SWA are no more able to fly their grounded MAX aircraft than any other operator is.

pattern_is_full

Disclaimer: Not PP (not for 30 years at least) but ATC and flight procedure designer.
While an extra 50m on the take-off run might not faze you, I would have thought even that extra 2% would start to worry you in a OEI situation. That margin between the book climb rate figure and the 1.6% contingeny surface (only ~100 ft/NM ) starts to get pretty thin doesn't it?.
We already have (or had) problems with ULH brand new generation large twins unable to take default SIDs under common temp/pressure conditions for our location due to OEI issues.

Having worked with 744Fs, I always kept my eye on the reg as quite often the DOW was different.

TotalBeginner

The calculations are dynamic in that the ground handlers have to start running calculations even before the aircraft is loaded so they know where and how much cargo can be placed onboard. This has to be tied in with how many passengers and where they are seated. The numbers are run many times in the course of loading a aircraft prior to departure. Many operators build a tolerance into the numbers to allow for last minute adjustments by the flight crew without rerunning all the numbers.
You can’t just load the aircraft and hope the numbers will be within limits.

What happened to the idea of scales on the landing gear? (Put very simplistically)

Sailvi767

I'm not sure that's the case for an aircraft like the B737. There are plenty of A320/B737 operators here in Europe who use a standard load plan and then just allow the Departure Control System to monitor passenger distribution. I'm also reliably informed that there are a few large European LCCs who perform the W&B calculation in the flight deck.

If its passengers and baggage only that's possible, the moment you introduce Cargo and DGR than it requires ground based professionals. This thread and the recent Wizz Air one have highlighted to me how little most flight deck crew know about weight and balance, and how many assume what their carrier does is what everyone does.

Better yet, insert trim tanks. Admittedly the way some very shrewd people managed to cut the flesh off with some single equipment operators is admirable. Same as anywhere else, it only works as long as it works.

It added too much weight.....

That is VERY good

Also a good bit of Heissenberg in action - you can't make an observation without changing the observed

ShyTorque

Why could the function not be performed by a simple strain gauge? These things weigh little.

At a guess, they would require to be calibrated periodically.

By weighing the aircraft. Which would be kind of self-defeating. :O

I always understood that it was not possible to have any method of weighing linked to the aircraft because, even on the ramp, a relatively small wind provides lift and changes the readout.

There were on-board weighing equipment on several aircraft including some B747 classics. One system was to check the gas pressure in the oleo struts. Pressue in the oleos goes up as weight increases as one can see during refueling. Problem was struts are "sticky" and hang up and go down in jerks and bumps.
There were some aircraft equipped with strain gauges, I think it was on the bogie beam. Problem there was the harsh environment they lived in on the landing gear. Very hard to maintain and how do you check for accuracy and at what intervals?
As an aside, one of the most tedious exercizes is weighing an aircraft. You have to check for the presence (or absence) of each and every item of ships equipment listed and get unlisted items off. Has to be done in a hangar to prevent wind-loads and rain from causing errors. You also have to drain fuel, etc. Weighing got a lot easier though with portable roll-on scales. Beats having to use load cells on the jack points which I have seen partially twist. Very scary to have an airplane jump off its jacks. It didn't fortunately in my case but I have seen the very large holes a jack makes in wing planks. That was caused by an operator trying to do a gear swing outdoors. Wind came up and aircraft jumped a wing jack. Very ugly.