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. you beat me Mark, probably the time I wasted beating my head against the wall and yelling. Service Bulletin GSSB74.

    The modification may be made by using one of the following options:

    • Kit # 027-00005-05 Cost: $399.00
    • Kit # 027-00005-06 Cost: $ 59.95

    This service bulletin is mandatory.

    nothing frosts my butt more than to see the “mandatory” statement attached to a service bulletin!

    looks like a great time to go back on floats

    I would also suggest a third option, install a T3 tailwheel.

    Years ago (well not that long ago, 2004) when I first looked at the Sportsman with another potential buyer (we both purchased one, both of us went on floats) we had some long discussions of the suitability of the Sportsman, both of us had concerns for the lack of structure or a cage in the tailcone section of the plane.


  2. 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!)

  3. 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.

  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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