The PT6 engine is one of the most reliable and cost-effective solutions that aircraft use today. However, the engine requires regular maintenance like any other engine in order to stay functional for a long time. One of the most important components that need to be focused on during the hot section inspection of this engine is the fuel nozzles that require regular servicing. Here are some tips on maintaining the fuel nozzles of your PT6.
Carry Out the Initial Inspection
The first thing to do is the initial inspection to check for possible damage to the sheath, adapter and nozzle tip. Checking the part numbers on these components before installation is very important. Fuel nozzles attached to incorrect parts can be very dangerous for the engine. Due to the similar appearance, these mistakes are quite common so always remember to check the part numbers.
After the installation comes the cleaning of the nozzles. You can find the proper cleaning procedure outlined in the P&W maintenance manual. It is preferable that you use a small-sized ultrasonic cleaner, focusing on the cleaning of one nozzle at a time. The cleaning process of fuel nozzles is time-consuming and should not be rushed.
If the fuel nozzles are not cleaned properly, they will need replacement more often. Therefore, the maintenance manual indicates that the nozzles should be cleaned repeatedly until they are cleaned up perfectly. Usually, the second cleaning is good enough to get a normal flow pattern back. After the nozzles are perfectly cleaned, you need to check for leaks. The leaks are possible between the adapter assembly, nozzle tips and lock tabs. The last check you need to make is of the flow. If there are any irregularities in the flow of any nozzle, that particular tip can be rejected and should be replaced.
Check the Sheaths
The last thing you need to check are the nozzle sheaths. The first thing to check is the thickness of dome of these sheaths. The minimum dome thickness required by most sheaths is .040 taken with a calibrated micrometer. The wear level when sheath and combustion liner come in contact should be .010. The measurement of nozzle port diameter, however, varies from model to model of the engine.
Proper fuel nozzle maintenance can increase the functionality and life of these nozzle tips, saving you the trouble of replacing them time and again and incurring huge costs.