They made no such written agreement.
A new union based on some solid union principles is the best thing that happened to all US Airways pilots.
Actually, they did make a written agreement. I believe they have three written agreements binding them to the Nic.
Exactly what "union priciples" are you trying to justify. The wholesale theft of your fellow workers jobs, or the complete lack of representation of those same co-workers. Perhaps it is the maliscious attacks in the forms of RICO lawsuits, corrupt section 29 charges, section 19 filings.
There are very few x-boxers over here. The rest of us know scum when we see it. So usapa would be well advised to keep the "we are a principled goup of union scumbags trying desperately to reneg on agreements we do not want to honor" arguements restrained for their closed door meetings with their inept legal cousel.