On 10th. November 1997, the pilot, having completed a commercial flight earlier that morning, was requested by a member of the operators maintenance staff to carry out a local test flight on EI-BYJ, to confirm that the maximum and minimum autorotation RPM was set correctly, among other requirements.
His passenger, a qualified helicopter engineer, was on board to record various readings laid down in a document of eleven pages, entitled "Flight Test Schedule Ref. 125 Iss. 1 April 1991". The pilot and the engineer discussed the contents of this document in detail prior to take-off.
This particular flight was carried out prior to the commencement of the helicopters annual inspection, which was necessary for the renewal of its Certificate of Airworthiness (C of A). It was intended that any collective pitch control or cyclic control rigging adjustment would be carried out during this annual inspection.