737-500 Down in Indonesia?

a reply to: Bluntone22

Black box will probably show an AOA of nearly vertical nose up by the time they noticed.
Couldn't have much air moving over the top of those wings, that is for sure.

a reply to: Slichter

I think that's exactly what it will show. They held the nose up as long as they could, not recognizing the stall, and by the time the nose fell through, it was far too late.

originally posted by: Zaphod58
a reply to: Bluntone22

The ADS-B data shows the were wings level and nose up, until just before impact. The were actually losing speed until under 2000 feet, when the speed jumps suddenly.

That’s the odd part to me, the wings being level and still attached should fall slower.
20 seconds is real close to free fall speed.
I guess the black box would clear up some things.

Ok here’s my math.
Please show me if I’m missing something cuz I’m not seeing it.


A 737-800 is just under 80,000 kg max takeoff weight.

10,000 feet is 3048 meters so let’s call it 3000.

An 80k kg object falling 3k meters will take 24.74 seconds to impact.

That of course does not factor in things like wind resistant over the wings or propulsion from the engines.

www.angio.net...

a reply to: Bluntone22

And it took just over 20 seconds to impact. They were at 10,900 feet at timestamp 07:40:06. The last reported data showed 250 feet at 07:40:27. At 07:40:26 and some change, the recorded speed jumped from 173 knots to just over 300 knots accounting for the difference.

This WAS freefall. They weren't moving forward, they were falling straight down. They were just doing it with the nose up, trying to climb.

The last known position was at 1440 local. At 1439 they crossed the coast in a climbing right turn.

a reply to: Bluntone22

Don't forget, that speed curve is forward speed, not vertical speed. The vertical speed was steadily climbing throughout the fall.

So your math is right, but I think you're just missing that you're not seeing a vertical speed curve.

The key might be that there is a common AOA illusion flying by the seat of your pants as you trade the feel of gravity for the feel of the wing braking force due to the ever increasing AOA.

Eventually (something like the need for) COTS antennae arrays should be understood.

They crossed the coast in a climbing right turn, then were directed to a 075 heading, but controllers noticed they were heading northwest instead. That was just before the crash.

a reply to: Zaphod58

If this was a case of thermal updraft with a sharp downdraft boundary on the NW side of an equatorial Pacific thunderstorm it might have been detected by the ground radar. You would think they would have mentioned that at least to the pilots if not the media covering the tragedy?

a reply to: Slichter

I'm thinking the leveling out from the turn caused them to get disoriented.

Claims that they have picked up signals from the black boxes.

www.bbc.co.uk...

Earlier on social media they were talking of finding parts of the wreckage and body parts. And that it was in only 75 feet or so of water?

a reply to: solidshot

Yes I distinctly remember them finding debris just hours after the accident. A very slow response if you ask me, they could of probably found it with basic sonar scanning equipment by now ...... hell .....a fish finder would probably find it.

a reply to: Catch_a_Fire

The slow response was reporting the cause of the crash, some newer model "black box" technology appears to be more like cloud based storage from a constant secure satellite link but this was a circa 1994 plane. Newly reported estimates claim 40,000 foot per minute descent. I think the official tactic is to dive the plane when you experience a downdraft to increase your forward speed and be ready to pull out as the downdraft mushrooms out at lower altitude. No reports of a downdraft boundary visible on radar so just have to wait for the official report which often takes months.

a reply to: Catch_a_Fire

Even if they had one, it takes time to get equipment there to more precisely locate it, and divers to get there and get ready, etc. The response is on par with any response to an accident of this type.

a reply to: Slichter

I still think they pulled the nose up thinking they were stalling, and fell flat until very low altitude. The ground speed didn't drop enough for a nosedive IMO.

a reply to: Zaphod58

Why would they pull the nose up if they thought they were stalling??

They should apply power and push the nose over if that was the case?

...or was that just a typo?

From the airspeed / altitude profile, it looks to me like they did nose over at just above 5000 AGL, but it was likely too late. As is evidenced by the sudden and dramatic reversal from decreasing to increasing airspeed.

a reply to: Flyingclaydisk

It was a typo. I'm still working on my caffeine intake and am at work, so I'm a little scatter brained right now. I was trying to say they pulled it up into a stall and didn't recognize that they were stalling until it was too late.

a reply to: Zaphod58

I figured as much.

Some other interesting data...

That airplane just stopped flying and fell out of the sky like a rock in the span of less than a second!

The airspeed curve is the most peculiar though. Notice how the airspeed went from about 280 kts to about 115 kts in less than 5 seconds. Anyone would expect the forward airspeed to drop in a stall, but not that fast. The altitude curve looks about how one would expect, but not the airspeed curve.

Did they maybe throw up the flight spoilers by accident? Reversers?

a reply to: Flyingclaydisk

I could see reverser activation causing that, if both activated. I'm not sure if the CFM has the lockout for in flight though.