What are the suggested airspeeds for airstart attempts from sea level to 15,000 feet msl?

The appropriate airspeeds for airstart attempts from sea level up to 15,000 feet mean sea level (MSL) are typically recommended to be in the range of 125-200 knots indicated airspeed (KIAS). This range is considered optimal for ensuring the necessary airflow through the engine for a successful airstart under various flight conditions.

At the lower end of this speed range, 125 KIAS provides sufficient airflow to assist in igniting the engine after a flameout, while maintaining controllability of the aircraft. On the opposite end, 200 KIAS offers an increase in dynamic pressure that aids in optimal engine performance during the airstart process.

Operating outside this range could lead to insufficient airflow, increasing the chances of a failed airstart, or excessive speed that may complicate recovery procedures afterward. This makes the choice of 125-200 KIAS a critical factor in successful engine restart procedures during flight.