AIR DRIVEN GENERATOR (ADG)

Question 1

WHEN WILL THE ADG AUTOMATICALLY DEPLOY?

Answer 1

The ADG will automatically deploy in the event of AC power loss and the aircraft is inflight (WOW).

Question 2

WHAT DOES THE ADG PROVIDE ELECTRICAL POWER TO?

Answer 2

AC electrical power is provided from the ADG to the ADG BUS which powers:
▪ AC ESS BUS
▪ HYD PUMP 3B (regardless of switch position)
▪ EICAS (voltage and frequency indications)

Question 3

IF THE ADG AUTO DEPLOYS, WHAT ADDITIONAL ACTIONS MUST BE DONE AND WHY?

Answer 3

In the event of an automatic deployment of the ADG, the manual deploy handle should still be pulled to allow the DC BATT BUS and DC ESS BUS to be powered through the ESS TRU 1. This allows the Captains Flight Instruments and Thrust Reversers to be powered in parallel with the MAIN and APU batteries after the A/C is on the ground (WOW).

Question 4

IF THE ADG FAILS TO DEPLOY, WHAT WILL POWER BE COMING FROM?

Answer 4

In the event the ADG fails to deploy automatically or manually the DC ESS BUS will be powered by the MAIN and APU batteries. HYD PUMP 3B will be inoperative on battery power.

Question 5

WHEN POWER IS RE ESTABLISHED AFTER THE ADG HAS BEEN DEPLOYED, WHAT MUST BE DONE?

Answer 5

After the deployment of the ADG, if the use of an ENG GEN or the APU GEN is reestablished, the POWER TXFR OVERIDE switch can be selected and will return the AC ESS BUS to the normal AC distribution system and HYD PUMP 3B will return to normal operation.