It doesn't. A trim run-away is a very very serious incident for any pilot.

There are procedures to deal with it, and we check trim override in pre-flight checks, but it's absolutely not an everyday thing.

> 737's are even safer here than many airliners, because after you disable the electric trim motors, you have manual wheels in the cockpit that you can rotate to set the trim back to what it should be. Some other airliners in common use don't have these manual trim controls - you have to disable a trim run-away in time, or it's game over.

This is not true at all either. There are no planes with a single electric trim that you cannot override. The FAA and EASA would refuse to certify those.

Whereas a 737 has physical cables connected from wheels in the cockpit to the stabilizer jackscrew.

Both circuits are electric, but they are separate systems on separate power busses to ensure you always have control.

You'll need to cite that, since it contrary to any information I can find on the Lion Air accident e.g.:

> The chief executive officer of Lion Air, Edward Sirait, said the aircraft had a "technical issue" on Sunday night, but this had been addressed in accordance with maintenance manuals issued by the manufacturer. Engineers had declared that the aircraft was ready for takeoff on the morning of the accident

Your claim that it was "unsafe to takeoff" and had "multiple broken sensors" is pretty remarkable. So I'll definitely need to see a source backing up such remarkable claims.

> "The aircraft suffered an airspeed indicator problem for its last four flights, including the flight to Denpasar. Thinking that it would fix the problem, the engineers in Bali then replaced one of the aircraft's AoA sensors, but the problem persisted on the penultimate flight [...] [the crew] recorded a twenty-degree difference between the readings of the left AoA sensor and the right sensor."

> "On 28 November, Indonesia investigators said the Lion Air jet was not airworthy on flight before crash."

More important though is that the 737 MAX differs wildly from earlier 737s in how much it relies on the AoA data. Mechanics and pilots not experienced with the MAX were probably operating under the (false) assumption that a bad alpha vane wouldn't be the end of the world. In fact displays indicating the angle of attack and warnings about disparity between the alpha vanes is an optional feature on the 737. It's considered that unimportant.

The key differences from earlier 737s are that the MAX uses the AoA data to calculate airspeed and that the MAX may use a single AoA input to try to kill you. I believe the former was disclosed, but considered how short the differences training is may have been easily overlooked. The latter, of course, was not disclosed until the crash.

> The chief executive officer of Lion Air, Edward Sirait, said the aircraft had a "technical issue" on Sunday night, but this had been addressed in accordance with maintenance manuals issued by the manufacturer. Engineers had declared that the aircraft was ready for takeoff on the morning of the accident

So you still haven't supported your extraordinary claim that the aircraft was:

> unsafe on takeoff.

In fact we know it was safe on takeoff.

Or rather, as airworthy as any other MAX flying around.

Not sure why you're being downvoted, as I haven't seen any evidence linked contradicting what you said.

> "On 28 November, Indonesia investigators said the Lion Air jet was not airworthy on flight before crash."

"not airworthy" means that it was unsafe.

It goes like this:

several flights report problem

maintenance "fixes" the problem

next flight reports that another, worse problem has appeared - bad enough that regulators have now said that the plane was "not airworthy" during this flight

maintenance "fixes" the problem

final flight impacts ocean at high speed

Your assertion is that since maintenance cleared the plane after the second fix, the plane must have been fine. To that, I point to the previous time maintenance cleared the plane, when it was demonstrably not fine.

“Indonesian investigators have said the Lion Air Boeing 737 jet that plunged into the sea, killing 189 people in October, was not airworthy on a flight the day before it crashed.

They further found that Lion Air must improve its safety culture and better document repair work on its planes.

The flight from Bali to Jakarta on 28 October had experienced similar technical issues to the doomed flight the next day from Jakarta to Pangkal Pinang, said Nurcahyo Utomo, head of Indonesia’s national transport safety committee (KNKT).

The pilot of the 28 October flight chose to press on to Jakarta after shutting down the plane’s anti-stall system, Utomo said.

“This is the basis of our recommendation to Lion Air. In our view, the plane was not airworthy,” he told a news conference in Jakarta.

...

But its investigators said that Lion Air kept putting the plane back into service despite repeatedly failing to fix a problem with the airspeed indicator in the days leading up to the fatal flight.”

-

So the aircraft spent several days flying with a broken sensor, sometimes without even an attempt at repair.

I've removed the multiple sensor part.

And was repaired between the two flights as I quoted above. Are you selectively ignoring the information in the very post you replied to?

Here's that information again to refresh your memory:

> The chief executive officer of Lion Air, Edward Sirait, said the aircraft had a "technical issue" on Sunday night, but this had been addressed in accordance with maintenance manuals issued by the manufacturer. Engineers had declared that the aircraft was ready for takeoff on the morning of the accident

You and the other poster seem to be basing your whole position on time not moving forward in a linear fashion: Failure, repair, flight. In that order.

Pointing out the previous day over and over while ignoring what occurred in the interim isn't a real argument.