[pullup]

Quite a difference as you say...
Has anyone ever heard of someone being “ injured” flying over a HIRTA site?

[nallen]

Interesting, gaz. Thanks. (It would appear that my Hinton circuits are in the clear, but tracking north along the M40 is now a risky business!)

[gaznav]

I’ve never heard of an injury from flying in a HIRTA but there are plenty of industrial injuries with folks working in the telecomms industry.

An engineer replaced a damaged feed horn of a microwave antenna, a 15-meter dish at an Earth Station of a television network, using a cherry picker. After finishing, he sent his technician to power up the transmitter, and attempted to lower the cherry picker down. The engine failed and the engineer was stuck next to the antenna, outside of its main lobe but well within the first sidelobe. The technician, unaware that the engineer was still close to the antenna, powered it up. The engineer was exposed to an intense microwave field for about three minutes, until the error was realized. There were no immediate symptoms; the next morning the engineer detected blood and solid matter in his urine, and visited a doctor, who found blood in his stool and massive bowel lesions. The engineer's medical problems lasted for many years.

Source: Microwave & Wireless Communications Technology, by Joseph J Carr (1996)



The sidelobes’ power can be 100s/1000s times lower power than the main lobe on a satellite parabolic antennna.

[ianfallon]

I’ve never heard of an injury from flying in a HIRTA but there are plenty of industrial injuries with folks working in the telecomms industry.

An engineer replaced a damaged feed horn of a microwave antenna, a 15-meter dish at an Earth Station of a television network, using a cherry picker. After finishing, he sent his technician to power up the transmitter, and attempted to lower the cherry picker down. The engine failed and the engineer was stuck next to the antenna, outside of its main lobe but well within the first sidelobe. The technician, unaware that the engineer was still close to the antenna, powered it up. The engineer was exposed to an intense microwave field for about three minutes, until the error was realized. There were no immediate symptoms; the next morning the engineer detected blood and solid matter in his urine, and visited a doctor, who found blood in his stool and massive bowel lesions. The engineer's medical problems lasted for many years.

Source: Microwave & Wireless Communications Technology, by Joseph J Carr (1996)



The sidelobes’ power can be 100s/1000s times lower power than the main lobe on a satellite parabolic antennna.

You’d need to know the power at Croughton and do the maths to see if this is even remotely comparable though. My gut feel is it isn’t as it would be orders of magnitude weaker but happy to be proved (mathematically!) wrong.

[ianfallon]

Does that military chart indicate any height info for those semi circles ?

[chevvron]

Following what Ianfallon and gaznav have said.
On my ATCO Cadet course we visited RAF Sopley. The radar there (not far from the old IBY VOR) was a Type 80 radiating 2.5 Mw peak power.
We were told that one day the scanner needed repainting so they stopped it in the quieter winter season (it only rotated at 4 rpm) and the painter, an Irishman, went up to paint it.
After 30 min or so, someone noticed the painter had taken his jacket and shirt off (middle of winter) and was working topless.
Then a horrible thought; they had stopped the scanner but had they switched off the transmitter?
It turned out they hadn't; the poor painter was literally cooked from inside out and died of his injuries.

[gaznav]

Does that military chart indicate any height info for those semi circles ?

The top height is for a fly by wire weaponised aircraft and so is not applicable to the type of flying we do - the actual figure is pretty high. For a lower susceptable aircraft it would be as low as ~1,100ft or so and the smallest semi-circle indicated on the chart.

But that is aircraft dependent and it is very specific - for example for a Rotax with electronic engine management/ignition then it would probably be larger. I also like to give these things a bit of a buffer, hence I don’t go closer than ~0.5nm and ~1,000ft from the North. I really don’t fancy damaging my pink body like Chevvron suggests!

If you want to be 100% safe stick to the CAA chart is my best advice but that is too big a buffer in my humble opinion.

Best

Gaz

PS. The power outputs remain classified and so the numbers have to be accepted at face value.

[Dave W]

There was an interesting off-topic discussion on HIRTAs, what they are and what they might affect, in a Red Tape thread a while ago. It adds a little to what's already been written here.

[David Viewing]

I'm usually pretty skeptical about RF interference with aircraft systems, let alone with the aircraft's occupants. However, routing N from Westcott up toward Birmingham the other day at 2500', the lovely Oxford radar became swamped with a repetitive low frequency buzz while approaching Bicester.

This noise came up on both boxes, and only on Oxford 127.75. When I advised the controller the (quite long) response was mostly unreadable, but I distinctly heard the word 'Croughton'. Other traffic on freq seemed to continue unaffected. Eventually approaching Banbury , Oxford became completely unreadable and I transmitted blind a freq change and left. The silence was like heaven!

Now of course this could equally be a fault in my aircraft, or some other cause. Probably should have MOR'd it, but put it out of mind until spotting this thread.

[TouringTuggy]

The Croughton folk told the gliding club years back that they don't really care about people flying over, but if you insist on orbiting overhead, remember that it's your gonads being irradiated. I think they were joking... (I often use -- and did today -- 27LH, skirting through Croughton to do so; same if using 33.)

A couple of guys based there came over for some gliding, and confirmed that they only receive at Croughton - so with nothing being transmitted it’s no issue flying through. Just as well as have been doing so for years...

[TouringTuggy]

Is the Sea Harrier still in the garden of the big house on that route from Croughton to Hinton?

Sadly, not seen in quite a while. It was ZD582 and on the Rowler Manor estate. The owner has quite a few farm buildings so it may be now inside?

It always hibernates, and comes out when the cookoos arrive.. or maybe it migrates with them!

[kanga]

..

A couple of guys based there came over for some gliding, and confirmed that they only receive at Croughton - so with nothing being transmitted it’s no issue flying through. Just as well as have been doing so for years...

there are (or used to be) some splendid antennae at Barford St John, too, but IIRC that's never been charted as a HIRTA

https://en.wikipedia.org/wiki/RAF_Barford_St_John

[Longfinal]

You need to compare your aircrafts HIRTA Rating with the published HIRTA Ratings in the RAF En Route Supplement (also known as the Red book).
Don’t have a HIRTA rating....thought so...no restriction then.
Least that’s the way it was....Much ado about nothing.

The Red Book (also known as BINA) is regrettably quite expensive. A much more detailed listing of HIRTAs is contained in the AIP (MIL) in the Low Flying section which is equally innaccesible to civil pilots.

The AIP(Mil) is available to all here https://www.aidu.mod.uk/aip/aipVolumes.html

[Dominie]

I thought we'd come to the forum decision a while back that it was best avoided if you have electronically armed bombs on board...

testing fuel for water religiously (like when the aircraft already flew and it hasnt been refuelled)

It's more likely to be leaky tank caps, so best checked after rainfall.

But it's also pointless if the aircraft HAS just been refuelled, as any water in suspension has not yet dropped out.

[gaznav]

You need to compare your aircrafts HIRTA Rating with the published HIRTA Ratings in the RAF En Route Supplement (also known as the Red book).
Don’t have a HIRTA rating....thought so...no restriction then.
Least that’s the way it was....Much ado about nothing.

The Red Book (also known as BINA) is regrettably quite expensive. A much more detailed listing of HIRTAs is contained in the AIP (MIL) in the Low Flying section which is equally innaccesible to civil pilots.

The AIP(Mil) is available to all here https://www.aidu.mod.uk/aip/aipVolumes.html

You need the UKMil Low Flying Handbook - I don’t think it’s available online as some of the HIRTA data is sensitive.