The SSIP (SSID) for the Cessna 152 airplane is based on the affected Model 152 airplane current usage, testing and inspection methods.
A practical state of-the-art inspection program is established for each Principle Structural Element (PSE).
A PSE is that structure whose failure, if it remained undetected, could lead to the loss of the airplane. Selection of a PSE is influenced by the susceptibility of a structural area, part or element to fatigue, corrosion, stress corrosion or accidental damage.
The inspection program consists of the current structural maintenance inspection, plus supplemental inspections, as required, for continued airworthiness of the airplane as years of service are accumulated.
The current inspection program is considered to be adequate in detecting corrosion and accidental damage.
The emphasis of the SSIP is to detect fatigue damage whose probability increases with time.
Since fatigue damage increases at an increasing rate with increasing crack length, earlier detection and repair minimizes the damage and the magnitude of the repair.
The SSIP is valid for Model 152 airplanes with less than 30,000 flight hours. Beyond this, continued airworthiness of the airplane can no longer be assured. Retirement of this airframe is recommended when 30,000 flight hours has been accumulated.
The function of the SSIP is to find damage from fatigue, overload or corrosion through the use of the Nondestructive Inspections (NDI) and visual inspections.
This Supplemental Inspection Document (SID) is only for primary and secondary airframe components. Engine, electrical items and primary and secondary systems are not included in this document. A list is included to show the requirements for the SID program for primary and secondary airframe components.
(a) The airplane has been maintained in accordance with Cessna's recommendations or the equivalent.
(b) If the SID is for a specific part or component, you must examine and evaluate the surrounding area of the parts and equipment. If problems are found outside these areas, report them to Cessna Aircraft Company on a reporting form. Changes can then be made to SID program, if necessary.
(c) The inspections presented in the SID apply to all Model 152 airplanes. The inspection intervals presented are for unmodified airplanes. Airplanes that have been modified to alter the airplane's design, gross weight or performance may need to be inspected more frequently. Examples of common STCs, which will require modified inspection intervals, include non-Cessna wing extensions, winglets, speed brakes, STOL conversions, vortex generators, tip tanks, under wing tanks and nonstandard engines. The owner and/or maintenance organization should contact the STC holder(s) or modification originator for obtaining new FAA-approved inspection criteria.
(2) A Corrosion Prevention and Control Program (CPCP) should be established for each airplane.