76-14-02 DEHAVILLAND AIRCRAFT of CANADA, LTD: Amendment 39-2663.
1. Applies to DHC-2 (L-20A, YL-20, U-6A) Airplanes, Serial Numbers 1 thru 1335 except 1283, 1318 and 1324, certificated in all categories, but not altered in accordance with DeHavilland Modification 2/1420.
Compliance required within the next 50 hours in service after the effective date of this AD.
Inspect for cracks and, if necessary, replace the fin pick-up front casting, P/N C2TF57, in accordance with paragraph "PROCEDURE" in DeHavilland Aircraft, Ltd., Engineering Bulletin, Series "B", No. 22, or an approved equivalent alteration.
2. Applies to DHC-2 MK III Turbo-Beaver Airplanes, Serial Numbers 3 thru 5, 7 thru 29, 31 thru 35, 37 thru 39, 41, 43, 44, 46, 48, 50, 52 and 54, certificated in all categories.
Compliance required within the next 25 hours in service after the effective date of this AD, unless already accomplished.
Repair the rudder horn skin and horn rib flanges in accordance with paragraph "PROCEDURE" in DeHavilland Modification Bulletin No. T2/2061 or an approved equivalent repair.
3. Applies to all DHC-2 MK III float or amphibious float equipped Turbo-Beaver Airplanes, except Serial Numbers 1662-TB36, 1684-TB52, 1686-TB54 and subsequent, certificated in all categories.
Compliance required as indicated, unless already accomplished.
a. Prior to further flight the following placard will be placed in clear view of the pilot: "Gross weight at forward C.G. limits restricted to 4000 pounds.
b. Upon alteration of the top and bottom caps of the horizontal stabilizer rear spar, in accordance with paragraph "PROCEDURE" in DeHavilland Modification Bulletin No. T2/2059, the placard required in paragraph (a) may be removed.
4. Applies to DHC-2 (L-20A, YL-20, U-6A) Airplanes, Serial Numbers 1 thru 9, certificated in all categories, unless already accomplished.
Compliance required within the next 25 hours in service after the effective date of this AD.
Visually inspect and, if necessary, replace the three attachment bolts on the tailwheel assembly in accordance with the 2d and 3rd paragraphs in DeHavilland Aircraft, Ltd., Technical News Sheet, Series B, No. 1, or an approved equivalent alteration.
5. Applies to DHC-2 (L-20A, YL-20, U-6A) float equipped Airplanes, Serial Numbers 1 thru 14, certificated in all categories, unless already accomplished.
Compliance required within the next 25 hours in service after the effective date of this AD.
Reinforce the front float pick-up fitting on the fuselage at the firewall with DeHavilland P/N C2-FS-3381, in accordance with paragraph 3. and 4. in DeHavilland Aircraft, Ltd. Technical News Sheet, Series B, No. 3, or an approved equivalent alteration.
6. Applies to DHC-2 (L-20A, YL-20, U-6A) Airplanes, Serial Numbers 1 thru 61 and 63, certificated in all categories, unless already accomplished.
(a) Prior to next flight, visually inspect the No. 10-32 mounting screws at each elevator mass balance weight for looseness and thereafter on a daily basis.
(b) Any loose No. 10-32 mounting screws must be replaced, in accordance with the applicable numbered paragraphs 1 thru 10 in DeHavilland Aircraft, Ltd., Technical News Sheet, Series B, No. 20 (Mod. 2/384) or an approved equivalent alteration.
(c) Upon replacement of all the No. 10-32 mounting screws, in accordance with procedure specified in (b), the daily inspections may be discontinued.
7. Applies to DHC-2 (L-20A, YL-20, U-6A) Airplanes, Serial Numbers 1 thru 66, certificated in all categories, unless already accomplished.
Compliance required within the next 25 hours in service after the effective date of this AD.
a. Reinforce rudder with DeHavilland P/N C2-TR-123 in accordance with numbered paragraphs 1 thru 3 in DeHavilland Aircraft, Ltd., Technical News Sheet, Series B, No. 22 or an approved equivalent repair.
b. Visually inspect rudder nose skinformer P/N C2-TR-47ND and if cracks are found, replace former with an unused part, using 1/8" cherry rivets - 8 required, in accordance with DeHavilland Aircraft, Ltd., Technical News Sheet, Series B, No. 22 sketch or an approved equivalent repair.
8. Applies to DHC-2 (L-20A, YL-20, U-6A) Airplanes, Serial Numbers 1 thru 9, 11 thru 13, 15 thru 50, 52 thru 61, 63, 64 and 66, certificated in all categories, unless already accomplished.
Compliance required within the next 25 hours in service after the effective date of this AD.
Replace the original main undercarriage tie bolt locking pins, P/N C2-U-381, with unused 3/8" diameter locking pins in accordance with the sixth paragraph and continuing thru g) iii) in DeHavilland Aircraft, Ltd., Technical News Sheet, Series B, No. 25 (Mod. 2/333) or an approved equivalent alteration.
9. Applies to all DHC-2 (L-20A, YL-20, U-6A) Airplanes equipped with Federal Aircraft Works AWB-4820 wheel-ski installation, certificated in allcategories, unless already accomplished.
Compliance required before the next flight and every 50 hours in service thereafter, after the effective date of this AD.
Inspect the AN5-24 bolt which secures Federal ski axle, P/N 10B1868 and Beaver wheel axle, P/N C2-U-193, to the undercarriage leg structure, for distortion or wear. Distorted or worn bolts are to be replaced with new AN5-24 bolts or approved equivalent bolts prior to further flight.
10. Applies to all DHC-2 (L-20A, YL-20, U-6A) Airplanes equipped with early model Federal Aircraft Works AWB-4820 wheel-skis, certified in all categories, unless already accomplished. The early model wheel-skis can be identified by a "T" shape aft arm stop welded to the saddle. This AD does not apply to the later model wheel-skis which have an inverted "U" shape aft arm stop welded to the saddle.
Compliance required within the next 25 hours in service after the effective date of this AD.
Incorporate the modification covering the installation of an aft arm stop bracket, in accordance with Federal Aircraft Works Drawing No. 10D2506 or an approved equivalent alteration.
11. Applies to all DHC-2 (L-20A, YL-20, U-6A) Airplanes equipped with DeHavilland Aircraft, Ltd. combination wheel-skis, certificated in all categories, unless already accomplished.
Compliance required as indicated:
(a) Prior to the next ski installation or prior to next flight with combination wheel-skis, inspect left and right retractable ski axle pin bushings, P/N C3US149-3, for excessive play or seizure in accordance with paragraphs 1, 2, 3, 14.2 and 14.3, in Dehavilland Aircraft, Ltd., Engineering Bulletin, Series B, No. 24, Issue 2 or an approved equivalent inspection.
(b) Bushings that are not worn may be retained in service provided that the area is adequately lubricated and the inspection specified in (a) is repeated at intervals not to exceed 100 hours in service from the previous inspection.
(c) Upon replacement of the ski axle pins and bushings, in accordance with numbered paragraphs 1. thru 13. under "PROCEDURE" in de Havilland Aircraft, Ltd., Engineering Bulletin, Series B, No. 24, Issue 2, including amendment No. 1 (Mod No. 2/1438), the 100 hour inspections may be discontinued.
Equivalent placards, signs, parts, inspections, procedures, instructions, repairs, alterations and modifications, as applicable, must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.
Upon request, with substantiating data submitted through an FAA maintenance inspector, the compliance times of this AD may be increased by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.
Compliance with the Airworthiness Directive must be noted in the log book of the aircraft by referencing the Airworthiness Directive number and the specific item complied with: i.e. AD 76 - - - (4) if item 4 is being complied with.
This amendment is effective July 12, 1976.