Hi all,Just as I got home from work today I observed two sets of contrails in the sky, the eastern one was white and another a short distance west was black. They were far enough apart to not be the same aircraft, yet close enough to obviously be flying together.I live west of Baltimore, Maryland. Any ideas? I checked the news and nothing's going on. The aircraft would have been approximately 330 degrees at 16 miles from BWI. Tim Dobrowolsky

Did the contrails appear to be comming from both engines or just one?This has nothing to do with your question but I was just wondering.Looking at each engine right at the wing might show this. With your amasement as to what you saw, you might not be able to answer this. They fly by so fast. I once saw a DC8 landing at CYWG and one of the engines appeared not to be running right. We worked near the airprot so for an aircraft watcher like me, I had a little time to follow the flight. The right engine looking from behind had a white thin whispy white smoke eminating from it. None of the other three engines had this. Black usually means too much fuel.JimCYWG

Tim - I've seen contrail shadows that look as you described. The true contrails were white and the shadows of the same contrails below on a very thin cloud layer appear black (gray). That could be why they looked like they came from planes flying together and on the same course. Since the white set was to the east, was it the morning sun angle that produced what you saw? ---Cloudy---

take a look at this:http://www.airliners.net/open.file/313566/M/

No, I was coming home from work, and the sun was setting to the west. So I don't think it was a shadow. I looked at the link posted above, and it was nothing like that. This contrail was solid black. It's a shame I didn't have a camera handy.....As far as which engine it was coming from, I couldn't tell because both aircraft were pretty high up. I could barely see the aircraft themselves. I would guess that if it were an engine problem, perhaps it was the west (right) engine and it's shadow was blocking out the east (left) contrail. Because there was no white in the second contrail.Thanks for the ideas.