Dear Hetfield and Tubby Linton,
Thank you both for your quick response. I really appreciated. I did not know that the pack valves would be closed with ENG start selector in CONT RELIGHT position.
During normal ENG start, HP Bleed valves are in AUTO position, and controlled OPEN (FCOM1-16-20, p5/6). Clearly, as you stated, Tubby Linton, by closing HP Bleed valve on the affected side it must “help to regulate the airflow demand within the engine.” I don’t mean to be a nit picky, folks, but I want to know how the closed HP valve helps regulate the airflow. If so, and it must be so, how come we don’t do the same to start ENG all the time?
During Hung Start, N2 is usually hanging below idle. I wonder if by closing HP valve, you force IP valve OPEN so that N2 can spin up easier…
I wish I have time and money to join the engineering school.
Anchor River