The SIB had very little to go off of, and had a lot of theory, conjecture and "best guess" which may be holding up the AIB.

Correct me if I'm wrong, but aren't AIBs and SIBs completely independent of each other. That's the point right?

Correct me if I'm wrong, but aren't AIBs and SIBs completely independent of each other. That's the point right?

They are independent in that they have completely separate boards and that the protected information from the SIB (protected witness testimony, SIB findings/recommendations, etc) are not shared. However, pure evidence (photos from a mishap, toxicology results, cockpit recordings, etc) are not protected and are thus passed along to the AIB. So I assume if the SIB was not finished with the evidence that the AIB needed, it may be held up.

This was in my news feed today:

"Too Tired to Fly?" by Time

https://nation.time.c...tors_picks=true

It has commentary asking questions about our 24/7 ops tempo combined with the report. It mentions several factors such as an exercise at the deployed location that kept the crew members from sleeping well. The commentary also questions the use of Ambien by the crew.

Terrible no matter how you look at it.

Edited to add: https://timemilitary.files.wordpress.com/2012/10/u-28_aib_021812.pdf

Link to AIB report.

Edited October 29, 201213 yr by Kilgore Trout

Page 32, Table 6 - Vertical Velocity increases from 3914 fpm to 11,752 fpm in 10 seconds. Sounds insane, is that really possible?

Edited October 29, 201213 yr by Kenny Powers

Page 32, Table 6 - Vertical Velocity increases from 3914 fpm to 11,752 fpm in 10 seconds. Sounds insane, is that really possible?

Granted, I'm no math major, but 11752 fpm is only about 196 feet per second; 60 MPH is 88 fps, so 11752 fpm is only about 200 mph vertical vector, right?

Granted, I'm no math major, but 11752 fpm is only about 196 feet per second; 60 MPH is 88 fps, so 11752 fpm is only about 200 mph vertical vector, right?

The final velocity is not suprising to me, just the rate of change between the two. The vertical speed went from 44 mph to 135 mph in 10 seconds. Seems like a lot with engines at idle and not falling directly out of the sky (though not far from it).

Edited October 29, 201213 yr by Kenny Powers

11.7kfps roughly equivalent to 117kts in the vertical.

Just a guess, but going from a shallow turn to inverted with a steep downward vector can be accomplished in less than 10 seconds. I haven't seen the SIB/AIB, so I'm not sure about aircraft attitude during the mishap, but going from ~3000 FPS to ~11000 FPS is certainly feasible if you've lost aircraft control. I used this mishap a few months ago to argue against taking away more flying hours in exchange for increased sim hours. You can't sim fatigue and spatial D, no matter how fancy the sim is.

The chart in the AIB shows a change in VV of ~1000 fps per second. That acceleration obviously exceeds gravitational acceleration. Can somebody who's a little smarter than me quickly run the numbers to see what the felt negative G produced by that type of change in VV would be? It's been a few years and I can't remember how.

How did they determine vertical velocity? I don't know the equipment load out of the U-28, but from what I've seen of the PC-12, it's a standard steam gauge. Most VSIs lag by a few seconds anyway. Add to that rapid accelerations, altitudes and turbulence, it's not reliable at all until the pressure equalizes.

How did they determine vertical velocity? I don't know the equipment load out of the U-28, but from what I've seen of the PC-12, it's a standard steam gauge. Most VSIs lag by a few seconds anyway. Add to that rapid accelerations, altitudes and turbulence, it's not reliable at all until the pressure equalizes.

From the AIB:

Enhanced Ground Proximity Warning System Data showing Altitude and Decent Rate in feet per minute.

The chart in the AIB shows a change in VV of ~1000 fps per second. That acceleration obviously exceeds gravitational acceleration. Can somebody who's a little smarter than me quickly run the numbers to see what the felt negative G produced by that type of change in VV would be? It's been a few years and I can't remember how.

Don't think of this as a pushover or a pull, I really wish I could see the ADI tapes from this, but I bet you could achieve such a VVI change at a relatively low perceived G loading. Ten seconds is a LONG time when it comes to something like this.

Edited October 29, 201213 yr by Napoleon_Tanerite

The chart in the AIB shows a change in VV of ~1000 fps per second. That acceleration obviously exceeds gravitational acceleration. Can somebody who's a little smarter than me quickly run the numbers to see what the felt negative G produced by that type of change in VV would be? It's been a few years and I can't remember how.

it's actually 1000 fpm per second, or 16.6667 fps per sec, which is less than 32.1 fps per sec gravitational acceleration?

The chart in the AIB shows a change in VV of ~1000 fps per second. That acceleration obviously exceeds gravitational acceleration. Can somebody who's a little smarter than me quickly run the numbers to see what the felt negative G produced by that type of change in VV would be? It's been a few years and I can't remember how.

A few things to note:

1. fps is a velocity, not an acceleration. Its the rate of change in velocity that determines acceleration, so (Vf - Vi) / Time.

2. The acceleration due to gravity is 32.2 ft/s^2 on earth. Quick calculations through the 27 data points given in the AIB shows that the plane never exceeded a vertical acceleration greater than ~ 22ft/s^2 or about 0.68g.

Edit:

If the nose was pitched down 36 degrees and the data in the table is accurate, that means they would have felt an acceleration, immediately before impact, equal to about 1.16g (the sum of the vertical and horizontal components of the acceleration).

Edited October 30, 201213 yr by Kenny Powers

From the AIB:

Enhanced Ground Proximity Warning System Data showing Altitude and Decent Rate in feet per minute.

copy, thanks. EGPWS, I guess pretty accurate. I should probably just read the investigation boards, huh?

I don't know the equipment load out of the U-28, but from what I've seen of the PC-12, it's a standard steam gauge.

Everything is digital except the standby ADI & pressurization panel on a U28.

The Board president's name is spelled wrong on the cover page. Well done.

Granted, I'm no math major, but 11752 fpm is only about 196 feet per second; 60 MPH is 88 fps, so 11752 fpm is only about 200 mph vertical vector, right?

Only 200 mph?

Spatial D is a killer. Trust your instruments unless you have significant reason to ignore them

Spatial D is a killer. Trust your instruments unless you have significant reason to ignore them

Wait, what?

Spatial D is a killer. Trust your instruments unless you have significant reason to ignore them

Says the one who only has instruments to stare at

Wait, what?

When your gas gauge shows "E" and you JUST took 110K from a tanker, chances are that your gauge is wrong. Likewise, when one of your instruments shows you in a 6 degree bank while the others show you at wings-level, don't trust the malfunctioning instrument

Says the one who only has instruments to stare at

remind me not to fly with you in IFR

remind me not to fly with you in IMC

Fixed.

Wait. Fucking nav...troll on troll...

Likewise, when one of your instruments shows you in a 6 degree bank while the others show you at wings-level, don't trust the malfunctioning instrument

Wait, what?

Now I'm even more confused. What if I actually am in 6 degrees of bank? And how do I recover? Can I even recover for that type of extreme unusual attitude?

Is there any way you could whip out a 69 slide ppt deck for me to study on this? That would be great.

On topic, this crash is horrible and a waste of four young studs.

TIME weighs in with their opinion: https://nation.time.com/2012/10/29/too-tired-to-fly/