Auxiliary Power Unit (APU)- How it Works and know all about its components- Airbus A320

[@maverickramos9805]

This is the BEST channel for CBT videos as you have merged all UPDATED CBT for controls & indications, normal, abnormals, basically important infos in one single video. Would be really nice if you can make videos for all systems and merge into one video for each system. 🙏

[@Valentin_MeL]

Very good and detailed guide. So during first start of the day it's better to press master pb, then check ecam page, if everything is normal and flap open and only then preess start pb, right? But is it ok during the emergency to just press Master pb, start pb and apu bleed without waiting any time?
And is it going to autoshut off if you missed Low oil pressure warning?

[@VirtualFlightTraining]

hi, during first start of the day on battery power only you must turn on the Apu master switch, pull the L40-CB, test the APU fire system and than turn on the start Pb.
With GPU connected to electrical system instead, you can turn the start switches pb on without waiting the FLAPS OPEN message. however, you have to wait about 3 seconds for the ECB to be power-up and self test.
in simple word, the starter motor only gets energized when the ECB gives the ok.
if you are interested in more details, you can take a look..

[@Valentin_MeL]

@@VirtualFlightTraining Hmm. It's strange. Why do i need to pull any CB's during a normal start? Pilots usually not autorized to pull any CB's unless it a procedure in ecam status or QRH.
i am only a sim pilot so far, so i may not know something but your request to pull a cb sounds strange to me.

[@VirtualFlightTraining]

@@Valentin_MeL I'll try to explain it in simple words.
as you say it may sound strange, but for safety reasons airbus has set up this procedure to eliminate any risk of an APU AUTO EXTINGUISHING EVENT.
In fact in AMM section 26-13 it says: On rear circuit-breaker panel 121VU, make sure that circuit breaker APU AUTO EXTIG GND TEST 30WF (L40) is open:
Do this to prevent an unwanted automatic fire-extinguisher discharge during the test.
this explains the 3-second fire test limit you hear for example in video tutorials, if you ever wondered why, this is the answer.
you've probably never seen this procedure, because so few people actually apply it, but both pilots and tech maintainers should.
I hope it is helpful to you, if you have any other doubts, you can contact me.😀

[@Valentin_MeL]

@@VirtualFlightTraining Ok, i will keep that in mind.

[@KramTurbine]

Thanks for this. Very informative

[@MadScientist267]

Yep. Finally got the lights on. Where's the 8 track?

[@nostalgeek2872]

When I was a kid, I thought that this was where planes pooped !😂😂

[@b43xoit]

Give temperature **differences** in Kelvin.