Home Apt Identifier: Code. Annual EFH Per Engine: Num. Hour/Cycle ratio: Ratio. Left Engine Right Engine Engine Serial Number: ESN. ESN. Current Engine Times: TSN. TSN. Time Since Last SV TSLSV. TSLSV. Current Engine Cycles: TSN. CSN. Cycles since Last SV CSLSV. CSLSV Company Generating invoice