Is it true that a US citizen who works outside the country avoids paying all US taxes but has to be outside the country a certain length of time in order to avoid paying them?

IRS Code Section 911: If you live and work out of the country for over 1 year, the earnings fro that employment, up to about $82,000 are exempt. Certan other benefits, like employer housing that may otherwise be considered income, are excluded to. Hence, most oversea's contracts run 13 months.