The U.S. aircraft register, updated daily
Parts

Calibration Trim

No failure report names the calibration trim. 2 FAA approvals let 1 company make a replacement calibration trim, Smiths Industries/Aerospace holding the most (2).

Approved replacement parts 2 parts manufacturer approvals

A parts manufacturer approval (PMA) lets a company other than the aircraft's maker make a calibration trim and sell it as an approved part for the models named. These are the companies holding such approvals for a calibration trim:

For these models most: Boeing 747 (2).

MakerPartReplacesFitsGrantedStatus
Smiths Industries/AerospaceCalibration Trim Unit 4215-07Boeing 60B92017-5Boeing 747-100, -200, -3001992-05-27current
Smiths Industries/AerospaceCalibration Trim Unit 4215-08Boeing 60B92017-9Boeing 747-100, -200, -3001992-05-27current

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.