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twtw commented on Similarities Between the Lion Air and Ethiopian 737 Max Crashes   thepointsguy.com/news/sim... · Posted by u/jaredwiener
Someone1234 · 6 years ago
> Between 043 and 610, there was further maintenance that included flushing the pilot valves and cleaning electrical connectors, but the AoA sensor was not replaced between 043 and 610.

They followed Boeing's procedure in attempting to address the issue again (after already replacing the sensor). That's a completely appropriate action.

> the next flight should definitely be aware of the incident on the flight prior.

It is in the log book. Is this a reference to something particular?

> 043 faced and overcame the exact same malfunction as 610 - to me that indicates a clear failure.

I agree, that's why maintenance conducted a repair.

> If you keep flying an aircraft that malfunctions on each flight, you're pressing your luck.

They attempted two repairs in accordance to the manufacturer's procedures within that time in order to resolve the malfunctions.

This post references the report and you clearly read it enough to know your original conclusion was mistaken, but are still arguing you're right by trying to shift the discussion. You've gone from "they flew a broken aircraft" to "alight, so they repaired it twice, but you cannot ever trust a malfunctioning aircraft again." By that logic every single commercial aircraft would be in the junkyard... Repairing malfunctioning systems is normal, attempting two different repairs isn't uncommon either.

twtw · 6 years ago
> You've gone from "they flew a broken aircraft" to "alight, so they repaired it twice, but you cannot ever trust a malfunctioning aircraft again."

If you think I've changed my argument, you misunderstood my comments. I still think that they flew a broken aircraft.

I'll stand by my statement that 610 should never have taken off, and I'm somewhat surprised that it is contentious. I don't care if all the protocols were followed and the logs made (though obviously the pilots of 610 didn't understand what the previous pilots had done to respond to their incident) - in retrospect, we know that the aircraft was not airworthy going into flight 610, so something needs to change so that next time that is detected before takeoff. Whether that is better observation of the protocols or better protocols, I'm not sure.

twtw commented on Similarities Between the Lion Air and Ethiopian 737 Max Crashes   thepointsguy.com/news/sim... · Posted by u/jaredwiener
Someone1234 · 6 years ago
That's a misstatement of what occurred. The aircraft had a fault on the previous two flights and was repaired before the fatal flight.

> Flight 610 should never have taken off.

A repaired aircraft should not take off?

twtw · 6 years ago
The preliminary report from the investigation of LNI610 disagrees with you: https://reports.aviation-safety.net/2018/20181029-0_B38M_PK-...

The AoA attack sensor was replaced prior to flight LNI043 (he flight prior to 610), in which the pilots declared pan-pan and had to manually override the auto trim systems (which include MCAS). Between 043 and 610, there was further maintenance that included flushing the pilot valves and cleaning electrical connectors, but the AoA sensor was not replaced between 043 and 610.

An aircraft that was repaired followed by one flight in which the pilots declared abnormal operation and performed 3 non-normal checklists should probably not fly again until they figured out what happened, and the next flight should definitely be aware of the incident on the flight prior. 043 faced and overcame the exact same malfunction as 610 - to me that indicates a clear failure. If you keep flying an aircraft that malfunctions on each flight, you're pressing your luck.

twtw commented on Introduction to Memory Management (2018)   memorymanagement.org/mmre... · Posted by u/lrsjng
pizlonator · 7 years ago
I get that it’s well intentioned but I wish folks stopped talking about the buddy allocator. It’s so obsolete. It’s not the fastest and it sure has some of the worst fragmentation due to very imprecise sizing.
twtw · 6 years ago
Can something be obsolete if it is still extremely widely used?

IIRC, Linux and FreeBSD both use a buddy allocator for physical memory, and I'm pretty sure it is used (in addition to other allocators) in jemalloc as well.

twtw commented on Similarities Between the Lion Air and Ethiopian 737 Max Crashes   thepointsguy.com/news/sim... · Posted by u/jaredwiener
twtw · 7 years ago
The comment you are responding to addresses the claim that the 737 max is not passively stable. It is less safe than other aircraft, but not because it requires active control for stable flight in any manner comparable to a fighter jet.

I'll direct you to some portions of my other comments that you seem to have overlooked:

> airlines and pilots were not informed well enough about MCAS

> previous auto trim systems could also be "out muscled" just by pulling back on the yoke without actually switching on the manual override.

----

> polluting this thread with lies

I'm pretty sure everything I've posted on this thread is either true or obviously an opinion. If some things are not true, please point them out specifically so that I can correct them.

Nowhere have I said that the lion air 610 accident only happened because of poor maintenance or pilots actions, but it is undeniably true that with different pilot actions and aircraft maintenance the accident would not have occurred.

twtw commented on Similarities Between the Lion Air and Ethiopian 737 Max Crashes   thepointsguy.com/news/sim... · Posted by u/jaredwiener
gambiting · 7 years ago
The Lion Air crash was a 2 months old plane. I'd expect a 2 months old plane to be air worthy even if some maintenance was neglected.
twtw · 7 years ago
But they neglected maintenance when serious issues with the plane were apparent. The pilots of the flights prior to 610 noted that the two AoA sensor readings differed by ~20 degrees, and nearly aborted their flight before overriding the auto trim.

Flight 610 should never have taken off.

twtw commented on Similarities Between the Lion Air and Ethiopian 737 Max Crashes   thepointsguy.com/news/sim... · Posted by u/jaredwiener
inetsee · 7 years ago
I am confused. When I read the article about the Lion Air crash, I thought one cause of the crash was that the pilots hadn't been properly trained in the manual override procedure that can deal with the problem with malfunctioning sensors.

I don't understand how a software update can override a completely manual override.

twtw · 7 years ago
The procedure that pilots are taught to override auto trim was unchanged, but I think that previous auto trim systems could also be "out muscled" just by pulling back on the yoke without actually switching on the manual override. It's that second part that people are pointing out (though I will in turn point out that the pilots on the flight prior to 610 faced similar issued and used the manual override to respond to them).
twtw commented on Similarities Between the Lion Air and Ethiopian 737 Max Crashes   thepointsguy.com/news/sim... · Posted by u/jaredwiener
freehunter · 7 years ago
It is possible for both a carrier to be more at-risk for crashes as well as a plane to be more at-risk for crashes.

The FAA issued an emergency operation directive for the 737 Max due to inaccurate sensors which could lead to a crash. I'm not entirely sure why you're ignoring that fact and deflecting to something unrelated.

twtw · 7 years ago
> deflecting to something unrelated

I don't think it is unrelated that the only accident thus far of a plane with a failure mode that is more difficult for pilots to respond to was on an airline with a notoriously bad safety record.

I fully recognize the fact that airlines and pilots were not informed well enough about MCAS, but I'm also not ignoring the other circumstances of lion air 610

Safety in depth - a single failure should not be a problem. 610 crashed as a result of MCAS, but also a number of other operational failures of Lion Air and the pilots.

twtw commented on Similarities Between the Lion Air and Ethiopian 737 Max Crashes   thepointsguy.com/news/sim... · Posted by u/jaredwiener
bgorman · 7 years ago
If Boeing is issuing software updates that disable manual override without telling pilots, Boeing is completely at fault here, and some of the engineers/executives should face criminal charges.
twtw · 7 years ago
> criminal charges

Boeing informed the FAA of the changes, and the FAA decided that the pilots and airlines did not need to be informed. Criminal charges for Boeing would be extremely surprising.

twtw commented on Similarities Between the Lion Air and Ethiopian 737 Max Crashes   thepointsguy.com/news/sim... · Posted by u/jaredwiener
aphextron · 7 years ago
>"Software combined with sensors would ensure the airplane would not tilt upward at an unsafe rate. The combination of the two would keep the nose at the precise right angle during all aspects of flight to prevent a potential stall.

This immediately struck me as completely negligent insanity. The thought of flying on a commercial airliner with no inherent stability, akin to a fighter jet, is horrifying to me. How this got past regulators is just mindblowing.

twtw · 7 years ago
This is a seriously misleading characterization of the 737 Max. If you read https://theaircurrent.com/aviation-safety/what-is-the-boeing... (the source of the article that 'acqq is selectively quoting) you will learn the following:

> MCAS is “activated without pilot input” and “commands nose down stabilizer to enhance pitch characteristics during step turns with elevated load factors and during flaps up flight at airspeeds approaching stall.

> Since it operates in situations where the aircraft is under relatively high g load and near stall, a pilot should never see the operation of MCAS.

In other words, the aircraft does not need MCAS for stability during flight in anything but exceptional circumstances. Normal flights should never have MCAS active.

This is not remotely similar to the aerodynamics of a fighter jet.

MCAS is a software mechanism designed to prevent stalls in extreme circumstances that can be overridden with the same method used to disable auto trim on previous models of the 737. The A320 has software to prevent phugiod motion in exceptional scenarios, except the A320's mechanism cannot be overridden by the pilot.

I don't care if you choose to never fly on a plane again, but don't spread this misinformed hysteria.

u/twtw

KarmaCake day1988January 22, 2018View Original