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Chinese Carriers, Ethiopian Airlines Halt Use of Boeing 737 MAX 8 Aircraft After Crash (reuters.com)
China's aviation regulator today grounded nearly 100 Boeing Co 737 MAX 8 aircraft operated by its airlines, more than a quarter of the global fleet of the jets, after a deadly crash of one of the planes in Ethiopia. From a report: However, a U.S. official said it was unclear what information the Chinese regulator was acting on because the investigation of Sunday's crash, the second involving the latest version of the narrowbody jet, was in the early stages. Speaking on condition of anonymity as the topic is sensitive, the U.S. official said there were no plans to follow suit, as the jet had a stellar safety record in the United States and there was a lack of information on what caused the Ethiopian crash.
I'm going out in a limb here but maybe they were acting on the information that another one had crashed.
Normally, I'm pretty happy to fly on any well maintained airplane, but a second crash within 5 months, where the early indications are that the plane crashed itself despite the best efforts of the pilots to prevent that, would make me cautious of flying on a 737 MAX 8.
How does that quote go: "To lose one parent may be regarded as a misfortune; to lose both looks like carelessness."
Unless Boeing get this sorted out very fast then folks will reinterpret "MAX 8" to be the maximum amount of time in minutes that the plane will stay in the air ...
Of course it may be a coincidence. But it is an extremely low probability coincidence.
Let's be clear. The 737-NG and A320 family both have total fatal hull loss rates of less than 1 in 10,000 aircraft years in operation. This is generous and includes all accidents: terrorists, captain suicide, mechanical issue, and pilot error.
The DC-10 - recognized as having a fatal design flaw with its cargo door and widely recognized as a "dangerous" airliner at the time - took 1,600 aircraft flight years before suffering two fatal accidents.
The 737 MAX 8 has had 2 hull losses in less than 300 flight years of operation. That is nearly 70 times higher than the 737-NG and A320 family.
The likelihood of the 737 MAX having the same ultimate failure probability as the 737NG and A320 and having two fatal hull loss accidents in only 300 flight years is something on the order of 1 in a 1000.
Even if the ET302 flight is boiled down to "pilot error" (like the Lion Air flight), that is just an excuse. If the ET302 had the same failure mode as the Lion Air flight, then the fact that you have two separate incidents with a loss of control (shortly after takeoff, meaning less room for root cause analysis, checklists, etc) is a design flaw. Full stop. Whether or not a pilot could recover is not relevant; an airframe should not be constantly testing pilots with unexpected loss of control.
It is still "safe" to fly a 737 MAX 8 relative to most other daily activities. You probably won't die if you fly on one. That said, relative to aviation standards and safety records that we have achieved in the past 50 years, the 737 MAX 8 - today, at least - appears like a veritable statistical death trap.
There aren't really that many Max 8s flying, and they haven't been doing so for very long, so a couple of crashes seems like a bad sign, particularly since they were very similar (immediately after takeoff). The Max also has a lot of new technology and new aerodynamic design, so it's not just a minor upgrade over previous 737s, which do have a long safety record.
The 737 Max is unstable at higher angles of attack so Boeing added a bit of software to correct if the angle of attack starts to get dangerous. From the Lion Air crash it sounds like there might be problems with the sensors, causing that system to improperly engage and actually put the plane into a dangerous dive.
Ethiopian Airlines got burned by the 787 battery fire issues too.
If I recall, the previous crash has been linked to a bad angle of attack sensor. This sensor is only used by a new stall protection feature in the 737 Max. When it fails, the stall protection algorithm thinks the plane is stuck in a nose up orientation, and tries to force the nose down... into the ground.
There are several things that should happen:
1. Interim corrective action. Disable stall protection on all 737 Max aircraft.
2. Quality control investigation into the angle of attack sensor reliability.
3. Implement diagnostic algorithms into the control strategy to detect failed angle of attack sensors automatically. A failed sensor should disable the stall protection feature automatically, and alert the pilot.
One of our competitors trademarked the term "hypothesis". From now on, we will call them "boneheaded ideas".
Computers should never have the last say in flying an airliner.
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
My point was that this was NOT in the fine manuals, so reading them wouldn't help... It was added in August of last year, which was AFTER the crash in Indonesia.
So I'm not blaming the pilots at all, I'm saying they didn't receive the necessary information for the safe operation of the aircraft with the new system installed, likely never experienced the problem in the simulator during their training. It may be that the aircraft was airworthy and controllable, but if you don't know what to do, haven't been trained to do it, It's hard to blame the pilots for not being able to deal with the problem.
I'm also pointing towards the maintenance staff's training and the aircraft's maintenance procedure documentation. This new feature wasn't well documented there either and the Indonesian aircraft experienced multiple issues with this system, which in hindsight where likely indicators of a failing sensor, but the maintenance crews never fixed the problem, their diagnosis procedures didn't find the pending fault, so they put the aircraft back into service..
So, RTFM wouldn't have produced a different result. The information just wasn't in there.
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101