McFarlane Aviation Products FAA-PMA Replacement Aircraft Parts

FAA-PMA Approved Vernier-Assist Throttle Controls

Vernier and Friction Lock - The Best of Both


You asked for it and now we have it. Not only do we offer Vernier-Assist for non-certified aircraft and an extended line of FAA-PMA approved controls, the breakthrough design is now approved on throttle controls for Cessna, Piper, Beechcraft, Grumman, and Bellanca.


Now FAA-PMA Approved! 

  • Jam-proof safety
  • Precision power adjustments
  • Smooth friction control
  • Light and compact
  • Standard Vernier performance without the button!
  • Catalog Information



McFarlane’s patented Vernier-Assist™ offers the pilot precision control of the engine, unlike anything else on the market! The Vernier-Assist assembly operates on friction alone by simply turning the knob, with no threads or locking balls/pins. It also allows for normal coarse movement by pushing in or out on the knob. Unlike standard threaded vernier controls, this design cannot be jammed. The friction control provides smoothness and precision when operating the throttle and a friction lock secures the control in position, but it can be easily overridden in the case of an emergency. It is SAFE!


These light weight controls use a patented roller action and do not use a positive lock thread engagement. Coarse adjustments are made by pushing the knob inwards or pulling the knob outwards. Fine adjustments are made by rotating the knob clockwise or counterclockwise. For extreme conduit routing or heavy carburetor load installation, slight inward or outward assist pressure could be required during rotation.

US Patent No. 8,485,057 B1 


Part Numbering Note:

Part numbers for Vernier-Assist™ are the same as McFarlane's original push-pull FAA-PMA approved controls, except the "MC" prefix changes to "MCVA". Examples:

Standard Push-Pull P/N MC9863056-2 or Vernier-Assist™ P/N MCVA9863056-2

Standard Push-Pull P/N MCS1222-1S or Vernier-Assist™ P/N MCVAS1222-1S

Standard Push-Pull P/N MCC299505-0101 or Vernier-Assist™ P/N MCVAC299505-0101



To find the control for your aircraft, go to Throttle Controls




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