Flight trials have begun of a vibration monitoring system that has been developed by Meggitt subsidiary Vibro-Meter to address a long-standing issue of number four bearing failures on some CFM International CFM56 engines.
The system, known as the advanced aircraft vibration monitor (AAVM), was due to fly on a Lufthansa Boeing 737 last week as part of a three-month test programme also involving El Al and Qantas, and later Aloha Airlines and Continental Airlines.
Vibro-Meter president Richard Greaves says Continental is "committed" to fleetwide implementation on its Boeing 737s on completion of a successful test programme.
He adds that talks are under way with Airbus over possible application on the CFM56s powering its aircraft types.
The primary purpose of the AAVM is to predict failures so that operators and maintainers can better manage the overhaul programme or act at short notice to prevent failures if required.
The CFM56 bearing issue is currently addressed through airworthiness directives mandating an inspection and replacement programme, which was introduced following two in-service failures.
Meggitt says: "In its first application, the AAVM will run a complex algorithm developed by CFMI to give a progressive indication of a potential bearing failure."
The AAVM, which is a development of Meggitt's original universal engine vibration monitor (UEVM), uses "roving" sensors that can be placed in various locations on the engine.
The system has been certificated by the US Federal Aviation Administration on the 737 family and the flight-test programme is mainly intended to validate the software algorithm.
Meanwhile, Greaves says Meggitt, which provides vibration monitoring on both Airbus A380 engine types, is "quietly confident" that it will provide engine condition monitoring on the Boeing 7E7. It was made Boeing supplier of the year for the UEVM work.
KIERAN DALY / LONDON
Source: Flight International
