corrective action as it exists today solves the problem regardless of cause because it completely depowers the trim motors.

Well, not necessarily. The trim motor is very powerful and probably* requires a relay to handle the current draw. So even with both switches turned off, if for some reason the relay contacts got 'welded closed', electrical power would remain flowing...

* Assuming that there is a mechanical relay and not a solid state relay. Even if the latter, solid state relays have been known to fail occasionally.

1 hour ago, KevinAu said:

My bet is that they did turn the trim system back on, even though that is not explicitly said so in this report. If the stab is too far out of trim, the airloads can prevent the manual trim wheel from moving. But by turning it back on, but not making a more definite nose up input, it allowed the mcas run to for that one last time that put them into terminal dive. I will speculate that it was probably the fo who flipped it back on when the wheel didn’t work for him, but didn’t make it clear that he had done so to the captain. The small nose up input may have been the fo trying it out on his yoke switch. But since the capt didn’t know he had that switch back, he never made a more definite nose up command. Again, I speculate.

And it could be, that by that time, the forces on the elevator were so strong (due to the high airspeed) that they couldn't have moved the trim wheel back sufficiently, even if they had turned off the system.  What a tragic situation for all.

Here's Boeing's response to the initial report.

 

https://boeing.mediaroom.com/2019-04-04-Boeing-CEO-Dennis-Muilenburg-Addresses-the-Ethiopian-Airlines-Flight-302-Preliminary-Report

I don't know if it`s true but I have read that there could be a criminal investigation into the FAA and Boeing over this. 

32 minutes ago, rjfry said:

I don't know if it`s true but I have read that there could be a criminal investigation into the FAA and Boeing over this. 

When we begin charging the designers with crimes when a design fails, that is when we stop advancing that industry.

Quote

I'm not sure if the AoA vane being faulty in both cases suggests a problem with AoA vanes on the MAX, but it is remarkable that the Lion Air maintenance was not able to correct the issue and the aircraft went back into the air in an unairworthy state (with the AoA vane still faulty).

It is even more remarkable that Boeing designed the MCAS system to take readings from only one AoA vane.