When will a retired [email protected] page drop out of search results?

Search, Crawl and Indexing of retired pages

Our [email protected] page retirement process puts pages behind authentication, causing the web server to return a 403 error to search crawlers.
After a document has been indexed, a 403 error does not result in immediate removal from the search index.
Retired pages are likely to drop from the search index in less than 12 days.
 
Details:

 

A page will be dropped after the search crawlers receive a 403 error on four consecutive attempts to retrieve the page.
For the Google Search Appliance, used for [email protected] searches and University of Minnesota search, a page may take approximately one month to drop from the search index, following the pattern described in this Google Search Appliance documentation:
Scenario
Recrawl Attempts
Document Removal from the Index

The search appliance encounters an error during crawling that could be a server timeout error (500 error code) or forbidden (403 errors).

First recrawl attempt: 1 Day
Second recrawl attempt: 3 Days
Third recrawl attempt: 1 Week
Fourth recrawl attempt: 3 Weeks

The document is removed if the search appliance encounters the error for the fourth time.