A320 Supplementary Procedure Question : ENG START WITH AIR START UNIT
 

Deal All

Kindly help me with this query

Question:
1. In the A320 Engine Start with Air Start Unit supplementary procedure, why does the procedure not require disconnecting external power after starting Engine 1 first, whereas if starting Engine 2 first, the procedure specifically instructs to disconnect external power?

2. What does solid circle and solid triangle mean in the supplementary procedure, I am not finding any reference to these symbols in the FCOM , kindly help me with a reference for these symbols

Thank you for taking time to answer
Regards

Hi overhead.
I have looked at the 6 FCOMs I have at my disposal and there are discrepancies.
One airline starts Eng 1 first and it quite clearly states to disconnect GPU after starting 1.
Some start engine 2 first and they say after first engine start to disconnect the GPU.
The Airbus FCOM implies starting eng 2 first and there it says to disconnect GPU after engine 2 started. What may be confusing is the next bit (with a solid square) where it says If the air start unit is used to start engine 1. This is if you are using ASU to start both engines in which case you have already disconnected the GPU (after eng 2) so no need to disconnect after Eng 1. The other option there (again with a solid square) is to use the x/bleed to start eng 1.

A bit rambling but hope it helps.
I will leave the symbol logic to someone on a higher pay grade.