First off the income will not be tax free. The US has a foreign earned income exclusion. If you stay out of the USA for a certain time, (used to be 330 of 360 days) it is about $80,000. You will have to pay tax on the rest unless your employer is going to pay it for you. (very unlikely). Tax implications are serious. You must file for the exclusion or lose it. Review expatriate tax law carefully before you make the decision. I did it for 2 years in Europe as an illegal alien and did so without paying local or US tax. My situation was dicey however. I would proceed with caution.

Secondly, I remember looking a chart of diseases. It was color coded to show regions of the world where certain diseases are a problem. The USA only had a few colors. India, however, had every color in the rainbow. Essentially, you are going to be exposed to everything over there. I've heard some guys say you will get very sick eventually. You better check it to the health services and insurance available.

Third thing. As an expat pilot you are only there because they need you. They don't really want you there. The second they don't need you is your last day. It doesn't matter what your "contract" says. You will not be able to enforce it. If you can live with that....Also be careful not to be a "scab." Labor over there (in Europe at least) can strike on a moments notice. If you fly during a strike the locals will not appreciate it. If you don't, your employer will not. This puts you in a difficult position.