Toeing the Line: The First Byrne Letter

  • E-Mail this Article
  • View Printable Article
  • Text size:

    • A
    • A
    • A

The complete text of the July 29, 1999, letter from Donald P. Byrne, assistance chief counsel, regulations division, to Robert Hackman. As referenced in the AVweb article "Toeing the Line: An FSDO Changes the Definition of 'Dual Controls'."

U.S. Department
of Transportation
Federal Aviation

800 Independence Avenue, S.W.
Washington, DC 20591


July 29, 1999


Mr. Robert Hackman

Dear Mr. Hackman:

Thank you for your letter dated April 26, 1999, to the Office of the Chief Counsel, Federal Aviation Administration (FAA), regarding flight instruction in aircraft with dual controls under 14 CFR section 91.109(a).  Specifically, you request an interpretation of the definition of "dual controls."

In your letter you state that a member of your organization, Aircraft Owners and Pilots Association (AOPA), received a warning letter that he or she was not in compliance with 14 CFR section 91.109(a) because the aircraft being used for flight instruction did not have dual controls (toe brakes).  This member was providing flight instruction in an aircraft equipped with toe brakes on the pilot's side but not on the flight instructor's rudder pedals.  The aircraft was equipped, however, with either a had brake or parking brake accessible to the flight instructor allowing the instructor to stop the aircraft.  You state that 14 CFR section 91.109(a) is clear about the requirements for dual control, however, the definition of dual controls is not clear.  You then ask "[w]hat is the definition of dual controls, specifically, are toe brakes part of that definition."  The answer to your question is discussed below.

14 CFR section 91.109(a) states, in pertinent part, that no person may operate a civil aircraft that is being used for flight instruction unless that aircraft has fully functioning dual controls.  This regulation was established to ensure that the flight instructor could take over the controls of the aircraft in case of a emergency.  The flight instructor must have his or her own access to the operating controls of the aircraft, except as otherwise provided under 14 CFR section 91.109(a).

The term "dual controls" under 14 CFR section 91.109(a) means that the operating controls accessible to the right seat of the aircraft must be capable of performing the same function as the operating controls accessible to the left seat of the aircraft.  It does not mean that the operating controls must be identical.  For example, in the scenario provided in your letter, the right seat of the aircraft does not need to have access to toe brakes but does need to have access to brakes (e.g. a hand brake or parking brake) to meet the intent of 14 CFR section 91.109(a).

This interpretation has been coordinated with Flight Standards Service (AFS).

We hope this satisfactorily answers your question.


/s/ Donald P. Byrne

Donald P. Byrne
Assistant Chief Counsel
Regulations Division