• Single Channel Mach Trim Fault:

  If a single channel failure occurred, there is no annunciation until you push the System Status Annunciator panel assembly (recall). When you push the annunciator panel, these annunciations show:

  
  *MACH TRIM light illuminated.
  *System Status Annunicator (6-Pack) "FLT CONT" illuminated.
  *Both Master Caution Lights Illuminated.
  
  

  When you release the annunciator panel assembly, the MACH TRIM light goes out but the FLT CONT light and Master Caution lights stay on. Push either the left or right Master Caution light (reset) to reset all the annunciations.

  
  Single Channel Mach Trim Fail Possible Causes:

  Before replacing any component perform BITE if available. Go to DFCS/Fault Review/Current Status/Channal A&B/Mach Trim, or run library test 33.

  
  

  1.Flight Control Computer (FCC)

  
  

  2.Integrated Flight System Accessory Unit (IFSAU)

  
  
• Dual Channel Mach Trim Fault:

  If dual channel failure occurred, these annunciations show:

  
  *Mach Trim Light Illuminated
  *System Status Annunicator (6-Pack) "FLT CONT" illuminated.
  *Both Master Caution Lights Illuminated.
  
  Dual Channel Mach Trim Fail Possible Causes:

  Before replacing any component perform BITE if available. Go to DFCS/Fault Review/Current Status/Channal A&B/Mach Trim, or run library test 33.

  
  

  1.Mach Trim Actuator

  
  

  2.Integrated Flight System Accessory Unit (IFSAU)

  
  

  3.Flight Control Panel

  
  

  4.Wiring

  
  

  5.Flight Control Computer (FCC)

  
  Flight Contol Panel:

  

  
  

  

  
  Circuit Breakers:

  AFCS SYS A FCC (DC): P18-1 = D2.

  AFCS SYS B FCC (DC): P6-2 = B3.

  Mach Trim A (AC): P18-1 = E6.

  Mach Trim A (DC): P18-1 = E7.

  Mach Trim B (AC): P6-2 = B2.

  Mach Trim B (DC): P6-2 = B1.

  
  
  Applicable deferrals 22-5-01=Mach Trim System (Single Channel).
  22-5-02=Mach Trim System (Dual Channel)

Training Only