JASDF F-35A crashed

As the good 'SWP' has mentioned - graphic from said PDF: download/file.php?id=30645 (5Mb)

I'll gawk at the Japanese documents later.

WRT HUD symbology, it's been aeons (maybe 20 years) since I (as a civilian chickenhawk, but not peacenik) last played a combat flight sim, so I'm merely familiar with the basic CCIP (for iron bombs), gun/missile reticle, nose reticle, pitch ladder, waterline, &c.

That -3 degree FPA in the AGCAS graphic converging to the big "X" for auto-recovery is equivalent to the FPA of an airliner (or fighter or anything) on a normal ILS. Very conservative system it appears.

It also appears this guy was seeing quite a bit more extreme flight path display than that, both in pitch and roll. "Fly-up, fly-up" is nice if you can determine which way is up. If it was vestibular and not a display misinterpretation, that's where a fool-proof display is necessary....if there is such a thing.

Looking at some representative pictures of the HMDS display from the Avionics forum, a couple of questions come to mind concerning the type of confusion with displays that can lead to misinterpretation.

In the first pic, how is it possible for the 'zero pitch line' (commonly called the horizon line, though incorrectly so) to overlay the terrain well below the zero pitch line as it passes through what appears to be a hill, with in fact the FPV symbol still on the 'zero pitch line' at the base of the hill? Also in the pic, the negative pitch line tabs that point to the zero pitch line are on the outboard ends of the lines themselves.

In the second schematic from the Norwegian discussion, the negative pitch line tabs are on the inboard ends of the lines, while the positive pitch line tabs are outboard. Never seen that before.

What would this guy have been looking at in that steep descent, assuming the display was functioning properly?

What would have been his best indication of "up"?

After awhile it gets to be doubledutch for me because I have not seen these things in use in practice myself but this may be helpful: viewtopic.php?f=62&t=16223&p=234221&hilit=color#p234221

"...4.1.1.1. Helmet Mounted Display Virtual Heads-Up Display (HMD v-HUD). Note that under some flight regimes, the horizon line and pitch ladder collides (coexists) with the airspeed, altitude and heading symbology, causing potential readability issues;...: http://www.e-publishing.af.mil/shared/m ... -35AV3.pdf (0.5Mb) URL noworkee - PDF now attached - see page 26 for instrument flying stuff - NOPE computer says 'update file is EMPTY' - tried uploading a GIF of quote to NOPE so go to the thread URL for full text

LOTS to read about HMDS: viewtopic.php?f=62&t=16223&p=221812&hilit=color#p221812

For concise summary, I read Japanese news articles.
Note: my comments in square brackets.

https://headlines.yahoo.co.jp/hl?a=2019 ... 4-mai-soci
https://www.jiji.com/jc/graphics?p=ve_s ... 0j-04-w360
https://mainichi.jp/articles/20190610/k ... 40/096000c

2019/06/10:
Accident F-35 trained with three other fighters.

19:25, altitude 9,600 m, when first round of training ended, pilot said "21 [callsign], two kills."
[He shot down two wingmen, or his two wingmen allowed themselves to be shot down by him.]

After one minute, ground control instructed him to descend, to avoid US military aircraft at 11,300 m, flying to Kadena AB, Okinawa Prefecture.
From altitude 9,600 m, he began to descend, and said "Hai [yes], ryoukai [understood]".

After 20 seconds, he descended 4,900 m [vertical distance], to altitude 4,700 m.
Very fast dive, above 900 km/h, and pilot probably had spatial disorientation.

19:26:15, ground control instructed him to turn left, and his final reply was "Hai, knock it off [stop training]."
This was after he turned left, and G-LOC chance was low.

After 15 seconds, he additional descended 4,400 m [vertical distance], above 1,100 km/h.

19:26:30, altitude 300 m, he disappeared from radars.
At blunt angle, he flew into ocean.

His voice was calm, did not evasive manoeuvre, and did not eject.
If mechanical trouble, chance was high that aircraft would decelerate while descending, but he descended at inappropriate supersonic speed.

From the F-35A ops procedures:

4.1.2. The primary unusual attitude reference is the HMD v-HUD. Do not use the HMD or SFD to recover from an unusual attitude or when executing lost wingman procedures except when no other attitude reference is available."

Is the v-HUD continually displayed in the HMD or is there is some pilot switching required to go from the HMD to HMD v-HUD?

Is it only displayed looking forward?

His voice was calm

....

he flew into ocean

So what cues the pilot to 'transition' to the v-HUD? Is it considered a PFR?

I think I'd be tempted to momentarily reference the PFR or SFD quite a bit a night.

Salute!

I m not surprised at using the V-HUD for a recovery, but after enduring one or two or... , my not so humble opinion is that the steam gauge attitude indicator rules! In any case, the V-HUD is better than the normal helmet display because it is referenced to your feet and seat!

Even the later HUD displays using vee-shaped pitch lines with little feet on the ends are not as intuitive as "blue side up, black down". On one bad move I made years ago, I was looking over shoulder and unintentionally entered a cloud. I had managed to crank in a healthy roll command ( Viper Block 15) and quickly looking forward helped the inner ear, NOT, heh eh heh. HUD was almost useless but using the basic attitude indicator was a piece of cake, and good thing as I was in the mountains and terrain clearance was not what you would like. You know - roll and then pull.

Gums opines...

On airliners with HUDs, PFRs were always head-down steam/MFD type....of course it's more straight forward when it comes to the HUD unusual attitude display in an airliner (or C-17/KC-46) type aircraft. You set pitch and roll thresholds, beyond which exceeding them results in automatic switching to the unusual attitude recovery display, the symbology specifically directed at recovery, though at times that switch-over itself could be disorienting.

With fighters there are normal occasions to fly thru any and every attitude so there's really no such thing as an 'unusual' attitude....only an unexpected or worse, undetermined one. I didn't care for that narrow little Block 10 HUD for flying instruments either....and that HMDS just looks claustrophobic and at times even overly informative.

F-35A USAF Flight Procedures afi11-2f-35av3(12) 07 Jun 2012 I can post stuff I can post!

Somewhere there is multi-page PDF about SPATIAL DISORIENTATION Explained PDF - this forum - gotta find it. Meanwhile:

Example from: LIES My Cilia Told Me - A Spatial Disorientation Primer Naval Aviation News NAN_vol94_no4_v16_lr
http://nanarchive.omnitecinc.com/20102012.aspx (probably not available here now - will be in the aforementioned PDF)

The OLD forum SD PDF is more complex than I thought with other stuff - & LESS SD - so I'll make anotherie soonish like.

On airliners with HUDs, PFRs were always head-down steam/MFD type....of course it's more straight forward when it comes to the HUD unusual attitude display in an airliner (or C-17/KC-46) type aircraft. You set pitch and roll thresholds, beyond which exceeding them results in automatic switching to the unusual attitude recovery display, the symbology specifically directed at recovery, though at times that switch-over itself could be disorienting.

With fighters there are normal occasions to fly thru any and every attitude so there's really no such thing as an 'unusual' attitude....only an unexpected or worse, undetermined one. I didn't care for that narrow little Block 10 HUD for flying instruments either....and that HMDS just looks claustrophobic and at times even overly informative.

So where was the incident pilot in your claimed normal distribution of pilot ability?
By your theory, he should have been nigh-invulnerable to spatial disorientation.

Right now he is in the distribution of pilots in the Pacific Ocean, a fairly large sample size, converging on a normal distribution, regardless of which variable or set of variables you pick.

What exactly is it that you do in aviation?

On airliners with HUDs, PFRs were always head-down steam/MFD type....of course it's more straight forward when it comes to the HUD unusual attitude display in an airliner (or C-17/KC-46) type aircraft. You set pitch and roll thresholds, beyond which exceeding them results in automatic switching to the unusual attitude recovery display, the symbology specifically directed at recovery, though at times that switch-over itself could be disorienting.

With fighters there are normal occasions to fly thru any and every attitude so there's really no such thing as an 'unusual' attitude....only an unexpected or worse, undetermined one. I didn't care for that narrow little Block 10 HUD for flying instruments either....and that HMDS just looks claustrophobic and at times even overly informative.

So where was the incident pilot in your claimed normal distribution of pilot ability?
By your theory, he should have been nigh-invulnerable to spatial disorientation.

"We believe it highly likely the pilot was suffering from vertigo or spatial disorientation and wasn't aware of his condition," Defence Minister Takeshi Iwaya told a briefing. "It can affect any pilot regardless of their experience."
[previous page 'krieger22' : http://www.reuters.com/article/us-japan ... ce=twitter

What exactly is it that you do in aviation?

I mainly brag about my math SAT score.

75 pages of Spatial Disorientation BADness PDF is attached. Other stuff such as HYPOXIA, G-LOC & Pilot Error not included.

Orientation and disorientation in aviation [this pdf is in the attachment below]
John Richard Rollin Stott 2013

“...Conclusions
Much of the basic physiological science of relevance to disorientation in aircraft has been elucidated many decades ago, some even before the advent of powered flight. The practical problem remains as to how the subject should be taught and demonstrated to each successive generation of pilots to forewarn them and maintain their awareness of the potential dangers of disorientation in flight.”

Source: https://www.ncbi.nlm.nih.gov/pmc/articl ... 48-2-2.pdf (0.75Mb)