Signal Light Test: Medical Flight Test Procedures for Pilots

What to Expect During the SLT for Pilots with Color Vision Deficiency

Apr 2014

Abbreviated Briefing:
  • A. General Process: Special Medical Flight Tests (MFTs) are conducted by aviation safety inspectors (ASIs) for applicants with physical deficiencies.
  • B. MFT and Practical Test can be combined for Certification and/or Ratings
  • C. It is Possible to Pass only the Medical Portion
  • D. Letter of Authorization (LOA) is required in advance of the MFT
  • E. Defective Hearing MFTs specify either open or closed cockpit
  • F. Defective Color Vision MFTs: 1st and 2nd class applicants must take and pass an Operational Color Vision Test (OCVT) and a color vision Medical Flight Test (MFT). Applicants for a third class medical certificate need only to take and pass the OCVT which has 2 parts:
    • Signal Light Test (SLT)
    • Demonstrate ability to read and identify colors on aeronautical charts during dayl +/- night conditions.
  • G. Completion of Medical Test: If during any of non-SLT MFTs, the applicant fails to meet the test standard, the ASI will terminate the test before it is completed. In contrast, the FAA requires that the entire SLT must be completed before an assessment is made regarding success or failure of the test.
  • H. Operating Limitations: Various restrictions may be placed on or removed from the pilot certificate.
  • Procedures (Except SLT)
  • Signal Light Test (SLT) Procedures
  • Possible Outcomes:
    • Medical Certificate
    • Statement of Demonstrated Ability (SODA)
    • Temporary Airman Certificate; or
    • Notice of Disapproval of Application

Guidance is compiled and interpreted by professional pilots and physicians at from the 2014 AME Guide, FAA and FDA web data ( &, instructions specified in the Aeronautical Information Manual, Federal Air Surgeon Bulletins from 1999-2015, and 14 CFR Part 61 and Part 67 (the FARs).

Special medical flight tests, which may lead to the issuance of medical certificates under Title 14 of the Code of Federal Regulations (14 CFR) part 67, section 67.401, are frequently required for applicants who do not meet certain medical standards.  These tests are conducted solely by inspectors and may be conducted only on the basis of a letter of authorization (LOA).  (See FAA Order 8700.1, figure 27-1.)  The LOA for a person who has requested a special medical test must be issued by the Aero medical Certification Division, AAM-300.  Concurrence from the regional Flight Surgeon is required before any operating limitations on pilot certificates issued to pilots with physical deficiencies can be removed



If you don't meet medical standards, don't despair immediately.  Inquire if a Medical Flight Test (MFT) might be appropriate in your situation.  You may even be able to combine your required practical test for a pilot certification (or additional rating) with your MFT.  This requires active coordination between the FAA Examiner, your AME and sometimes Air Traffic Control (ATC), but thousands of pilots have successfully acquired or restored their aviation credentials through MFTs.  To learn more about this, discuss the feasibility with your flight instructor and your AME.  You will need a Letter of Authorization (LOA) and will need to review the procedures for the type of MFT you are seeking.  Just like any other checkride, you must familiarize yourself with the tasks and the passing standards.  It is possible to independently pass or fail either the practical and/or medical demonstration portions of the checkride.  If you have a color vision problem, review the Signal Light Test (SLT) procedures; otherwise review the general MFT procedures.



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Reminder: use to familiarize yourself with aviation medical regulations and guidelines, but always discuss your specific situation with one or more AMEs before dedicating resources toward expensive clinical workups. Find an AME now