mystery aircraft

At night, from my 925-foot perch on the west rim of the Connecticut River Valley, I can see the headlights of planes lined up as they approach BDL from Long Island Sound to the south. Typically, I can simultaneously see the headlights of two planes, sometimes three planes, each separated by the requisite airspace that such maneuvers require.

Some nights they pass to the east of my location on a straight up the river valley approach to BDL. Other nights they veer to the west off that straight up the river valley approach and end up passing directly overhead on a roundabout approach to BDL. (When they fly overhead, they are so low that I can hear them lower their landing gear in preparation for landing.)

Last night, I took the Pies out for last call at 10:05 PM and I saw three planes lined up on their approach to BDL. As I waited for the dogs, the first two passed to my east on the straight up the river valley approach to BDL.

The third plane was different; its headlights were not what I typically see. Usually, I see only one large point of light per plane until the plane passes more closely. The third plane had two large points of light side-by-side connected by a lighted horizontal bar (see my accompanying drawing).

When I originally saw it, I assumed it was traveling toward me, like a pair of connected headlights, but then I realized it was traveling along the horizon and I was viewing it from its side with one globe of light at its front end and the other globe of light at its rear end.

It flew along my horizon starting at approximately my south-southeast, moved west and then north, the whole time remaining about 40 degrees above my horizon. I lost it in the trees to my north-northwest.

The craft was too far away to see anything but its lights. Its speed was typical for the airliners I usually see.

There were one or two other distant planes in the area at the time and they were so distant that I could not tell which direction the faint jet engine sound I heard was coming from, i.e., from the mystery craft or the other distant planes.

Early on, I thought it might be a helicopter because it looked so unusual, but even at a distance, helicopters have an unmistakable sound and I did not hear that when I saw the mystery craft.

I am stumped as to what I saw last night. Any solutions to the mystery would be appreciated.