Effective Date: 15 June 98
Starting
Analysis of engine starting consists basically of evaluating the operation of the starting system under various conditions during ground and flight starts, and to define the inflight relight envelope.
Ground Starting
Ground starting will be conducted using various modes of starting such as crossbleed from all other engines individually and at various power levels, using the APU, and starts from ground air source, etc. Each of these starts will be analyzed by determining the time to stabilized idle, and the maximum TGT. This will be evaluated from time histories of gas generator parameters during the start, or by visual observations of the flight station instruments.
In-flight Starting
In-flight starts will be conducted to evaluate relight capability, and to define the starter assist envelope. Concurrent with this, windmilling start data will be obtained, for example, the windmilling rotor speed for which an unassisted airstart can be made, as shown below.
The overall test results will be presented on a plot of altitude versus airspeed with each attempted start shown as a point on this chart (Figure 1) . The in-flight starting envelope will be drawn to include the satisfactory starting attempts.
Time history plots of representative starts will be produced of pertinent engine parameters obtained from data recorded on the PCM tape. Indication of ignition ON and HP shutoff valve OPEN (i.e., "Ignition and Fuel" switch ON), light OFF, and Idle N3 speed will be included in these plots.