Precision Approach Radars

[cbrjock]

Hi Pete
Went to the other end today RWY 18, and yes there is the same PAR marks

Hi Ian,

thought so, not 100% sure but think they would've been painted on to mark the point of touchdown noted after the equipment had been calibrated for both ends of runway.

Pete

[canberra]

Hers some words which anyone whos worked in a military tower will remember " coming coming coming on on on on coming coming coming ". When 115/flight checkers turned up they would go out on to the runway with a theodolite and talk to the pilot and say whether or not he was on the glidepath. That was fortunately eventually done away with and they went over to what were called IRFIS lights. But it was serious pain in the posterior when the radar and ils were being calibrated, Gutersloh had the right idea and did it on a weekend.

[Dr_Bishop]

Argh the PAR, CR62... Fond memories indeed.

Nicknamed 'Sexy Fingers' by GRSF for sending Binbrook's PAR off the rails at least once a month. Belated apologises to any Ground Radar bods on this site!

Anyway, you are all looking at the wrong end, this is the business end:



I would be happy to talk you through how you do a talkdown, 1980's style!

[canberra]

Back in 93 Barkston got the PAR consoles from Wildenrath, it was part of the grand enhanced RLG status for the airfield. After a couple of weeks the consoles were taken away and the enhanced RLG plan was binned.

Now does anyone know where those consoles ended up? My guess is Henlow. But what would Henlow have done with them?

[jaydeeare]

I've read this Thread with great interest as I have installed and recovered quite a number of the old SLA 3C's.

This experience led to get my first job in Civvy Street with Cossor Electronics system testing the SLA 3C replacement, the CR 62 (Falconer).

Some of the pictures shown here of the CR62 I have actually worked on.

The Llanbedr system is of interest due to one of the antenna cabins (can't remember which one now) was returned to us because during its installation it got badly damaged after it got dropped!

I remember the whole team who worked on the CR62 at Harlow with a certain amount of fondness. Unfortunately, some have since passed away. The CR62 system I found to be exceptionally good and reliable.

I was part of the team that installed the SLA 3C and new tower at RAF Honington, and then system testing it's replacement the CR62 at Harlow. so at the time I was partially responsible for the PAR facility for Honington from 1975 until the removal of the CR62 in.....??? Quite an achievement(?)

Thanks for starting this Thread as it brought back quite a number of memories.

[cbrjock]

The CR62 system I found to be exceptionally good and reliable.

Can't argue with that, most enjoyable and interesting part of the fitters course at Locking IMHO.

[ChrisTheAncient]

A brief history of early PAR systems based on my experiences up until 1974.

The original talk-down/ground controlled approach (GCA)/Precision Approach Radar (PAR) as used in the UK was an American system designated MPN-1 (Mobile Pulse Navigation equipment) which combined a search radar and talk down radar facility built into a series of towable trailers. It was not used in the UK for very long as it was superseded by what was commonly (and mistakenly) called AN/CPN-4 (which was air transportable and held together with nuts and bolts. To avoid copyright problems… photo here… http://www.radarpages.co.uk/oral/jdiamond/jdiamond.htm
The derivative usually used by the RAF was AN/MPN-11 made by Gilfillan which was riveted together and had a different search radar aerial. Ditto about photographs… http://100thentrylocking.myfreeforum.org/sutra2396.php.

As can be seen, there was a radar truck with a search radar antenna on to top. The chimney was an aerial that scanned in a vertical plane to assess an aircraft’s position relative to the glidepath and the other ‘grey looking’ patch housed the azimuth antenna which scanned in a horizontal plane and assessed the aircraft’s position relative to the approach line.

Inside the radar truck were all the electronics gubbins to make it work and three controllers’ positions – each having a search display and a talk-down display…http://home.comcast.net/~k6df/radar.html.

Attached to the end of the radar truck was a power truck containing two diesels or one diesel and a rotary converter to turn UK 230V 50Hz into the 115V 60Hz required by the American equipment. This truck also contained the necessary HVAC systems for the ‘ops’ truck.

Inevitably, there was (at least) a rest truck and a workshop truck along with the GCA vehicles.

The convoy was usually parked on a specially-built hard standing at the side of the runway and not far from the touchdown point. A ‘loop’ road would usually be there as well between the runway and an adjacent taxiway (or cross runway) as the radar truck and conjoined power truck were virtually impossible to reverse! In the event of a runway change, the whole convoy would be towed to the alternative location and used a series of markers and cats’ eyes to ensure precise positioning.

As radar developed and Watch Towers became Air Traffic Control Towers, there were occasional retrofits to the MPN-11 that allowed the radar displays to be put in an Approach Control Room with remote control facilities of the radar included (not very common as far as I know).

As the gear was all American and was on a ‘lease lend’ contract, an alternative was needed!

The most common search radar used for GCA was the Cossor 787 which was replaced by the Plessey AR-1. The displays were installed in the Air Traffic Control Approach Control room.

The first PAR used was the PAR-3B (sorry, I can’t find a photo). This was a trailer-mounted rig about the size of an MPN-11 ‘ops’ truck that could be parked at an appropriate point at the side of the runway and moved in the event of a runway change. This was a bit of a sore point and some PAR-3Bs were actually turntable mounted to simplify matters.

Not very long after came the PAR-3C made by ST&C. This did have to be mounted on a turntable and so was, inevitably, mount mid-way to one side of the runway mid-point between the touchdown points. In form, design and manufacture, it was very like a garden shed with a fat chimney!... http://www.flightglobal.com/pdfarchi...0-%201787.html shows the one that was installed at Coltishall – but they all looked like that.

The radar display used relied on two display tubes: one for glidepath and one for approach line http://www.radarpages.co.uk/mob/nava...es/fig13_5.jpg The only picture that I can find of a console is at www.RAFBinbrook.co.uk (you need to register - and it is well worthwhile for airfield lovers - it must be the definitive site for Binbrook!) and it shows the Approach Control Room in Airfield - Airfield Buildings -The Tower. Looking from right to left, there is the CRDF/CADF console, two Plessey AR-1 control positions and, in the far, dim regions, the two PAR consoles used for final approach talk down.

I left the RAF in 1974 and, yes, things did change and new radar systems came into being - including the Cossor CR62 PAR - which can be in the post above from Dr_Bishop. As for those ‘mushrooms’... I know nothing!

I hope the above ramblings give an insight into the earlier days of GCA.

[cbrjock]

Interesting read there, ChrisTheAncient, and some useful links too thanks.

The first PAR used was the PAR-3B (sorry, I can’t find a photo). This was a trailer-mounted rig about the size of an MPN-11 ‘ops’ truck that could be parked at an appropriate point at the side of the runway and moved in the event of a runway change. This was a bit of a sore point and some PAR-3Bs were actually turntable mounted to simplify matters.

At Stanley there was both the 3B and trailer mounted CR62, don't know whether they actually got the latter to work tho', it didn't like the cold!!! If ever I find the rest of my Stanley pics of them I'll post them up.

Pete

[ChrisTheAncient]

Pete...

You're welcome. And perhaps one or two other people have a better insight as well, now.

[ChrisTheAncient]

I have, recently, written a 'book' about my life at RAF Binbrook during the 60's.

One chapter of the book was about life on an MPN-11 GCA which we had for a while when the Tower was undergoing a major refit. For those that like that sort of reading, I have attached that chapter.

The complete 'book' is too large to upload at over 100 pages (about 1Mb as a pdf file). But if you would like to read it (contains some adult themes), send me a pm with your email addy and I'll gladly send it to you.