Prop Governor Maintenance Tips for Optimal Safety and Performance
When it comes to routine aircraft maintenance, certain components are critical to the performance and safety of your aircraft. One such component is your propeller governor—a small device that plays a big role in keeping your craft airborne by controlling the speed and pitch of your propellers.
Whether you’re a seasoned pilot or new to aircraft ownership, minding your prop governor maintenance is essential for keeping your aircraft in prime operating condition. Unfortunately, we’ve seen many operators overlook this key component—and miss out on more than a few prime flying days as a result.
Why is aircraft propeller governor maintenance critical to the operation of your aircraft?
First, let’s review the function of a prop governor.
The propeller governor is responsible for controlling the speed and pitch of your aircraft propellers. That, in effect, controls the power delivery and performance of your prop mid-flight. By regulating your prop’s pitch, this governor maintains an ideal engine RPM and provides the necessary thrust for takeoff, climb, and cruising. So, a properly functioning prop governor is vital for maintaining precise control over your aircraft propeller, enhancing your overall aircraft performance, and maximizing your fuel efficiency.
How does a prop governor work?
To understand how detrimental a malfunctioning aircraft prop governor really is, it’s helpful to understand exactly how this component works.
The prop governor is a variable speed and variable control oil pump that utilizes a combination of mechanical and hydraulic systems to adjust the angle of your aircraft propeller blades. The governor increases or decreases oil pressure against your propellers, adjusts their pitch, and responds to changes in flight conditions and pilot inputs in real-time.
Most propellers require between 275-340 psi to change angles. Some propellers require as much as 600 psi. But engines typically maintain an oil pressure of around 50 psi. A prop governor is designed to significantly increase that pressure.
By changing the oil pressure supplied to propeller blades, the prop governor can move the blades to increase or decrease pitch. And as the angle of your propeller blades is adjusted, the engine RPM will increase or decrease due to changing pitch of the blades.
Through precise mechanisms and sensing devices, your governor ensures your propellers maintain the right angle and RPM, so your engine can operate within its optimal power range. This intelligent control system, when properly maintained, delivers a smooth, safe, fuel-efficient flight experience.
What happens if your prop governor malfunctions?
A couple of the most common consequences of a failing prop governor are:
Pressure loss
If your aircraft propeller governor’s seals begin to leak or the gaskets wear out, the governor can lose its ability to hold pressure. Without enough pressure to push the blades forward and increase resistance, your engine RPM can continue to increase well past its optimal range, resulting in overspeed. This overspeed condition puts excessive stress on your engine components, which can cause severe engine damage or even catastrophic failure, if left unaddressed. That’s why it’s vital to have your prop governor inspected and overhauled or exchanged if you notice wild swings in your engine’s RPM, or struggle to control the angle of your propellers.
Oil leaks
Another possible consequence of poor prop governor maintenance is oil leaks in your aircraft. If your prop governor develops a leak, it can allow oil to drain into the engine area. Not only is this a significant fire hazard, an oil leak can cause damage to critical systems. To address this problem, you may have to repair multiple components, in addition to exchanging or overhauling the malfunctioning prop governor.
How often should you perform prop governor maintenance?
Prop governor maintenance requirements vary based on your aircraft’s classification.
If you operate under Part 135 commercial operation regulations, you’re subject to specific requirements called Time Between Overhaul (TBO). Your exact requirements depend on your aircraft model and engine type. In some cases, the TBO for your prop governor is the same TBO for your engine itself. In that case, you can send your engine and prop governor off for overhaul at the same time. Other models may require a prop governor overhaul or exchange based on years in operation or flight hours.
If you operate under Part 91 general aviation regulations, there isn’t a mandated maintenance protocol specifically for prop governors. However, it’s still highly recommended to include prop governor inspections and maintenance as part of your regular aircraft maintenance process. As a general guideline, we recommend having your engine and its associated components, including your prop governor, looked at at least every five years. Especially considering some minor malfunctions, like small oil leaks, can be difficult to detect early on.
Proper maintenance of your propeller governor is vital to the performance and overall safety of your aircraft. Gaskets wear, seals leak, and oil can become contaminated with few symptoms or warning signs. That’s why frequent maintenance and careful monitoring of your aircraft’s critical systems is crucial for the operation (and enjoyment!) of your aircraft.
At Aircraft Accessories of Oklahoma, our aircraft prop governor specialists will get you back in the air, sooner
Our family-owned and operated facility in Tulsa, Oklahoma is the only repair station in the state approved to offer Turbo Prop Governors. Our experienced local team of aircraft technicians are committed to providing exceptional service, and quality repairs, overhauls, and exchanges on a variety of models.
To have your turbine engine prop governor or turbo prop governor overhauled or exchanged, give us a call at 918-835-9924 or send us a message today.
