Ronald laments:<<<
my AC breaker (50AMPS)  trips as soon as I get airborne, taxing is not a problem, run up is ok too.
>>>

I suspect that my friend Dr. Katz is correct that there is insufficient cooling for the condenser causing higher overall system pressure leading to a higher pressure ratio and higher compressor current, tripping the breaker.

Other possibilities include:

Excessive freon charge, leading to a high system pressure.

Defective expansion valve.

Defective breaker.

Poor voltage regulation from the electrical system. High sustained RPM causes higher voltage leading to higher compressor current.

Undersized wiring causing a large voltage drop resulting in compressor stall.

Poor connection at the breaker leading to resistance heating and tripping at lower than rated current.

Low buss voltage caused by gear hydraulic pump (HPU) and AC compressor running simultaneously.

Or it could be something else...

Regards
Brent Regan