ELEC DC ESS FAULT

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▪︎This content is Not an official document and does not represent the views of Airbus or any other aviation authority.

▪︎The information provided may be incorrect or misinterpreted and should not be relied upon for decision-making. 

▪︎Always refer to official documents and consult with a qualified aviation professional before making any decisions based on the information provided in this blog post.

▪︎The information provided in this blog post is based on personal study and review.

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An electrical DC ESS fault ECAM can have various effects on aircraft, differing by model. Sometimes, this ECAM is launched on the simulator for practice purposes, helping to learn how to use the audio switching on the upper overhead panel.

 

 

Audio Switching selector on A320, ACP and RMP 3.

 

 

 

RMP and ACP 

Before we delve into the DC ELEC ESS bus fault, I used to think of the RMP and ACP as a single communication unit and didn't pay attention to their differences. However, it is essential to understand the difference between the RMP and ACP. 

The RMP (Radio Management Panel) and the ACP (Audio Control Panel) are, as the names indicate, actually separate components.

RMP and ACP

 

Each RMP can control any VHF transceiver. RMP1 and RMP2 are connected directly to all VHF transceivers, (whereas RMP3  is connected to them via RMP1 and RMP2).

RMPs are connected together so that each RMP is updated to the selections made on the other RMPs.

 

RMP (Radio Management Panel) is the device used to tune frequencies for radios like VHF1, VHF2, HF1, and others. The ACP (Audio Control Panel) is the device that manages audio communication, allowing the selection of various communication channels, adjusting volume, and managing transmissions and receptions from radios and interphone systems  .

 

RMP and ACP

 

In addition to this article, let's explain the difference between the RMP and ACP in the A320.

Except for HF devices, aircraft usually have VHF1 and VHF2. Pilots can tune VHF frequencies using the Radio Management Panel (RMP). The RMP allows pilots to select and adjust the desired communication frequencies. Through the Audio Control Panel (ACP), pilots can choose which communication equipment they are using. The ACP enables pilots to select and manage the audio sources for communication and navigation, deciding which radios to listen to and transmit on, as well as adjusting audio levels for each source. 

In summary, the RMP is used for tuning frequencies, while the ACP is used for managing audio and communication equipment.

 

For example, when there is a failure of RMP 1 + RMP 2, pilots can still use their ACP with RMP 3. Similarly, when there is an ACP 1 + ACP 2 failure, pilots can use ACP 3 with the audio switching selector and their RMP 1 or RMP 2.

 

In A320 aircraft, the failure status of a DC ESS BUS FAULT affecting RMPs and ACPs varies by aircraft.

 

 

ELEC DC ESS BUS FAULT ECAM

 

the autopilot (and autotrust) can be lost and pilots fly the aircraft first and after the ecam is genuine, commencing ecam action with selecting VHF 2 OR 3. since VHF 1 is inoperative. 

ELEC DC ESS BUS FAULT ECAM INOP SYSTEM (can differ by the aircraft)

 

Looking at the INOP system table, ACP 1, ACP 2, and RMP 1 are inoperative.

Since all ACPs on both the captain's side and the first officer's side are inoperative, to recover audio control ability, pilots use the audio control switch panel to select CAPT 3 or F/O 3.
RMP 2 is still operative. Audio switching enables the pilot to use their acoustic equipment and ACP 3 in case of ACP 1 or ACP 2 failure or both.

Acoustic equipment refers to the pilot's handmike and sidestick push-to-talk button.

 

In this ELEC DC ESS BUS FAULT ECAM, ACP 1 and ACP 2 will be lost, so the pilot can use audio switching to select CAPT 3 or F/O 3.

With ACP 1 and 2 lost, if the pilot switches audio control to CAPT 3, the captain can use his handmike and push-to-talk switch on his sidestick. He can select the external transmission key (VHF 2 or VHF 3) on the ACP 3 panel on the overhead panel.

However, the captain's side loudspeaker is also inoperative, so the first officer (F/O) cannot hear the radio communication since the F/O's side ACP is also inoperative. Switching to F/O 3 enables the F/O's ACP and F/O's side loudspeaker. In this case, the captain should continue to fly since the F/O would be handling communications. If switching audio control back to CAPT 3 is necessary, it will allow the F/O to fly, but without the speaker.

 

And since the RMP 1 is not available. flight crew needes to use RMP2(FO side) to tune the frequency.