157 Dead Ethipian Airlines Crash in New Boeing 737 Max

It was a brand new airplane delivered in November. Unlike many African airlines Ethiopian Airlines has a very good safety reputation.

Rather bad news for Boeing. Two of their brand spanking new model aircraft nosediving into the ground minutes after take-off.

Seems like there’s a major design flaw.

Obviously we have no idea why Flight 302 went down, but obviously that’s a hell of a suspicious coincidence.

In both crashes the pilot asked for permission to return to the airport almost immediately upon takeoff. In the case of Lion Air 610 it appears something was wrong with the aircraft’s angle-of-attack sensors, at least.

Surprised Boeing isn’t in majorly serious hot water now. Two crashes with no survivors. There ought to be airlines canceling their 737 MAX orders left and right right now.

Shhhh… Boeing crashing along with their planes is not good for the Seattle economy.

I’m praying for the families of the victims, and that the cause turns out to be simple: found and fixed quickly.

The crashes are many months apart.

And there’s this post on Pprune:

And there is a report that the plane had engine problems.

I worry about this because the MAX 8 is becoming quite common, and some members of my family fly a lot. Here in Canada Westjet flies the 737 almost exclusively on its North American routes, and some of them are the MAX 8. The 737 fleet overall represents fine well-established airplanes with an excellent safety record, but this is potentially very bad news for the MAX 8 (and 9). AIUI, in the interests of more efficient operation the new LEAP engines on the MAX 8 are mounted slightly forward and higher than engines on previous models, which gives the aircraft some unusual flying characteristics that could cause an upward nose pitch in some conditions of manual flight. To compensate, there’s a system called MCAS that is supposed to detect this situation and automatically command the stabilizer trim nose down.

The Lion Air crash two months ago was apparently due to faulty angle-of-attack (AOA) sensors that activated the automatic nose-down stabilizer trim. The flight apparently experienced wildly fluctuating altitude and vertical speed as the pilots presumably fought with the flight management computer. From what I’ve read the Ethiopian flight didn’t experience these oscillations, but did dip in altitude and then regain altitude before finally going down, all within the first few minutes of flight, which may be suggestive of a similar problem.

After the Lion Air crash, Boeing issued an emergency operations bulletin stressing that pilots be trained to set the stabilizer trim cutout switches to the “cutout” position and leave them there in the event of symptoms of erroneous AOA data. If there is any significant commonality at all between the causes of the two crashes, the MAX 8 and 9 would likely be grounded pending a permanent resolution.

According to this Twitter post (linked from the PPRuNe site) which captured live flight data, it sure looks like the Ethiopian flight was experiencing wild variations in reported vertical speed similar to Lion Air. Much too early to reach conclusions, but this tentatively points to at least a superficial similarity that could be very bad news for Boeing and the MAX 8.

The Lion Air flight had a less experienced crew, so when the MCAS started interfering with the flight, they didn’t know what was causing problems, they didn’t have the situational awareness to shut the MCAS off.

After the Lion Ari crash, Boeing released new training that is actually pretty simple, “See those switches? turn them off”. (Okay more complex than that, but for a pilot, pretty simple.)

With the flight crew in this crash being much more experienced, and should be aware of how to prevent the situation that caused the Lion Air crash, I would think that it would be a different problem.

Downside would be that that means that there is another fatal flaw on Boeing’s newest airframe, does not bode well.

Or, it could be the same problem and the pilots didn’t recognize what was going on.

In the latest updates, the people who perished in the crash were citizens of 35 countries including 8 Americans and a hugely disproportionate number of Canadians – 18.

Also now appearing in the mainstream media is acknowledgement that, as I said earlier, the vertical speed of the aircraft was wildly fluctuating during takeoff. Other tentative evidence suggests that engine thrust was nominal. If all these facts are correct – which is far from certain – it does tend to suggest an AOA/MCAS issue perhaps commanding a nose-down stabilizer trim, raising a disturbing commonality with the Lion Air crash.

As to why so many countries one partial explanation is:

I’d hate to think that a crew couldn’t deal with an angle-of-attack issue. It looks like it stalled but I’m confused. If there was an airspeed issue then they would have kept the nose down until they could accelerate to a speed sufficient to begin climbing.

This is a lot of dead people. Boeing needs to get way out in front on this.

It appears that manual override can be hard to achieve once bad AOA data starts to pitch the nose down unless one follows the cutout procedures. The Boeing Operations Manual Bulletin released after the Lion Air crash states:
In the event of erroneous AOA data, the pitch trim system can trim the stabilizer nose down in increments lasting up to 10 seconds. The nose down stabilizer trim movement can be stopped and reversed with the use of the electric stabilizer trim switches but may restart 5 seconds after the electric stabilizer trim switches are released. Repetitive cycles of uncommanded nose down stablilizer continue to occur unless the stabilizer trim system is deactived through the use of both STAB TRIM CUTOUT switches in accordance with the existing procedures in the Runaway Stabilizer NNC. It is possible for the stabilizer to reach the nose down limit unless the system inputs are counteracted completely by pilot trim inputs and both STAB TRIM CUTOUT switches are moved to CUTOUT.
This is probably the most comprehensive overview I’ve yet seen of the AOA and stabilizer trim system on the 737 MAX.

Note that at this point it’s not established that this had anything to do with the Ethiopian crash.

China, Indonesia, Ethiopia have all grounded the 737 Max:

Meanwhile, American Airlines and Southwest and a bunch of international airlines are still flying them. Among Canadian-based airlines, so is Westjet and Air Canada. I mentioned Westjet as being a predominantly 737-based carrier, but actually Air Canada owns more of the MAX 8 models than WJA. WJA has 13 MAX 8s while ACA has 24. By coincidence AAL also has 24 MAX 8s, SWA has 35.

Why not just have a stick shaker but not stick pusher?

There’s been some talk around here that the quality of Boeing’s airplanes has declined since more and more parts are manufactured all over the world and shipped here for assembly. I don’t know the basis for comparison as in when this started happening on a large scale.

I seem to remember a previous Boeing CEO saying something to the effect he’d like to see the company basically become a design bureau based in Chicago. I do remember seeing the quote about wanting to be “a virtual manufacturer”.

This is quite an informative graphic.

It clearly shows the erratic vertical speed and gives a better perspective than the raw numbers of the aircraft’s inability to gain any significant altitude above ground level, as opposed to the reported “above mean sea level” numbers. It hardly ever attained an altitude of much more than 1000 ft AGL except at the very end, when it was at around 1500 ft and the transmissions ended. These are the live feeds from presumably the ADS-B transmissions, not the flight data recorder which has been found but not yet analyzed.

The tower would have seen that they never climbed above 1000 ft AGL. That’s pattern altitude for a small plane and based on the lower graph they weren’t in a position to return to the airport. It was in trouble and whatever was directly in front of them was their next landing zone. It sounds like it stalled and nosed in.

Locals on the ground said they saw material and smoke coming from the plane. They may have hit a flock of birds or picked up FOD off the runway and destroyed an engine.

from BBC

Several witnesses who worked in the farmland below the plane’s flight path told the Reuters news agency they heard loud rattling noises coming from the aircraft and saw billows of smoke and debris in its wake as it made a low turn over the fields.

“When it was hovering, fire was following its tail, then it tried to lift its nose,” said one witness, Gadisa Benti. “When it passed over our house, the nose pointed down and the tail raised up. It went straight to the ground with its nose, it then exploded.”