The CA Spectrum Service Dashboard view will cover per Service under Information Tab - subview "Outage History" - then item "Recent Outages" a table showing the recent outage entries. Here the customer would like to see more information per Outage and related service health and how this service is affected for this outage.

Is it possible to add an extra column with the "Service" to show the "Location" causing this outage?

Sample:  Service will cover service entry named "Area51". 
Area51 (Type SM_Service) is composed of multiple Sub-Components of type SM_service .. and may be cascaded to additional sub-service components.
In a chain of relation this is i.e. Area511 <-> Runway007|Runway10|RunwayAlpha .. <-> UFOservice|HELIservice|JETservice|TAXIservice <-> Devices(*)

How to extend the "Recent Outage" for Area51 service table - to i.e. show that one single outage entry is related to   "Area511:Runway10:TAXIservice:DeviceA"
and the one other outage is related to  "Area51:RunwayAlpha:HELIservice:DeviceB".

The intention is, to then see from the Outage entry directly the full "location"/hierarchy for the affecting service chain which is responsible for this outage.

<Please see attached file for image>

This applies to all supported CA Spectrum platforms on all support host-platforms and to all current CA Spectrum releases.
 

This is currently not customizable - as there is no Service Location attribute supported by SM_Service ModelType. 
Adding a new column to the Recent Outage Table is not possible using XML change alone. This is because the outage table values are rendered using Java code. 
Please ask the customer to raise an enhancement request for this to create a renderer(code) function to read and compose this info.