About 15 minutes ago I heard then saw a large commercial 6 - 8 place helicopter (sorry do not know my copters but similar to military copters but quieter) passing by. At first thought it was following US-29 then as it broke off realized it was going south following the A&WP sub of CSX. The copter had a boom extending about 15 ft in front secured by a perpendicular pole attached to the copter underneath the cockpit and guy wires on each end of the pole ande to lower rear of copter. A cable fed from some kind of sensor on the end of the boom to the copter. In addition in front and extending above the tail rotor was another shorter boom that extended backwards at a 45 degree angle to the horizontal which also had some kind of sensor and cable attached to that boom. The altitude of the copter was approximately 200 ft above ground level (AGL).
Obviously some kind of engineering survey but what? MC - PDN any ideas?
My wierd mind conjures up the image of this strange looking chopper as being a remote control unit for operating several trains at once in a given territory by hovering over a rail line. A chopper pilot and one assistant could actually operate several trains remotely from the air relieveing the payroll of up to five train crews. That or they are looking for a lost quarter dropped off the hind end of a busness train by a young vice president.
Probably a LIDAR survey/ mapping of the R-O-W - laser or radar interrogating/ sweeping of the ground surface for very detailed and precise aerial mapping, at that altititude. The ‘guts’ of that equipment - cameras/ sensor platforms, lenses, computers, etc. would most likely be in a more protected position in the body of the chopper, and looking out through a port in the deck/ floor. I can’t imagine right now what would be in the sensors at the ends of the booms for mapping purposes - other than GPS position locating antennas, where they would be out from the interference in the direct path from the overhead satellites that might otherwise occur if they were under the main rotor. May be there are 2 for redundancy, a cross-check, and more accuracy ?
Most likely, as Paul says, a lidar survey for preliminary engineering purposes, planning or GIS.
If something else is going to be built, a photogrammetric or conventional survey will follow that meets national map accuracy standards.
(CSX adopted and rented UP’s Do-Maps PMV cars for their GIS, so it’s most likely not GIS. Also could be a utility survey for a fiber optic line on RR R/W.)
It specifically mentions ‘‘Railroad Mapping’’ as a ‘‘Project Application’’ about 1/3 of the way down the page, and says this about the GPS antennas: “The antenna is mounted on the tail fin of the helicopter to prevent any signal interference by the rotor system and to prevent multi-pathing of the GPS signal.”
But looking at the photos on their ‘‘Facilities and Aircraft’’ webpage, I didn’t see any indication of the front boom on any of the aircraft.
One other thing I omitted mentioning in my previous post - this is a crummy time of the year to be doing aerial mapping with any visible-light
The depiction sure looks like a double-track railroad - complete with overhead catenary frames ! - being mapped. The pods on the booms on the sides of the helicopter are labeled as the GPS receivers - the LIDAR gear is in a pod underneath on the belly.
Some further research and review indicates that some LIDAR systems and frequencies are capable of ‘seeing through’ and even characterizing vegetation, so perhaps my previous concern about that is not so big of a problem after all.
The problem with Lidar is (lack of) ground truthing and getting enough checks to verify the work.
(You literally can make pipes “jump out of the ground” with terrain models generated by the process while you are “tuning out” the vegitation ground clutter…)
Just because the engineer gets a coordinate from the data generated by Flimap, etc. doesn’t mean the data’s any good. BNSF has had it’s construction engineers get burned by this, more than once, trying to get a cheaper solution than conventional survey data or photogrammetry. The technology is still evolving and it still has hurdles to get over like meeting National Map Accuracy Standards. Too many civil engineers, especially recent grads,can’t tell you the difference between acuracy and precision, much less see the issues with Lidar. (Similar to the problem with people running around with $100 handheld GPS units thinking they don’t need surveyors anymore[D)])
(There are graduate civil engineers running around out there who never took a single basic route surveying course on the way to their degree[sigh] - ABET ought to be screaming foul!)
I was an aviation mechanic for the last thirty years of my career, and can say I’ve seen some pretty strange things attached to all sorts of aircraft.
The feds, and I’m including DEA, FBI, and many other agencies have cameras attached to their aircraft that are beyond the imagination of most of us, and it is kept as quiet as possible. The cameras attached to one DEA airplane I worked on could spot Marijuana and read license plates from 5,000 Ft above ground level.
Of course anything is possible. It may have been an aerial survey. OTOH, it may have been big brother scouring along the tracks for illegal activity. Just an observation from one who keeps those things flying.
You thinking it was security or monitoring for a special move - such as nuclear or radioactive materials - or haz-mats, maybe even chemical weapons such as to/ from the Anniston, Alabama Arsenal/ Army base ?
You guys have asked a lot of interesting questions and I will fill in as possible.
I am installing a new attic siding attic fan and was there when the copter was first heard. I went to the second floor pourch to observe the copter as I could tell it was going slow. (estimate about 20 Kts).
PDN’s picture of the Bell 206-L3 was similar to the copter but it was some what longer looking a lot like what we see in many war movies of soldiers going into battle.
It was painted a white color with some other rather commercial looking swirls etc not like any DEA or other black ops air craft I have seen.
I did not see a registration but was more interested in the layout. Naturally my camera was unavailable in my bedroom.
The sensor above and behind the tail rotor could have been a GPS antenna as I cannot keep up with all different kind of antennas. The front boom definitely was well forward of the rotor plane.
the guy wire system for the front boom suggested that the load on the end of the boom was more than an antenna, Also there may have been a guy wire from the top of the cockpit to the front boom but do not hold me to that observation. Maybe guy wires to hold the boom very steady?
Did not observe any type of camera under copter but do not rely on that observation.
8… Went back to my fan work and did hear a slow southbound train about 5 min after the copter but was not interested and then decided to post my observations.
The ROW is somewhat clear (worked 2 -3 years ago) as there is not much vegetation over the tracks now but it will need future clearing due to our southern pines starting to lean over the tracks again.