Who are those guys?

[Alderney]

For over two years now (and maybe longer) a white Robinson R-44 has been regularly flying west across Heathfield Park, East Sussex at pretty low level, then doing a smart 180 on the edge of Heathfield town and hurtling off again to the east. Always the same manoeuvre.

It usually (but not always) happens on a Monday or Tuesday, and seems to be about every two weeks, but it might be weekly and I've just not always seen it. The earliest I've ever observed this is 0915 and the latest is 1820. On rare occasions it is substituted with a blue and white JetRanger. Sadly I'm never close enough to get a tail number.

I don't have a problem with it - it's interesting to watch, and sometimes my wife will draw my attention to it - but I'm really curious as to what's going on. Is it a cross-country exercise of some kind? It's much too fast for any survey purpose, I would have thought.

Most recent sighting Tue 11 Sept 2012 at 1135. Previous sighting Wed 29 Aug 2012 at 0955.

Can you solve a local mystery? Just who are those guys and what are they doing?

[Bravo73]

Possibly a pipeline/powerline survey aircraft, from HeliAir. The types they operate certainly fit the description.

[MBJ]

Bound to be gas pipeline. They have to be looked at every fortnight and the inspection software will require the aircraft to be within a couple hundred yards of the line at around 500ft AGL. The turn is probably the end of that particular spur.

[krypton_john]

So it's just a visual inspection - no scanning equipment involved?

[Alderney]

Sounds reasonable, thanks. No power lines round there as far as I know, but a buried pipeline is certainly a possibility. Can't see anything on Google Earth.

But what are they looking for? It flies pretty fast.

[Comms Boy]

In a prevoius life i was involved with investigating reports from the Aerial survey section of BG.
Basicaly any heavy plant parked anywhere near the NTS is potentialy a hazard.
These pipes are identified by Orange and white marker posts on road crossings.
The size of pipe can be up to 48 inch and run at up to 70Bar so any leak would be serious.

So if a Large tracked vehicle / digger suddenly turns up in a field near the NTS expect a visit.

regards
P

[Helinut]

The history of high pressure pipelines shows that the main source of major leaks comes from third party activity. Most of the other leak hazards can be monitored internally by pigs and similar.

Most of it is construction activity and similar. The pipeline company has wayleave contracts with the landowners, including"not disturb" clauses. Somehow these don't seem to protect the pipeline.

[onetrack]

Just Google "tractor gas pipeline explosion" and you'll notice some very nasty pipeline/machinery contact events in the results.
Even just mowing alongside pipeline easements is exceptionally hazardous, and more than one tractor operator/farmer has died in a ball of flame when he hit a pipeline valve hidden in the grass.
Pipeline owners get very nervous when any heavy construction or farm machinery approaches their pipelines, so they like to be proactive, and head 'em off at the pass.