Hi Guys, Lots of interesting comments. May I digress slightly, but in a similar field.
B738 Engine Inflgiht Start. X-bleed using GND start switch. You're at lowish level below Fl100. QRH says minimum N2% for fuel on is 11%. Normal for engine start is 25% or max motoring. On the GND 25% is first.
I teach to wait for 25% or max motoring for inflight start at low levels. The envelope goes to FL270. If you can get 25% why not wait. Faster = cooler and better chance of a successful start IMHO. At high levels you may max motor belwo 25%, even down to 11% I presume. I see other SFI's have been teaching slam it in at 11% and it doesn't matter if you can reach higher. QRH says 11% is Ok so do it.
Thoughts?