Just because you have been involved in an accident and suffer PTSD as a result doesn't give anyone the 'right' to sue for compensation.
PTSD is indeed a terrible thing to have to go through...but it is just a way for the human body and mind to 'cope' with the ordeal. A bit like 'pain' and 'shock.'
Someone could sue for a third party causing these syptoms, through negligence or intent but does that really apply in this case? I can't see any way that US Airways could have averted this accident, it is just a risk of flying.
Some people seem to be just money orientated....
