Another Boeing 737 Max-8 crash

What’s that you say? Your first job is to fly the airplane? And shit.

 

the range of the Stab trim is such that at full nose down trim, I don’t think full aft elevator is enough to compensate. The nose down control forces would have gradually become heavier and heavier until you were holding full back stick- all the while the trim wheel was running and running and running. Shutting it off at that point was a waste of time. Hitting the brakes after the car was already sailing off the cliff. Might have still been recoverable by trimming against MCAS with the electric trim, depending on how low they were. The checklist calls for cutting it off because it assumes you’ll catch the runaway in the first 10 sec or so.

trim is very powerful- look at FlyDubai 737 crash- captain lost his bearings during a Go-around in bad weather (basic instrument flying) over trimmed to a nose down condition, causing an unrecoverable dive.
My point is Any airplane can be put into an unrecoverable situation, unfortunately.

 

Thanks for the explanation. Scary that a trim system can run to a extent that the normal manual control becomes ineffective. Its like a cars alignment being so far off that you have to put a full turn off steering in just to go straight. Then no steering left to turn when you need it.

 

Well, it wasn't a MAX, but nobody is going to mention that 737-800 that went down in China? They've actually got decent video of the plane going in, and it's straight down at max speed. Lost 25k in altitude in 2 minutes. Seemed intact from what you can see, which maybe speaks to the air crew doing something?

 

I'll wait to pass judgement as I'm not sure if it was an ex-pat crew or locals.

The aviation "experts" in China do not make me warm and fuzzy on the locals knowing what they are doing when they say stuff like:

"Another expert, Wang Ya'nan, chief editor of Beijing-based Aerospace Knowledge, told China's Global Times newspaper: "It is very likely that the aircraft lost power at cruising altitude, resulting in the pilot losing control of the aircraft."

As this is complete BS.

RIP to the PAX and crew....

 

Really hope that’s a translation error… although I doubt it was… yikes.

 

All we really know is that the video shows the plane seems to be intact shortly before impact- so no inflight breakup. Hopefully the recorders can be found and we can get some answers.

Very sad for all involved.

 

Can't even begin to imagine how frightening that must have been.

 

I'm not an airplane guy, so take that into account, but even if you lost all power at cruising altitude, can't you get some glide out of it to at least find some flat land? Also wondering at the speed they were going in that dive, can you even pull out of that, or does the pressure on the control surfaces basically lock them into position?

 

Ugh that video was horrible. RIP


In other news, I think there is something wrong with this wind sensor. It was windy today, but not that windy . In the same flight today I hit 194GS while cruising in the mooney and 44GS in the climb back with the head wind. Was the only dumb ass out there for awhile that wasn't an airliner... gotta get them hours!

 

Gino could answer better but probably not. The biggest issue is puling too many g's and breaking the tail off.

The googles suggest the 737-800 has a mile per 1000 foot glide ratio of about 3:1. So a plane at 25,000 ft above ground should glide ~75 miles.

Look up the gimli glider to see how its done.

 

Everything I know about aeroplanes can be summed up as fucked if I know, but with that minuscule amount of knowledge, wouldn’t maintaining a less steep descent require yanking back on the yoke to try and maintain a nose up attitude? If the flying tube lost all power, would there be an ability to control the flaps? How much faster would air speed decrease when trying to maintain attitude versus permitting the plane to nose down?

Physics is a bish.

 

If you lose power you drop the nose and glide. Every plane has a best glide speed...somewhat weight and temp dependent...you fly at/near that speed. For aot of planes that can be a few to several miles glide for every 1000ft. It should be a no brainer

 

Green dot in the Airbus is L/D Max. In layman's terms, best glide speed and best climb speed.

I highly doubt it was expat pilots. Covid got most contracts canceled and those guys sent packing.

 

So ELI5 again. If the pilot tried to extend out the glide, is it possible that air speed dropped too much while still at too high an altitude and created an inescapable dive?

 

That thing came down like a lawn dart. Highly doubtful in this case.
They went from level flight at 29,000ft to impact in under 2 minutes. Intentional nose over like German wings or structural failure in flight are my two guesses.

 

Thanks. I didn’t know those details.

 

They’d have nosed the aircraft over to maintain air speed. And glided a while back. As they lost altitude they’d have kept pulling up to try and stay out of the ground and would have essentially stalled at some point close to the ground. A nose over like that and virtually a vertical dive would have only happened if they lost the tail or someone purposely did it.

 

Even a total loss of power (engines) at 33,ooo ft should equate to a glide range of about 75 miles- coming straight down means out of control.

Pushing the nose over and holding it there at high altitude can cause an unrecoverable dive due to Mach tuck- aerodynamically the tail becomes ineffective. Or on recovery from some kind of un-intentional high speed dive, you could over G the tail and break it, which could cause the second out of control dive. Similarly, if it goes over on it's back (rolls inverted) at high altitude, it takes a very careful hand to recover from that and not over G the tail and break it.

All of those scenarios are not something that just happens- it's induced by accident or midair collision, or missile taking the tail out.

Of course we're totally speculating at this point, we literally know nothing. I'm worried that the impact was so great that there won't be much left of the black boxes. I know they can withstand some serious G impact, but this is extreme.

 

News outlets are saying “a black box” has been found, but, no indication of which one it is (voice recorder or data recorder).