It's all quite simple.
I was personally told by three separate VP's at DAL about seven years ago, that....'we will never again purchase a four engine type and, if we buy or merge with another carrier that has four engine types, they will be sold as rapidly as possible, without disrupting scheduled service
And, we will never be in the freight business again.'
Now, as for Kalitta, we all remember this...
CHICAGO (AP) _ A cargo plane bound for New York's Kennedy International Airport landed safely at Detroit Metropolitan Airport after losing an engine somewhere over Michigan.
The Kalitta Air jet took off from O'Hare International Airport in Chicago late Wednesday. It later reported mechanical problems with one of its engines, a Federal Aviation Administration spokeswoman in Chicago said.
The Boeing 741-R was able to fly but was diverted as a safety precaution to Detroit, where it landed without incident, FAA officials said. No one was injured.
After the landing, airline personnel discovered the engine was completely gone, FAA officials said.