This AD requires operators of Airbus Helicopters MBB‑BK 117 series fitted with Honeywell LTS101‑650B1 or LTS101‑750B1 engines (where those engines have been subject to Honeywell SB LTS 101B‑73‑10‑0127 Rev 2) to install wiring and associated hardware so an electronic engine overspeed controller can be incorporated, following Airbus Service Bulletin SB‑MBB‑BK 117‑90‑103 Rev 1. It is intended to prevent power turbine overspeed and uncontained engine failure; compliance is mandatory before further flight and must be done concurrent with Requirement 2 of AD/LTS/13 Amdt 1.