Parameters

aircraftId

Type: SystemInt32

Return Value

Type: NullableInt32
The first good altitude seen for the aircraft or null if no good altitude currently exists.

The sanity checker maintains a history of altitudes that have been received, up to the point where a call to CheckAltitude(Int32, DateTime, Int32) returns a ProbablyRight result. Once an altitude is probably right you can call this method to get the earliest altitude seen that is probably correct when compared to the latest altitude. If the latest altitude is not ProbablyRight then this method returns null. Once two ProbablyRight altitudes are seen in succession the history will be wiped and the function will return null until the aircraft is removed from the history (which happens after roughly 10 minutes regardless of configuration settings).