Burl’s Aircraft, LLC

P.O. Box 671487

Chugiak, Alaska 99567-1487

(907)688-3715 (907)688-5031 fax

Email~ burl@biginalaska.com web: www.burlac.com

June 8, 2010

MANDATORY SERVICE BULLETIN

No. 15AC06-08-10

Brief history:

Over the past 12 years it has become apparent that there is a potential problem 

brewing in relation to the main wing spar cap angles in the Rogers (Aeronca)

15AC Series Sedan.

Since first discovered in June of 1998, there have been at least 34 wings that 

have been affected with intergranular corrosion and exfoliation of either the 

upper or lower, or both, wing main spar cap angles. 

Sedan owners have up until now been verbally warned of this potential problem 

and were given fairly cursory advice and instruction on how to inspect the main 

wing spar cap angles for this type of corrosion. 

Those that were found to have the problem have been corrected with the 

installation of new, replacement, PMA’d spar cap angles to facilitate the 

necessary repairs.

This problem has never been linked to any one particular cause. At first it was 

thought the corrosion was caused by stress (over loading the aircraft) or poor 

heat treat process of the main spar cap angles or both. The fact that some aircraft 

have been operated as agricultural sprayers was looked at as possible scenario. 

Saltwater operation was thought to play a part in this problem, too. To date, no 

one particular cause or set of operational circumstances has been determined to 

be the culprit for this anomaly. 

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Mandatory Service Bulletin No. 15AC06-08-10, continued;

Immediate action required:

Within the next ten (10) hours of operation and not more than three (3) months

after receipt of this Service Bulletin, the following preliminary initial inspection 

must be completed:

First, remove the cotter pin, nut and attaching AN4-7 bolt on the aileron pushpull rod, P/N 3-983 from the 2-1164 aileron actuating arm/bracket on the 

aileron. Rotate the aileron on its hinges up and forward on top of the wing to 

allow access to the lightening holes in the rear spar. 

Using a good quality, strong halogen flashlight or equivalent light source, 

looking through the afore mentioned rear spar lightening holes, in the areas 30-

36 inches inboard and outboard of the wing lift strut attachment fitting that is 

riveted to the main spar web, carefully inspect the exposed trailing edges of both 

the upper and lower main spar cap angles for signs of cracking, intergranular 

corrosion or exfoliation. 

This type of corrosion is characterized by the similarity in appearance to a stack 

of newspapers as seen from the cut edges. Refer to AC43.13-1B, Change 1, 9-

27-01, Chapter 6, Section 2, page 6-7, para. 6-17 and page 6-8, para. 6-18.

If no corrosion is found during this phase of inspection then proceed to the next 

step.

Within the next 25 hrs of flight but not more than three (3) months, install 

new wing inspection hole skin reinforcement doublers, P/N 2-1272-2 and the 

associated 2-1285-2 3-screw cover plate at the locations indicated, fore and aft, 

of the main wing spar along the length of both wings as per the enclosed sketch, 

SK 15AC06-08-10.

During the cover plate and doubler installation, re-inspect the main spar caps, 

both upper and lower to determine if there is any (further) evidence of corrosion. 

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Mandatory Service Bulletin No. 15AC11-08-08, continued;

Upon completion of cutting the holes for the doublers, provided no corrosion is

evident or very slight evidence of corrosion is present, spray the spar cap angles, 

upper and lower, with ACF-50 corrosion inhibitor or equivalent AFTER painting 

or repainting of the wing if painting is required. 

Finish installation of the doublers and paint the rivet heads with an artist’s brush 

to match the wing color. Paint the covers and screws to match and install on the 

aircraft. 

If heavy or severe corrosion is found no further flight is permitted until the 

proper repairs have been undertaken. 

No splicing of the spar cap angles is approved. They must be replaced in their 

entirety as a single piece. Replace any and all affected wing skins, spar webs, 

doubler plates, etc. as necessary. 

New upper cap angle, P/N 7-817-5 and lower spar cap angle, P/N 7-817-6, the 

wing inspection hole reinforcement doubler, P/N 2-1272-1 and cover plates with 

screws, P/N 2-1285-1 are available from Burl’s Aircraft, LLC, P.O. Box 

671487, Chugiak, Alaska 99567. Phone (907)688-3715.

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