Aircraft Engines and Gearboxes
MetalSCAN
In-service aircraft bearing and gearbox component damage can progress to failure in 100’s or even 10’s of hours. Through the use of MetalSCAN, it is now possible to monitor the progression of this damage on-line and in-flight, and to provide multi-level warning to maintenance and operating staff before failure occurs.
Originally developed for the F22 Advanced Tactical Fighter engine, MetalSCAN is now available in versions for a range of aircraft applications, including both military and commercial applications. The product provides state-of-the-art engine and/or gearbox protection and health monitoring for many of the world’s most advanced aircraft including the F22 Raptor, F35 Joint Strike Fighter, Eurofighter Typhoon, Bombardier C Series, Mitsubishi Regional Jet (MRJ) and PC12 aircraft.
The MetalSCAN sensor is installed in the full flow of the lubrication system in a suitable location ahead of the system filter. The sensor’s signal conditioning electronics can be integrated directly into the engine control or monitoring unit or helicopter HUMS, or it can be implemented in a standalone configuration depending on the aircraft monitoring system architecture.
FilterCHECK
When the lubricated components of aircraft engines or gearboxes are damaged, debris enters into the lubrication system and is captured by the system filter. FilterCHECK unlocks that information contained in the filter to help operators identify specific damaged components within of their critical equipment.
FiterCHECK has been incorporated into several fixed and rotary wing aircraft maintenance programs. Used in conjunction with other health monitoring techniques, it has proven to be effective in identifying the on-set of critical component failures.
For example, the Pratt & Whitney J52 turbojet engines of the US Navy’s EA-6B aircraft were experiencing a serious in-flight shutdown problem. The root cause of this problem was traced to engine bearing damage. Since this damage could not be detected by traditional oil monitoring techniques, GasTOPS worked closely with the US Navy, the engine manufacturer and scientists from Joint Oil Analysis Program of the US Department of Defense to deploy FilterCHECK with qualified warning and alarm criteria based on the FilterCHECK analytical data. In the first six months of the program, the new filter debris analysis procedure identified six bearing damage events, preventing a potential in-flight shutdown from occurring in all six cases.
Integrated Health Monitoring
GasTOPS has worked closely with the Canadian Air Force to develop and execute an Integrated Health Monitoring (IHM) program for the CAF’s fleet of Sea King helicopters. Development of the program has followed a structured, reliability-centered approach whereby the root-causes of aircraft downtime are first identified, data collection and condition assessment procedures for specific failure modes are developed and defined, and these procedures are then qualified by a process of in-service data collection and analysis. The condition monitoring methods employed on the program include periodic vibration analysis, sampled fluids analysis, filter debris analysis and precision shaft alignment.
Specific problems addressed by the IHM program have included excessive engine and main gearbox vibration levels, secondary vibration-induced failures (e.g. engine mount cracking and seal leaks), engine bearing failures, nuisance chip lights, and main gearbox freewheel unit bearing failures. An integrated database is used to support the in-service data collection and analysis activities as well as the engineering effort to systematically develop, demonstrate and qualify new condition monitoring procedures.
Since its inception, the IHM program has made a significant positive impact on the availability of Sea King fleet and its operating costs, reducing both scheduled and unscheduled downtime. Specific benefits of the program to-date include:
- Improved time on wing for the main gearbox;
- Improved Mean Time Between Removal for the engines;
- Reduction in tail rotor drive shaft and intermediate gearbox installation times;
- Reduction in the number of maintenance flights as well as reduced man-hours and flying time for each such flight; and
- Elimination of the nuisance chip light problem.