The U.S. aircraft register, updated daily
Parts

Air Only

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

For these models most: Cessna S550 (2), Cessna 560 Citation V, Ultra, Encore and Excel (2), Cessna 550 Citation II (2), Cessna 501 Citation I/SP (2), Beechcraft B200 King Air B200 (2), Beechcraft A200 (2), Beechcraft 200 King Air 200 (2).

MakerPartReplacesFitsGrantedStatus
Aircell INCAir Only Transceiver assembly with Data Module 900001-4Beech Raytheon) (200, A200C, 200C1996-10-31current
Aircell INCAir Only Transceiver asembly without Data Module 900001-3Beech Raytheon) (200, A200C, 200C1996-10-31current

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.