UBIT on Debt-Finance Property

[JAY21]

I working my way throug IRC 514 on debt-financed property but not sure if I'm understanding it correctly. Ignoring other reasons why a trustee should not invest in real property, if a qualified trust (plan) purchases real property (improved) and obtains a mortgage that meets the structural requirements of 514©(9) (i.e., fixed price, not depedent on future revenues, no lease-back, reasonable terms..etc..) is the rental income earned on the property subject to UBIT ? There are so many exclusions and exceptions in this code section I'm doubting if I understand it right.