Back in 1991/92 I was part of a group that chartered a flight from DTW-FRA and FRA-DTW both summers. There were 2 separate flights for the group that traveled at different times in July. The aircraft was a Lufthansa 757-300.

All 4 flights on the return trip FRA-DTW all had to divert. The two I was on diverted to Montreal for fuel and the other two flights diverted to Iceland one year and then Montreal the next.

The 757-300 is a bit different then the 757-200 but I remember quite a few years back getting into a disagreement with a friend who said I was mistaken that I was on a 757 as it just not have the range to fly the route. So chances are likely that there will be significant issues running the CDG & AMS flights in the summer as well.

I think everyone here knows United(CO) is wrong for doing this. Maybe it will take a class action lawsuit to force them to do the right thing. Personally I think it is suicide for them to try this crap at IAD with the abundance of lawyers in the DC area.