72-20-01 HAWKER SIDDELEY AVIATION LTD.: Amdt. 39-1523. Applies to Hawker Siddeley deHavilland Model DH-114 "Heron" airplanes.
Compliance required as indicated.
To prevent possible fatigue failure of the primary airplane structure accomplish the following:
(A) Before the accumulation of the total hours' time in service specified in Column B for the applicable component specified in Column A, or within the next 100 hours' time in service after the effective date of this AD, whichever occurs later, and thereafter before the accumulation of the specified total hours' time in service on the replacement component, comply with the applicable paragraph of this AD specified in Column C:
Column A Component
Column B Service Life
Column C AD Paragraph
(1) Airframes
30,000 Hours
(B)
(2) Each component of an airframe not otherwise specified in this AD.
30,000 Hours
(C)
(3) Wing assemblies which do not incorporate modification 520, and fuselage center section lower spar booms, P/N 14FS2939 that do not incorporate modification 492.
3,500 Hours
(D)
(4) Wing assemblies that incorporate modification 520 and which have not been reworked in accordance with
paragraph (e)(2).
15,000 Hours
(E)
(5) Wing assemblies which incorporate modification 520 that have been reworked in accordance with subparagraph (E)(2).
15,000 Hours' since reworked in accordance with subparagraph (E)(2) or 30,000 hours' total time in service
whichever occurs first
(E)(1)
(6) Vertical fin front attachment fittings (R.H. and L.H.).
15,000 Hours
(F)
(7) Elevator trim tab connecting rods P/N 14TE.431A (R.H. and L.H. Elevator).
15,000 Hours
(G)
(B) Replace an airframe with an airframe of the same part number or a part number approved by the Chief, Aircraft Certification Staff, FAA, Europe, Africa, and Middle East Region, that has accumulated less than 30,000 hours' time in service.
(C) Replace each component of an airframe with a component of the same partnumber or a part number approved by the Chief, Aircraft Certification Staff, FAA, Europe, Africa, and Middle East Region, that has accumulated less than 30,000 hours' time in service.
(D) Comply with either of the following:
(1) Replace the wing assembly with a wing assembly that has modification 520 incorporated and that has accumulated less than 15,000 hours' time in service, including the hours' time in service prior to the incorporation of Modification 520, and incorporate modification 492 on the wing carry-through structure in the fuselage center section in accordance with DeHavilland Aircraft Service Modification News Sheet, Modification No.: HERON 492, as amended through Amendment No. 3, dated March 6, 1956, or an FAA-approved equivalent.
(2) Incorporate Modification 520 on the wing main spar lower boom in accordance with DeHavilland Aircraft Service Modification News Sheet, Modification No.: HERON 520, Issue 2, dated December 17, 1956, or an FAA-approved equivalent, and incorporate Modification 492 on the wing carry-through structure in the fuselage center section in accordance with DeHavilland Aircraft Service Modification News Sheet, Modification No.: HERON 492, as amended through Amendment No. 3, dated March 6, 1956, or an FAA-approved equivalent.
(E) Comply with the following:
(1) Replace the wing assembly with a Modification 520 Wing Assembly of the same part number that has accumulated less than 15,000 hours' time in service, including the hours' time in service prior to the incorporation of Modification 520, or
(2) If the wing assembly has not accumulated 30,000 hours' time in service, including the hours' time in service prior to the incorporation of Modification 520, and the rework specified in this subparagraph has not been accomplished, rework the wing assembly as follows:
(i) Rework the basic wing structure by incorporating modification 1585 in accordance with Hawker Siddeley Aviation Limited ModificationLeaflet "Civil Modification" for Modification No.: HERON 1585 with Amendment No. 4 incorporated, or an FAA-approved equivalent.
(ii) Replace the existing flap datum hinge links with new links, P/N 14 WF.453 (L.H.) and P/N 14 WF.454(R.H.) or an FAA-approved equivalent, unless already accomplished within the last 4,000 hours' time in service;
(iii) Replace the existing forward fork joint fittings (P/N 14 WF.1) and the forward eye joint fittings (P/N 14 WF.3), located between the inner and center flap sections with new fittings of the same part numbers in accordance with Hawker Siddeley Aviation Limited Repair Drawing RD. 14 WF.109, dated January 23, 1970, or an FAA-approved equivalent;
(iv) Replace the small angle brackets located on the forward face of the rear vertical flange at wing rib No. 01 near the inner flap section inner hinge bracket attachment with new brackets, P/N 14 W.5621 and 14 W.5623 (Modification 1076, full version) or an FAA-approved equivalent.(v) Replace the engine mounting pickup straps, P/N 14-2W.555ND, and strap doublers, P/N 14 W.1715ND, with new straps and strap doublers of the same part numbers in accordance with paragraph 5.2 of Hawker Siddeley Aviation Limited, Technical News Sheet; Series: HERON (114) No. W.15, Issue 1, dated October 27, 1969, or an FAA- approved equivalent; and
(vi) Replace the magnesium parts in the flap hinge assemblies with aluminum-copper alloy parts by incorporating modification 1098 in accordance with Hawker Siddeley Aviation Modification Leaflet "Civil Modification" for Modification No. HERON 1098, with Amendment No. 2 incorporated, or an FAA-approved equivalent.
(F) Replace -
(1) Vertical fin front attachment fittings with new fittings, P/N's 14.FS-4669 (left hand) and 14.FS-4670 (right hand), in accordance with DeHavilland Aircraft Service, Modification News Sheet No. HERON 869, dated December 12, 1956, or an FAA-approved equivalent, and
(2) Vertical Channels,P/N's 14FS.187 (left hand) and 14FS.188 (right hand) on the aft face of the stub fin portion of Bulkhead 6 with new channels of the same part number in accordance with Hawker Siddeley Aviation Limited, Repair Drawing RD.14FS.293, dated February 10, 1972, or an FAA-approved equivalent.
(G) Replace elevator trim tab connecting rods, P/N 14 TE.431A, and fork engs, P/N 4T.55 (two each per airplane), with new rods and fork ends of the same part number.
(H) Operators who have not kept records of hours' time in service on any part to which a provision of the AD applies shall substitute airplane hours' time in service in lieu thereof.
(Hawker Siddeley Aviation Limited, Technical News Sheet; Series: HERON (114) No. M.9, Issue 2, dated July 3, 1972, covers this same subject.)
This amendment is effective upon publication in the Federal Register as to all persons except those persons to whom it was made immediately effective by the airmail letter dated July 27, 1972 which contained this amendment.