• IVSI Notes:

  The source of vertical speed information to the IVSI is IRU #1 for the Captains IVSI and IRU #2 for the F/O’s IVSI. The IRU sends vertical speed data directly to the IVSI over a 429 digital data bus. Vertical speed information from the IRU’s to the IVSI’s is on-side only. There is no switching capability for VSI source information on classic aircraft.
  
  VSI Pointer

  1.An NCD or fail condition will cause the pointer to blank. If the IRU is OFF or in the ALIGN mode this will be a normal condition. If the IRU is in NAV or ATT the pointer should be in-view.
  
  VSI Flag

  There is an amber boxed VSI flag located in the lower right portion of the display. This flag will be in-view if:

  1.There in an NCD condition.
  
  2.The source data is failed.
  
  3.There is an indicator failure.
  
  Blanking Due To Overheat

  The TA/VSI is an LCD indicator and is sensitive to excessive heat. If the indicator does overheat it will cause the display to blank out.

  1.Check to ensure that the brightness adjustment is not in the full bright position. If it is turn the brightness down low and let the indicator cool down.
  
  2.Another thing that can cause this is excessive dust accumulation on the case of the indicator. Check for this as well.
  
  IVSI INFORMATION:

  

  
  Circuit Breakers:

  VSI #1: P18-2 = B6.

  VSI #2: P6-1 = C4.

  IRU 1 (AC): P18-2 = D4.

  IRU 1 (DC): P18-2 = D5.

  IRU 2 (DC): P6-1 = D11.

  IRU 2 (AC): P6-1 = D12.

  
  
  Applicable deferrals 34-40-01=Traffic Collision & Avoidance System.
  34-40-02=Combined(TA)&(RA) Dual Display Inop.
  "No MEL for VSI"

Training Only