Modifications & Supplemental Type Certificates (STC) – Aircraft Leasing / Lease Return
Modifications might well be carried out by a lessee during the aircraft lease; this can be a modification from the OEM (Original Equipment Manufacturer) holding the TC (Type Certificate) for that airframe such as Boeing, Airbus or the same applies for an engine OEM such as Pratt & Whitney for example.
When a modification is not from the Type Certificate holder, it is called an STC (Supplemental Type Certificates).
We would expect to see a list of incorporated modification’s noting it is important to review both the incorporated and removed modifications. On the report ensure that you consider ICA’s (Instructions for Continued Airworthiness) and check that the report where applicable details future work required with the threshold or remaining life until the works are required.
Even STC’s that are not in use can have current ICA’s and it is important to review these also.
Details provided on the report should include:
-Document reference / title & typically ATA reference.
-Date of incorporation.
-Status of the STC/Modification.
-What Repeat Inspections are associated.
-Hours and Cycles at implementation.
-Identification of affected component or specify aircraft.
-Any due dates for work required in future.
There are also many more considerations with the STC’s that would be reviewed; they can be a complex consideration and one where considerable time scale and cost can result if ICA or records are not present.
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