The U.S. aircraft register, updated daily
Parts

To Warning

0 failure reports named the to warning in the last ten years, 25 since 1995. The reports call it "to warning", "to warning sw", "to warning unit".

Reports by year

0369126199512521999
Reports by year, as a table
reports
19956
199612
19975
19992

Sources: the FAA's service difficulty reports since 1995 (a report is a part that failed and was fixed, as filed by an airline, repair station or owner; the count shows reporting as much as reliability) and the parts manufacturer approvals in the FAA's Dynamic Regulatory System. The part name is the reporters' and the approval holders' own words, reduced to the first plain words so that spellings meet.