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FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

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Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#131

Post by dreamcompiler »

lkrubner wrote: post #124
iClaudiusX wrote: post #78

Earlier quoted context omitted.

The root problem is the culture at Boeing and the FAA has shifted from safety first to profit first. The investigative reporting from The Seattle Times[0] indicates that safety engineers were pressured to avoid delays to rush out a competitor to the A320. Furthermore, their safety analysis was based on flawed assumptions to meet an artificial constraint of not requiring pilot simulator training in order to appease th…

Fukushima? That doesn't belong on the list. There is some limit to any engineering decision. Complaining about MCAS is totally reasonable, but it would be unreasonable to argue "The Air Max is not safe because if I hit it with enough Stingray missiles it won't fly anymore." Like, yeah? No kidding? Fukushima was designed to survive the earthquake, and it did, it just wasn't designed to survive the earthquake and also…

But it could have been quite easily by simply siting the backup generators above ground. That was a stupid design error. Tsunamis are not unknown in Japan after all.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#132

Post by phs318u »

lkrubner wrote: post #124
iClaudiusX wrote: post #78

Earlier quoted context omitted.

The root problem is the culture at Boeing and the FAA has shifted from safety first to profit first. The investigative reporting from The Seattle Times[0] indicates that safety engineers were pressured to avoid delays to rush out a competitor to the A320. Furthermore, their safety analysis was based on flawed assumptions to meet an artificial constraint of not requiring pilot simulator training in order to appease th…

Fukushima? That doesn't belong on the list. There is some limit to any engineering decision. Complaining about MCAS is totally reasonable, but it would be unreasonable to argue "The Air Max is not safe because if I hit it with enough Stingray missiles it won't fly anymore." Like, yeah? No kidding? Fukushima was designed to survive the earthquake, and it did, it just wasn't designed to survive the earthquake and also…

Though one might argue that the risk of tsunami is not independent of the risk of (certain kinds of) earthquake for pacific rim nations. Failure to take that into account might be considered a design decision.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#133

Post by bjourne »

Since this thread is already full of armchair airplane engineers opinions about the root cause, I'll add mine too: Never ever write new software under the condition that it must work EXACTLY as old software. It can't be done and you'll always miss something.

Case in point: Wine. They've been at it for years and the emulation layer is still far from perfect. It works 99% of the time which is good enough for games, but I wager not for airplane control systems.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#135

Post by jussij »

jacquesgt wrote: post #81
th0ma5 wrote: post #51

Earlier quoted context omitted.

To be fair, ignoring user input could have potentially have saved Air France 447... I mean I actually can't think of an automated fool proof system that would've fixed 447, but incorrect input was a major factor.

AF 447 wasn’t all that different from this situation. One of the co-pilots was trying to pitch the nose down to recover from the stall. The other was panicking and trying to pitch up. The plane averaged their inputs, without giving feedback via the stick that this was happening. It wasn’t until very late in the flight that they figured out what was happening, and then it was too late to recover. Obviously there was s…

I don't the flight control was averaging the pilot inputs.

From this link: https://en.wikipedia.org/wiki/Air_France_Flight_447#Human_fa...

In April 2012 in The Daily Telegraph, British journalist Nick Ross published a comparison of Airbus and Boeing flight controls; unlike the control yoke used on Boeing flight decks, the Airbus side stick controls give little visual feedback and no sensory or tactile feedback to the second pilot.

Ross reasoned that this might in part explain why the pilot flying's fatal nose-up inputs were not countermanded by his two colleagues.

In a July 2012 CBS report, Sullenberger suggested the design of the Airbus cockpit might have been a factor in the accident. The flight controls are not mechanically linked between the two pilot seats, and Robert, the left-seat pilot who believed he had taken over control of the aircraft, was not aware that Bonin continued to hold the stick back, which overrode Robert's own control.

That suggest there was only ever one pilot flying and the way that pilot reacted to the situation had a big part to play in the final crash.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#136

Post by mrpippy »

halter73 wrote: post #103
th0ma5 wrote: post #51

Earlier quoted context omitted.

To be fair, ignoring user input could have potentially have saved Air France 447... I mean I actually can't think of an automated fool proof system that would've fixed 447, but incorrect input was a major factor.

IIRC, the cockpit voice recording included a comment from one of the co-pilots about how pulling back on the yoke couldn't cause a stall. The assumption was that the Airbus's fly-by-wire system would prevent it and ensure the aircraft still climbed as long as the pilot held back on the stick. The co-pilot apparently didn't realize that the sensor issue that disabled the autopilot also disabled the stall prevention. A…

Apparently (think I read in the Langewiesche feature) the plane ended up in such a deep stall that the flight control software started ignoring the AoA sensor data (as implausible) and the STALL warning stopped. But when the co-pilot stopped pulling back on the stick, the AoA decreased, and the STALL warning sounded again.

This might have convinced him that easing off on the stick was actually causing the stall, which was tragically misguided.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#137

Post by dingaling »

jussij wrote: post #135
jacquesgt wrote: post #81

Earlier quoted context omitted.

AF 447 wasn’t all that different from this situation. One of the co-pilots was trying to pitch the nose down to recover from the stall. The other was panicking and trying to pitch up. The plane averaged their inputs, without giving feedback via the stick that this was happening. It wasn’t until very late in the flight that they figured out what was happening, and then it was too late to recover. Obviously there was s…

I don't the flight control was averaging the pilot inputs. From this link: https://en.wikipedia.org/wiki/Air_France_Flight_447#Human_fa... In April 2012 in The Daily Telegraph, British journalist Nick Ross published a comparison of Airbus and Boeing flight controls; unlike the control yoke used on Boeing flight decks, the Airbus side stick controls give little visual feedback and no sensory or tactile feedback to the…

> That suggest there was only ever one pilot flying

"Pilot flying" is a human-factors title, not a software function-lock. It just indicates who has control responsibility at that moment but it is not enforced by technical means.

It is intended to eliminate ambiguity in crew functions; the PF can be a newbie copilot even if the commander of the aircraft is a 30-year-service Captain who would become the PNF at that point. Its all part of Crew Resource Management theory.

There should only be one PF in a cockpit at any one time, precisely to avoid the situation that arose with the Air France flight where the computer was receiving inputs from two pilots.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#138

Post by jonknee »

jussij wrote: post #84
blackflame7000 wrote: post #32

Earlier quoted context omitted.

The original 737 had a terrible safety record at first because of a rudder hard-over flaw. It then went on to become the most used in history

Hence the reason I said time will tell. But there are also many examples of aircraft with terrible early safety records that never recovered from their bad start.

> But there are also many examples of aircraft with terrible early safety records that never recovered from their bad start.

From Boeing? They have a history of sorting their shit out. Maybe this time is different, but I doubt it.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#139

Post by jussij »

dplgk wrote: post #34
ngcc_hk wrote: post #9

Not going to trust that model, like dc10 (?). May work not engineer. But as customer, only get 1 life. Not as software beta tester.

Surely they'll rename the plane at this point.

I could see how in the day of the internet that move might backfire rather badly.

The new plane might quickly turn into a internet meme.

Re: FAA Finds New Risk on 737 Max, Orders Boeing to Make Changes

#140

Post by phs318u »

_Codemonkeyism wrote: post #102
iClaudiusX wrote: post #78

Earlier quoted context omitted.

The root problem is the culture at Boeing and the FAA has shifted from safety first to profit first. The investigative reporting from The Seattle Times[0] indicates that safety engineers were pressured to avoid delays to rush out a competitor to the A320. Furthermore, their safety analysis was based on flawed assumptions to meet an artificial constraint of not requiring pilot simulator training in order to appease th…

"The common throughline is a broken culture where deviance is normalized and those who speak out are ignored." The must read on the issue says so too. "The Seven Signs of Ethical Collapse: How to Spot Moral Meltdowns in Companies", Marianne M. Jennings

Thanks for the steer. Wasn’t aware of this. Just read her presentation and loved it.
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