G1000 Supplemental Maintenance Manual Page 7-40Textron Nav III Series Revision 3190-02128-046. The PFD informs the operator if the installation has passed or failed the vibration test. Ifthe test fails, the specific measurements causing the failure are identified and associatednumeric values are displayed on the PFD.NOTEShould a failure occur, the technician may perform the Engine Run-up test upto 3 times successively before corrective action must be taken. If the test doesnot pass after three attempts, then the installation should not be consideredreliable until the source of the vibration problem is identified and remedied. Inthe event of repeated failure of the engine run-up test, record the values thatare reported to be out of range for future reference.The following are potential causes for failure of the engine run-up test:a) Vibration motion of GSU/GRS and/or GMU44 caused by neighboringequipment and/or supports.b) Mounting screws and other hardware for GSU/GRS and/or GMU44 notfirmly attached.c) GSU/GRS connector not firmly attached to unit.d) Cabling leading to GSU/GRS or GMU44 not firmly secured to supportingstructure.e) An engine / propeller that is significantly out of balance.7. Press the ENT key on the PFD to conclude this procedure, then the aircraft can be taxiedback and the engine can be shut down for final testing. Continue to Section 7.10.5.GSU/GRS/GMU TestStart the displays in normal mode. The ADAHRS/AHRS attitude and heading informationdisplayed should become valid within 1 minute of power-up as shown in Figure 7-7 if at leastone GPS receiver has a valid position. If GPS is unavailable, the ADAHRS/AHRS initializationmay take up to 2 minutes.
