this incident happened a long time ago.

we witnessed a ufo come above a army reserve helicopter.  I didn't focus so much on the ufo as the cone shaped green light that slowly came from the ufo to envelope the huhie helicopter, and not any further.  
i know what kind of helicopter as one of the witnesses was a door gunner in veitnam.  we could see the people in the helicopter looking up at the ufo.  learned later it was a flight from revenia to cleveland.  the helicopter dropped very fast along with the green light.  
my friend told me that the helicopter could not drop that fast even if it lost power as the pilot would pitch the blades to slow the descent.  
the helicopter the ascended very fast to original altitude.  the green light then ascended slowly bank to the ufo. the ufo then was gone in a blink of the eye.  
I have herd of only one other case of this green light.  my biggest question is, if light can be slowed down doesn't it follow that it can be made to go faster up?  ((name deleted))
I believe that the witness alludes below to the well-known Coyne case, which occurred in early October 1973.  We believe that the helicopter first ascended, and then descended, the opposite of what the person indicates below.  PD