Re: Boeing 737 and 737 MAX software

[robin.vowels@gmail.com]

On Monday, May 6, 2019 at 12:29:13 AM UTC+10, robin...@gmail.com wrote:
> On Saturday, April 6, 2019 at 8:16:22 AM UTC+11, Paul Rubin wrote:
> > Does anyone know anything about this?  It has been under some criticism
> > lately.
> > 
> > I have heard that the 777 software was almost entirely in Ada.  It also
> > sounds as if Boeing's software operation may have slipped in recent
> > years, not good news for the 737 MAX.
> 
> It seems that computers (and their computer programs) 
> are not really suitable to take command of aeroplanes. 
> 
> This week appeared a re-run of the (then new) A320 fatal crash on 
> a demonstration flight (Air Crash Investigations). 
> 
> In that case, the computer overrode the pilot, 
> even when the pilot called for full power and climbing. 
> Power was increased, but the computer failed to set 
> the ailerons to climb, so that the plane continued 
> flying horizontally at 30 feet and into trees at the end of the runway. 
> The pilot had made a gross error in flying too close to the ground 
> (30 feet), and the computer thought that the pilot wanted the 
> plane to land. 
> 
> Tonight was screened on TV a report on the two new Boeing 737 MAX 
> planes that crashed -- one in March this year and another in 
> October last year. 
> 
> In both cases, a sensor failed; it was the input to the stall 
> correction computer.  The computer sensed that the plane was 
> about to stall (it wasn't), and put the nose down.  But the 
> attitude of the planes was set to 60 degrees, which is an 
> awfully steep dive, and not merely a minor correction to help 
> the plane to avoid a stall. 
> 
> The pilot had five seconds to consult  a "check" list 
> (a thick manual) as to what to do.  Even if he had been 
> able to correct the problem (by adjusting the ailerons), 
> the computer applied the stall correction again for 
> 10 seconds (which resulted in another steep dive), 
> and the pilot had another 5 seconds to correct the 
> problem. This 5/10-second cycle repeated ad infinitum. 
> In one case, the plane was close to the ground, as it had 
> not long before taken off from the runway. Each steep dive 
> took the plane closer to the ground ... 
> 
> One major point of the TV report was that Boeing had never 
> made mention of this software feature in any manual, 
> so no pilots had been trained to deal with a situation 
> in which software took over flying the plane. 
> 
> Three questions: 
> 1. Whatever happened to the stick shaker? 
> 2. Why was the dive so ridiculously steep? 
> 3. Why did not the autopilot save the plane 
>    as it careered towards the ground? 
> 
> Usually the best operator of a plane is the pilot, 
> and he should always be able to take over from 
> any computer program (autopilot or stall correction) 
> and to fly the plane manually in the event that the 
> automatic equipment fails.

CNN says today (6 May 2019):

<<In its statement Sunday, Boeing maintained that the software
  issue "did not adversely impact airplane safety or operation." >>

Are they (Boeing) stupid?

TWO of the planes crashed as a direct of the software issue.

CNN also revealed that Boeing knew of the problem months before
the crash.

In offering the MAX to customers, Boeing claimed that no new training
was required.
That was a bare-faced lie.  Boeing concealed the existence of
the stall software, and there was nothing about it in any of
the manuals issued to companies that bought the plane.

Pilots required training in order to be able to deal with the
sudden control of the plane by the stall software.

The insidious problem of the software (iterated above) is that
it doesn't just correct the plane's attitude; it repeatedly
does so at 5-second intervals, thereby preventing the pilots
from making a recovery.

Most disturbing: were the malfunction of the sensor to take place
immediately after take-off (or very soon thereafter),
there is no way that the pilots could recover,
with the software repeatedly putting the nose down.