Service Information Letter (SIL)
Letter sent by an aircraft, aircraft engine or aircraft component manufacturer detailing a maintenance improvement programme.

Service Level Agreement
A formal agreement, usually as part of a contract, between an operator and an external service provider, or in some cases, and internal service provider, that:
ƒ specifies, in measurable terms, the services the external provider is expected to perform;
ƒ becomes the basis for monitoring of the performance of the external service provider by the operator..

Service Literature
Service Literature includes all source documents (other than manufacturers' manuals and amendments thereto) detailing aircraft, engine, component and equipment modifications and/or inspections, and revisions thereto requiring review by engineering. They include;
ƒ Service Bulletins (SB) and other documentation from manufacturers and vendors;
ƒ company Engineering Requests (ER);
ƒ correspondence or other information requiring consideration for maintenance or modification cables (e.g. alert information from vendors);
ƒ NAA Orders and/or regulations detailing mandatory requirements;
ƒ data from any other sources (e.g. other airlines, foreign airworthiness authorities, country of manufacturer, customers)

Servicing
Maintenance carried out on an aircraft, aircraft engine or aircraft component. Equivalent Terms: Maintenance

Shift-Handover (Maintenance)
The handing over of the status of aircraft maintenance from one ‘finishing’ maintenance crew to the ‘starting’ crew to ensure continuity of maintenance. This usually accomplished by the use of a suitable Shift-handover Log Book or sheets with a system of acknowledgment.

Shipper’s Declaration of Dangerous Goods
A prescribed form signed by the person (shipper) who offers a shipment of dangerous goods for transport on an aircraft; such declaration indicates that the dangerous goods are fully and accurately described by their proper shipping names and that they are classified, packed, marked, labelled, and in proper condition for transport by air in accordance with the relevant regulations.