A320 APU Fuel Pump
 

Hello guys,

my friend and I were have a discussion about whether the APU fuel pump is a DC pump or AC pump. The electrical schematic clearly shows that it is supplied by AC Ess Bus or the Static Inv Bus, therefore it has to be an AC pump. Just need a clarification on this.

On a side note, he also believes that a PFR which contains no ECAM warning but shows a long list of Fault messages does not require any corrective maintenance action. Do you guys agree?

Thanks!

You answered your question yourself, there is no pump in the aircraft thats dc, whether its a fuel pump or electrically driven hydraulic pump.
What your friend says is wrong, many defects generate fault messages without an ECAM warning, some fault messages are considered normal and negligible and mainly occure due to power transfers...etc and many of which are filtered out by the PFR filter.

Thanks for clearing up my doubts.

My friend has probably mistaken the 737s' DC operated APU fuel boost pump with the A320s'.

With regards to the negligible fault messages , how would you differentiate them from those that require corrective action if there are no ECAM warnings to correlate with?

Please advise if I have the following wrong:
1. ECAM warnings consist of Class 1 and 2 faults only. These are also primary and independent faults.
2. Failure messages consist of Class 1 and 2 faults only.
3. A PFR shows Class 1 and 2 faults only.
3. Class 3 faults can only be accessed on ground via the Avionics Status Page using the MCDU
4. Class 1 and 2 Failure messages and ECAM warnings can be accessed in flight via the Current Leg Report and Current Leg ECAM Report respectively using the MCDU
5. Only Class 2 faults are indicated under the Maintenance item of the ECAM Status Page which is only available on ground when both engines are stopped.

Cheers

Normally this info can be found in SIL 00-028.