In simple terms, the Green Time is the remaining usable operating life of an engine before a removal off-wing and transport to an overhaul shop for a Shop Visit (SV).
For those that are new to the aviation business, an operating airline will typically lease an engine for the duration of the SV in order to keep the aircraft flying or they may have a spare engine in their pool, the SV can take months.
Note: Green Time is NOT just a simple calculation of remaining utilisation (Flight Hours FH/ Flight Cycles FC) before it’s next SV. Several factors influence the amount of Green Time remaining:
· EGT Margin
· LLP Remaining Life
· Engine Condition (Borescope findings)
· Maintenance History
· AD compliance
These will be explained deeper on upcoming posts.
Green Time has a significant influence on the commercial value of an asset and is integral when it comes to asset decision making by the lessor and also by the very lucrative engine trading sector of aviation by companies like StandardAero, FTAI and SetnaiO.
On Technical Records reviews you will often come across wording “the LLP limitation becomes the determining factor”, the best way to explain this is to make the distinction between Green Time vs LLP Life.
· Green Time, is the estimated remaining operating time before next SV.
· LLP Life, is the remaining flight cycles on an internal part of the engine and before it reaches its mandatory retirement limit it must be replaced on an SV.
A real-life example would be, an engine has 5,000 hours of estimated Green Time based on performance but only 1,000 cycles remaining on a critical LLP, then the LLP limitation becomes the “determining factor”.
The IALTA, combined & discounted, Technical Lease Training Programme covers AD/SB reviews very well and we also have a dedicated Engines/Gear Course within the programme with reviews of LLP, Back-to-Birth, components review and much more.
The best-in-class course for Aircraft Engine Record reviews.