94-18-04 R1
UNIVAIR AIRCRAFT CORPORATION
Amendment 39-9173Docket No. 94-CE-05-AD
Revision issued March 1995.
Revises AD 94-18-04, Amendment 39-9017.
Applicability: Models Ercoupe 415-C, 415-CD, 415-D, 415-E, and 415-G, Forney F-1 and F-1A, Alon A-2
and A-2A, and Mooney M10 airplanes (all serial numbers), certificated in any category.
NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of
whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For
airplanes that have been modified, altered, or repaired so that the performance of the requirements of this
AD is affected, the owner/ operator must use the authority provided in paragraph (d) of this AD to request
approval from the FAA. This approval may address either no action, if the current configuration eliminates
the unsafe condition, or different actions necessary to address the unsafe condition described in this AD.
Such a request should include an assessment of the effect of the changed configuration on the unsafe
condition addressed by this AD. In no case does the presence of any modification, alteration, or repair
remove any aircraft from the applicability of this AD.
Compliance: Required within the next 12 calendar months after the effective date of this AD, unless already
accomplished (See Note 2).
To prevent wing damage caused by a corroded wing outer panel structural component, which, if not
detected and corrected, could progress to the point of structural failure, accomplish the following:
(a) Install inspection openings in the outer wing panels and inspect the wing outer panel internal
structural components for corrosion in accordance with the PROCEDURE section of Univair
Service Bulletin (SB) No. 29, Revision B, dated January 2, 1995. Prior to further flight, repair any
corroded wing outer panel internal structural component in accordance with the instructions
contained in the above-referenced service information.
NOTE 2: Complying with the original version of Univair SB No. 29, dated January 27, 1994, or Univair SB
No. 29, Revision A, dated June 7, 1994, is considered equivalent to the requirements of paragraph (a) of
this AD, and is considered "unless already accomplished" for this portion of the AD.
(b) Send the results of the inspection required by paragraph (a) of this AD to the Manager, Denver
Aircraft Certification Office (ACO), 5440 Roslyn Street, suite 133, Denver, Colorado 80216. State
whether corrosion was found, the location and extent of any corrosion found, and the total hours
time-in-service of the component at the time the corrosion was found. (Reporting approved by the
Office of Management and Budget under OMB No. 2120-0056.)
(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the
Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location
where the requirements of this AD can be accomplished.
(d) An alternative method of compliance or adjustment of the compliance time that provides an
equivalent level of safety may be approved by the Manager, Denver ACO, 5440 Roslyn Street, suite
133, Denver, Colorado 80216. The request shall be forwarded through an appropriate FAA
Maintenance Inspector, who may add comments and then send it to the Manager, Denver ACO.
NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD,
if any, may be obtained from the Denver ACO.
(e) The inspection and installation required by this AD shall be done in accordance with Univair
Service Bulletin No. 29, Revision B, dated January 2, 1995. This incorporation by reference was
approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51. Copies may be obtained from the Univair Aircraft Corporation, 2500 Himalaya Road,
Aurora, Colorado 80011. Copies may be inspected at the FAA, Central Region, Office of the
Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(f) This amendment (39-9173) revises AD 94-18-04, Amendment 39-9017.
(g) This amendment becomes effective on March 24, 1995.
FOR FURTHER INFORMATION CONTACT:
Mr. Roger P. Chudy, Aerospace Engineer, FAA, Denver Aircraft Certification Office, 5440 Roslyn Street,
suite 133, Denver, Colorado 80216; telephone (303) 286-5684; facsimile (303) 286-5689.
Service Bulletin No.29 Rev B
OUTER WING PANEL INSPECTION
SUBJECT: Visual Inspection of outer wing panel structure for evidence of corrosion.
MODELS AFFECTED:
All Ercoupe 415-C, 415-CD, 415-D, 415-E and 415-G aircraft.
All Forney F-1 and F-1A aircraft.
All Alon A-2 and A-2A aircraft.
All Mooney M10 aircraft.
COMPLIANCE:
Inspection required within the next one hundred hours of operation or at the next periodic inspection,
whichever occurs first.
STATEMENT OF DIFFICULTY:
There have been field reports of severe corrosion in the outer wing panel structure of several aircraft.
The most effective means of preventing corrosion damage is early identification and correction.
However, the original design configuration does not provide adequate means for routine visual
examination of the wing panels during periodic inspections. Consequently, this Service Bulletin
provides for the installation of strategically placed inspection openings to allow for complete visual
access to the wing panel structure, and calls for an inspection to establish the current condition of the
structure. The inspection openings will then allow routine inspections to be accomplished as required
under FAR Part 43, Appendix D, (f).
PROCEDURE:
1. The following optional procedure is intended only as preliminary inspection to determine if a major
corrosion problem exists, prior to installing the permanent inspection openings in the wing panels.
If equipment is available, cut borescope hole in center of inspection opening locations as
shown on
diagram SB-29 , Rev. B. Inspect wing interior and make preliminary assessment of wing condition.
FAA Advisory Circular AC 43-4A, "Corrosion Control for Aircraft", dated 7/25/91 or later, should
be used to identify and treat corroded areas. Service Memos 45, 58, 58A, 64 and Service Bulletin
No. 27 concern outer wing panel structure and should be reviewed at this time. If preliminary
examination reveals conditions that are not repairable through an inspection opening, remove wing
covering as required and repair or replace unairworthy parts prior to further operation. Replace
covering. Install inspection openings and covers per Steps 2, 3 and 5. If borescope equipment is
not available, proceed to Step 2.
2. Inspection opening location -
Locate inspection openings on the lower wing surface per the enclosed diagram, SB-29 , Rev. B.
Aircraft with factory covered metal skinned wings may already have existing inspection openings.
SB-29, Rev. B. includes these openings.
CAUTION
If the opening locations specified by the diagram interfere with any skin stiffeners on metal
skinned wings, alter the opening location to clear the stiffener.
3. Cutting procedure -
Metal skinned wings - Cut 3.50 inch diameter inspection openings at the locations of No. 2 above and
deburr.
Fabric covered wings- Remove finish to bare fabric at the locations of No. 2 above. Attach reinforcing
ring (P/N 483-15) with Rand-O-Bond, Super Seam or cement approved for use with covering process
STC. If the wing is covered with synthetic fabric, it is recommended that a cover patch be applied over
the inspection ring to prevent the ring peeling away from the fabric surface. Apply finish as required to
touch-up area surrounding reinforcing rings. Carefully cut out center opening of ring.
NOTE
The four outboard inspection openings in each wing may have already been installed per Service
Bulletin No. 27.
4. Inspection procedure -
Using the openings made in Step 3 above, inspect the wing panel structure for corrosion and
unrepaired damage. FAA Advisory Circular AC 43-4A, "Corrosion Control for Aircraft", dated
7/25/91 or later, should be used to identify and treat corroded areas. Service Memos 45, 58, 58A, 64
and Service Bulletin No. 27 concern outer wing panel structure and should be reviewed at this time.
Repair or replace any parts considered unairworthy prior to further operation.
5. Cover plate installation -
After inspection is complete, install cover plates (P/N 483-10) in each opening. On metal skinned
wings, secure each cover plate at the leading edge with one 4 X 3/8 TRA sheet metal screw.
6. Required documentation -
Make log book entry stating compliance with Service Bulletin No. 29B. Weight and balance change is
considered negligible.
DRAWING NO. SB-29
INSTALLATION - INSPECTION HOLES
ERCOUPE
SERVICE MEMORANDUM
No. 45
SUBJECT: OUTER PANEL LEADING EDGE SKIN DENTS
1. This memorandum is prepared to give information of the effect of dents in the outer panel leading
edge skin. On Ercoupes Serial Nos. 1 to 112, inclusive, the leading edge was fabricated of 52S
½H aluminum sheet .013" thick. As this stock could be easily deformed, the leading edge material
was changed to 24ST aluminum sheet .016" thick. This change to heavier, thicker material on the
leading edge was effective on Ercoupe Serial No. 113 and up. With this in mind, more careful
inspection should be made on Ercoupes Serial Nos. 1 to 112, inclusive, for any dents or
deformation. Serious dents should be removed or repaired, as soon as possible, in accordance
with C.A.A. Manual No. 18 covering Repairs and Alterations.
2. A dent or deformation of the leading edge skin will cause a slight increase in drag and a decrease
in lift, especially at low speeds. The extent of the effect is dependent upon the size, shape and
position of the deformation, so that a hard and fast rule of what is a "serious defect" cannot be
easily expressed. In general, if the damage does not affect the structural integrity and does not
extend for more than one foot along the leading edge, it should not cause serious flying difficulties.
However, whenever an airplane is reported as seriously wing-heavy or tending to drop a wing at low
speeds, a careful inspection for leading edge deformation should be made and large defects
corrected.
3. If the leading edge is distorted enough to require replacement, only the heavier gauge outer panel
leading edge skin. (415-14002-1) will be available.
ERCOUPE
SERVICE MEMORANDUM
No. 58
SUBJECT: OUTER PANEL INSPECTION AND REPAIR
1. During the past two years we have received reports of several serious Ercoupe accidents,
apparently involving wing panel failures. Complete investigation does not indicate any inherent
weakness of the wing structure, and, quite to the contrary, the ruggedness of Ercoupe construction
was conclusively proven in each case. There are, however, some facts brought out in the
investigations which we feel should be called to the attention of Ercoupe owners and all operators
having occasion to inspect and repair Ercoupes.
2. Improper maintenance of the wing fabric was the initial cause of one fatal Ercoupe accident
reported. In this case the fabric on the leading edge of the wing split and pulled off while plane was
in flight.
3. It appears that the dope and fabric of the leading edge of the Ercoupe wings deteriorates more
rapidly than the remainder of the wing covering. Special attention should therefore be given to the
inspection of the leading edge area and steps taken to protect the fabric whenever cracks appear
in the dope. With proper care Ercoupe wing fabric can be expected to maintain its strength for as
long as 5 years. Exposure to the elements, especially sunlight, materially reduces the life of doped
fabric.
4. C.A.A. Manual CAM-18 describes proper methods for maintaining and reconditioning wing fabric.
The dope used on Ercoupe wings is a nitrate dope, (not "hot dope" as rumored) and may be
rejuvenated with a high quality rejuvenator. The factory has tested and approved "Fabri-Coat" and
"Sky Lac", both of which have proved to be satisfactory rejuvenators for the original dope. There
are, however, other suitable rejuvenators available. If the wing fabric has already been rejuvenated
or coated with lacquer or other material, rejuvenation is not recommended. If deterioration of the
fabric has progressed far enough so that there is any question as to the strength of the fabric at the
leading edge, it is recommended that the leading edges be reinforced. This may be done by
application of a wide pinked tape, or with use of strips or aircraft fabric, doped to the surface after
rejuvenation.
5. While we have particularly stressed the importance of preserving the leading edge of the Ercoupe
wings, the remainder of the fabric surfaces should also be properly cared for. The complete fabric
surface may be rejuvenated satisfactorily and re-doped with two or three coats of good grade
nitrate dope. A panel should be completely re-covered if rejuvenation cannot be performed
satisfactorily, or if the fabric does not test up to the required strength (56# per inch). The necessary
covers, tape, and dope are available from the Ercoupe distributor dealer organization. Covers are
part numbers 415-14001-3 L R, and are grade "A" fabric.
6. During investigation of the several Ercoupe accidents, the rivets in wing tip splices of Ercoupes in
service were found to be loose. Suspicion existed that the outer panels may have collapsed while
the planes were in flight. as a result of the wing tip joint failures. However, static tests on the loosest
joint found during investigation showed decisively that in spite of the loose rivets the joint, and
consequently the outer panel, was more than strong enough to carry the design air load.
7. While the loose rivet joint tested strong enough, it is recommended that the joints be checked and
loose ones be repaired at 100 hour inspections. To check for such a loose joint. rock the airplane
slowly by applying upward pressure on the wing at the beam tip. If the rivet joint is loose a slight
motion will be felt between the main beam and the wing tip beam. This joint is approximately 36
inches from the wing tip (see Service Manual, figure 10, or Parts Catalog, Figure 7). The motion
between the two parts will sometimes create a grating noise; however, a dry joint in the landing
gear makes a similar noise.
8. If the joint is found to be loose the rivets should be replaced and the following procedure is
recommended:
a. For access, cut a large hole in the fabric of the lower wing surface on the forward side of the
front beam at the splice joint, which is 48" from the spar tip.
b. Cut a small access hole just large enough to uncover the rivets on the upper surface at the joint,
which is 36" from the spar tip. Raise up the L. E. skin and trim it out to expose the rivet heads.
c. Drill out the six countersunk rivets (AN 426-AD-4-5) attaching splice plate to the beam lower
cap strip and the beam tip (415-14029), and the six similar countersunk rivets on the upper cap
strip joint.
d. Enlarge the rivet holes to 5/32" diameter. After this operation the countersink cut will still be
visible; do not countersink further.
e. Re-rivet the splice plates using 12 universal head rivets (GLM 25-2AD-5-5) placing the head of
the rivet outside the wing. The rivet head will be deformed slightly in filling up the countersunk
area. By working through the hole in the lower surface, the rivets in both upper and lower joints
may be bucked.
f. Cover the new rivets with masking or cellulose tape to protect the fabric and patch the fabric in
accordance with C.A.A. Manual #18 or other approved method.
The outer panels of all Ercoupes after serial No. 4894 have universal head rivets installed in the
wing tip splice joint at time of manufacture, and should therefore not develop the looseness
described above.
9. It is recommended that a special inspection be made of all Ercoupe wing panels as soon as
possible to determine condition of dope and fabric on them, and for loose tip joints in all Ercoupes
prior to serial No. 4894. It is further recommended that owners be advised of the urgency to repair
any deterioration or damage in the wing fabric of their airplanes as soon as such deterioration or
damage is observed.
ERCOUPE
FEBRUARY 12, 1953
SERVICE MEMORANDUM
No. 58A
SUBJECT: OUTER PANEL INSPECTION AND REPAIR
1. Service Memorandum #58, issued in May 1950, called attention to the necessity of properly
maintaining Ercoupe wings. At this time we believe it desirable to reiterate these instructions. The
fabric on most of the 1946 Ercoupes has deteriorated to the point where it should be replaced, if
this has not already been accomplished, and the same holds true for the 1947 Ercoupe. The fabric
on Ercoupes of later vintage may or may not be in satisfactory condition, depending upon prevailing
storage and weather conditions as well as their care.
2. It has been brought to our attention by the C.A.A. that there have been several reports of loose
rivets in the wing spar sp1ice as discussed in paragraph 6 of Service Memorandum #58.
Apparently this memorandum has not been brought to the attention of the owners or maintenance
personnel concerned with the airplanes in question and it is therefore suggested that all Ercoupes,
serial #4893 and earlier be re-inspected for loose joints in accordance with the above
memorandum unless the wings were modified in accordance with paragraph 8 of that
memorandum. Any later airplanes which do not have the original wings should likewise be
inspected for possible difficulty in this respect.
3. It is suggested that at the time of re-cover of any wings the replacement of the countersunk rivets by
universal head rivets be accomplished whether or not the joint shows signs of looseness.
ERCOUPE
NOVEMBER 13, 1952
SERVICE MEMORANDUM
No. 64
SUBJECT: REPAIR ASSEMBLY, OUTER PANEL REAR SPAR
1. A new service assembly, S.A. 24, has been developed and just approved by the C.A.A. This
assembly is designed to simplify repair of damage to the inboard end of the outer panel rear spar,
providing the damage does not extend outboard of a point 15" from the inner rib.
2. The service assembly comes complete with the hinge fitting and is drilled for rivets. The sp1ice
plate to attach the assembly to the stub of the original spar, which is cut off in accordance with
instructions, is factory installed on the assembly. The undamaged portion of the spar need not be
removed from the wing in making the repair. Rivets and instructions for installation are supplied with
the assembly.
UNIVAIR AIRCRAFT CORPORATION
OCTOBER 12, 1987
SERVICE BULLETIN
NO. 27
WING TIP INSPECTION
SUBJECT: VISUAL INSPECTION OF WING TIP AREA FOR EVIDENCE OF CRACKS.
MODELS AFFECTED:
All Ercoupe 415-C, 415-CD, 415-D, 415-E and 415-G aircraft.
All Forney F-1 and F-1A aircraft.
All Alon A-2 AND A-2A Aircraft.
All Mooney M10 aircraft.
COMPLIANCE:
Inspection required within the next ten hours of operation or at next periodic inspection which ever
occurs first.
STATEMENT OF DIFFICULTY:
It has been reported that an Ercoupe with previous wing tip damage has been involved in a wing
failure accident. This type of failure may have been caused by hidden damage that was not
discovered or properly repaired at the time of occurance.
PROCEDURE:
1. Inspect aircraft log book for references to wing or wing tip damage repair. If any history of wing or
wing tip damage is found proceed to item 3.
2. If no references are found pertaining to wing or wing tip damage in the log book do not assume
that there was no previous damage. It is very possible that some damage may have occured and
been repaired but not logged in the 40+ year history of some of these aircraft. Visually inspect the
leading edge and lower side of the wing and wing tip for indications of patched fabric or any
irregularities in the wing surface that may indicate concealed damage. Pay particular attention to
the outer 4 wing rib bays. If any indications of wing or wing tip damage are present proceed to item
3.
DRAWING NO. SB27
SERVICE BULLETIN 27
3. If items 1 or 2 indicate any damage the following method may be used to check for hidden damage.
Even if items 1 or 2 yield no indication of damage it is recommended that the following method be
used to confirm no hidden damage exists.
A. Locate the inspection openings in lower wing surface per the enclosed wing diagram. For
metal covered wings the rib centerline can be determined by the row of rivets that secure the
skin to the rib and the back edge of the tip spar is even with the back edge of the skin section.
CAUTION
If the hole locations specified will cut into any skin stiffeners on metal covered wings alter the
hole location as required to clear the obstruction.
B. On metal covered wings cut 8 each 3½ inch diameter inspection holes and deburr openings.
On fabric covered wings remove finish to bare fabric at each opening location and attach
reinforcing ring P/N 007-85012-78 (or equivalent) with Rand-O-Bond or Super Seam fabric
cement (or equivalent). Apply finish as required to touch up area surrounding ring and 8 new
cover plates. Cut out center opening of ring carefully.
C. Using the new openings cut in step B for access, inspect all wing ribs in the tip area for security
of attachment and any possible cracking. Inspect for rib buckling or any other compression
damage that may result from leading edge impact. Repair or replace any damaged parts prior
to further flight. Inspect the tip spar splice joint per Ercoupe Service Memorandums 58 and 58A
to confirm that 5/32 diameter universal head rivets are installed and that they are not loose.
D. After inspection is complete install 8 new cover plates P/N 007-12761-02 (or equivalent) over
openings in lower wing. On metal covered wings secure each cover plate at the leading edge
with one AN530-4-6 sheet metal screw (or equivalent).
E. Make log book entry stating that Ercoupe Service Bulletin No. 27 has been complied with.
PPLANT, OFFICES AND WAREHOUSES: 2500 HIMALAYA ROAD, AURORA, CO 80011
TELEPHONE: (303) 375-8882
FAX Number: (303) 375-8888
WORLD-WIDE MANUFACTURERS AND DISTRIBUTORS OF ERCOUPE AND STINSON PARTS AND
ASSEMBLIES.
FAA Repair Station No. VS3R930L - Airframe
Service Bulletin No.29 Rev A
OUTER WING PANEL INSPECTION
SUBJECT: Visual inspection of outer wing panel structure for evidence of corrosion.
MODELS AFFECTED: All Ercoupe 415-C, 415-CD, 415-D, 415-E and 415-G
aircraft.
All Forney F-1 and F-1A aircraft.
All Alon A-2 and A-2A aircraft.
All Mooney M10 aircraft.
COMPLIANCE: Inspection required within the next one hundred hours of
operation or at the next periodic inspection, whichever
occurs first.
STATEMENT OF DIFFICULTY:
It has been reported that several aircraft have been found to have severe corrosion in the outer wing panel
structure. There is no existing provision for complete visual inspection of the outer wing panel structure.
PROCEDURE:
1. Preliminary inspection (optional) -
If equipment is available, cut borescope hole in center
of inspection opening locations as shown on diagram
SB-29 . Inspect wing interior and make
preliminary assessment of wing condition. FAA Advisory
Circular AC 43-4A, "Corrosion Control for Aircraft",
dated 7/25/91 or later, should be used to identify and
treat corroded areas. Service Memos 45, 58, 58A, 64 and Service Bulletin No. 27 concern
outer wing panel
structure and should be reviewed at this time. If
preliminary examination reveals conditions that are not
repairable through an inspection opening, remove wing
covering as required and repair or replace unairworthy
parts prior to further operation. Replace covering.
Install inspection openings and covers per Steps 2, 3
and 5. If borescope equipment is not available,
proceed to Step 2.
2. Inspection opening location -
Locate inspection openings on the lower wing surface
per the enclosed diagram, SB-29 . Aircraft with
factory covered metal skinned wings may already have
existing inspection openings. SB-29 includes
these openings.
CAUTION
If the opening locations specified by the diagram interfere with any skin stiffeners on metal
skinned wings, alter the opening location to clear the stiffener.
3. Cutting procedure -
Metal skinned wings - Cut 3.50 inch diameter
inspection openings at the locations of No. 2 above and
deburr.
Fabric covered wings- Remove finish to bare fabric at the
locations of No. 2 above. Attach reinforcing ring (P/N
483-15) with Rand-O-Bond, Super Seam or cement approved
for use with covering process STC. If the wing is
covered with synthetic fabric, it is recommended that a
cover patch be applied over the inspection ring to
prevent the ring peeling away from the fabric surface.
Apply finish as required to touch-up area surrounding
reinforcing ring. Carefully cut out center opening of
ring.
NOTE
The four outboard inspection openings in each wing may have already been installed per Service
Bulletin No. 27.
4. Inspection procedure -
Using the openings made in Step 3 above, inspect the
wing panel structure for corrosion and unrepaired
damage. FAA Advisory Circular AC 43-4A, "Corrosion
Control for Aircraft", dated 7/25/91 or later, should be
used to identify and treat corroded areas.
Service Memos 45, 58, 58A, 64 and
Service Bulletin No. 27 concern
outer wing panel structure and should be reviewed at
this time. Repair or replace any parts considered
unairworthy prior to further operation.
5. Cover plate installation -
After inspection is complete, install cover plates (P/N
483-10) in each opening. On metal skinned wings, secure
each cover plate at the leading edge with one 4 X 3/8
TRA sheet metal screw.
6. Required documentation -
Make log book entry stating compliance with
Service Bulletin No. 29. Weight and balance change is considered negligible.
[Figure]
PLANT, OFFICES AND WAREHOUSES: 2500 HIMALAYA ROAD, AURORA, CO 80011
TELEPHONE: (303) 375-8882
FAX Number: (303) 375-8888
WORLD-WIDE MANUFACTURERS AND DISTRIBUTORS OF ERCOUPE AND STINSON PARTS AND
ASSEMBLIES.
FAA Repair Station No. VS3R930L - Airframe
Service Bulletin No.29
OUTER WING PANEL INSPECTION
SUBJECT: Visual Inspection of outer wing panel structure for evidence of corrosion.
MODELS AFFECTED:
All Ercoupe 415-C, 415-CD, 4l5-D, 415-E and 415-G aircraft.
All Forney F-1 and F-1A aircraft.
All Alon A-2 and A-2A aircraft.
All Mooney M10 aircraft.
COMPLIANCE:
Inspection required within the next one hundred hours of operation or at the next periodic inspection,
whichever occurs first.
STATEMENT OF DIFFICULTY:
It has been reported that several aircraft have been found to have severe corrosion in the outer wing panel
structure. There is no existing provision for complete visual inspection of the outer wing panel structure.
PROCEDURE
1. Preliminary inspection (optional) -
If equipment is available, cut borescope hole in center of inspection opening locations as shown on
diagram SB-29 . Inspect wing interior and make preliminary assessment of wing condition. FAA
Advisory Circular AC 43-4A, "Corrosion Control for Aircraft", dated 7/25/91 or later, should be used to
identify and treat corroded areas. Service Memos 45, 58, 58A, 64 and Service Bulletin No. 27 concern
outer wing panel structure and should be reviewed at this time. If preliminary examination reveals
conditions that are not repairable through an inspection opening, remove wing covering as required
and repair or replace unairworthy parts prior to further operation. Replace covering. Install inspection
openings and covers per Steps 2, 3 and 5. If borescope equipment Is not available, proceed to Step
2.
2. Inspection opening location -
Locate inspection openings on the lower wing surface per the enclosed diagram SB-29 . Aircraft with
factory covered metal skinned wings lay already have existing inspection openings. SB-29 includes
these openings.
CAUTION
If the opening locations specified by the diagram interfere with any skin stiffeners on metal
skinned wings, alter the opening location to clear the stiffener.
3. Cutting procedure -
Metal skinned wings - Cut 3.50 inch diameter inspection openings at the locations of No. 2 above and
deburr.
Fabric covered wings- Remove finish to bare fabric at the locations of No. 2 above. Attach reinforcing
ring (P/N 483-15) with Rand-O-Bond, Super Seam or cement approved for use with covering process
STC. If the wing is covered with synthetic fabric, it is recommended that a cover patch be applied over
the inspection ring to prevent the ring peeling away from the fabric surface. Apply finish as required to
touch-up area surrounding reinforcing rings. Carefully cut out center opening of ring.
NOTE
The four outboard inspection openings in each wing may have already been installed per Service
Bulletin No. 27.
4. Inspection procedure -
Using the openings made in Step 3 above, inspect the wing panel structure for corrosion and
unrepaired damage. FAA Advisory Circular AC 43-4A, "Corrosion Control for Aircraft", dated
7/25/91 or later, should be used to identify and treat corroded areas. Service Memos 45, 58, 58A, 64
and Service Bulletin No. 27 concern outer wing panel structure and should be reviewed at this time.
Repair or replace any parts considered unairworthy prior to further operation.
5. Cover plate installation -
After inspection is complete, install cover plates (P/N 483-10) in each opening. On metal skinned
wings, secure each cover plate at the leading edge with one AN530-4-6 sheet fetal screw.
6. Required documentation -
Make log book entry stating compliance with Service Bulletin No. 29. Weight and balance change is
considered negligible.
DRAWING NO. SB-29
INSTALLATION - INSPECTION HOLES
PLANT, OFFICES AND WAREHOUSES: 2500 HIMALAYA ROAD, AURORA, CO 80011
TELEPHONE: (303) 375-8882 TELEX: 317327
FAX Number: (303) 375-8888
WORLD-WIDE MANUFACTURERS AND DISTRIBUTORS OF ERCOUPE AND STINSON PARTS AND
ASSEMBLIES
FAA Repair Station No. VS3R930L - Airframe
