Originally Posted by
wolf539
Though rules of separation vary depending on the airspace in which a jetliner is flying, in general, air traffic controllers and pilots are required to maintain a horizontal distance of 5 nautical miles between 2 aircraft flying at the same altitude. For altitudes at and below 29,000 feet, vertical separation must be maintained at a minimum 1,000 feet. For altitudes above 29,000 feet vertical separation must be maintained at a minimum of 2,000 feet.
Actually this is incorrect. In 2005, the FAA instituted RVSM (Reduced Vertical Separation Minimums) over most of the country mandating increased airplane performance and decreasing minimum separation to a mere 1000 feet vertical. Most of the rest of the world with the exception of very remote oceans and parts of Russia currently use RVSM between FL290 and FL410.
Source:
http://www.faa.gov/about/office_org/.../enroute/rvsm/
Oh... PS... OP, welcome to Flyertalk. Not sure what your background is, but there's little-to-no chance of danger as both planes had
TCAS which would have automatically provided warnings and directions for both planes to follow had their respective flight paths encroached significantly on each other.