TURBOPROPENGINES TURBOPROP ENGINES

Prestart Procedures

The various covers protecting the aircraft must be removed. Engine tailpipes should be carefully inspected for the presence of fuel or oil. A close visual inspection of all accessible parts of the engines and engine controls should be made, followed by an inspection of all nacelle areas to determine that all inspection and access plates are secured. Sumps should be checked for water. Air inlet areas should be inspected for general condition and foreign material. The compressor should be checked for free rotation, when the installation permits, by reaching in and turning the blades by hand.

The following procedures are typical of those used to start turboprop engines. There are, however, wide variations in the procedures applicable to the many turboprop engines, and no attempt should be made to use these procedures in the actual starting of a turboprop engine. These procedures are presented only as a general guide for familiarization with typical procedures and methods. For starting of all turboprop engines, refer to the detailed procedures contained in the applicable manufacturer's instructions or their approved equivalent.

The first step in starting a turbine engine is to provide an adequate source of power for the starter. Where an air turbine starter is used, the starting air supply may be obtained from a gas turbine compressor (GTC), an external source, or an engine crossbleed operation. To start the first engine, use a GTC or low pressure, large volume tank. Start the remaining engine(s) using bleed air from the running engine.

While starting an engine, always observe the following:

1. Never energize the starter while the engine is rotating.
2. Do not move the power lever of any engine while it is being bled for crossbleed starting.
3. Do not perform a ground start if turbine inlet temperature is above that specified by the manufacturer.
4. Do not use bleed air from an engine that is accelerating.

Starting Procedures

To start an engine on the ground, perform the following operations:

1. Place the start selector switch to the desired engine and the start arming switch (if so equipped) to the "start" position.

2. Turn the aircraft boost pumps on.

3. Place the fuel and ignition switch on.

4. Position the low rpm switch in low or normal (high).

5. Make sure that the power lever is in the "start" position. If the propeller is not at the "start" position, difficulty may be encountered in making a start.

6. Depress the start switch and, if priming is necessary, depress the primer button.

7. Make sure the fuel pump parallel light comes on at, or above, 2,200 rpm and remains on up to 9,000 rpm.

8. Check the oil pressure and temperature. Maintain the power lever at the "start" position until the specified minimum oil temperature is reached.

9. Disconnect the ground power supply.

If any of the following conditions occur during the starting sequence, turn off the fuel and ignition switch, discontinue the start immediately, make an investigation and record the findings.

1. Turbine inlet temperature exceeds the specified maximum. Record the observed peak temperature.

2. Acceleration time from start of propeller rotation to stabilized rpm exceeds the specified time.

3. There is no oil pressure indication at 5,000 rpm for either the reduction gear or the power unit.

4. Torching (visible burning in the exhaust nozzle other than normal enrichment) or excessive smoke is observed during initial fire up.

5. The engine fails to ignite by 4,500 rpm or maximum motoring rpm (whichever is first), and rpm stagnates or begins to decay.

6. Abnormal vibration is noted or compressor surge occurs (indicated by backfiring).

7. There is fuel spewing from the nacelle drain, indicating that the drip valve did not close.

8. Fire warning bell rings. (This may be due to either an engine fire or failure of an anti-icing shutoff valve to close.)