AbstractAircraft maintenance outsourcing and offshoring is now prevalent in the airline industry. In the USA, the safety implications of this shift in work organisation have aroused serious concerns — concerns magnified by six serious incidents between 1995 and 2009. Subsequent investigations, audits and reviews of outsourced maintenance activities identified significant failures in regulatory oversight. However, the air safety enforcement agency — the Federal Aviation Administration — was slow to respond to these shortcomings, despite sustained criticism from other US government agencies responsible for transport safety and governance. This paper provides a case study of regulatory failure and the difficulty of reshaping regulatory regimes in the context of rapid changes to work organisation. It highlights challenges in regulating outsourcing and subcontracting — challenges not confined to the USA — as well as problems in reshaping enforcement regimes.