6 ESSENTIAL TOOLS FOR DIY TURBOFAN ENGINE LINE MAINTENANCE
Get equipped to take care of basic turbofan engine line maintenance activities on your own. Our maintenance expert recommends these six must-have DIY tools.
1. BORESCOPE KIT AND GUIDE TUBES
A borescope is a valuable tool for any engine, but it’s particularly useful for those being maintained on condition. Once your engines reach a certain usage threshold, you’ll need to start inspecting them to see if they need an overhaul.
Francis de Gruchy, a 20-year P&WC veteran who provides frontline support for all PW300 engine models told Airtime that the borescope itself standard no matter the engine model. However, he pointed out that the guide tubes for inserting the borescope into various engine ports can vary depending on the engine. "If you have a mixed fleet, you'll need to make sure you get the right guide tubes for each model. Check your maintenance manual for details," he recommends.
Budget permitting, you should invest in a borescope with measuring capabilities so that you can measure any deterioration, such as the length of cracks. That information can help us give you more accurate maintenance advice.
Francis told Airtime that in recent years, on-condition maintenance is becoming more prevalent among the operators he supports. Technologies like P&WC's FAST™ solution have become a tremendously helpful tool to help them make decisions. By delivering wirelessly captured full-flight analyzed engine data, FAST gives operators the confidence to potentially prolong the need for pre-scheduled maintenance.
2. SEAL REPLACEMENT TOOLS
Over time, the seals on a turbofan engine's accessory gearbox could show signs of leaking—this applies to both neoprene seals found on older turbofan engines or the magnetic and carbon-face seals used on newer models.
These leaks are easy to identify by oil stains on the bottom of the cowling, which should be obvious when you do a visual inspection of the engine and externals during normal scheduled maintenance.
Fixing it is simple enough—just follow the instructions in your engine’s maintenance manual. But if you don’t have the right tools, you’ll have to call a maintenance crew every time you have to replace a seal.
3. OIL PRESSURE ADJUSTMENT AND COLD START VALVE TOOLING
If there’s a change in your engine’s oil pressure, one of the first things to do is check the pressure adjustment and cold start valve to make sure it’s clean and in good condition.
“You’ll need to disassemble the pistons and springs. It could be dangerous to do that without the right tooling. You could pinch your fingers or get hit by a flying part,” Francis warns.
4. OIL AND FUEL FILTER REPLACEMENT TOOLING
Oil and fuel filter replacement are part of scheduled maintenance, and for aircraft with a propensity for fuel contamination, these may also be advisable on an unscheduled basis.
If you’re going to do your own oil and fuel filter replacements, you can’t just pull them out by hand. There are specialized tools for removing the cap and in some cases the filter itself.
5. FAN BLADE REMOVAL AND INSTALLATION TOOLING
For engines with a bladed fan, such as PW300 models, windmilling is a potential issue if the aircraft is left outside without engine covers. Wind turning the fan while the engine is shut down will cause slight friction as the titanium blades shift in their pockets, audible as a distinctive clicking sound. Cold weather conditions can further affect the blades, making covers even more important.
“It’s not a question of how often you fly but how often you don’t fly. Over a long time, the metal-on-metal friction will induce fretting. This produces microscopic titanium dust that will accumulate and may cause some vibration during engine operation,” Francis explains.
“The solution is to clean the fan blades one by one and apply lubricant grease to them. That requires special tools for removing and installing the blades, and also for taking off the nose cone on some models.”
6. HELICAL INSERT TOOLING
Helical inserts or helicoils are used to secure steel screws in aluminum or magnesium housing. Sometimes screws get stuck inside these inserts due to corrosion or heat distress.
As a result, if you try to remove the screw during disassembly, the insert will be pulled out along with it. When that happens, it’s helpful to have an insert toolkit on hand.
“Every good mechanic should have an insert toolkit. It’s not just for engine maintenance—it can be used anywhere on the aircraft where there’s a screw,” Francis explains.
It ultimately comes down to your budget and how you want to handle your maintenance, but in my opinion, these tools are must-haves. In the long run, you’ll help lower your costs by doing the maintenance work yourself where possible.
Want more tips on tools? Learn about another handy item for turbofan operators, the flyaway kit, which can help ensure you have the right parts on hand at the right time.