ModSum question by student

[youngeng]

I have no idea what a ModSum is. I am reading an AD an understand what an AD and SB are but do not understand how they are connected to a ModSum

Modsum 4-126330, Fuel Tank System Design Left and Right Side (SFAR 88) Retrofit. Approved instructions for the incorporation of Modsum 4-126330 are contained in Bombardier Service Bulletin (SB) 84-57-09 Revision B, dated 3 September 2008, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada

In this case what is a ModSum exactly? Is it just a list of instructions to follow and how is it connected with a SB and AD. I know that an SB is made because of an AD but do not understand anything about a ModSum

Thanks

[Mechta]

Modification Summary?

[Exup]

Modification Summary sounds like it could be right.
SB's do not come from AD's, lots of SB's are optional & have nothing to do with AD's, whereas AD's are Mandatory.

[tpng conehead]

Modification Summary. Its a list of all the modifications.

[Rigga]

SBs are issued by an OEM and are recommended actions required to maintain the airworthiness of a part, component, system or aircraft.
On being made aware of a safety concern, an Airworthiness Authority (FAA, CAA, EASA, etc.) may issue an AD mandating the implementation of an SB (or ASB), normally developed by an OEM, within a stipulated period.