SPA.HOFO.155 Vibration health monitoring (VHM) system

GENERAL Any VHM system should meet all of the following criteria:

(a)VHM system capability The VHM system should measure vibration characteristics of rotating critical components during flight, using suitable vibration sensors, techniques, and recording equipment. The frequency and flight phases of data measurement should be established together with the type certificate holder (TCH) during the initial entry into service. In order to appropriately manage the generated data and focus upon significant issues, an alerting system should be established; this is normally automatic. Accordingly, alert generation processes should be developed to reliably advise maintenance personnel of the need to intervene and help determine what type of intervention is required.

(b)Approval of VHM installation The VHM system, which typically comprises vibration sensors and associated wiring, data acquisition and processing hardware, the means of downloading data from the helicopter, the ground-based system and all associated instructions for operation of the system, should be certified in accordance with CS-29 or equivalent, established by the Agency. Note: for applications that may also provide maintenance credit (see Federal Aviation Administration (FAA) Advisory Circular (AC) 29-2C Miscellaneous Guidance (MG) 15), the level of system integrity required may be higher.

(c)Operational procedures The operator should establish procedures to address all necessary VHM subjects.

(d)Training The operator should determine which staff will require VHM training, determine appropriate syllabi, and incorporate them into the operator’s initial and recurrent training programmes.

GENERAL Operators should utilise available international guidance material provided for the specification and design of VHM systems. Further guidance can be found in:

(a)CS 29.1465 Vibration health monitoring and associated AMC;

(b)Federal Aviation Administration (FAA) Advisory Circular (AC) 29-2C Miscellaneous Guidance (MG) 15 — Airworthiness Approval of Rotorcraft Health Usage Monitoring Systems (HUMSs); and

(c)United Kingdom Civil Aviation Authority (UK CAA) CAP 753 — Helicopter Vibration Health Monitoring.