Trouble analysis of the flight control systems requires the same systematic approach as any other hydraulic system. In many instances, malfunctions are written off with incorrect corrective actions on the maintenance action form (MAF). The corrective action, Could Not Duplicate, or Replaced Suspected Component, often results in a repeat discrepancy or loss of the aircraft. Thoroughness in determining the cause of a malfunction cannot be overemphasized. Trouble analysis of the flight controls will require complete cooperation with other work centers that are involved in the operational checkouts. Most flight control systems have electrical input, as well as mechanical input from autopilot, automatic flight control systems, or stabilizing augmentation systems. Inputs occasionally cause erratic and/or misleading aircraft flight characteristics. Flight characteristics can be misinterpreted, and the resultant write-up in the aircraft discrepancy portion of the aircraft flight record book may be vague or misleading. To gain further insight regarding the vague discrepancy, the maintenance crew should question the pilot who experienced the malfunction.

Isolating the mechanical and hydraulic portion of the flight control system from systems that provide automatic input will serve to pinpoint the actual problem area. The MIM provides troubleshooting/ trouble analysis aids and appropriate schematics. The MIM allows for the systematic checking out of the system and associated components. In some MIMs these aids are general in nature and limited to the more common causes of failure. Several MIMs combine the operational checkout procedures with trouble analysis aids. Steps of the checkout procedures are performed in rigid sequence, and any discrepancy must be corrected before proceeding to the next step.

A thorough knowledge of the system involved and consistent use of the mechanical and hydraulic schematics will expedite the trouble analysis process. Excessive time required for troubleshooting should be documented on a separate VIDS/MAF. This will separate the actual repair time from troubleshooting time. Separate VIDS/MAFs provide more accurate input information to the Maintenance Data Reporting System.

When the malfunction has been determined and corrected, the complete system should be opera-tionally tested. Testing should occur in all modes of operation to verify system integrity. Quality assurance inspection during repair progression, testing, and of the end product is a must. When prescribed in the applicable periodic maintenance information cards, test flight requirements are mandatory. The test flight pilot is briefed by a qualified quality assurance representative regarding the nature of the discrepancy and corrective action taken.