Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

Post by itronitron » Fri, Mar 22, 2019, 9:45 PM UTC

flappysquirrel wrote: post #261

jandrese wrote: post #249

Earlier quoted context omitted.

Crash causes: 1. Faulty MCAS 2. Insufficient pilot training 3. Boeing design changes (MCAS used to be disabled automatically if the pilot applied sufficient counter-input, this feature was removed in the -MAX series, requiring the pilot to explicitly disable the system using a separate button) Take away any 1 of those causes and the plane doesn't crash. They all had to happen at the same time for these two tragedies…

>MCAS used to be disabled automatically if the pilot applied sufficient counter-input, this feature was removed in the -MAX series What was the reasoning behind this change?

Presumably so that the pilot can be blamed for not knowing the procedure to manually disable the automatic system that is flying the plane into the ground.

Post by mjevans » Mon, Mar 25, 2019, 9:23 PM UTC

js2 wrote: post #259

ddalex wrote: post #257

Earlier quoted context omitted.

One of the issues I'm perceiving with the Strings Of Things that Go Wrong / Swiss Cheese model is that as we fix more and more of the ~more likely~ faults to appear, the faults that will continue to appear will be of the less likely variety, so to say more obscure corner cases. The problem is that training cannot efficiently prepare somebody to identify and fix obscure corner cases while under pressure.

Maybe not plausible, but why not give the pilot a single switch to disable all automation so they can fly the plane without interference.

The reason some of this automation exists is because modern airplanes have, extremely rough corner cases.

In particular, the very thing that is causing the MAX incidents is one of those features that is designed to ADD stability.

The main issue however is that the system is both reading too few external sensors, and is also not reacting to contradictory human inputs.

An ideally designed system might have the following features:

  * Read data from ALL installed sensors that might be applicable.
  * If data from sensors is not within a reasonable bound,
    scream bloody murder about that for a human to make a decision.
  * If human input contradicts the intended direction of the plane,
    scream bloody murder about that for a human to make a decision.

Potential decisions might include designating one or more inputs as faulty, or entirely disabling the function in question. Such an operating mode SHOULD be an exception and should be very obvious for anyone looking at the plane / systems.

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix