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Some Questions about Para-Visual Displays (PVD)  
User currently offlineKimon From , joined Dec 1969, posts, RR:
Posted (4 years 6 months 2 weeks 2 days 23 hours ago) and read 11310 times:

Hello Everyone,
What is this?
Is is this standard on all flightdecks?
Does anyone have pictures?
Many many thanks.

50 replies: All unread, showing first 25:
 
User currently offlineFabo From Slovakia, joined Aug 2005, 1219 posts, RR: 1
Reply 1, posted (4 years 6 months 2 weeks 2 days 23 hours ago) and read 11344 times:

I have ran a search about this thingy last week, and it came off pretty well (Here in Tech/Ops). Basically, it is a barber pole thingy that, provided you have your takeoff runways localizer dialed, should guide you on keeping the centerline. The lines, it being barber pole, are moving in some way telling you in which direction to correct. It has been used for ex. on Tridents and is still present on some planes, I think there were some 757s mentioned and maybe SQ 747s.


The light at the end of tunnel turn out to be a lighted sing saying NO EXIT
User currently offlineTristarSteve From Sweden, joined Nov 2005, 3982 posts, RR: 34
Reply 2, posted (4 years 6 months 2 weeks 2 days 23 hours ago) and read 11328 times:

It was introduced on the Hs Trident for BEA for Cat3B autolands and lo viz takeoffs. It is a little rod that rotates in front of each pilot. It is very intuitive and if you follow it you follow the centreline. It is driven by the localiser, and only used on the ground. It has been fitted to all BEA and BA aircraft since, but I don't think anyone else has it?

User currently offlineKimon From , joined Dec 1969, posts, RR:
Reply 3, posted (4 years 6 months 2 weeks 2 days 23 hours ago) and read 11311 times:

Sounds like a good idea!
Why are not not all aircraft equiped with it?


User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 4, posted (4 years 6 months 2 weeks 2 days 20 hours ago) and read 11290 times:



Quoting Kimon (Reply 3):
Sounds like a good idea!
Why are not not all aircraft equiped with it?

That's like asking why aren't all aircraft equipped with autoland...lots of them don't need it.

The function that PVD provides is on most autoland aircraft, it's just not done with the barber pole thingy. You can get rollout guidance from a localizer display, the PFD, the HUD, possibly on the synthetic vision systems on many GA aircraft, etc.

Tom.


User currently offline411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 5, posted (4 years 6 months 2 weeks 2 days 18 hours ago) and read 11287 times:

PVD's were originally developed in the USA by the Collins Radio Corporation, and test flown on several aircraft, for both airbourne and ground use.
One was fitted to a Gulfstream One aircraft that was owned by the radio/television personality, Arthur Godfrey.

Further demand in the USA was not anticiapted, and the project was cancelled by Collins, for civil use.

If I recall correctly, the PVD's used on BEA/BA aircraft were originally developed by Smiths International....the same folks that designed the triplex autoland system used on the HS.121 Trident.
BA TriStar aircraft were also fitted with PVD's.
Worked very well, in service.


User currently offlineKimon From , joined Dec 1969, posts, RR:
Reply 6, posted (4 years 6 months 2 weeks 2 days 13 hours ago) and read 11258 times:

Qouting CX flyboy:

I do not know a lot about the PVD as none of Cathay's aircraft have them fitted. They are an option on certain airliners and an option Cathay has elected not to buy. As far as I know, it is a simple instrument showing the localizer signal relative to the aircraft position and used to identify that an aircraft has lined up on the correct runway by ensuring that the localizer signal of the ILS for that runway makes the instrument line up in the middle. Essentially it is a long strip and the localizer signal is a line on the strip. If the localizer is to the left of the strip it means the localizer is to the left of the aircraft and vice versa. If the aircraft is lined up on the correct runway then the strip should be in the middle.

All aircraft have the ability to tune the ILS and have it display on the PFD (Primary Flight Display - for modern aircraft) or on other instruments for older generation aircraft. I do not actualy see a need for a PVD other than the fact it is in your face more...but if you do a correct job of checking whether you are on the correct runway before you add thrust to depart, you can do this with the ILS instrumentation or the PVD. In SQ006's case, they used neither, even though the PVD would have been right infront of them staring them in the face.

http://www.airliners.net/photo/Catha...ays/Boeing-747-467(BCF)/1448902/L/

In this photo you can see the Cathay 747-400 cockpit. On the left hand side on top of the coming there is a magazine laying there. Just to the right of the magazine, built into the combing is a strip painted brown left to right. This is where the PVD would go, had Cathay opted for the option. The PVD slot is repeated on the First Officer's side.

http://www.airliners.net/photo/Singa...Airlines/Boeing-747-412/1189126/L/

Now look at the singapore airlines 747. You can see the brown strip is replaced by an actual instrument although it is not very clear in the photo. This is where the PVD is.


User currently offlineMandala499 From Indonesia, joined Aug 2001, 6769 posts, RR: 76
Reply 7, posted (4 years 6 months 2 weeks 2 days 8 hours ago) and read 11231 times:



Quoting Kimon (Reply 3):
Sounds like a good idea!
Why are not not all aircraft equiped with it?

Costs... not just in price, but it's another thing to maintain and monitor for the engineers... hence, running costs too (even if negligeable).

Additional costs for no additional value doesn't run well with the bean counters at the head office.

Do a row zero test and a row 5 test  biggrin 



When losing situational awareness, pray Cumulus Granitus isn't nearby !
User currently offlineTristarSteve From Sweden, joined Nov 2005, 3982 posts, RR: 34
Reply 8, posted (4 years 6 months 2 weeks 2 days 5 hours ago) and read 11212 times:

Quoting Tdscanuck (Reply 4):
You can get rollout guidance from a localizer display, the PFD, the HUD,

I believe the main reason for the PVD on the Trident was low visibility take offs. It was much more sensitive than a localiser display, and being on the glareshield you could see it while looking fwd.
You must remember that when the Trident was designed in the early 60s, it was foggy at LHR. In those days of Cat nothing, the airport was closed in November for days at a time. Then the British Government banned the use of coal in household fires (we started using coke instead) and the smog (smoke-fog) that blanketed London for days on end slowly disappeared. When the Trident Cat3 was finally in use, its reason for development had faded away.
I remember the choking yellow smog in around 1963. I had to walk along the kerbside with a torch wjile my dad drove behind me. I was there to make sure he didn't drive into a parked car. You don't see fog like that nowadays.
Anyway in the fog, with PVD, the Tridents were taking off from LHR when noone else was moving. They didn't need PVD for landing as they had full autoland with rollout steering (rudder channel).

The BEA/BA crews liked the PVD so much they fitted it to the BAC111, B757 B767 Tristar and B747 as well. It was a tiny little unit, and provided much safety on low viz take offs.

[Edited 2010-01-16 07:36:36]

User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 9, posted (4 years 6 months 2 weeks 2 days 2 hours ago) and read 11196 times:



Quoting TristarSteve (Reply 8):
I believe the main reason for the PVD on the Trident was low visibility take offs. It was much more sensitive than a localiser display, and being on the glareshield you could see it while looking fwd.

I suspect this function has been fully supplanted by the HUD today, which provides all these benefits plus at lot more other useful information.

Tom.


User currently offlineKimon From , joined Dec 1969, posts, RR:
Reply 10, posted (4 years 6 months 2 weeks 1 day 22 hours ago) and read 11176 times:

Tom,
You hit the nail on the head!
HUD is the king!
Kimon


User currently offlineHAWK21M From India, joined Jan 2001, 31667 posts, RR: 56
Reply 11, posted (4 years 6 months 2 weeks 1 day 11 hours ago) and read 11149 times:

Got this thru Email:-

The PVD instrument guides the pilot along the runway centreline during roll-out in poor visibility.

Guidance is provided by vertical white and black strips, which move to the left or right, according to the deviation from runway centreline.

The display uses liquid crystal and is within the pilot's field of view when looking outside. It is connected to the flight guidance system and to the flight warning computer of the aircraft, or equivalent sources. The system comprises the autoland warning and the picture generator.

regds
MEL.



Think of the brighter side!
User currently offlineKimon From , joined Dec 1969, posts, RR:
Reply 12, posted (4 years 5 months 3 weeks 6 days 7 hours ago) and read 10936 times:

PVD in action:
Download this http://www.asc.gov.tw/asc_en/downfil...=/asc_en/../downfile/SQ006_ENG.pdf
and go to page 182.


User currently offlineFaro From Egypt, joined Aug 2007, 1534 posts, RR: 0
Reply 13, posted (4 years 5 months 3 weeks 6 days 2 hours ago) and read 10877 times:

IIRC, all Airbus aircraft have it under the denomination "Runway" lateral guidance mode, little pole thingy that moves about at the bottom of the PFD on takeoff (and maybe rollout too).

Faro



The chalice not my son
User currently offlinekimon From , joined Dec 1969, posts, RR:
Reply 14, posted (4 years 5 months 3 weeks 3 days ago) and read 10738 times:

PVD in action:
http://www.aerowinx.com/html/gallery04.html


User currently offlinekimon From , joined Dec 1969, posts, RR:
Reply 15, posted (4 years 5 months 3 weeks 1 day ago) and read 10631 times:

Will PVD cease to exist and be supplanted by HUD?
I guess that PVD will no longer be available as optional on the 748?


User currently offlinekimon From , joined Dec 1969, posts, RR:
Reply 16, posted (4 years 5 months 1 week 1 day 10 hours ago) and read 10407 times:

FYI:All BA aircraft have PVD.
Even on 773-ER.


User currently offlinekimon From , joined Dec 1969, posts, RR:
Reply 17, posted (4 years 5 months 1 week 1 day 2 hours ago) and read 10357 times:

Has anyone ever seen PVD on an Airbus?
The para-visual display has been developed as optional equipment for the A320. Mounted on the glareshield, the instrument guides the pilot along the runway centreline during roll-out in poor visibility. Guidance is provided by vertical white and black strips, which move to the left or right, according to the deviation from runway centreline.The display uses liquid crystal and is within the pilot's field of view when looking outside. It is connected to the flight guidance system and to the flight warning computer of the aircraft, or equivalent sources. The system comprises the autoland warning and the picture generator.


User currently offlinekimon From , joined Dec 1969, posts, RR:
Reply 18, posted (4 years 5 months 1 week 4 hours ago) and read 10298 times:

Since all BA aircraft are equipped with PVD,the RVR minimum is 75 meters as opposed to others (non-PVD) which is 125 metres.

[Edited 2010-02-24 09:28:51]

User currently offlinekimon From , joined Dec 1969, posts, RR:
Reply 19, posted (4 years 4 months 3 weeks 4 days 7 hours ago) and read 10037 times:

The PVD requires the ILS for the take-off runway to be on and tuned. It will then give left/right corrections about the runway/ILS centreline. It follows that if the aircraft is not on the correct runway the PVD will not unshutter as the corrections are accurately given about the ILS centreline and not outside the narrow ILS beam.

User currently offlineFabo From Slovakia, joined Aug 2005, 1219 posts, RR: 1
Reply 20, posted (4 years 4 months 3 weeks 4 days 7 hours ago) and read 10023 times:

What the hell are you trolling about here, now via PMs too?


The light at the end of tunnel turn out to be a lighted sing saying NO EXIT
User currently offlinemandala499 From Indonesia, joined Aug 2001, 6769 posts, RR: 76
Reply 21, posted (4 years 4 months 3 weeks 4 days 6 hours ago) and read 10017 times:

Quoting Fabo (Reply 20):
What the hell are you trolling about here, now via PMs too?

LOL, U got that too???
Kimon, what's the point? why with the PMs too? We can read well and clearly over here in the forum.
No, I do not have any pictures or diagrams on the PVD's schematic... and I wonder why you seem to be obsessed witht he PVDs????

Mandala499



When losing situational awareness, pray Cumulus Granitus isn't nearby !
User currently offlinekimon From , joined Dec 1969, posts, RR:
Reply 22, posted (4 years 4 months 3 weeks 4 days 4 hours ago) and read 10006 times:

The four airlines which are PVD equipped are:BA,LH,SQ and QF.
If it were so useless,why did the above-mentioned bother having it?
Just multiply the cost of each PVD unit per total combined of the four fleets comes to nearly $1m!


User currently offlinemandala499 From Indonesia, joined Aug 2001, 6769 posts, RR: 76
Reply 23, posted (4 years 4 months 3 weeks 4 days 2 hours ago) and read 9998 times:

Quoting TristarSteve (Reply 2):
It was introduced on the Hs Trident for BEA for Cat3B autolands and lo viz takeoffs.

Just read that PVD was required for Cat3b landings on the Tristars...

Quoting kimon (Reply 18):
Since all BA aircraft are equipped with PVD,the RVR minimum is 75 meters as opposed to others (non-PVD) which is 125 metres.
Incorrect. Current types in service with PVDs are: 744, 777, 763ER with the 744s I think the only one that have the PVDs on both sides, the 767s and 777s only have it on captain's side. The A32Xs, 757s and the 737s don't have the PVDs... and when they had the Concorde, it didn't have the PVD.

Quoting kimon (Reply 22):
If it were so useless,why did the above-mentioned bother having it?

Who said it was useless? It comes down the cost-benefit analysis, probably for many airlines the PVD's cost benefit analysis is so marginal or negative they decided not to use it...

Let me elaborate on my reply #7:
An airline limited to Cat I ILS conditions for landing would have little benefit for the PVD... but airlines that have a lot of ops into airports that are prone to have Cat III conditions, may result in them better off having the PVD. Hence:

Quoting kimon (Reply 22):
The four airlines which are PVD equipped are:BA,LH,SQ and QF.

We can see that there are very few takers for the PVD in the world.
Qantas only has it on the 744s (not on their 742s/743s/74SPs), and the exBA 763 (I think they're deactivated on these). The original QF 767s don't have the PVDs, neither does any of their 737s (-300/400/800s, with the 800s having the HUD).

Lufthansa only has it on the 744s. They had them on the 340s, but had them taken out/removed by the time the A346 entered service. The A319s and A321 don't have them, yet, the 320s seems to have had them early on. All but the 744s, had the PVDs on the left side only it seems, when it was still fitted.

SQ only has it on the 744 passenger versions. None on the other types, including the 744Freighters.

So, very useful? I don't think so as the airlines that use them only has it on certain types.

Why have it?
Well, look at where the aircraft that have them operate? QF/BA/LH/SQ has it on their 744s... for good reason, the last thing they wanted when they had their 744s new, they didn't want to suffer from weather delays in Cat III conditions. Again, crew scheduling is a big reason for this as the 744 routes put them on the limits of the 2 crew duty limits.

BA can justify all their widebodies having the PVDs because their base, LHR, is extremely busy, and by the time they would arrive in LHR on a bad day, the alternates are probably already full. And any weather advantage they can get, is worth a lot of money for the company.

Qantas and SQ, only their 744s have the PVDs... I guess long haul ops into Europe has something to di with that... not surprising it's not fitted on the other aircraft... By the time the 380s arrived, they decided it was not worth having it on the 380 (perhaps an HUD was better to have).

For LH, again, why only the 320 on the narrowbody? Well, the 320 was the first Airbus narrowbody they operated, maybe they just wanted to try... it's not fitted on the 319s/321s. For the 744, again, same reason as stated for BA.... the last thing they want is crew scheduling nightmare because the viz is 100m instead of 125 (so the 75m minimum is useful). For the narrowbody, well, if the weather is so bad, chances are you're not going to get anywhere because the next destination is probably fog-bound too... plus, whilst a no big deal, why go out in less than landing minimums? You'll end up having to divert if something goes wrong after V1.

Again, for the narrowbody, I guess costs of keeping all the crew on Cat III (which is where the PVD would be useful for various reasons), just cost too much money.

But then... is it useless? No... if it was, they'd be phased out by now even by BA.

Qantas only has it on their 744s... and ex-BA 763s (the -336ERs).
767-338ER without PVD

View Large View Medium
Click here for bigger photo!

Photo © Charlie W Carter (EGTESkyGod)



767-336ER exBA with PVD slots (no info whether it's used or not)

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Click here for bigger photo!

Photo © Dmytro Myrnyy



LH A343 with PVD left side only?

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Click here for bigger photo!

Photo © Daniel Werner



And without:

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Click here for bigger photo!

Photo © Viktor Laszlo - Budapest Aviation Photography



A342 with PVD left side only?

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Click here for bigger photo!

Photo © Konstantin von Wedelstaedt



On the 777s in BA, the PVD is left side only.

View Large View Medium
Click here for bigger photo!

Photo © Tamas Kolos-Lakatos



Mandala499



When losing situational awareness, pray Cumulus Granitus isn't nearby !
User currently offlinekimon From , joined Dec 1969, posts, RR:
Reply 24, posted (4 years 4 months 3 weeks 4 days ago) and read 9974 times:

Thanks,Mandala499!
Excellent research!
Just one burning question:which aircraft have HUD which would finally supplant PVD once and for all?

[Edited 2010-03-08 13:19:00]

25 tdscanuck : HUD doesn't necessarily supplant PVD...it all depends on what functions are implemented on the HUD. That said, HUD's are an option on 737 and standar
26 Post contains images mandala499 : Since you mentioned the airlines, just go to the photo search engine, and look in the flightdeck photo category for the airlines and search for it an
27 b78710 : some of our 744's have them, some don't, so i'm guessing there isn't an SOP for them to be used
28 kimon : Are you with VT or BA? VT do not have PVD at all. 744F or PAX?
29 Pihero : And that's the problem. As far as I know, there is no HUD with a "Ground director", the picture is of the centerline and it's position relative to th
30 b78710 : neither passenger
31 kimon : All BA 744 and 773 are PVD equipped.
32 Post contains links kimon : http://www.pprune.org/engineers-tech...892-para-visual-display-query.html http://www.pprune.org/engineers-tech...9-para-visual-display-744-pvd.html
33 mandala499 : Here's something to keep you occupied: CX has provisions on their 744s for PVD, but the pics on a.net have yet to show one in use/active. (covered).
34 faro : A little confusion re Airbus's "Runway" lateral guidance mode on take-off: is this or is this not a PVD even if it's only shown on the PFD? Is it of t
35 kimon : Thanks,Mandala499! I shall start digging up the photos of the various airlines you mentioned. Just one point:my BA 773 captain confirims that PVD is o
36 Post contains images mandala499 : Yes, but not for regular passenger transport. Where I used PVD was however, not in regular passenger transport flying. We had custom made PVDs. It wa
37 kimon : Excellent!Wow most impressed with your customised PVD! This is what they should have updated it to include a vertical indicator! BA are the greatest f
38 mandala499 : Our PVDs did NOT have vertical indication... one of the reason why we switched to the portable eye-level display unit was to have the vertical indica
39 mandala499 : You'll also notice BA's older A320-211s with CFM engines have the PVD left side, the IAE engined A320-232s, don't nor the A319s/321s don't have PVDs e
40 kimon : Sorry,I could not find any BA 773 FD photos. Thanks for the BA 744. I noticed that on MH and CX that the PVDs have been removed and their slots insert
41 Post contains links tdscanuck : That's because British Airways only has 777-200's. http://active.boeing.com/commercial/...ageid=m25062&RequestTimeout=100000 Tom.
42 Post contains images mandala499 : Yeah, they've ordered the 773ERs, but not yet delivered... Anyone know when they're being delivered?
43 kimon : Did not realize that they had no 773!! How backward of them! No self-respecting fleet can be without 773! Well spotted! This is simply because of thei
44 Post contains images mandala499 : Actually, BA has operated non-RR powered aircraft in the past.... Their 772s consist of non-RR powered (GE-powered examples). Their old 320s (the -10
45 kimon : Touché, Mandala499! AF has 30 773s and 12 on order. I think one day BA will disappear as the vultures are already circling. Long gone are the halcyon
46 tdscanuck : Um...what? RR is pretty much on technology par with GE. Better in some things, worse in others (as is usually the case in aviation). I don't think so
47 Post contains images mandala499 : AF has been trying over the past 30 years to make CDG on par as hub with LHR... with AMS and FRA joining the fray, but LHR is still there as a desire
48 CX flyboy : Actually the most useful function of the GMCS is not to help with taxying, but when on the bay just prior to pushback to see whether you have a tug,
49 Post contains links Chamonix : Amazing PVD From 05:32 - 06:19 http://www.youtube.com/watch?v=BMydKAcqKCg&feature=related
50 Post contains links Chamonix : HS-748 fitted with 6 PVDs http://www.flickriver.com/photos/egbj/5359654355/
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