The General Aviation Thread


So out of 350 aircraft, two have crashed killing everyone on board. The FAA grounded the 787 for battery fires even though zero fatalities.

Thing is, the 737Max is now a core aircraft of some airlines, especially Southwest. Southwest may not be able to recover if they are grounded, so my guess are pressuring the FAA like crazy to keep them flying while the software fix rolls out.

This is going to be a big story today. CNN 1 minute ago - “pressure almost unbearable for FAA to ground 737 max.”


Planes to UK are turning around:


American and Air Canada as well. Most of the American flights are pretty much anything out of Miami.


Per this article, SW has about 10% of it’s flight hours made by the 737 Max. Wonder what kind of liability Boeing has towards the airlines that are currently or might have to cancel flights.


As someone who flies weekly on Southwest this has me concerned. I’ve only been on a MAX once or twice- usually my flights are serviced by traditional 737s. Still, that much of the fleet being grounded will likely impact my travel in some way because of shuttling planes around. Southwest flights are already near max capacity most of the time so this has the potential to suck.

Putting my software engineer hat on, I suspect Boeing has been working on this fix since the first crash and have issued a zillion notices to the airlines about safety procedures if the MCAS has trouble. This likely will mitigate future problems now that pilots are aware of what could go wrong. Still sucks and Boeing has the burden of proving their planes are air safe going forward.


Something completely different:

Fuck yea!


Canada was almost alone with the US on not grounding the 737 Max, but that just changed. They’re citing satellite data indicating similarities between the Ethiopia flight and the Lion Air flight. 737 Max 8s are now grounded in Canada.


The FAA just grounded the 737 Max.


The very last country to do so according to multiple sources.


Ouch for WN.


It only makes up 4.5% of their fleet, I guess. Wonder how big of an impact that’ll make.


Norwegian Air has announced they’re going to sue Boeing for lost revenue.

This could get expensive, fast.


Southwest just issued this:

Southwest is aware of media reports stating that the Boeing 737 MAX 8 fleet will be grounded in the United States. We are currently seeking confirmation and additional guidance from the FAA and will respond accordingly in the interest of aviation safety. Once we learn more, media updates from Southwest will be posted on


Didn’t realize that it was that small, but I guess that I don’t get all that many B38M flight progress strips with SWA on 'em. Are they still having issues with their mechanics?


What’s sad is that, reading the discussions of the first Max crash, it’s mentioned that it would have been possible to recover the aircraft by disabling the autopilot and MCAS systems.

How is it that current 737 Max pilots weren’t made aware of this emergency procedure in the meantime, while awaiting the software updates?

A lot of junk in the PPrune thread, but some good info on the MCAS, etc. It’s not necessarily needed for flight, but was rather added due to certification requirements around control forces and angle-of-attack:

There is a cert requirement that as AOA increases, the nose up pilot command required must not decrease. This is demonstrated at fixed thrust levels so there is no change in thrust pitching moment. The 737MAX issue here that gives rise to the need for MCAS is that as AOA increases the lift provided by the engine cowling that is so large and mounted so far forward of the wing causes a nose up pitching moment that results is a decrease in the column pull needed to maintain a steady positive AOA rate. That characteristic is not compliant with the requirements. MCAS comes active during this maneuver putting in nose down stabilizer that must be countered by the column. The net effect of engine cowling lift and MCAS nose down stabilizer as AOA increases is that the column needed to complete the maneuver does not decrease part way through the range of AOA for which characteristics must be demonstrated. 737MAX without MCAS fails the cert demo. 737MAX with MCAS passes the cert demo.

Also, the MCAS is getting the attention because it commanded the control inputs that led to the crash, but the root cause is faulty angle-of-attack sensors, which are what caused the MCAS to trim the elevators down in the first place. Similar sensor issues (though airspeed, not AoA) resulted in the AF447 crash.


Sounds like it, but I’m not privy to any special info other than what I can google. Southwest appears to be by far the biggest operator of the max, at least in the US, but that still only amounts to 35 planes out of 755 in their current fleet.


It’s mainly Airbus in Europe right? They wouldn’t cry over the grounding there much. At least at first.


Was trying to confirm that myself. It was November 7th that the FAA directed that Boeing’s new instructions be added to all flight manuals:


There was a story after Lion Air went down that the American Airlines pilot’s Union was pissed that they hadn’t been told about disabling MCAS.


Some good info here, thanks. I was particularly saddened by the Ethiopia crash. It was on its way to Nairobi, meaning that there would have been more than a few safarigoers on that flight (I only just recently left Kenya from Nairobi myself), and they are almost universally great people. Then you have all those UN people going down for a conference on the environment. So we lost a number of humans who cared about stuff other than themselves, always a sore loss.

I’ve also seen that it reinforces dumb stereotypes about African aviation. This wasn’t a sub-saharan airline with a terrible record, ethiopian are good, and Ethiopia as a country needs all the business it can get.