AD 86-19-10

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AD Number:
86-19-10
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; MOONEY AIRCRAFT CORPORATION Models M20 and M20A (all serial numbers) airplanes
Subject:
Wooden Structures
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
10/06/1986
Make:
Mooney Aviation Company Inc
Model:
M20 | M20A
Product Type:
Aircraft
Product Subtype:
Small Airplane
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 86-19-10
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-5408

AD NUMBER:   86-19-10

SUBJECT HEADING:   Airworthiness Directives; MOONEY AIRCRAFT CORPORATION Models M20 and M20A (all serial numbers) airplanes

ACTION:  

SUMMARY:  

DATES:   Effective October 6, 1986.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
86-19-10 MOONEY AIRCRAFT CORPORATION: Amendment 39-5408. Applies to Models M20 and M20A (all serial numbers) airplanes certificated in any category.

Compliance: As indicated in the body of the AD.

To preclude structural failure due to deteriorated wooden structures, accomplish the following:

(a) Within the next 30 days after the effective date of this AD, if AD 76-15-01 has not been previously complied with, or within 12 calendar months after the last 12 month repetitive inspection required by AD 76-15-01, whichever is applicable, and each 12 months thereafter accomplish the wood structure proof load tests, modifications and visual inspections specified in paragraphs (d), (e), (f) and (g) of this AD and repair all discrepancies found prior to further flight.

(b) The empennage proof load tests and modification and inspection requirements of paragraphs (a), (d) and (e) are not required on airplanes modified with an all-metal empennage installed per Mooney Service Bulletin (S/B) Kit No. M20-170-1.

(c) Within the sixth month after the accomplishment of the inspections required by paragraph (a) of this AD, or within 12 calendar months after the last six month interval repetitive inspection required by AD 76-15-01 and each 12 months thereafter, whichever is applicable, accomplish the empennage and wing inspections specified in Parts IIA, III8, III9, and III10 of Mooney S/B No. M20-170A dated February 24, 1969, and repair all discrepancies found prior to further flight.

(d) On airplanes not equipped with an all-metal empennage, proof load test the empennage and supporting structure as follows:

(1) Apply proof loads to the vertical fin spar as shown in Figure 1 of this AD. Apply the load to the right side and then to the left side. Apply proof loads to the rudder hinges of the fin as shown in Figure 3 of this AD. Apply hinge proof loads to the right side and then to the left side.

(2) After the initial proof load testing in paragraph (d)(1) of this AD, at intervals not to exceed one year, apply the proof loads to the vertical fin spar and rudder hinges as shown in Figures 1 and 3 of this AD. Apply the loads in one direction only during each 12 month inspection cycle by applying the loads to the right side at the end of the first interval and alternating load direction similarly thereafter.

(3) If the empennage fails during the proof loading specified in paragraphs (d)(1) or (d)(2) of this AD, prior to further flight, replace the wood empennage with an all-metal empennage in accordance with the instructions contained in Mooney S/B Kit No. M20-170-1. The empennage is considered to have failed when complete separation of the vertical fin from the horizontal stabilizer occurs, fin spar cracks occur, the hinge separates or loosens from the fin, other wood failures occur, glue joint failures occur, or permanent deformation occurs as shown in Figure 2 of this AD.

(e) Modify and inspect the wood empennage as follows:

(1) If fin failure did not occur during the proof load application specified in paragraphs (d)(1) and (d)(2) of this AD, prior to further flight, modify the vertical fin and visually inspect the empennage as follows:

(i) Modify the vertical fin by adding inspection access holes and reinforcing straps in accordance with Parts IB and IC of Mooney S/B No. M20-170A dated February 24, 1969, unless previously accomplished.

(ii) Visually, and if necessary using the methods in paragraph (h) of this AD, inspect the empennage in accordance with S/B No. M20-170A dated February 24, 1969, Parts IA and II and repair any discrepancies found prior to further flight.

(f) Prepare the wing and wing carry-thru structure for inspection in accordance with instructions in Part III of Mooney S/B No. M20-170A dated February 24, 1969, and as follows:

(1) Remove the wing to fuselage fairings and fillets.

(2) Remove all the wing and center section access doors and panels. (Refer to Figure 5 of Mooney Service Bulletin (S/B) No. M20-170A).

(3) Remove the sealing tape at the wing-fuselage joint.

(4) Remove the rear seat and auxiliary fuel tank for access to the wing center section.

(5) Remove flap gap metal seal strips from the top trailing edge of both wings.

(6) Disconnect and remove the wing flaps and ailerons.

(g) Visually, and if necessary using the methods in paragraph (h) of this AD, inspect the wing and wing carry-thru structure and repair any discrepancies found prior to further flight in accordance with instructions in Part III of Mooney S/B No. M20-170A dated February 24, 1969, and as follows:

(1) Inspect the areas around wing to fuselage attach fittings for evidence of deterioration or joint separation.

(2) Inspect the flap and aileron attach bolts, bearings, bushings, and hinge fitting attach bolts and bushings for evidence of rust, corrosion, and wear. See Figure 6 in Mooney S/B No. M20-170A dated February 24, 1969.

(3) Visually inspect the wood end-grain surrounding bolt holes for evidence of rust, discoloration, deterioration, and evidence of moisture accumulation at the trailing edges of the wings.

(4) Visually inspect the rear stub spar for glue bond separations, water stains, and wood rot. If these inspections identify any questionable areas in which possible deterioration may exist in the concealed spar caps, prior to further flight, determine the condition of the internal spruce core in accordance with paragraph (h) of this AD. See Note 1 of this AD.

(5) Visually inspect all accessible areas of the main spar from the fuselage center line (BL 0.0) out to left and right wing Station 59.25 for glue bond separations, water stains, and wood rot. If these inspections identify any questionable areas in which possible deterioration may exist in the concealed spruce spar prior to further flight determine the condition of the internal spruce core in accordance with paragraph (h) of this AD. See Note 1 of this AD.

(6) Visually inspect the accessible interior of the wing using a flashlight and mirror, for wood decay, water and/or wood stains, pooled dust/dirt which may indicate evidence of previous standing water, rust or corrosion on metallic surfaces, wood discoloration, and detectable moisture. See Note 1 of this AD.

(7) Inspect the upper and lower exterior surfaces of the wing, including the wheel well, for the following: See Note 1 of this AD.

(i) Indications that the wood immediately below the fabric is soft or contains excessive moisture (i.e., swollen). Soft wood may be located and/or confirmed by depressing the wing's surface in the vicinity of the area in question with a rounded, blunt instrument and comparing its hardness to that of good wood. Note that any areas being compared must have identical substructure.

(ii) Indications that the fabric/paint is delaminating from the wood surface (bubbles, discoloration, boils, soft spots and other surface flaws).

(iii) Cracks or breaks in the paint which could allow water to enter the wing.

(iv) Any other exterior damage which would allow water to penetrate the fabric/paint barrier and enter the wood.

(8) Visually inspect the rear spar in all areas it is accessible from the fuselage center line out to the left and right wing tips for wood rot, water stains in wood and glue joint separation. Pay special attention to the area around all flap and aileron hinge supports, including the support ribs, lower wing skins, spars and closeout strips at wing stations 22.0 and 147.0 (flap inboard and outboard hinge support ribs).

(9) Inspect all drain holes on the bottom of the wing to ensure they are completely open and free of burrs and/or pieces of fabric.

(10) Visually inspect the fuel scupper areas of the main and auxiliary fuel tank fillers for sealant condition between scupper boxes and wing structure.

(11) Check main and auxiliary fuel tank scupper drains to be sure they are not clogged.

(12) Visually inspect aileron and flap fabric covering under metal gap strips in accordance with Mooney S/B No. M20-29 dated December 4, 1957.

(13) Visually inspect the areas of the upper wing surface trailing edge under flap gap metal seals for fabric or wood deterioration. Be alert for deteriorated wood around screw holes used in holding the metal strip to the wing.

(14) Visually inspect, if necessary repair, and refinish the main landing gear wheel well area in accordance with Mooney S/B No. M20-67 dated February 15, 1960.

(h) If during any inspections specified in paragraphs (e) and (g) of this AD there are visual indications of wood deterioration below the surface, prior to further flight, inspect and test these areas to assure their structural integrity by using one or more of the following:

(1) Test for soft/decayed wood with a sharp probe such as an awl or sharp pocket knife.

(2) Disassemble the structure as necessary to gain access to the area and perform a detailed visual inspection.

(3) Tap the wood area in question with a small rounded blunt instrument approximately the size of a small pocket knife. Compare the sound to similar areas that are not suspect. Assuming similar understructure, an abrupt change in sound to a less or non-resilient sound may indicate decay below the surface.

(i) If significant structural repair of the wing main spar, rear spar empennage is found necessary as a result of the inspections and tests of the preceding paragraphs, prior to initiation of the repair, contact Mooney Aircraft Corporation, Post Office Box 72, Kerrville, Texas 78028; Telephone (512) 896-6000, or the local Mooney Aircraft Repair Center, or FAA Airplane Certification Office, ASW-150, FAA, Southwest Region, Post Office Box 1689, Fort Worth, Texas 76101; Telephone (817) 624-5164, to arrange for engineering review and approval of the repair design.

(j) Within 30 days after the accomplishment of the first inspection required by paragraph (a) of this AD, the appropriately rated airframe mechanic who performed the inspection shall fill out and sign the one time reporting form included as Attachment 1 to this AD and mail it to the following address: DOT/FAA, Airplane Certification Branch, ASW-150, Post Office Box 1689, Fort Worth, Texas 76101. (Reporting approved by the Office of Management and Budget (OMB) under OMB No. 2120-0056).

NOTE: This is a one time only reporting requirement.

(k) An equivalent method of compliance with this AD may be used if approved by the Manager, Airplane Certification Branch, ASW-150, FAA, Southwest Region, Post Office Box 1689, Fort Worth, Texas 76101.

All persons affected by this directive may obtain copies of the documents referred to herein upon request to Mooney Aircraft Corporation, Post Office Box 72, Kerrville, Texas 78028, or FAA, Office of the Regional Counsel, Room 1558, 601 East 12th Street, Kansas City, Missouri 64106.

Note 1: The surface features described in the paragraphs of this AD may be accentuated by illuminating the surface with a light source at a shallow angle. The following technique may be used by an experienced inspector to detect soft and/or decayed wood in the wing spars. Tap the wing directly above and below the spars with a small rounded blunt instrument approximately the size of a small pocket knife. Start at the outboard end and move inboard, listening to the sound generated by the wing.

The sound quality will change slowly. If the change is abrupt or if the sound is not resilient, the wood directly below the surface may be deteriorated due to decay.

Note 2: Shelter - Owners and operators are encouraged to shelter the airplanes, to keep the airplane out of rain storms, and to protect the fabric surface from unnecessary exposure to the deteriorating effects of the sun.

Note 3: Maintenance - Owners and operators are encouraged to be selective in who performs maintenance on their airplane. Only personnel extremely experienced in wood airplane inspection and repair should be contacted.

Note 4: The inspection intervals required by this AD differ from the inspection intervals shown in Mooney Service Bulletin No. M20-170A. The intervals in this AD are the same as AD 76-15-01 which this AD supersedes.

Note 5: Repairs to primary and secondary structure may be accomplished with reference to:

(a) FAA Advisory Circular No. 43-13-1A: Acceptable Methods, Techniques and Practices Aircraft Inspection and Repair, Department of Transportation, Federal Aviation Agency 1972; available through the Government Printing Office.

(b) ANC-18: Design of Wood Aircraft Structures, Chapter 4, Munitions Board Aircraft Committee June 1951.

(c) Mooney Aircraft Corporation Engineering Drawings; the specific drawings required will depend on the affected structural components.

(d) Mooney Service Bulletin No. M20-170A dated February 24, 1969.

Note 6: Design of major repairs to primary wood structure (main and stub spars and ribs receiving loads such as landing gear loads or loads related to attachment of moveable control surfaces to fixed surfaces or attachment of fixed surfaces to the fuselage) should be reviewed and approved by Mooney Aircraft Corporation or an FAA Designated Engineering Representative having appropriate ratings or by FAA Aircraft Certification Division engineers. This is not intended to apply to those situations wherein a deteriorated part is replaced with an entire new part of like design.

This AD supersedes AD 76-15-01, Amendment 39-2673.

This amendment becomes effective October 6, 1986.




FIGURE NO. 1 - APPLICATION OF FIN SIDE
PROOF LOAD ON MAIN SPAR







FIGURE 1A
RECOMMENDED FIN PROOF LOAD METHOD
(INCLUDING LOWER RESTRAINT)












VIEW LOOKING FORWARD

FIGURE NO. 2 - FIN PERMANENT DEFORMATION
LIMITS







FIN SIDE VIEW

FIGURE NO. 3 - FIN - RUDDER HINGE SIDE PROOF
LOAD APPLICATION


86-19-10 ATTACHMENT 1

Inspection Results Reporting Form, Mooney M20 and M20A Wood Structure Inspection.

I. Airplane Model No. , Serial No. .

II. Airplane N-Number .

III. Does the airplane have a metal empennage installed:
Yes NO
If no, go to IV, if yes, skip to V.

IV. For airplanes that have the wooden empennage:

- Did the visual inspection of the empennage result in discovery of any failed glue joints, rotted wood or delaminated wood?
Yes No
If yes, describe location and extent of problem.
- Did the visual inspection of the empennage result in discovery of any deteriorated paint or fabric covering?
Yes No
If yes, describe location and extent.
- Did the visual inspection of the empennage result in discovery of any indications of water inside the empennage?
Yes No
If yes, describe where it got in and where it pooled.
- Did the empennage pass or fail the proof load tests of paragraph (d)?
Yes No
- This inspection and testing of the wood empennage on this airplane results in the conclusion that its overall general structural condition is:
Poor
Fair
Good
Excellent
- Make any comments you wish to make about adding or deleting inspections and testing of the wood empennage on M20 and M20A airplanes.

V. Wing inspection results.
- Did the visual inspection of the wing and wing carry-thru result in discovery of any failed glue joints, rotted wood or delaminated wood?
Yes No
If yes, describe location and extent of problem.
- Did the visual inspection of the wing and wing carry-thru result in discovery of any deteriorated paint, fabric covering plugged drain holes or deteriorated scupper box seal?
Yes No
If yes, describe problem, location and extent.
- Did the visual inspection of the wing and wing carry-thru result in discovery of any indications of water inside the wing?
Yes No
If yes, describe where it got in and where it pooled.
- This inspection of the wing on this airplane results in the conclusion that its overall general structural condition is:
Poor
Fair
Good
Excellent
- Make any comments you wish to make about adding or deleting inspections of the wing on M20 and M20A airplanes:
Mechanics Name:
FAA Certificate Number:
Date:




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