The FAA has issued a Special Airworthiness Information Bulletin (SAIB) for Piper Model PA-28-140 airplanes with the Power Flow Systems, Inc. STC SA02168AT kit installed. The SAIB was issued by the same FAA Aircraft Certification Officer who approved the STC most recently (Todd Jackson, Jan. 27, 2017) and it points out that an AD is not needed in this situation, only a visual inspection.

From the FAA

This Special Airworthiness Information Bulletin (SAIB) is to alert owners, operators, and maintenance technicians of Piper Aircraft, Inc. (Piper) Model PA-28-140 airplanes with Power Flow Systems, Inc.

Supplemental Type Certificate (STC) SA02168AT kit installed of an airworthiness concern related to the carburetor throttle control arm bracket impacting the collector assembly. The interference between the throttle control arm and the collector assembly may prevent the engine from reaching the maximum power stop on the carburetor.

At this time, the airworthiness concern is not an unsafe condition that would warrant airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part 39.


On August 15, 2017, a Piper Model PA-28-140 airplane with a newly installed Power Flow Systems, Inc. STC SA02168AT kit experienced a reduction of engine power and consequent crash. During the accident investigation, it was observed the throttle arm bracket came in contact with the Power Flow System STC’d exhaust collector heat shield. This interference prevented the throttle control arm from attaining full travel. Due to this interference, the carburetor throttle arm could not make contact with the maximum power stop on the carburetor, which resulted in a reduction in engine power.


The FAA recommends that operators of Piper Model PA-28-140 airplanes with a Power Flow Systems, Inc. STC SA02168AT kit installed do the following:

  • Visually inspect (engine power off) the throttle control arm clearance. During the inspection, put the throttle lever in the full forward position.
  • Visually confirm that the throttle control arm bracket is not impacting the collector assembly.
  • Verify that the throttle control arm is contacting the maximum power stop on the carburetor in accordance with applicable airframe rigging procedures.

For Further Information Contact
Todd Jackson, Jr., Aerospace Engineer, Atlanta Aircraft Certification Branch; 107 Charles W. Grant Parkway, Atlanta, GA 30354; phone: 404-474-5567; fax: 404-474-5606; e-mail:

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