What altitude does the starter assisted relight envelope begin?

The starter-assisted relight envelope begins at FL210. This altitude is significant in aviation as it signifies the point above which the atmosphere becomes more thin, and certain operational procedures change for aircraft.

At FL210, the atmospheric conditions are such that an aircraft may experience decreased engine performance during a relight attempt. This altitude supports the need for immediate action items that pilots must adhere to in the event of engine failure or a need for a relight. The inclusion of such procedures ensures enhanced safety by equipping pilots with the necessary protocols to follow when encountering engine issues at higher altitudes.

Understanding that FL210 is critical for ensuring safety and effective aircraft management provides a clearer picture of the operational altitude ranges where specific actions must be taken. It is crucial for pilots to be well-versed in these altitudes to efficiently manage their aircraft's performance and to respond to in-flight emergencies effectively.