Put another way, the 737 Max has a statistic of 1 catastrophe per 500k flights, whilst the 737 was 1 per 10 million, basically 20 times as much.
This is criminal behaviour, and people need to go to jail. The MAX should never be allowed to fly again.
Put people in jail for negligence, sure. But we should be criminalizing based on that negligence and not on its results.
[1]: https://en.wikipedia.org/wiki/List_of_accidents_and_incident...
They would have looked at the failure rate of the AoA sensor and the failure rate of the recovery procedure and the fact that there had been one fatal crash. That gave them a reasonable estimate of the risk. Based on that analysis they should have grounded the plane, but Boeing apparently convinced them that with pilot awareness of the problem that the recovery procedure would be more effective. Unfortunately that was overly optimistic.
The FAA's report, which predicted an elevated crash rate for the 737 MAX, was written in December 2018. Three months before the second crash.
> Put people in jail for negligence
The higher ups new this was a tragedy waiting to happened they just hope its going to be their successors that will have to pay. Negligence is definitely too light or a term for this. This is knowingly putting people lives in jeopardy in the name of extra % in profits.
The fault doesn't lie with the engineers who built the system...not to mention I would be very surprised if they were professionally certified.
It lies with the managers who wrote the specification that said that for business reasons the new plane must not require any additional training or type certifications, and cut costs by implementing the required systems with a non-redundant sensor.
(I agree.)
Let's not split the wrong hairs.
In other words, if all new plane models were as safe as the 737 (1 catastrophe per 10 million flights), about 5% of those new plane models would have at least one catastrophe within the first 500k flights.
Yes.
> The MAX should never be allowed to fly again.
No. Even at 20x the failure rate, flying in a Max -- even with an unmodified MCAS -- is still vastly safer than driving on a per-distance-travelled basis. Part of the problem is that commercial aviation has gotten so ridiculously safe that we've lost all perspective on risk assessment. The Max is actually fundamentally a safe plane. What made it unsafe was the totally fucked up attempt to make its flight characteristic the same as the old 737 so it and its pilots would not have to be re-certified. The right answer is to re-certify. That's expensive, but a lot cheaper than scrapping an entire fleet of brand new planes. Grounding the entire fleet forever is throwing out the baby with the bathwater.
I did the math one time with very conservative numbers (thinking it'd be an easy win) and got shockingly close:
https://news.ycombinator.com/item?id=19983686
If you have an alternative reference or more exact numbers I'd love to see them!
So, the correct comparison would not be to driving, but to flying in other planes with similar range that are already available. I am no expert, but I do not get the impression that it is looking good in this respect.
By "re-certify", do you just mean the pilots? Or do you include the plane itself?
The original problem was that the FAA requirement for how the stick force has to vary with angle of attack could not be met, because of the new engines having to be so far forward: instead of the stick force continuing to increase with higher AoA, it started to decrease at some point because of the pitch up moment due to the engines.
The simplest way to fix that would have been to increase the ground clearance so the engines could be moved back to where they were on previous 737s. That, of course, would have had to be done in the design stage, before planes started being built. I'm not sure if it would be possible to retrofit existing 737 MAX planes to do this.
If the physical airframe stays the same, then there has to be something in the flight controls that compensates for the pitch up moment of the engines at higher AoA in order to meet the stick force requirement. MCAS was an attempt to do that while keeping everything "close enough" to previous 737s. If that constraint is dropped, there might be a way to keep within the FAA stick force requirement without having the same failure modes as the MAX does, but that would still require a new type certification for the plane.
I don't think people are making the comparison of Max vs driving. They are making the comparison of Max vs other air planes.
There are four main changes to the B737 MAX flight control system software that have been developed to prevent future accidents like the ones that happened with the Lion Air and Ethiopian Air flights. They include the following:
1. Angle of Attack (AoA) comparison – an addition to MCAS that will now compare readings from both angle of attack sensors on the aircraft. If there is a difference of more than 5.5 degrees the speed trim system will be disabled. Also included in this change is something known as a “midvalue select” which uses data from both sensors together to create a third input that will help to filter out any AOA signal oscillatory failures or spurious sensor failures. This modification will prevent MCAS from commanding nose down trim when a single AoA sensor reports a false AoA as it happened in the two accident flights.
2. MCAS resynchronization – this change will account for manual electric trim inputs made by the pilot while MCAS is activating. It will track whatever input the pilot makes and return the pitch trim to that setting when MCAS retrims back to normal.
3. Stab trim command limit – is an addition that will limit the maximum nose down trim that the automatic flight control system can command to prevent the pitch trim from reaching an uncontrollable situation.
4. FCC monitors – software monitors have been added to the flight control computers that will cross check pitch trim commands against each other. If a difference is detected by these monitors the automatic trim functions are disabled. This protection helps prevent erroneous trim commands from a myriad of causes that could occur in the automatic flight control system.
These design changes in the software that controls the automatic pitch trim features including MCAS should prevent angle of attack sensor failures from causing the pitch trim to operate when it should not. Further, they should prevent the trim from activating erroneously for other reasons as well.
* https://transportation.house.gov/download/kiefer-testimony
There is nothing magical about this linear relationship; it is an intuitive configuration for pilots, but many other aircraft do not follow it. The requirement makes sense for single-certification, but we must be clear in understanding what is actually happening with this system.
The system counters the hazard of pilots experienced in 'regular' 737s getting close to stalling without realizing, due to lighter stick inputs not having the intended effect. Any MCAS malfunction would direct their attention to this issue.
Actual anti-stall systems (MCAS is not anti-stall, nevermind some shoddy reporting) would still function if a pilot were to approach this flight envelope. This includes cabin alerts, stick shakers, etc.
The scenario where MCAS cuts out, and it's in the envelope of conditions where it actually functions, and the pilots fail to notice this, and the MCAS inputs were needed to avoid approaching a stall, and the pilots fail to correct and avoid the stall .. it's a contrived hypothetical.
MCAS is not a system that activates on a normal flight. Only in relatively extreme circumstances does it even function, and then it only seeks to make intuitive pilot behavior less likely to approach stall conditions. A good pilot monitoring airspeed, trim angle, AoA, etc. will be able to avoid a stall just as well without the system.
Flying has become so safe that the public no longer considers it risky, but the FAA never updated its targets. So when Boeing wanted to trade safety for market share there was no basis to stop them.
To illustrate the change in attitude it used to be common for airports to sell life insurance for the flight directly at the gate. This continued as late as the 1980s.
https://www.insurancebusinessmag.com/us/news/breaking-news/a...
The FAA set a standard that makes flying way safer than driving, a risk people happily undertake all the time, but people still overestimate the risk of flying and demand more safety improvements.
The fact that life insurance was being sold, meant the flying public _thought_ they were taking significant risks (even if they weren't).
Now, such life insurance would be laughable, which means the public _does not_ think it's taking any risks. The general public's risk tolerance for flying has dropped dramatically.
So, based on that, it seems the example perfectly demonstrates the point. The public thinks flying is much less of a risk now than it used to.
How about telling me what you're linking to, not just giving me a raw, opaque link?
Is this document publicly available now? Did anyone find it?
>787 Lithium-Ion Battery Containment:
>Before the AIR Safety Review Process was implemented in mid-2015, there were other examples of FAA management accepting applicant’s positions over the concerns of FAA technical specialists, the FAA’s aerospace safety engineers. For example, during initial certification review of the new technology 787 lithium battery system design the certification of the 787, an FAA technical specialist determined the lack of a fireproof enclosure could result in catastrophic failure due to uncontrolled fire from the battery. He proposed to FAA management that the special conditions design of for the airplane system lithium-ion battery should include a requirement for a steel containment structure that would be vented overboard. FAA management overruled the specialist. The specialist worked to modify a new special condition that was applied to the battery installation so a containment system would be required. Unfortunately, FAA managers pushed to delegate 95 percent of the certification to the applicant, including the high risk, new technology, battery installation. Without FAA safety engineer oversight, the ODA found the design without an enclosure to be compliant. Sadly, after certification, the airplane system lithium-ion battery experienced two extremely dangerous fire events and the FAA mandated the 787 fleet to be grounded. The design changes the FAA mandated to allow the 787 to fly again included a steel battery containment box that was vented overboard; as originally proposed by the FAA aerospace engineer.
* https://transportation.house.gov/committee-activity/hearings...
edit: better link https://docs.house.gov/Committee/Calendar/ByEvent.aspx?Event...
The only initial San Jose Terminal 3 ($1.2+ billion) international airline was JAL, and they had to stop flying for about a year. This was a terrible blow to the airport.
The engineer who advocated a battery box was not just correct, but following basic principles - even the Cessna 172 has a metal battery box:
https://www.knots2u.net/battery-box-cessna-172-stainless-ste...
Heck, I even tell IT departments to use a stainless-steel "bathtub" under water-cooled computer systems. Each time I'm called a Cassandra, until it starts leaking, then it's like, "Well of course. Anybody would do it that way."
Source: commercially-licensed airplane pilot.
FAA's credibility is in the dumps, along with the Boeing's.
edit: I found more. In particular Pierson's attachment included emails and ends with a listing of 15 emergencies over 13 months and the Summary of Subject Matter includes a quick run-down of various Boeing happening beyond the MCAS.
https://docs.house.gov/Committee/Calendar/ByEvent.aspx?Event...
