Flight Instructor for Rotorcraft Category Helicopter Rating › XI. Emergency Operations › Task J. Ground Resonance

HI.XI.J.R2

Risk management

Recognition of the onset of ground resonance.

Study note

Get a short, cited explanation of this element written from the FAA handbooks: the core idea, the numbers that matter, common test traps, and a quick self-check.

From the FAA library

Pilot's Handbook of Aeronautical Knowledge p. 5-11
Chapter 5: Aerodynamics of Flight › Ground Effect
Figure 5-16. Ground effect changes airflow. Ground effect also alters the thrust required versus velocity. Since induced drag predominates at low speeds, the reduction of induced drag due to ground effect will cause a significant reduction of thrust required ... downwash, and wingtip vortices, there may be a change in position (installation) error of the airspeed system associated with ground effect. In the majority of cases, ground effect causes an increase in the local pressure at the static source…
Helicopter Flying Handbook p. 11-11
Chapter 11: Helicopter Emergencies and Hazards › Ground Resonance
Ground Resonance Helicopters with articulating rotors (usually designs with three or more main rotor blades) are subject to ground resonance, a destructive vibration phenomenon that occurs at certain rotor speeds when the helicopter is on the ground. Ground resonance ... balance rotor. The unbalanced rotor disk vibrates at the same frequency (or multiple thereof) of the airframe’s resonant frequency, and the harmonic oscillation increases because the engine is adding power to the system, increasing the magnitude (amplitude…
Aviation Instructor's Handbook p. 9-1
Chapter 9: Techniques of Flight Instruction › Integrating Instruction Techniques › Ground Instruction
Integrating Instruction Techniques A flight instructor uses many instructional techniques during ground instruction, when using simulation, and during hands-on aircraft training. Since flight training costs are high and new aircraft are more complex than in the past, the total ... time without sacrificing the quality of the end product. This section looks at teaching techniques in greater detail. Ground Instruction Ground instruction can be highly effective if it follows an overall plan designed to prepare the learner for flight…
14 CFR Part 141 — Pilot Schools Open
14 CFR Part 141, Appendix H to Part 141—Ground Instructor Certification Course
Part 141, Appendix H to Part 141—Ground Instructor Certification Course 1. Applicability. This appendix prescribes the minimum curriculum for a ground instructor certification course and an additional ground instructor rating course, required under this part, for the following ratings ... Ground Instructor—Basic. (b) Ground Instructor—Advanced. (c) Ground Instructor—Instrument. 2. Aeronautical knowledge training. (a) Each approved course must include at least the following ground training on the knowledge areas listed in paragraphs…
Aviation Maintenance Technician Handbook - Powerplant p. 4-65
Chapter 4: Engine Ignition & Electrical Systems › Bonding & Grounding › General Bonding & Grounding Procedures
Figure 4-115. Repairing broken wire by soldering and potting. Figure 4-116. Connecting terminals to terminal block. Bonding & Grounding Bonding is the electrical connecting of two or more conducting objects not otherwise connected adequately. Grounding is the electrical connecting ... return of current. Primary structure is the main frame, fuselage, or wing structure of the aircraft. Bonding and grounding connections are made in aircraft electrical systems to: 1. Protect aircraft and personnel against hazards from lightning discharge, Provide current return…