Not_Delta 191

[3WE]

For some reason I do not_remember this crash: https://www.ntsb.gov/investigations/Acc ... AR9503.pdf

However, I find it extremely interesting.

1. It is very similar to Delta 191, and I’m always interested in my hometown Ozark 809 FH-227 crash.

2. BUT, this occurred after we supposedly fixed everything with quadrant-based wind shear alerts and procedures.

3. Much like Delta 191, this was a rapidly-developing, small storm.

4. Subtlety different, the plane ahead reported a smooth ride (the plane ahead of 191 did not REPORT anything, but supposedly encountered a severe shear. The plane ahead of 809 went around)

5. In both cases, some weather reporting was missed, but, unlike 191 and Ozark 809, the meteorologists seemed to be tracking mundane build ups. With 191, supposedly meteorologists were saying, “wow, this sucker is getting strong” in the minutes before the crash. With 809 a big system was already warning level, and it was more about its arrival on the approach path.

6. This crash and 809 both make mention of “walls of water”. I wonder if that has ever been researched as a possible signature that might be teased out of radar?

7. Very similar to 191, the crew identifies the activity, and discusses potential shear. With 191, the speed increase is noted but not immediately addressed. Here, the PM says 20 knots fast, go around. (809 discusses the weather, but downburst wind shear isn’t really “a known thing” back then.)

8. In both jet cases, the flying pilots are faulted for letting the nose drop and not extracting full performance, with (my favorite “yeah but”) the stall warning did activate which means they weren’t not_trying to climb. With 191, TOGA power was called for. Here, they were supposedly using a “normal go-around” power instead of some slightly higher setting. They were cited as also being slow to get the gear up. And again, this crash was after the development of the “Delta 191 procedures and sim trainings. (809 did not get a heavy duty performance analysis and may not have had much FDR data.)

9. It’s interesting to contrast a big, lumbering jumbo jet and a “sporty” DC-9-31, but maybe JT-8Ds spool up slow, much like an RB-211.

10. The estimated wind shears were fairly similar and very impressive in this and 191.

11. Similar to 809, the pilots survived, with a similar death toll.

12. I don’t know the exact details, but terminal Doppler radar, with shear detection wasn’t installed yet, and I guess there was no on board shear detection vs nowadays.

13. I’ll have to think/study more- I always felt that 191 was a fumble as the meteorologists were noticing the storm and because in Texas, they have those intense, high-base “dry” thunderstorms” that act like ITS. The Carolina’s (and Flyover’s) are much more juicy- but it almost feels that the US Air encounter was unavoidable given everything.

There’s things I’ve missed, but I think I’ll post this now. I’ll probably double post since Bobby has his “never fly into red” personal procedure.

[flyboy2548m]

Is there a question there somewhere?

[Verbal]

No.

[Gabriel]

Is there a question there somewhere?

No.

Yes

6. This crash and 809 both make mention of “walls of water”. I wonder if that has ever been researched as a possible signature that might be teased out of radar?

[3WE]

Is there a question there somewhere?

Well, this is a discussion forum, so one question is what do we think about this crash?

Are the similarities not_remarkable?

How did they crash the plane in the post Delta 191 era with all the sim training and even the low tech wind shear alert system?

Did the missed wind shear information really change things?

What do we think of Evanie’s comments?

And sure, “wall of water” might be something you can see on Radar and correlate to a serious downburst?

Nevertheless, thanks for checking in.

[Not_Karl]

Is there a question there somewhere?

Well, this is a discussion forum, so one question is what do we think about this crash?

Are the similarities not_remarkable?

How did they crash the plane in the post Delta 191 era with all the sim training and even the low tech wind shear alert system?

Why weren't ALL windshears banned after Ozark 809 and Delta 191?

Did the missed wind shear information really change things?

What do we think of Evanie’s comments?

And sure, “wall of water” might be something you can see on Radar and correlate to a serious downburst?

Nevertheless, thanks for checking in.

Expanded.

[3WE]

Is there a question there somewhere?

Why weren't ALL windshears banned after Ozark 809 and Delta 191?

Expanded.

You can’t ban wind shear, silly, you’ll have to ban flying, instead.

[3WE]

I do not believe the captain, based on a somatogravic illusion, ordered the first officer to nose over, and that the first officer blindly complied (or complied, because he also felt the somatogravic illusion).

I know it’s total, ass-hat, outsider speculation, but I’m thinking that a nose down input might be based on slow speeds and stall warnings.

Am I wrong about this flyboy? This symbol: “?” indicates a question.

[flyboy2548m]

Nevertheless, thanks for checking in.

You're welcome. As a reminder, if you have a question for me, there is a section for that.

[Gabriel]

Airdisaster 730b MAX-NEO, SOP 13.7 b iii, rev A07 Jan 2022

"QUESTIONS TO AIRLINES PILOTS SHALL ONLY BE ANSWERED IN THE AIRLINE PILOT Q&A FORUM"

[3WE]

Ironing:

1. This isn’t a busy airport.

2. I don’t think they fly THROUGH the tornado, just next to it…pretty darn close, although the plane banks a bit.

https://www.youtube.com/watch?v=D5CLNC1kPsQ

Additional comments (said before):

3. A great dose of altitude and being in FDnH climb mode are probably good things.

4. The NWS was watching, and there were warnings on the storm. The plane very likely had on-board wind shear detection.

5. It was not_raining in the immediate vicinity of the tornado (not_unusual but what does aircraft radar see?)

6. There were numerous options to turn, and avoid this cell, and yet we apparently followed the Holy RNAV departure procedure.

[Not_Karl]

https://www.youtube.com/watch?v=D5CLNC1kPsQ

OMG, the horror!!!!! ... of being in a 737! Look at all the pieces that fell from it, floating in the breeze...

[3WE]

https://www.youtube.com/watch?v=D5CLNC1kPsQ

OMG, the horror!!!!! ... of being in a 737! Look at all the pieces that fell from it, floating in the breeze...

No big deal, just door plugs, engine cowlings, control surfaces, cabin roofs. Move along.

[ocelot]

I do not believe the captain, based on a somatogravic illusion, ordered the first officer to nose over, and that the first officer blindly complied (or complied, because he also felt the somatogravic illusion).

I know it’s total, ass-hat, outsider speculation, but I’m thinking that a nose down input might be based on slow speeds and stall warnings.

Look at the FDR traces from the end of the report. The annotations are nearly illegible, but you can find the "push it down" one, and it happened during mild but not significant airspeed decay. What it happened during was a sustained downward acceleration (look at the "normal accel" line) and well... that can feel like you're slowing down. So I think I agree with the conclusion.

That said, the reduction in pitch at 35 seconds (so a bit later, after they firewalled the engines) is puzzling, but maybe it's more of the same...

[Gabriel]

You are welcome

FDR.jpg

[Gabriel]

I do not believe the captain, based on a somatogravic illusion, ordered the first officer to nose over, and that the first officer blindly complied (or complied, because he also felt the somatogravic illusion).

I know it’s total, ass-hat, outsider speculation, but I’m thinking that a nose down input might be based on slow speeds and stall warnings.

Look at the FDR traces from the end of the report. The annotations are nearly illegible, but you can find the "push it down" one, and it happened during mild but not significant airspeed decay. What it happened during was a sustained downward acceleration (look at the "normal accel" line) and well... that can feel like you're slowing down. So I think I agree with the conclusion.

That said, the reduction in pitch at 35 seconds (so a bit later, after they firewalled the engines) is puzzling, but maybe it's more of the same...

Despite the "push it down" instruction from the PIC, the push down inputs by the FO (PF) were brief in duration and small in deflection.
It looks to me that most of the pitch down motion was not commanded, but the result of a wind that went from 30+ head to 20+ tail with the subsequent loss of 30 kts of airspeed (despite the plane having positive longitudinal acceleration), and of encountering a ~2000 fpm downdraft.

[Gabriel]

FDR.jpg (1014.24 KiB) Viewed 263 times

[3WE]

Quote = Gabriel

Blah blah blah + Graph

Thank you for the graphs and comments- same to Ocelot.

Yes, I see a tiny, brief pitch down input
…towards the end of a period of reducing airspeed and pitch.

I agree, the actual, sustained nose-over seems largely uncommanded.

I see that the pitch down input comes before the stick shaker.

I’ll keep my contention that the “command” to push was due to airspeed, but can’t be a response to the stick shaker which was activating due to negative AOA. “And experienced military pilots are going to ignore the instruments and follow their somatobuttoks”.

Evan gets under my face and makes me blue in the skin with “The stupid pilot should have been pulling up during the negative AOA downburst.

Having watched Delta 191 a lot- I still guess that there was a push over due to lower speeds. But towards the end, the speed is quite healthy while there’s a slight nose up attitude and they settle onto the ground (when the pilots should have pulled up more, there was another shove over). (There’s even Swiss cheese that it AI could have kept the spoilers down, only some grass would have died, the term mud flaps would apply and there would be paperwork.

I’m feeling that this was a tougher wind shear: lower to the ground.

The go-around was called appropriately and full power was called out. A climb was established and then lost as the airspeed got pretty darn low. I guess we can criticize a failure to not have the stick shaker going off half the time.

On the other hand, I still think the indications were of a little rain shower, not_an L-1011 dropper.

/Blathering and thanks for a sane discussion. Additional thoughts welcome.

[3WE]

If you are focusing on trying to execute a fairly high performance go-around with a climb and wanting to avoid the ground, you can tunnel vision and push over.

Makes sense to me.

[3WE]

“I (3BS) have the procedure down.”

[ocelot]

That plot is a lot more readable! Too bad it's missing the normal acceleration trace though, that one matters.

[3WE]

I read an opinion…this isn’t verbatim, but it was suggested that maybe the go-around was going well, resulting in the pilots not_addressing checking their power settings and maybe not_doing the “all-out” pull up, AND THEN THEY WERE SUDDENLY hit with what I will term an epic 191-ish downdraft and speed loss…

Something that might be a bit challenging…

I’ll repeat Nav-5’s old comment that there were some engines being cooked here and there when crews were encountering every-day wind shears and doing Full-Evan-Arm-Chair escape maneuvers.

[Gabriel]

That plot is a lot more readable! Too bad it's missing the normal acceleration trace though, that one matters.

It’s not missing. It’s right there in the blue section. I re-traced the plots and re-shuffled (including bringing up the wind plots that were in the next page) to have a longitudinal section in red (thrust, long acc, headwind and airspeed) and a vertical section in blue (control column, normal acc, vertical wind, pitch and altitude)