Commercial: Engine Prognostics.

By Vicki P. McConnell

Aircraft operators and OEMs are demanding smarter sensors to monitor turbine engine performance

From sensors to software, enhanced elements in turbine engine health monitoring and management systems (EHMS) are well worth their Krugerrand weight for providing faster, more detailed engine lifetime prediction.

In the "time is money" canon by which turbine aircraft engines are designed and operated, the ultimate equation seeks optimum on-wing time and minimum maintenance, repair and overhaul (MRO) down time. That makes the requirements for engine monitoring systems simple: first, collect data from engine operations (primarily through sensors) that can be accessed for MRO and warranty action.

Next, do so preferably well ahead of costly component failure and with the ability to distinguish false-positive or acceptable exceedances to avoid unnecessary LRU replacement or engine tear downs (through diagnostic/prognostic software tools). The system technology for achieving this performance, and indeed more sophisticated predictive capability, is anything but simple. Even the identifying language for such systems is changing.

Among alternative semantics to EHMS are: engine monitoring systems (EMS), engine performance monitoring (EPM), engine condition monitoring (ECM), health and usage monitoring system (HUMS), engine health management systems (EHMS), as specified in the revision this May of the ARP1587 specification from the international Society of Automotive Engineers' Aerospace division, and model- based prognostics and health monitoring (PHM). For the purposes of this article, EHMS suits.

Along with shifting semantics are the increased levels of engine operating performance information desired by OEMs and their customers. In fact, contemporary EHMS architecture is about as complex as the aircraft's full architecture, whether rotary or fixed wing, military or commercial.

GE Aviation's 75,000-pound takeoff thrust GEnx turbofan will power the new Boeing 787 Dreamliner and the 747-8 Intercontinental and …