Ethiopian airliner down in Africa

[The Ancient Geek]

Unreliable airspeed at takeoff sounds like a pitot problem.
In many areas of africa there are small wasps which habitually try to set up home in pitots so pitot covers are fitted whenever an aircraft is on the ground.
Did someone forget to remove a cover ?

Just a random thought, it has happened before........

[Silver Pegasus]

Both recorders found.

[log0008]

Where will the boxes be read? In Washington?

Also NTSB will be busy at the moment, currently JT610, GT3591 and now ET302 all underway and all very significant incidents.

[hans brinker]

Originally Posted by NWA SLF

Ironic that members here who blame the MCAS system already are switching to A320s for their flights which also have the same type angle of attack sensors along with software to prevent a stall and have received faulty see also from sensors resulting in a fatal crash before the crew could respond. It was 10 years ago the A320 with 3 sensors had 2 freeze due to maintenance, the software selected those 2 to use neglecting the third working AOA sensor because it differed, put the plane into a stall preventing dive at an altitude from which the crew could not recover before plunging into the Med. darn Boeing copying AB.

This was an acceptance flight, the crew was rushed and did flight testing while on the approach (as opposed to doing it at 14.000ft, where they would have had time to recognize the fault). They deliberately attempted to stall the aircraft (if it had been a B737 it would have stalled too, and at 3000 ft probably would not have recovered either). Boeing didn't copy Airbus, Boeing's MCAS takes input from ONE AOA and allows it to run the trim all the way, in an Airbus you need 2 out of 3 to fail at the same time to get the same result (and the only reason 2 failed in your example is because MX didn't follow established procedure, not some unexpected design issue). "ironic" indeed....

[Kazt]

Indonesia has grounded all 737 Max as well.

[SigWit]

Originally Posted by arketip

Yes, but from what I understand, the MCAS does not behave/look like a runaway trim

Correct, it is different from the scenarios we normally practice in sim.

And on top of that, it comes with airspeed unreliable indications and stickshaker, which draws a lot of attention to them in an already high workload phase of flight.

[Azgalor]

Originally Posted by SigWit

Correct, it is different from the scenarios we normally practice in sim.

And on top of that, it comes with airspeed unreliable indications and stickshaker, which draws a lot of attention to them in an already high workload phase of flight.

What is different?

[SigWit]

Originally Posted by Azgalor

What is different?

How we normally detect and identify a runaway trim is when we counter the trim which halts it, and then let go, after which the trim immediately runs agains.

With MCAS you counter the trim which doesn’t halt it but runs it in the direction you command it, let go, the trim stays in position. You direct your attention to the airspeed unreliable and stickshaker again. Then after some seconds the trim starts running again.

[Eboy]

Originally Posted by log0008

Where will the boxes be read? In Washington?

Also NTSB will be busy at the moment, currently JT610, GT3591 and now ET302 all underway and all very significant incidents.

The NTSB has a bigger-than-usual investigative backlog due to nearly all employees not working during the 35-day government shutdown. Some investigations aren't going to get the attention they normally would.

[Sailvi767]

Originally Posted by arketip

Yes, but from what I understand, the MCAS does not behave/look like a runaway trim

Sure it does, the trim moves uncommanded. The 737 gives more notification of this than any other aircraft. Yes if you push a trim switch it stops for 5 seconds but it’s stll uncommanded trim.

[xetroV]

Originally Posted by Azgalor

Oh, this different. I was just a bit confused. So you still see that trim is wrong, trim wheels running etc. But the trick is that it comes back again. I though you do not know that it is trim problem.

Erroneous MCAS intervention does not look like runaway trim, it looks like speed trim. Which intervenes so frequently with automatic trimming during routine climbs that a slowly turning trim wheel in that flight phase may very well get unnoticed, especially in a very high workload situation (continuous stickshaker and unreliable airspeed).

[silverstrata]

Originally Posted by arketip

Yes, but from what I understand, the MCAS does not behave/look like a runaway trim

Indeed it does not - MCAS is not continuous, nor does it stop with opposite trim.
... (Note: intermittent trim is normal on every flight - caused by speed trim.)

And a runaway trim does not have a stick shaker blaring.

And the stab-trim cutout switches are upside down.
We are all told about the nefarious holes in the cheese. Well here is a hole in the cheese - emergency switches fitted upside-down - and yet know-alls come onto this forum and defend one of the holes in the cheese - perhaps the very hole that might have saved the day, had it been plugged...!

Silver

[Longtimer]

Both flight recorders retrieved from Ethiopian 737 crash site

Both flight recorders retrieved from Ethiopian 737 crash site

• 11 March, 2019
• SOURCE: Flight Dashboard
• BY: David Kaminski-Morrow
• London

Recovery personnel have retrieve both flight recorders from the Ethiopian Airlines Boeing 737 Max 8 which crashed shortly after take-off from Addis Ababa on 10 March.

The airline states that personnel have recovered the cockpit-voice and digital flight-data recorder from the crash site.

It reiterates that the carrier has grounded the remainder of its 737 Max fleet pending clarification over the cause of the accident.

[Maninthebar]

AoA/Airspeed and MCAS

A lot of speculative thought and I add some....

If MCAS is implicated in this and the Lion accident then it is not just the implementation of this software that needs to be thought through.

Should we not also ask about the quality of the data being received by the system? For Lion we are (reliably?) informed that the accident aircraft had been the subject of erroneous AoA data on at least one previous flight and that this had then resulted in the replacement of the sensor. We have generally assumed from the published evidence that the accident flight ALSO suffered from this issue.

At this point William of Occam scratches his head and is wondering whether there is something else in common which is more likely than two sequential AoA failures.

[Azgalor]

Originally Posted by xetroV

Erroneous MCAS intervention does not look like runaway trim, it looks like speed trim. Which intervenes so frequently with automatic trimming during routine climbs that a slowly turning trim wheel in that flight phase may very well get unnoticed, especially in a very high workload situation (continuous stickshaker and unreliable airspeed).

Oh, so trim wheels are moving and everything, it is visible. But it is not speeding away, it is more like making mess slowly and unnoticedly. It loos really mischievously.

[Sailvi767]

Originally Posted by HowardB

I would like to note that Boeing appear have a suffered disproportionate number of crashes where their aircraft dived nose first into the ground:-

• 737-200, UAL flight 585 (rudder problem)
• 737-300, USAir flight 427 (rudder problem)
• 737-800 FlyDubai flight 981 (loss of control during go around. Wikipedia indicates stabilizer trimming was involved)
• 737 Max 8 Lion air flight 601 (suspected AOA/MCAS issue)
• 767 Atlas Air Flight 3591 (unknown problem)
• 737 Max 8 Ethiopian Airlines (unknown problem)

The only other incident I recall involved the Douglas (now Boeing) MD80 series.

Even though spread over many years, it does appear to be pattern, notwithstanding the very different causes involved. I cannot remember any of the competing airliners having similar problems - Fokker, BAC, Convair, Sud Aviation, Airbus etc.

You have had three recent Airbus crashes where they impacted the water, two in similar circumstances. You had one A340 climb uncommanded over Greenland and just miss a A330 which would have been one of the worst accidents in history. There have been uncommanded nose down pitching moments that resulted in a Rube Goldberg procedure of trying to shutdown two ADR’s on the overhead panel but leaving a third running.

[SigWit]

Originally Posted by Sailvi767

Sure it does, the trim moves uncommanded. The 737 gives more notification of this than any other aircraft. Yes if you push a trim switch it stops for 5 seconds but it’s stll uncommanded trim.

Well, so is speed trim. But I wouldn’t be going out of my way to accomplish the runaway stabilizer NNCL on every departure I fly.

[acatal]

as a non-pilot and finance guy (apologies) I feel it necessary to note that Boeing stock has increased by 26% since Lion Air...i wonder if this metric is the one that takes precedence above all else. (those who bought stock during the "troubled" early days of the 787 would be sitting on 10 fold profits...)

[RoyHudd]

Direct Law landing

I flew Alternate Law and landed Direct Law in a 321 after AOA transient due icing. (Unreliable Speed, A/THR and AP lost, all recovered after we climbed above the icing level,which was FL220). Direct Law in the a/c was easier than the sim, not bad at all

The only problem Airbus pilot have is, that “your plane” situation forces you to fly aircraft you don’t know (character of the flight controls and aircraft response on side stick is very sensitive). 99% of the time on the sim, we never fly Direct Law....

[/QUOTE]

[cervo77]

Question: is this plane dangerous? if you have children, are you going to let them travel on board of A 737 max ?