If the helmet malfunctions can the f35 fight without it?

Just curious, I assume the plane has a traditional HUD and the displays can serve as backup for telemetry and avionics info? The cockpit is so Spartan in terms of buttons I wasn't sure what backup flight and targeting controls exist.

'brillo' you have assumed incorrectly. I think you will be aware the F-35 has no conventional HUD. However the F-35 does have a virtual HUD displayed in the HMDS Helmet Mounted Display System - on/inside the helmet visor which the pilot is able to see at all times with basic flight parameters displayed and other targeting functions turned on and off by command. This virtual HUD vHUD has the forward look and will show where ever the pilot looks. However it can also on command show a rear view. All this is explained at some length in another long thread. However you must be willing to read it. Probably starting backwards from a point I will show here soon....

Also on this long thread you will see the answer to all your questions most likely. Yes the Panoramic Cockpit Display shows it all. An F-35 pilot has commented that 'he could complete the mission with a paper bag over his helmet' to obscure the outside view and rely entirely on the PCD we can assume.

'brillo' you could go to this thread: Helmet-mounted displays in this 'AVIONICS' subsection:
viewtopic.php?f=62&t=16223

Then using the 'search' function - top left almost - by entering the search term "vHUD" (without the quote marks) you will find in an order of your choosing lots of posts about vHUD. If there are too many you can search the search results again with another term of your choosing.

For example this 'hit' from the search will show the front (ordinary) view of vHUD whilst in the same thread there is the "rear vHUD view" and otherwise scattered throughout this F-35 forum. WHY? Because it is unusual to say the least:

viewtopic.php?f=62&t=16223&p=288480&hilit=vHUD#p288480

For the sake of whatever the FWD & REAR vHUD views in the HMDS are replicated below. AND yessireebob there are backups. For example on this same 'HMDS' thread you will see the 'standby flight indicator' (or whatever it is called - I'll check). Are you from pPrune? Here is a video short view of the vHUD FRONT VIEW ONLY. Best click on the 'YOUTUBE" icon to go to Ubend and watch the video at the highest resolution/full screen for more detail.

Here is a video showing the PCD Panoramic Cockpit Display. The screengrab shows the 'SFD' Standby Flight Display'. In this video Mike Skaff points toward this travel simulator view of the vHUD which (because of restrictions of the travel sim) is shown forward on the sim screen. So you will have to imagine it is the vHUD.

The same HMDS thread indicated above should have a bunch of terms to search such as 'cowpie' for the throttle with a bunch of buttons that are also on the 'stick' (search for these terms in that thread). And then there is this recent video showing HOTAS in action and the FMS (FULL MISSION SIMULATOR) with screen grabs of the PCD and in the video.

The helmet, RH PCD, LH PCD and SFD all have their own display generators. Thus, there is lotsa redundancy in the event of some kind of issue. A "HUD" an be displayed on the PCD if so-desired, not unlike most 4th Gen aircraft with MFDs.

Also, vHUD looking "rearward" overstates the case. That picture is simply what one sees outside the normal FOV -- decluttered -- but in this case with weapon employment data presented because there is an air target designated and a weapon in flight.

'QS' however would not the DAS view be there IF the pilot has it enabled? How useful is DAS looking to the rear when on lookout for bogies in the six o'clock?

If there is a plane on the F-35's "six" and it's close enough for the Mk1-Eyeball to see it, then the EODAS units have already detected it, tracked it, and shared that info with the rest of the fleet.

Thanks 'SWP'. My question is refined : Using DAS and looking to the rear via the switched view through the vHUD - is that Mk.1 eyeball view useful to the pilot (now discounting the symbology in the vHUD - a stretch perhaps to imagine - however most here have only seen video sims of the view and I'm asking for the opinion of anyone who has seen a 'real' view via the FMS for example (maybe that view is not possible there). The 'travel simulator view' is not a realistic representation of the vHUD so it does not count. Perhaps it is impossible to say without flying the aircraft in the circumstances described?

Perhaps what is seen will be useful to the eyeball of the pilot once he/she is used to the view with the vHUD. It seems the HMDS with vHUD takes some getting used to but once the pilot is comfortable with it then they cannot do without it.

'QS' however would not the DAS view be there IF the pilot has it enabled? How useful is DAS looking to the rear when on lookout for bogies in the six o'clock?

The DAS image projected on the visor is referenced to where the helmet is pointed -- not to where the pilot's eyes are looking. Additionally, DAS on the visor is fundamentally for night use only -- it needs a darker background to be seen in a useful fashion.

But, let's go back to the 'rear view'... Think about how hard it is to crane one's head around to look aft (regardless of what kind of visibility we have in the aft quadrant). We twist our head around as far as it can (somewhat) comfortably go, and then what distance our head doesn't go (biomechanically speaking) we do what? ...we move our eyes.

The jet doesn't know where the pilot's eyes are looking -- it only knows where the helmet is pointed in reference to a boresight position established when the jet is powered up.

As Spud points out, in most circumstances DAS will already have detected, tracked and alerted a pilot to the presence of something in its collective FOV long before a pilot will see it with the naked eye.

"The 'travel simulator view' is not a realistic representation of the vHUD so it does not count."

Actually, having seen the traveler and discussed with the guys who fly the jet -- it is.

OK 'QS' that makes sense. Then to look 'aft' the pilot needs to look straight ahead then switch the HMDS vHUD view to 'aft'.

I'll guess pilots will have to get used to interpreting the 'aft' symbology for any other clues not presented by that symbology. What that might be I have no idea - just spitballin'.

The FMS 'trainer' pilot is able to view the eye position of the pilot trainee in the FMS. Will this 'eye-tracking' come into effect in another update to the HMDS? Here is a bit of a story about it:

"...[1st para] integrates eye tracking and Electroencephalography (EEG) technology into an HMD enabled F-35 training environment to extend traditional behavioral metrics and better understand how a pilot interacts with data presented in the HMD...."
viewtopic.php?f=62&t=16223&p=288642&hilit=Electroencephalography#p288642

OK I see another 'QS' post. Hmmmm.... not having seen the 'travel sim' except on a video then is the 'travel sim' able to show the rear vHUD view?

OK 'QS' that makes sense. Then to look 'aft' the pilot needs to look straight ahead then switch the HMDS vHUD view to 'aft'.

I'll guess pilots will have to get used to interpreting the 'aft' symbology for any other clues not presented by that symbology. What that might be I have no idea - just spitballin'.

The FMS 'trainer' pilot is able to view the eye position of the pilot trainee in the FMS. Will this 'eye-tracking' come into effect in another update to the HMDS? Here is a bit of a story about it:

"...[1st para] integrates eye tracking and Electroencephalography (EEG) technology into an HMD enabled F-35 training environment to extend traditional behavioral metrics and better understand how a pilot interacts with data presented in the HMD...."
viewtopic.php?f=62&t=16223&p=288642&hilit=Electroencephalography#p288642

OK I see another 'QS' post. Hmmmm.... not having seen the 'travel sim' except on a video then is the 'travel sim' able to show the rear vHUD view?

The vHUD is always presented at boresight and boresight only -- in a virtual sense, where an actual HUD would be located in the physical world. There is no 'aft' symbology, there is what I will call 'decluttered' symbology any time one is pointing the helmet outside a notional HUD FOV.

The article you cite is about (quote) "...efforts to develop and evaluate..." such a system. It does not exist in either the FMS or the jet today.

Here is a good vid that shows the HUD and what it looks like as the pilot swivels his head in and out of the forward FOV.

OK 'QS' noted the 'under development' status of eye-tracking. I'm still puzzling over the aft vHUD view. YES it was not clear to me where the vHUD is perhaps. Still puzzled. The vHUD is in front of the pilot view and moves with the helmet? OR does it remain locked in space where a REAL HUD would be in front of the pilot BUT not moving? Remember for someone not having used a HUD before and now having to imagine a virtual HUD not having seen any 'real life simulation' of the same - this is not easy to imagine - just using words alone.

'SWP' has posted a vHUD video as I typed. However the other day I posted a 'vHUD video' with captions that better explained what was being shown in the video. I'll go get it before more posts occur.

OK thanks all - I get it now. Here is the clip below.