Airstart (Starter Assisted) from Flight Level 210 to Sea Level requires what targets?

• A. Vref - Vmo and 0-45% N2
• B. Vref - Vmo and 60-70% N2
• C. Vref - Vmo and 0-30% N2
• D. Vref - Vmo and 50-60% N2

Answer: (A)

In an airstart using the starter, the key is to get the engine to light-off safely by controlling the core spool with the starter. The correct target is to keep N2 in the low range during the start attempt, specifically from 0 up to about 45% N2. This keeps the starter within its comfortable operating limits while allowing ignition to occur as fuel is introduced. At the same time, you want the aircraft to stay within the airspeed band from Vref to Vmo to ensure adequate ram air and stable engine demand during the start. If N2 rises much beyond the 45% mark before light-off, the starter may be overstressed and light-off can become unreliable. If you try to start with N2 too low or lose the appropriate ram air conditions, ignition may not occur reliably. So the safe, practical target during a starter-assisted airstart from high altitude down to sea level is 0–45% N2 with airspeed between Vref and Vmo.