The U.S. aircraft register, updated daily
Parts

Computer Altitude

No failure report names the computer altitude. 2 FAA approvals let 1 company make a replacement computer altitude, 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 computer altitude and sell it as an approved part for the models named. These are the companies holding such approvals for a computer altitude:

For these models most: Boeing 747 (2).

MakerPartReplacesFitsGrantedStatus
Smiths Industries/AerospaceComputer Altitude Alert 70-200-0960B40083-9Boeing 747-SP, -200B, -200F1999-06-23current
Smiths Industries/AerospaceComputer Altitude Alert 70-200-0860B40083-8Boeing 747-200B, -200C, -300 Series1999-06-23current

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.