The Importance of Engine Preservation

September 20, 2016

If you are not flying your aircraft at least once every sixty days, following proper engine preservation procedures is essential to avoid significant and unnecessary maintenance expenditures on your TFE731 engine. 

Details for engine preservation are found in the TFE731 LMM, Ch 72-00-00/Servicing/Preservation, but Honeywell has recently made changes to the procedures in the form of Temporary Revisions.  These changes now require an installed TFE731 engine to be run every sixty days.  In addition, after one hundred and eighty days of non-operation, the oil must be drained and replaced. Honeywell no longer requires the fuel system to be preserved.

One of the simplest ways to avoid any costly maintenance associated with improper storage is to run the engine every sixty days. Importantly, these actions need to be documented in your logbook similar to all other flight and maintenance activity.

When an engine has not been run in 60 days, but less than 180 days, a SOAP analysis for water content will determine if the operator can continue the 60-day run process, or if the engine must undergo a complete teardown to inspect for damage, inclusive of the oil pump and all mainline bearings. 

If the 180 day interval is exceeded, an additional fuel analysis is required that could result in a complete engine teardown and overhaul of the fuel system components. This potentially expensive work scope (and any resulting repairs, shipping and engine removal/re-installation) is not covered by MSP, or any other engine maintenance program.   

Engine preservation is one of the most important preventative measures to control unnecessary maintenance expense – the effort it takes to follow the correct procedures will save you time, money and headaches in the long-run.