Monitoring of foreign objects ingested into the intake of a gas turbine aero-engine

Due to the high cost of Foreign Object Damage (FOD) and the associated risk to flight safety, there is a requirement for technology which can reliably monitor foreign object ingestion and subsequent damage. Such a system would reduce inspection demands whilst improving safety. It would also permit tracking of FOD events, providing information on when FOD occurs, thereby allowing solutions to be found or the hazard avoided. Stewart Hughes Limited has developed two systems which monitor debris in the gas path of jet engines and gas turbines. The Ingested Debris Monitoring System (IDMS) monitors debris ingested into the intake of the engine; the Engine Distress Monitoring System (EDMS) monitors debris produced by engine gas path component faults. Both systems detect the electrostatic charge associated with the airborne debris. By correlating IDMS and EDMS data, the effect of the ingested material on the engine can be assessed. IDMS and EDMS were installed on a Rolls-Royce Spey Mk 101 aero-engine during a trial conducted at DTEO, Shoeburyness. The main objective of the trial was to develop and demonstrate a technology capable of discriminating ingested debris types. A further objective was to determine whether actual damage caused by the ingested debris could be detected. The engine tests included the controlled seeding of debris, both damaging and non-damaging, into the engine intake. This paper describes the capability of IDMS to detect ingested foreign objects and integration of IDMS and EDMS data to successfully fulfil the trial requirements.