RVSM Maintenance Best Practices
Sofema Aviation Services www.sassofia.com looks at RVSM Maintenance Best Practices. The maintenance Program should contain the maintenance practices outlined in both the applicable aircraft maintenance Manual (|AMM) and Component Maintenance Manual (CMM) for each Aircraft Type
The following items serve as an example and should be reviewed for compliance in respect of RVSM approval and we typically be required as part of an approved maintenance program
All RVSM equipment should be maintained in accordance with the component manufacturer’s maintenance requirements and the performance requirements outlined in the approved data package.
Any modification, repair, or design change which in any way alters the initial RVSM approval, should be subject to a design review by persons approved by the approving authority.
Any maintenance practices which may affect the continuing RVSM approval integrity, e.g., the alignment of pitot/static probes, dents, or deformation around static plates, should be referred to the approving authority or persons delegated by the authority.
Built-in Test Equipment (BITE) testing is not an acceptable basis for system calibrations, (unless it is shown to be acceptable by the airframe manufacturer with the approval authorities agreement) and should only be used for fault isolation and troubleshooting purposes.
Some aircraft manufacturers have determined that the removal and replacement of components utilizing quick disconnects and associated fittings, when properly connected, will not require a leak check. While this approach may allow the aircraft to meet static system certification standards when properly connected, it does not always ensure the integrity of the fittings and connectors, nor does it confirm system integrity during component replacement and reconnections. Therefore, a system leak check should be accomplished any time a quick disconnect static line is broken.
Airframe and static systems should be maintained in accordance with the airframe manufacturer’s inspection standards and procedures.
To ensure the proper maintenance of airframe geometry for proper surface contours and the mitigation of altimetry system error, surface measurements or skin waviness checks should be made if needed to ensure adherence to the airframe manufacturer’s RVSM tolerances.
These tests and inspections should be performed as established by the airframe manufacturer. These checks should also be performed following repairs, or alterations having an effect of airframe surface and airflow.
The maintenance and inspection program for the autopilot should ensure continued accuracy and integrity of the automatic altitude control system to meet the height keeping standards for RVSM operations.
This requirement will typically be satisfied with equipment inspections and serviceability checks.
(ix) Where the performance of existing equipment is demonstrated as being satisfactory for RVSM approval, it should be verified that the existing maintenance practices are also consistent with continued RVSM approval integrity.
Examples of these are:
Automatic altitude control system
ATC altitude reporting equipment (transponders 14 CFR 91.215)
Maintenance Practices for Noncompliant Aircraft.
Those aircraft positively identified as exhibiting height-keeping performance errors which require investigation should not be operated in airspace where RVSM is applied until the following actions have been taken:
The failure or malfunction is confirmed and isolated by maintenance action and,
Corrective action is carried out as required to comply with RVSM requirements and duly verified to ensure RVSM approval integrity.