Foresee the 4-C’s when Maintaining NVIS-NVG Systems
AMT’s who work on aircraft configured with Night Vision Imaging Systems (NVIS)/ Night Vision Goggle (NVG) systems must have the ability to foresee Criticality, Currency, Configuration and Compatibility.
Criticality: NVIS are FAA approved for installation through Type Certificate Data Sheet (TCDS) or Supplemental Type Certificate Data (STC) processes. It is important to recognize the NVGs are appliances and are part of the overall NVIS even though not physically connected to the aircraft. NVGs compatible with installed NVIS lighting systems are identified in the flight manual supplement (FMS). The NVG manufacturer or an FAA certificated repair facility provides NVG maintenance documents with approved repair specifications.
Currency: Data currency and accuracy is imperative. Don’t overlook any data that may be associated with or related to system installation. Review, understand, and verify before working on NVIS equipped aircraft. A seemingly simple maintenance action could affect the NVIS system.
Configuration: This must be maintained at all times. Any changes to configuration must be supported by FAA approved data. Check, recheck and check again to confirm what you are about to work on will not alter system configuration. Even a minor maintenance action such as changing a light bulb could affect configuration. Check the approved data - all the data!
Compatibility: System compatibility is critical to maintain. Be cognizant of subsequent aircraft modifications. Field Approvals are not authorized for NVIS modifications. Remain wary of actions such as Airworthiness Directives and or Service Bulletins and confirm their compliance will not or did not alter system compatibility.
