This excerpt taken from the PCG 10-K filed Feb 18, 2005.
4.4. Outage(IMS) Data Reporting
All Outages which interrupt the flow of power on PTO Transmission Facilities under the ISO's Operational Control shall be reported by the PTO to the ISO. Outage(IMS) reports shall include the date, start time, end time, affected Transmission Facility, and the probable cause of the Outage(IMS) if known.