HI.XI.H.K3
KnowledgeVarious frequency vibrations and the possible components that may be affected.
From the FAA library
- Chapter 11: Helicopter Emergencies and Hazards › System Malfunctions › Low-Frequency Vibrations
Abnormal Vibration With the many rotating parts found in helicopters, some vibration is inherent. A pilot needs to understand the cause and effect of helicopter vibrations because abnormal vibrations cause premature component wear and may even result in structural failure ... With experience, a pilot learns what vibrations are normal and those that are abnormal and can then decide whether continued flight is safe or not. Helicopter vibrations are categorized into low, medium, or high frequency. Low-Frequency Vibrations Low-frequency…
- Chapter 4: Helicopter Components, Sections, and Systems › Electrical Systems
exceeding the output of the alternator or generator, and the battery is helping to supply electrical power. This may mean the alternator or generator is malfunctioning, or the electrical load is excessive. An ammeter displays the load placed ... alternator or generator causes the load meter to indicate zero. Electrical switches are used to select electrical components. Power may be supplied directly to the component or to a relay, which in turn provides power to the component. Relays…
- Chapter 11: Helicopter Emergencies and Hazards › System Malfunctions › Medium- and High-Frequency Vibrations
Medium-frequency vibrations are felt through the entire airframe, and prolonged exposure to the vibrations will result in greater pilot fatigue. Most tail rotor vibrations fall into the high-frequency range (2,100 cycles per minute or higher ... felt through the tail rotor pedals as long as there are no hydraulic actuators to dampen out the vibration. This vibration is felt by the pilot through his or her feet, which are usually “put to sleep” by the vibration…
- Chapter 7: Automation & Flight Path Management › Reliance on Automation
Automation The use of automation comes with certain cautions. Automation should reduce workload, but in some instances, it may create more work, confusion, and contribute to errors. At other times, automation may lull pilots into complacency. Pilots who consistently rely ... autopilot for flight path management may experience degraded ability to fly manually when required to do so. For example, when flying in icing conditions, an automated system may make control inputs to compensate for ice accumulation. However, if the system…
- Chapter 7: Aircraft Systems › Fuel Systems › Fuel System Icing
tank. To prevent fuel contamination, avoid refueling from cans and drums. In remote areas or in emergency situations, there may be no alternative to refueling from sources with inadequate anti-contamination systems. While a chamois skin and funnel may ... only possible means of filtering fuel, using them is hazardous. Remember, the use of a chamois does not always ensure decontaminated fuel. Worn-out chamois do not filter water; neither will a new, clean chamois that is already water…
- Chapter 11: Communication & Navigation › Installation of Communication & Navigation Equipment › Vibration Isolation
Vibration Isolation Vibration is a continued motion by an oscillating force. The amplitude and frequency of vibration of the aircraft structure will vary considerably with the type of aircraft. Avionics equipment is sensitive to mechanical shock and vibration ... normally shock mounted to provide some protection against in-flight vibration and landing shock. Special shock mounted racks are often used to isolate avionics equipment from vibrating structure. [Figure 11-158] Such mounts should provide adequate isolation over the entire…