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

“Serving the aviation community since 1982”

September 9, 2011

Installation Instruction No. 

SB 15AC06-08-10

To be used in conjunction with

Installation Sketch No. SB 15AC06-08-10

Introduction

The following instructions are for installing the 2-1272 reinforcement doubler and 2-1285 

inspection cover assemblies into the Rogers (Aeronca) 15AC and S15AC Sedan airplanes with 

the wings still attached to the fuselage AND if the wings are removed from the fuselage. 

If, in the course of installing the inspection cover and doublers, slight corrosion is encountered 

in the upper and/or lower wing spar cap angles, determine if the corrosion can be dealt with at 

this level of inspection. If moderate to severe corrosion is detected then the aircraft must be 

removed from service to determine the extent of damage to the spar cap angles. This would 

probably require the removal of the wings and skins to do a more detailed inspection. This 

could possibly include replacing the spar cap angles with new parts.

Also, corrosion may have spread to the adjoining wing skins and main spar webs. These 

components must be inspected as well and repaired or replaced as necessary.

Installation

1) Study the enclosed installation sketch thoroughly before drilling or cutting any holes in 

the wings.

2) Lay out the pattern on the appropriate wing bottom skins according to the sketch. If 

there is any conflict with any stiffeners that were installed by Aeronca that interfere 

with the exact placement of the doublers in the sketch, it is permissible to relocate that 

doubler in that bay to not interfere with the stiffener.

3) Locate the center of each hole to be cut into the wing skin. Using a compass or a set of 

dividers, lightly scribe a 3.5” diameter circle onto the wing skin. 

NOTE: this is the I.D. of the doubler; use this circle to center the doubler on the hole. 

Do not cut any center holes in the wing yet.

4) Referring to Sketch No. SB 15AC06-08-10 for proper placement/dimensions, locate the

doubler centers on the wings. Match-drill the wing skins with a #40 pilot drill using 

each doubler as a template for that hole.

(1 of 4)
 Installation Instruction No. SB 15AC06-08-10, continued

5) Upon completing Step 4 for all the doublers, go back to all the centers and re-scribe the 

wing skins to a 4.00” diameter circle. 

6) Drill a #30 pilot hole in the wing skin. Enlarge the hole to whatever size the pilot is on 

your fly cutter or hole saw. 

7) Either invert the pilot drill on the fly cutter or hole saw or use a replacement drill blank

of the same diameter to use as a smooth pilot to cut the 4.00” diameter holes in the 

wings. This will keep the center constant and not allow the cutter or saw to wander and 

enlarge the hole. Exact hole size is critical for the cover to fit properly.

8) When cutting the 4.00” diameter hole, it is recommended that the center be set first. If 

using a fly cutter, use a variable speed drill to power the cutter at a very slow speed. 

Even better yet, turn the fly cutter by hand. Most of the skins are either .020” or .025” 

thick. Only the skin directly aft of the main fuel cell is .032” thick.

9) Once the holes are all cut and deburred, proceed with the further inspection of the wing 

spar cap angles, main spar web, rib attaching flanges and skins.

10) Refer to AC43.13-1B, Chapter 6, Corrosion Inspection & Correction, Section 2, Types 

of Corrosion, Section 6, Corrosion Removal Procedures, Section 7, Basic Corrosion 

Removal Techniques, & Section 8, Aluminum & Aluminum Alloys for guide lines on 

their appropriate topics. These parts of the AC43.13-1B are taken directly from AC43-

4A, Corrosion Control for Aircraft. For more detailed information go online to the 

original document:

AC43-4A, Corrosion Control for Aircraft, Dated 07/25/1991 

 

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/a7ffc0f8

b6216a43862569b5005081ed/$FILE/AC%2043-4a%20.pdf

11) If only light or slight corrosion is encountered, clean the affected areas as per AC43.13-

1B, Chapter 6, Section 6, page 6-22, Table 6-1, ref. Aluminum Alloys except Clad 

Aluminum and Clad Aluminum. Also reference page 6-23, Figure 6-14 and para. 6-118 

for methods of removal of corrosion. 

If any intergranular or exfoliation corrosion is found, especially on the upper or lower 

(or both) spar cap angles, then the aircraft must be removed from service and the 

affected cap angle(s) and any other damaged parts must be replaced with new parts. 

This situation indicates the extreme extent that the corrosion has advanced and thus 

renders the aircraft unairworthy. 

(2 of 4)

 
Installation Instruction No. SB 15AC06-08-10, continued

12) Once any corrosion has been dealt with properly, prime the doublers with zinc 

phosphate (Federal Spec. TT-P-1757A) and install them in their respective locations

using the following method to insert the doublers into the wing if the wing is fully 

assembled whether or not it is installed on the aircraft. UNDER NO CIRCUMSTANCES 

ARE THE DOUBLER RINGS TO BE CUT OR SPLIT UNLESS ALTERNATE INSTALLATION 

INSTRUCTIONS ARE FOLLOWED IN DRAWING NO. 2-1272 SPLICE.

A) For the doublers aft of the main spar, remove the lower wing root fairings and 

pass the three (3) pre-primed doublers through the 2

nd lightening hole in the 

intermediate butt rib and the second rib outboard, dropping one of the doublers 

in the second rib bay. Progressively pass the remaining two (2) doublers into

their respective bays by using the inspection holes cut in the wing skins to pass 

the doublers further out into the wing.

B) Another method that may be used is to remove the aileron push-pull rod from 

the aileron control horn and move the push-pull rod to the side. Pass the preprimed doublers through the push-pull rod slot in the wing forward toward the 

aileron bell crank. Pass the three (3) primed doublers inboard using the already

installed aileron bell crank installation and inspection cover through the 

intermediate rib 2nd lightening hole, dropping one of the doublers in the 6

th rib

bay and passing the remaining doublers inboard to their respective rib bays 

using the pre-cut holes for access to move the doublers. 

C) To install the pre-primed doublers forward of the main spar: 

On the outboard end of the wing at STA. 137.02, ref. Sketch No. SB 15AC06-

08-10, measuring from the aft edge of the leading edge nose skin, bottom of 

wing, drill out and remove nose rib rivets at 5.6”, 7.7”, 9.8” and if necessary at

11.9” to allow separation of the wing skins to slip the doublers between the 

skins. 

Insert 5 each for the right wing, 4 each for the left wing, into the rib bay between 

STA. 137.02 and STA. 124.25 between the -5 L/R and -6 L/R skins. 

Pass the doublers through the first lightening hole in each nose rib, into each rib 

bay, to drop a doubler at its required location. Replace the rivets at STA. 137.02 

that were removed to perform this operation immediately. 

NOTE: The first lightening hole in the nose rib is the same diameter as the O.D. 

of the doubler. The doubler has been slightly modified with 2 opposing “flats” 

sheared from the edges to allow ease of passage of the doubler through the hole 

in the nose rib. 

DO NOT FORCE THE DOUBLER THROUGH THE NOSE RIB HOLE; IT WILL 

DESTROY THE INTEGRETY OF THE NOSE RIB. ROTATE THE DOUBLER 

UNTIL IT PASSES THROUGH THE LIGHTENING HOLE EASILY.

(3 of 4)
 Installation Instruction No. SB 15AC06-08-10, continued

13) Once all the doublers are in place, use 3/32” clecos in every other hole and re-drill the 

skins and doublers to a #30 hole. Install the supplied MS20470AD4-4.5 rivets. Remove

the clecos and install the remaining rivets.

14) It is recommended that, if the wing is to be disassembled for replacement of skins 

 and/or wing spar cap angles, the location of the doubler centers and rivet patterns be 

completed in the old skins prior to disassembly so that the pattern may be accurately

transferred to the new skins with a minimum of effort. Upon reassembly of the wing, 

the skins and doublers can then be primed with zinc phosphate and the doublers 

installed onto the skins using the supplied M20470AD4-4.5 rivets before the skins are 

attached/re-attached to the ribs and spars. 

 15) Upon completion of the installation of the doublers or replacement of spar cap angles, 

doublers and skins, repaint the wings and the new inspection covers as necessary. 

It is required that the inner surfaces of the wing be treated with ACF-50 (or equivalent) 

anti-corrosion compound. This treatment must be done after the wings are finished and 

repainted. The anti-corrosion compound is an oil based material and will interfere with 

paint adhesion should it leak out from the lap seams of the wing skins.

Make the following entry into the aircraft logbooks or permanent records:

“This aircraft has been modified and repaired in accordance with Rogers Service Bulletin No.

SB 15AC06-08-10 as applicable to Rogers (Aeronca) Model 15AC & S15AC Sedan airplanes. 

 At minimum, this required the installation of 15 new 2-1285 inspection covers and 2-1272 

doublers in the wings fore and aft of the main spar assembly. Weight change is negligible.” 

NOTE: If skins and spar caps were replaced, enumerate which skins and which cap angles were 

replaced in the aircraft records. This is FAA Accepted Data; no 337 is required for compliance 

with this Service Bulletin; it is a logbook or permanent records entry only.

______________________________________END__________________________________ 

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