STC SA4-21
FAA DRS lists SA4-21 as Current · Reissued, held by Staggerwing Museum Foundation Inc., for Hawker Beechcraft Army AT-11 and Hawker Beechcraft C18S. Recorded change: Fuel system modified to provide dual wobble pumps and suction crossfeed and attendant plumbing. Snapshot dated June 30, 2026.
Recorded modification
What the FAA record covers
SA4-21 identifies the approval, recorded holder, named aircraft, and modification scope. It does not confirm kit availability, serial-number effectivity, data rights, price, or installation authority.
Applicability
Aircraft named in FAA DRS
Named aircraft: Hawker Beechcraft Army AT-11 and Hawker Beechcraft C18S. Confirm the approved model list, serial effectivity, configuration, and certificate revision.
Buyer checks
Confirm before sourcing
Related fuel systems STCs
Fabrication of Onboard Systems Model 200-299-00 Fuel Drain Guard Kit in accordance with Federal Aviation Administration (FAA) approved Onboard Systems Master Drawing List No. 155-111-00, Rev. 6, dated March 11, 2011, or later FAA-approved revision and Installation of the Fuel Drain Guard Kit.
FAA holder: Onboard Systems International LLC
Fabrication and installation of an external aerial liquid dispensing tank.
FAA holder: Carson Helicopters Inc
Installation of Airframe-Mounted Fuel Filter.
FAA holder: Airbus Helicopters Canada Limited