<story><title>Delays in Boeing Max Return Began with Near-Crash in Simulator</title><url>https://www.bloomberg.com/news/articles/2019-11-08/delays-in-boeing-max-return-began-with-near-crash-in-simulator</url></story><parent_chain></parent_chain><comment><author>danso</author><text>FWIW, the near-crash in the simulator was apparently not directly related to MCAS, but occurred when Boeing &amp;quot;simulated what would happen if gamma rays from space scrambled data in the plane’s flight-control computers.&amp;quot;&lt;p&gt;&amp;gt; &lt;i&gt;In one scenario, the plane aggressively dove in a way that mimicked what happened in the crashes on the grounded jetliner, the people said. While such a failure had never occurred in the 737’s history, it was at least theoretically possible.&lt;/i&gt;&lt;p&gt;&amp;gt; &lt;i&gt;Because at least one of the pilots who flew the scenario in a simulator found it difficult to respond in time to maintain control of the plane, it needed to be fixed, according to two people familiar with the results.&lt;/i&gt;&lt;p&gt;However, the next sentence seems to belie the implication that this was just an edge case:&lt;p&gt;&amp;gt; &lt;i&gt;The answer was to modernize what was a relatively antiquated design on the 737.&lt;/i&gt;&lt;p&gt;So, of all the things that caused Boeing&amp;#x2F;FAA to realize and the accept the 737 needed to modernize its decades-old design, it was a simulated edge case involving &amp;quot;gamma rays from space&amp;quot;? Hate to be overly cynical, but that sounds like the kind of CYA thing you&amp;#x27;d say when you don&amp;#x27;t want to admit it you made a huge mistake by deferring modernization in the first place, of which the MCAS concept was a major and disastrous symptom.</text></comment>
<story><title>Delays in Boeing Max Return Began with Near-Crash in Simulator</title><url>https://www.bloomberg.com/news/articles/2019-11-08/delays-in-boeing-max-return-began-with-near-crash-in-simulator</url></story><parent_chain></parent_chain><comment><author>zaroth</author><text>The can of worms has been officially opened, and this may turn out to be a case study in how bad software and outsourcing your centers of excellence can bankrupt a company.&lt;p&gt;If TFA is to believed, Boeing has embarked on a project to take what is currently a master-slave failover design and jury-rig it into a master-master real-time system. This is based on bad performance in the simulator—not because of MCAS—but while testing errant memory errors from a simulated gamma ray strike!&lt;p&gt;The obvious question of how can dual-master ever work when they disagree if there isn’t a 3rd source of truth to vote out the failure? This means the software running in both computers has to somehow agree which one is wrong, while one of them is in a potential failure state. This... isn’t how flight control systems are designed from first principals.&lt;p&gt;I’m not a flight system designer, but there must be hundreds of physical, electrical, and architectural considerations taken at every point in the design process which enable multi-master controllers with the ability to vote out a failure. Everything from the particular sensor suite, the number of sensors, the way they are wired, the way data is acquired and bused through the system, the timing and synchronization of the system clocks, the way that control outputs are calculated, queued, and ultimately issued to downstream controllers... none of the necessary pieces will be in place in a system which up until now makes you select a single master controller before embarking on your flight.&lt;p&gt;The only conclusion I can reach is that Boeing has lost its mind, and this project is absolutely doomed to fail. The architecture that Boeing has apparently committed itself to now is extremely difficult to design from first principals and a blank slate. I just don’t see how it’s something that can realistically be papered onto a legacy dual-computer system after the fact.&lt;p&gt;The part in TFA about “adding a wire” practically made me spit out my coffee. The sheer level of arrogance that Boeing management must have to think this would be possible - is just a classic example of an elitist MBA management group totally disconnected from any technical domain expertise. Boeing said they would have this ready for certification &lt;i&gt;by the end of this year&lt;/i&gt;?!</text></comment>