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Purpose of main rotor blade tracking

Aviation Mechanic Airframe (AMA) practice question 3 of 11 on Rotorcraft Fundamentals. ACS element AM.II.N.K7 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Airframe (AMA) practice mode.

Question bank updated 2026-09-22

QUESTIONWhat is the purpose of main rotor blade tracking?

  1. ATo bring all blade tips into the same tip path
  2. BTo match main rotor rpm to the engine output rpm
  3. CTo set equal pitch angles on all rotor blades
Show the answer and explanation

Correct answer: A. To bring all blade tips into the same tip path

  • A — correct Blade tracking determines the positions of the blade tips relative to each other while the head is turning and brings them into the same tip path throughout the entire cycle of rotation.
  • B — incorrect Engine and rotor speeds are compared on a dual-needle tachometer during clutch engagement; that has nothing to do with the position of the blade tips.
  • C — incorrect Setting maximum and minimum blade pitch angles belongs to rigging and its functional check, while tracking deals with where the tips travel.

BACKGROUND

Blade tracking is the process of determining the positions of the tips of the rotor blades relative to each other while the rotor head is turning, and of determining the corrections needed to hold those positions within tolerance. The blades should all track one another as closely as possible, and the purpose is to bring the tips of all blades into the same tip path throughout their entire cycle of rotation. The flag and pole method marks each blade tip with chalk or a grease pencil in a different color and can be used on any helicopter that does not have jet propulsion at the blade tips. The most common electronic tracker consists of a Balancer/Phazor, Strobex tracker, and Vibrex tester, using a concentrated light beam flashing in sequence with the blades so a fixed target at the tips appears stopped. Electronic tracking is accomplished in four steps: ground tracking, hover verification, forward flight tracking, and autorotation rpm adjustment.

STUDY TIP

Keep tracking and balancing separate in your head: tracking is about where the tips travel, while balancing is about weight distribution measured as vibration amplitude and clock angle.

KEY POINTS

  • Tracking finds the relative positions of the blade tips while the head is turning.
  • Its purpose is to put all tips in the same tip path through the whole cycle of rotation.
  • Methods include flag and pole marking and electronic trackers such as the Strobex and Vibrex equipment.

SOURCES

  • FAA-H-8083-31B ch02 "Rotor Blade Tracking" (sources/ama-airframe/ch02.txt)
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MORE ON ROTORCRAFT FUNDAMENTALS

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-31B Aviation Maintenance Technician Handbook – Airframe, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.