Start faults on A320 with CFM
 

Hello
I’ve been operating on Airbus with CFM almost a year now . Coming from A320 with IAE and having experienced a few start faults in actual operations ( and simulator ) I want to clarify some differences I saw in the FCOM on this issue. Here is the FCOM extract I want to clarify
It seems to me that the FCOM suggests that the FADEC will attempt several auto-cranks followed each time by a start attempt . This is definitely not how an IAE engine would behave ( IAE only displays and performes 1 Dry crank . There is no display of “New start in progress” ecam , nor have I seen one been attempted even without the ECAM saying so )

If you have seen it can you please comment on your experience?

I have operated both types of engine.
If the CFM autostart fails then it can perform up to 3 start attempts each with a dry crank in-between. The FADEC will perform this automatically reducing the fuel schedule in stages but using both ignitors.
The IAE is different as it would NOT perform another autostart after a start failure the ECAM will just display ENGINE MASTER (AFFECTED 1(2)) .......... OFF after it has performed an auto crank.
I hope that helps.

Thank you applecrumble . It answers exactly what I was looking for , for CFM

With regards to ENG crank, when a dry crank is required is it necessary to switch APU BLEED on? I am confused if the switch is in crank is that enough or does there need to be an air source like BLEED to turn the engine.

Thank you.

Yes you need APU BLEED or any other bleed source ( from other engine, Air Start Unit) you were using to start the engine at the first place.

Thank you, makes sense.