If you own or are thinking of owning a turboprop airplane, you might be wondering whether the propeller blades need to be replaced. Many aircraft parts have a finite lifespan. Landing gear tires, for instance, typically need to be replaced every 150 to 400 landings, whereas the brakes can last for up to 1,000 landings. Of course, there are other parts that rarely or never need to be replaced, such as the fuselage.
The Basics of Propeller Blades
Propeller blades play an important role in the operation of airplanes with turboprop engines. Turboprop engines are gas turbine engines that drive a propeller. They feature an internal combustion chamber that burns a mixture of gas and air. As they burn this mixture, turboprop engines will turn a propeller connected to the front.
Like all mechanical parts, however, propeller blades will experience wear and tear from regular use. Exposure to moisture, extreme temperatures, vibrations and even small debris can weaken them.
Propeller blades can also become bent. According to the U.S. Federal Aviation Administration (FAA), bent propeller blades won’t be aligned with each other, resulting in excessive vibration and a loss of thrust.
Regular Inspections
For both safety and performance purposes, many aircraft propellers require regular inspection. Some of them have an inspection interval of 100 flight hours, whereas others have an inspection interval of 200 flight hours. Regardless, once a propeller has reached its required inspection interval, it must be inspected by a mechanic.
Regular inspections allow mechanics to identify problems with propeller blades early — before they turn into more serious problems. Minor corrosion, for example, can often be cleaned. Allowing corrosion to go unchecked, though, can result in a loss of strength and efficiency, at which point the blades may need to be replaced.
Time Between Overhaul (TBO)
Some aircraft propellers have a time between overhaul (TBO). The TBO can be listed in calendar time or flight time, such as five years or 1,000 flight hours.
Propeller blades are “overhauled” upon reaching their TBO. The blades may be cleaned and refinished, or they may be sharpened. Depending on the condition of the blades, they may be replaced altogether.
Some forms of blade damage, such as small dents, nicks, or scratches, can often be repaired by a certified technician. However, if a propeller blade has large cracks or shows signs of serious structural damage, replacement is typically the only safe option.
