Conversion of UL Tugs to N-Numbers ELSA

From the Towlines column written by Tracy and Lisa, published in Hang Gliding & Paragliding

From Hang Gliding & Paragliding Magazine, March 2007
By Tracy Tillman and Lisa Colletti

In this issue of Towline we will continue our discussion of Sport Pilot issues, particularly in regard to the conversion of our tugs to E-LSAs (experimental light sport aircraft). Converting an ultralight vehicle to an FAA-registered certificated aircraft requires an understanding of a wide range of detailed technical, regulatory, and paperwork issues that we will try to simplify for you as much as possible.

Lisa: January 31, 2008 is the deadline for converting overweight or two-place ultralights used in our current fleet of tugs to FAA-registered E-LSAs. After that date, it will not be possible to convert an existing unregistered tug to an E-LSA. An overweight or two-place ultralight tug that is not converted to an E-LSA by January 31, 2008 can continue to be flown until January 31, 2010, but after that date that it cannot be flown at all, as the FAA will consider it to be an unregistered aircraft without an airworthiness certificate. Very light tugs that actually meet the definition of a true ultralight may continue to tow hang gliders under Part 103 rules, without being N-numbered, as long as USHPA's aerotowing exemption #4144 remains in effect.

Tracy: OK, what do we have to do by the January 31, 2008 deadline to get our tug converted, certified as airworthy, and registered as an E-LSA?

Lisa: One option is to go directly to the source and read thousands of pages of FAA regulations and advisory circulars to learn the details, such as the Sport Pilot Final Rule on "Certification of Aircraft and Airmen for the Operation of Light-Sport Aircraft"[ref. 1]; Title 14, Part 21 of the Code of Federal Regulations on "Certification Procedures of Products and Parts" [ref. 2]; FAA Order 8130.2F CHG2 on "Airworthiness Certification of Aircraft and Related Products" [ref. 3]; and other documents available from the FAA's Light Sport Aviation Branch [ref. 4], such as "Light Sport Aircraft Registration"  [ref. 5].

Tracy: Oh, a little light reading! You missed one. Encompassed in another thousand or so pages is the two-part AC 43.13-1B CHG1 [ref. 6] and AC 43.13-2A CHGH2 [ref. 7] FAA Advisory Circular document on "Acceptable Methods, Techniques, and Practices - Aircraft Inspection, Repair and Alterations." That is the one we used for reference at the 16-hour Light Sport Aircraft Repairman-Inspection certification course that we attended last year [ref. 8].

Lisa: Those official FAA documents and resources are the best ones to use, which is why we listed them, but it is very difficult to wade through all that information.

Tracy: Ya think?

Lisa: For ease and practicality, the best thing to do is to just order the "E-LSA Conversion Kit"[ref. 9] from the Experimental Aircraft Association (EAA) for less than 20 bucks. The conversion kit includes a very straight-forward 15-page guide that explains the entire process in very simple terms, along with the FAA forms, a fireproof metal data plate, and labeling placards needed to convert an ultralight to an E-LSA.

Tracy: OK, but then what do we have to do?

Lisa: First, reserve a custom N-number if you want one. A reserved number is not required. The FAA will just assign one, selected at random, if you don't care what number you get. But if you do want a special number, you should reserve it as soon as possible. The process is very easy: Just search the numbers that are currently available on the FAA's Aircraft Registry Web site [ref. 10] and reserve the number online using a credit card. The cost is only $10, and the reservation can be renewed annually.

Tracy: What's the next step?

Lisa: Second, prepare the aircraft to meet FAA airworthiness standards. This means making sure that all the hardware, covering, controls, instrumentation, wiring, engine and fuel systems are going to be considered "in a condition for safe operation" [ref. 11] by the DAR (designated airworthiness representative)/FAA airworthiness inspector. Ideally, it would mean that your aircraft components and systems would meet all the standards described in Advisory Circular (AC) 43.13-1B, "Acceptable Methods, Techniques" and practice "Aircraft Inspection and Repair" [ref. 6]. However, due to the nature of ultralight design and construction, and other FAA regulations affecting experimental aircraft instruction, it is problematic to strictly apply all of the rules of AC 43.13-1B to ultralights transitioning to E-LSAs. Also, individual DARs/inspectors may interpret each situation somewhat differently. It is the inspector's opinion that matters, as he or she will be the one who signs the airworthiness certificate [ref. 11]. None-the-less, it is important to apply AC 43.13-1B standards as much as possible to the components and systems. Examples of just a few of the things to check or change include use of aircraft-grade hardware, checking to make sure that bolts have enough threads showing beyond the nuts and that bolts that act as hinge pins use castle nuts and safety pins rather than nylocks, making sure that safety wiring is done properly, and installing proper instrumentation labels and operational placards. If you have a reserved N-number, do not place it on the aircraft at this time, if you still want to fly it.

Tracy: In addition to AC 43.13-1B, I've found some good Web sites that have been developed and some good articles that have been written about conversion to meet airworthiness standards, such as Dennis Demeter's "Getting Ready for Sport Pilot" technical series in Ultralight Flying Magazine [ref. 12]. Some additional references that are very helpful for figuring out some of these technical details are listed at the end of our article [refs. 13-16]. What's the next thing to do?

Lisa: Third, register the aircraft by mailing in the FAA AC Form 8050-1  "Aircraft Registration Application" and the FAA AC Form 8050-88A "Affidavit of Ownership for Experimental or Special Light-Sport Aircraft." Both forms are included in the EAA's "E-LSA Conversion Kit" [ref. 9], along with specific directions about how the forms should be filled out. When the FAA sends verification of your registration and N-number to you on the "Hard Card" FAA Form 8050-3 [ref. 17], it is no longer considered an ultralight, it is considered an uncertificated aircraft. You can no longer fly the aircraft until it has been inspected and certificated [ref. 18].

Tracy: It is my understanding that making small mistakes or having inconsistencies on those forms can create big problems later, so it is very important to follow the directions and recommendations given by the EAA in the  "E-LSA Conversion Kit." What's the next step?

Lisa: Fourth, place the N-number, "Experimental" placard, and fireproof data plate on your aircraft, calculate the weight and balance, and complete the required paperwork in preparation for the Airworthiness Certification Inspection. The N-number must have lettering at least three inches high and should be displayed horizontally on each side of the vertical tail surfaces or on the fuselage sides for a fixed-wing aircraft . For a trike, the numbering could be on a nose fairing or on a plate that is attached to one of the tubes or structural members of the trike [ref. 19]. Dennis Demeter has a very good article on calculating weight and balance for E-LSAs in the eighth article (March 2004) of his series [ref. 12], and examples are also given in the EAA's  "E-LSA Conversion Kit." In addition to documentation for weight and balance, the DAR or FAA inspector will require a 3-view drawing or picture of the aircraft, a  "program letter" that is basically a letter to the FAA stating what your experiment is and how you plan to use it [ref. 20], and FAA Form 8130-6  "Application for U.S. Airworthiness Certificate." Also, have a blank "Condition Inspection Checklist" ready for the inspector. Again, blank forms and examples are provided in EAA's "E-LSA Conversion Kit."

Tracy: What about FAR 91.207?

Lisa: Oh, you mean the regulation requiring that all two-place fixed-wing airplanes must have an emergency locator transmitter (ELT) installed. An ELT will have to be installed on a two-seat Dragonfly or other fixed-wing tug for the inspection, but an ELT does not have to be installed on a single-seat fixed-wing aircraft or on a weight-shift trike, even if the trike has two seats [ref. 9].

Tracy: Are we ready for the inspection?

Lisa: Yup. The final step is to have the aircraft inspected by an FAA FSDO or MIDO inspector, or a designated airworthiness representative (DAR). The FAA has a list of available E-LSA DARs [ref. 21] on their Web site, or you can contact your local FSDO to find an inspector. It may take longer to arrange for an inspection with an FAA FSDO inspector, but they will not charge for the inspection. An E-LSA DAR may have better availability, but it is common for them to charge $300 to $400 for conducting the inspection.

The aircraft must be complete and flyable and in a safe condition for operation [ref. 14]. Having engine and airframe logbooks that document all previous maintenance or inspections will help the inspector to determine that the aircraft is safe for operation. When the DAR or FAA inspector gives you your airworthiness certificate he or she will also specify "operating limitations"  for your aircraft, which are considered a part of your airworthiness certificate [ref. 22], and which are based on the "program letter" documentation that you developed for the inspection. Among other things, that letter should describe the aircraft's use for towing unpowered ultralights and LSA gliders, per the following statement from part 144.d(14) on page 145 of FAA Order 8130.2F CHG2 [ref. 3]: "No person may operate this aircraft for compensation or hire, except this aircraft may be used for compensation or hire to conduct towing of a light-sport glider or an unpowered ultralight vehicle in accordance with 91.309. NOTE: When operating limitations (13) and/or (14) are used in place of limitation (12), limitation (13) applies to flight training and will expire January 31, 2010. Limitation (14) applies to towing, which has no expiration date."

Tracy: That is an extremely important statement, and verifies the ability for us to use our converted E-LSAs for towing indefinitely, whereas converted two-seat trainers can only be used for training until January 31, 2010. Would the tug now be ready to use for towing again?

Lisa: Not quite. The "operating limitations" will specify a test-flight program period that will consist of a certain number of hours that are to be flown in a certain area until your test-flight program is completed [ref. 13]. This flight testing is meant to show that the aircraft is safe and controllable throughout all normal maneuvers and has no hazardous operating characteristics [ref. 22].

Tracy: Anything else?

Lisa: After the tug is certificated as an E-LSA, the owner may continue to maintain the aircraft, but the aircraft must be inspected annually by an A&P mechanic or an LSA (maintenance) repairman. The owner can perform their own annual inspection if they obtain an LSA (inspection) repairman certificate, by attending a 16-hour LSA repairman-inspection certification course. Because it is now an N-numbered aircraft, it can now only be flown by a pilot with a sport pilot (or higher) license, and it can only be flown for towing by a pilot with a private pilot (or higher) license with a tow endorsement.

Tracy: Wow, that's a great overview on what to do! However, the devil is in the details - and there are lots of details. The list of essential references provided below will guide readers to some excellent sources of detailed information and examples for converting an ultralight to an E-LSA. We'll follow up with more information about requirements for tow pilots and maintenance in our upcoming columns.


  1. "Certification of Aircraft and Airmen for the Operation of Light-Sport Aircraft." Sport Pilot Final Rule, FAA docket number FAA-2001-11133, July, 2004:  
  2. "Certification Procedures for Products and Parts." Title 14 CFR 21.191(i)(1) :  
  3. "Airworthiness Certification of Aircraft and Related Products." FAA Order 8130.2F CHG2:$FILE/Order%208130F%20with%20chg%202%20incorporated.pdf 
  4. FAA Light Sport Aviation Branch information:  
  5. "Light Sport Aircraft Registration":  
  6. Advisory Circular AC 43.13-1B CHG1:  
  7. Advisory Circular AC 43.13-2! CHG2:  
  8. "Light Sport Aircraft Training Providers":  
  9. "E-LSA Conversion Kit":  
  10. FAA Aircraft Registry Web site:  
  11. "Preparing for an Airworthiness Inspection" by Michael Huffman, EAA Sport Pilot and Light Sport Aircraft magazine, April 2006.  
  12. "Propwash: Getting Ready for Sport Pilot" (9-part series) and "Propwash: Hard Facts about Hardware" by Dennis Demeter, Ultralight Flying Magazine, July 2003-May 2004.  
  13. "Sport Pilot Aircraft Certification Guide" Web site by Bill Czygan:  
  14. "Guide to Converting your Ultralight to an Experimental Light Sport Aircraft" on ASC Web site:  
  15. "Twisted Tails: Keep Your Act Together with Safety Wire" by Ishmael Fuentes, Kitplanes magazine, May 2006.  
  16. "Wingtips: Nicopress Fittings" and "Wingtips: The Fine Art of Making Cables" by Dennis Pagen, Ultralight Flying Magazine, December 2005 & February 2005.  
  17. "E-LSA Application" on ASC Web site:  
  18. "The E-LSA Registration" by Jim Groebner, EAA Sport Pilot magazine, December 2006.  
  19. "How to Get You Aircraft Ready for Sport Pilot" Web site by Amy Wiley and Chuck Wales:  
  20. "Program Letter" example:  
  21. FAA list of available LSA DARs:  
  22. "Transitioning your Ultralight" by Mary Jones et al, EAA Sport Pilot magazine, January 2005.


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