DC System Malfunctions

Question 1

Based on these indications, what is the diagnosis?

Answer 1

A single tru failure

Question 2

Based on these indications, what is the diagnosis?

Answer 2

Dual TRU failure

Question 3

What considerations should you make in the event of a Dual TRU failure?

Answer 3

Recall that the battery should last approx 15 minutes.

To conserve power, consider turning off certain
DC equipment to reduce the battery drain, such as the MFDs, EEDs, UHF, EGI, VOR/ILS, etc.

Radio uses a lot of power, so use it sparingly by minimizing calls, using mic clicks, or brevity.

Consider configuring before loss of DC or turning
off the battery until on final (battery may not come back on line) — Otherwise, plan on alternate gear extension and a no flap landing (if not lowered before loss of DC power)

Notify controller to coordinate lost comm plan, etc… and/or get a chase aircraft if weather is a factor

Maintain VMC, expedite recovery, and land ASAP

Question 4

In the event of a Dual TRU failure, what should an immediate action be just prior to pulling out the checklist?

Answer 4

AAP Backup control mode knob - BOTH

Question 5

Based on these indications, what is the diagnosis?

Answer 5

RIght ESS bus failure

Key Indications:
Loss of both MFDs and EEDs
AOA indexer lights/displays fail
Loss of UHF radio and TACAN

Question 6

Based on these indications, what is the diagnosis?

Answer 6

Left ESS bus failure

Key Indications:
Loss of both UFCP
Loss of the VHF radio and VOR/ILS
Flap and speed brake are inop
Loss of standby ADI (in approx 9 min)