NTSB was able to get fuel samples from the engines......fuel was clean! #4 Engine suffered a Compressor Stall at rotate. #1 Engine had a turbine failure after being advanced to Emergency Thrust!
A couple of weeks later, the replacement plane also suffered a compressor stall at rotate. The Pratts don't seem to do well at high altitude runways. Any kind of air disturbance seems to cause the compressor stalls???