Helicopter vibration can present dangers to the aircraft and both passengers and crew members on board. Not only can it shorten the lifespan of certain aircraft components, but it can also make flight both uncomfortable and unsafe. Part of regular maintenance for aircrafts is to determine any sources of vibration and take steps to rectify those issues. This ensures that the aircraft is safe to fly and that all parties involved have a positive experience on board.
When performing aircraft maintenance, you’ll typically run a helicopter vibration analysis to determine the source of these issues. It’s important to note that any vibration severity that’s measured above 1.01 to 1.2 inches per second (IPS) is rated as “dangerous,” but measurements for vibration in aircraft below that point can still cause problems. It’s essential to determine the types and the origins of the most common helicopter vibrations and to prioritize regular maintenance for aircrafts to promote safety, quality, and comfort.
What Are Frequency Vibrations?
Frequency vibrations — which can be rated as low-, medium-, or high-frequency — are caused by specific kinds of equipment adjustments or malfunctions. Low-frequency vibrations are often caused by disturbances in rotor revolution, while medium-frequency vibrations can typically be attributed to loose components that affect the rotor system. High-frequency vibrations can result when certain components (e.g., gears, drive wires, engines, fans, or shafts) rotate at speeds that meet or exceed those of the tail rotor. Performing regular maintenance for aircrafts can prevent many of these issues from occurring in the first place.
What Are Lateral and Vertical Vibrations?
Lateral and vertical vibrations can also occur when certain helicopter components fall out of alignment or are in disrepair. Certain imbalances or cracked, loose, or worn-out parts can cause lateral vibrations. And if a rotor blade becomes misaligned, this can cause a vertical vibration. It’s essential that these blades be balanced and in good condition to ensure the minimization of vibrations.
What Are Ground Resonance Vibrations?
These kinds of vibrations are seen as the most serious, as they have the potential to destroy aircraft. Unlike other kinds of vibrations listed here, ground resonance vibrations occur only when a helicopter is grounded (rather than when it’s in the air). If a helicopter’s rotor system contains imbalanced components, has improper tire pressure, features incorrect landing gear adjustments, or contains defective rotor blade dampeners, ground resonance vibration could occur. This is yet another reason why regular maintenance for aircrafts can prove vital.
While having a certain amount of vibration present in any type of aircraft is unavoidable, it’s imperative that these vibrations be regularly analyzed and that the aircraft is serviced on a consistent basis to ensure potential side effects are alleviated.