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July 13, 1984


Dear Fisher Ultralight Owner:

Prior to the issuance of the FAA’s Advisory Circular 103-7, there was no established method to test compliance with FAR Part 103’s maximum cruise speed of 55 knots and maximum stall speed of 24 knots other than flight testing the aircraft in question. AC-103-7 allows two methods of proving that an air- craft will comply with the maximum cruise speed and stall speed limitations:

1)
Calculations using simplified formulas and graphs.

2)
Actual flight testing documented by a technical

standards committee which is recognized by a national pilot organization.

The formula and graph method is oversimplified and heavily skewed in favor of the conventional tube and wire ultralight. For example, using this method no rigid, double surfaced wing with an area of less than 145 square feet can meet the stall speed requirements unless it has flaps. At Fisher, we thoroughly tested our prototypes to ensure that they would meet the requirements of FAR 103 prior to marketing these aircraft as ultralights.

A technical standards committee was formed and recognized by the Experimental Aircraft Association to flight test our ultralights and document the results. Enclosed is the Documentation of Technical Standards Committee Findings on your type of aircraft which verifies that it will comply with FAR Part 103. If you build your aircraft according to our plans and use the engine and propeller combination pro- vided by Fisher as standard equipment, this document will be accepted by the FAA as “satisfactory evidence” that your air- craft meets the maximum stall speed and cruise speed limita- tions of FAR Part 103.

If you significantly alter the design of the aircraft or use other propeller and/or engine combinations other than those supplied by Fisher as standard equipment, you must have your aircraft tested by a technical standards committee of your choice and at your own expense in order to prove compliance with Part 103.


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