Duncan Aviation advises that all operators of Honeywell engines that do not run them frequently and want to keep them off the Damaged Engine List should spool them to N1 rotation speed once a month and make a logbook entry. Duncan also said engines dormant longer than six months require fuel system preservation. “Because of the depressed economy, many flight departments are reducing aircraft utilization,” Mike Bernholtz, turbine engine service sales rep, said. “We’ve seen an increase in the number operators who are experiencing the effects of long-term storage of their TFE731 engines when proper preservation procedures have not been followed.” According to Bernholtz, a typical repair for an unpreserved engine is a complete teardown to inspect mainline bearings, and the exchange of the fuel pump, fuel control, fuel manifolds and oil pump, as well as the replacement of all accessory/transfer gearbox bearings. “There are additional costs associated with this type of work scope, including other squawks found at disassembly, engine changes and shipping,” he added. “These are very costly repairs that engine programs such as MSP or JSSI will not pay for. The time and money it takes to follow the proper preventative procedures is well worth the effort.”