Sportsman Service Bulletin #74 – Fuselage Tail Cone Damage


Glasair Aviation published a service bulletin to address crushed or delaminated portions of the tail cone near the aft tailwheel bracket. The SB is applicable to all Sportsman aircraft serial numbers 7000-7450.

Service Bulletin #74 can be downloaded from the Glasair Aviation website or from our document library.

For more about this bulletin, refer to this topic in the GAOA forum.

Sportsman SB 74 Tailwheel Assembly Compressing Foam Core
Tailwheel assembly compressing foam core.

From the Service Bulletin:

It has come to our attention that a number of Sportsman tailwheel installations have resulted in crushed and/or delaminated fuselage laminates near the aft tailwheel bracket. This is due to occasional shock loads transmitted through the small wedge shaped aluminum block above the tailwheel leaf springs. In several extreme cases, partial dis-bonding of the aft most fuselage bulkhead flange (Bulkhead “E”) to the fuselage may have occurred.

Some of the dis-bonds are easily visible, while others may appear to be superficial. In most cases, sanding off the interior fuselage laminates on the lower third of the flanges of bulkhead “E” and along the fuselage seam above the tailwheel leaf spring assembly exposes deeper cracks, voids, and delamination.

This service bulletin covers the removal of the tailwheel assembly, inspection of the aft fuselage between bulkheads “D” and “E,” reinforcement of this area, and the optional, but recommended replacement of the aft tailwheel attachment.

Through the investigation of this problem we became aware of a small likelihood of occurrence of failed laminates attaching bulkhead “E” to the fuselage shell. Out of an abundance of caution we request that all fuselages Serial No: 7300 – 7450 perform the bulkhead flange inspection.

Sportsman Service-Bulletin-74-Tailwheel-Aft-Spring-Block
Aft bay of fuselage, tailwheel assembly and horizontal stabilizer removed.

Notable Replies

  1. FYI folks, in case you are like me and have spotted the inconsistency in wording, I’ve asked Glasair to clarify whether they are referring to fuselage serial number or kit serial number. I have likewise asked them to re-issue the service bulletin with this clarification in place.

    (Very little bugs me more than a poorly-written document, especially when it has “mandatory” pasted all over it. If you’re going to issue a Service Bulletin, make sure it’s right, and maybe run a draft past a couple of users of the product to check it for sanity!)

  2. I sent an email to Airframes Alaska about a T3 system, previously described by Dennis Vanatta:

    The website says the T3 isn’t currently in production for the Sportsman, but has been done only as one-off installations:

    There are probably enough people interested in a T3 after this service bulletin to make it worthwhile for them to produce a Sportsman installation. Perhaps some sort of group buy.

  3. To Randi’s point… if you are talking with the factory, Omar, please let them know the service bulletin should contain a parts list of all the parts included in each of the two SB implementation kits. Asking for $400 without giving any indication of the value the customer is receiving for that cash outlay is pretty high-handed. Not to mention, as those who are supposed to implement the SB, we need to know what parts come with the kit and what parts we might reasonably be expected to furnish ourselves.

    As an example, does either kit include resin and all associated chemicals to promote and catalyze it? If not, a purchaser of the SB kit might be in for a mighty big surprise, especially if they live at the end of a long supply chain in Africa or Scandanavia.

    Additionally, to Sven’s point, the SB applicability should be amended such that compliance is required for taildraggers but is optional for trikes, and that conversion from trike to taildragger configuration brings with it a requirement for implementing the structural enhancements outlined in the SB. A copy of the SB should be included in the parts list for taildragger conversion kits purchased from Glasair. Likewise for trike owners, a one-time inspection, by any reasonable means, should be clearly delineated in the SB text, with guidance provided for optional inspections any time a tail strike is suspected.

    Lastly, the SB instructions should, as a final step, include instructions to update the aircraft technical logs indicating compliance with the SB (including the extent to which the SB was complied with, such as “inspection carried out” for trikes). This is a pretty glaring omission from the original SB text.

    I will reiterate that Glasair should be embarrassed to produce a Service Bulletin with this many errors and omissions, and so much evidence of a glaring lack of consultation with the community of owners/operators. Glasair has a history of issuing SB’s in a vacuum and this history reflects negatively on the perception of their professionalism as an aircraft design house and even worse on their reputation for developing positive customer relations. (Remember the customer-developed bolt-on seat belt mod, and the significant improvements developed by customers to improve the factory technique for installing the “slingshot” vertical stabilizer spar beef-up? Yes, these are a few of the SB missteps made by the factory that come immediately to mind.)

  4. Details of Group Buy of T3 Suspension system for Sportsman

    Dan DuFault has agreed to extend a group buy discount to the Glasair Owners members.

    To meet the conditions for obtaining this group buy, we need at minimum orders for 10 kits .

    The price for Sportsman T3 Suspension with “saddle mount” for this group buy will be $787.50 plus $25 shipping to CONUS for a total of $812.50 . Cost for shipping to locations outside CONUS will be quoted on request.

    Terms will be “payment in full” with order via check or money order. Add 3% to product price plus shipping for PayPal payment (ie $812.50 + $24.38 = $836.88 PayPal CONUS).

    The cutoff date for this group buy is April 17th. This means that April 17th is the last day to have full payment in Dan’s hands otherwise pricing reverts back to $875 plus shipping and any other costs.

    Deliveries are expected to begin early May with product in hand around the 5th – 10th of May.

    Make checks / money orders for payment in full:

    Supercubs North

    Sent to:

    Dan Dufault
    Supercubs North
    88 Calderwood lane
    Lincolnville Maine 04849


    PayPal Payments to:

    Group Buy Coordinator

    Rocky Morrison

  5. Just got an email back from Glasair in regards to using a borescope to inspect the flanges for trike gear configured aircrafts:

    " A high quality, well-lit photo should allow for inspection of the bulkhead to fuselage joint just fine. If the inspecting A&P or builder determines the quality of the joint to be acceptable using the borescope this can be a method of compliance with the service bulletin. If there is uncertainty after the borescope inspection we recommend proceeding to visual inspection, and from there to a repair if necessary."

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