F-16 jet crashes at base outside Las Vegas

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by ruderamronbo » 16 Oct 2018, 22:02

https://www.airforcetimes.com/news/your ... -maneuver/

My usual source for reports, Air Force Magazine, hasn't posted the full report yet

http://www.airforcemag.com/AircraftAcci ... ?Year=2018

The report is available here but I can't get to it... https://www.nellis.af.mil/News/Article/ ... -released/

https://afjag.usaf.afpims.mil/publicmed ... REPORT.PDF


"Thunderbirds pilot Maj. Stephen Del Bagno temporarily lost consciousness during a high G-force maneuver and was incapacitated right before a fatal crash in April.

The Air Force on Tuesday released the report on the investigation into the April 4 crash at the Nevada Test and Training Range near Nellis Air Force Base."

:salute:


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by hoghandler » 16 Oct 2018, 23:46



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by Gums » 19 Oct 2018, 17:34

Salute!

What a sad accident report. I am surprised by several numbers.

I have not talked with a slot pilot in years, but may/should in order to allay my feelings
+++++++++++++++++++++=
I was present in a flight when we had our first g-loc in the Viper. The pilot was a stud and back seat IP recovered the jet. It departed but did not stabilize in a deep stall, so IP recovers while calling "knock it off". and then it happened again with one of our first B-course studs ( no prior fighter time but a FAIP). The HUD film from that episode has been on TV several times. Our boss called all of us in to the main brief room that afternoon and we watched the film.

So a few weeks later I am with another of the "B' course studs and walla! Bottom of an escape and looking over shoulder at "bandit" high above when the gees reduce. I think the guy is extending to gain some energy. Then I look forward and his head is bouncing off the canopy rail. "Knock it off" on radio, and "hey! talk to me." on intercom. Ee went home and spread the word. Soon lost a cadre member who had been re-assigned to the weapons school and the HUD film showed tha classic high gee within a few seconds and then 1 gee +/- depending upon his trim.

So I have seen this, and I don't know why I never had it myself, since I had great HUD film of reaching 8.7 gee within about 3 seconds on a break turn. Guess it's the grunt and clench early, then yank. Plus I was older.

The gee-loc occurs most of the time due to onset rate and not absolute gees. Before the Eagle and Viper we could not get to those gees real fast. So you had grey out, tunnel vision and blackout. But gee-loc was a different bear. You went lights out and were out of it for many seconds.
++++++++++++++++++++++++++++++=
I am surprised at the gees for some portions of the maneuver ( previous flight data recordings). 5 or 6 gees seems reasonable to me for many portions of the maneuvers, but not many. Seems 4 or 5 gees would suffice 95% of the time unless you were late or the flight path of other members required a sudden yank.

I am also surprised at the negative gee numbers.

Oh well, a sad thing and I hope the Birds look at the practice film to spot any trends.

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by outlaw162 » 19 Oct 2018, 18:51

Isn't this what Auto-GCAS is for?


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by Gums » 19 Oct 2018, 19:36

Salute!

I think they can turn it off, just like the Cat 3 FLCS laws back in the day.

I also point out that the "recovery" gizmo is prolly set for very conservative numbers, and does not allow for the "x" gees in "y" seconds and "z" AoA limits.

i still have troubel with the gee numbers for the previous 20 or so missions.

Lastly, I seem to remember the first Viper rejoins after the bomb burst, and it was out in front of the viewing stand, but different than the one depicted here. And back in the previous aircraft it seemed that the rejoin was away from the crowd and the solo pilots kept viewers busy.

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by durahawk » 20 Oct 2018, 06:08

outlaw162 wrote:Isn't this what Auto-GCAS is for?


I've heard the OFP version that the Thunderbirds use is an older version without AGCAS because the newer software didn't give them the rudder authority they needed.

This is frustrating for those that developed AGCAS because a separate "airshow mode" was separate set of fly up rules developed specifically for the Thunderbirds.


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by outlaw162 » 20 Oct 2018, 16:06

One would think the ramifications of a special AGCAS mode (or lack of) would have been mentioned in the report summary....maybe I missed that.

Haven't been to a show for awhile, but in the past I recall the narrator used to make the point that the maneuvers and skills being demonstrated were representative of the same maneuvers a typical fighter guy would perform day to day....

I guess that's not true anymore.


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by Gums » 21 Oct 2018, 00:35

Salute!

Unless the FLCS laws for yaw are vastly different, the rudder trim is a deflection and not a variable, I also doubt that the total deflection is less than what we had 40 years ago.

When I talked with the original Viper T-Birds, the wingies said they trimmed the nose into the formation just a tad. I think "Yum Yum" , #4 , suggested a slight forward trim, and that would work lots better than the older planes' trim because it would be a constant gee regardless of airspeed.

Not sure if the "break X" is used anymore, but I guarantee it would have been flashing just about the time he lost it and well before he started to make concious stick inputs. Fer chrissakes, he was diving down at a very steep angle. The HUD tape would have shown this.

FInally, that rejoin sequence for all the members is certainly not something the rank-and-file jocks ever try. And the flight path by #4 is definitely the toughest and involves that split-s and prolly more gees than any other position. Still having trouble understnding over 8 gees so early coming down the back side.

Well, threw the nickel on the grass last spring, and I hope we don't ever see another loss like this one.

Gums sends...
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"God in your guts, good men at your back, wings that stay on - and Tally Ho!"


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by hoghandler » 21 Oct 2018, 22:49

Just watched a few videos on youtube showing the manuver done during some airshows. I got a better understanding of what the report says happened and what the videos show how manuver supposed to go. Really sad that this happened and it happened so fast.


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