73-17-03 HAWKER SIDDELEY: Amdt. 39-1703. Applies to de Havilland Model DH- 114 "Heron" airplanes.
Compliance is required as indicated.
To prevent failure of the lower flap hinge-to-wing attachment bolts at Rib No. 7, the fork joint fitting (P/N 14 WF.1) and the eye joint fitting (P/N 14 WF.3) at Rib No. 2, and the angle brackets at Rib No. 01, accomplish the following:
(a) Within the next 500 hours' time in service after the effective date of this AD, unless already accomplished, replace the lower two flap hinge-to-wing attachment bolts and nuts at Rib No. 7 with new bolts (P/N A.25/10E) and nuts (P/N 14W 5781) in accordance with Hawker Siddeley Modification No. Heron 1303, dated December 31, 1969, as amended by Amendment No. 1 dated May 7, 1970, or an FAA-approved equivalent.
(b) Before the accumulation of a total of 13,000 hours' time in service, or within the next 300 hours' time in service after the effective date of this AD, whichever occurs later, unless already accomplished within the last 900 hours' time in service, and thereafter at intervals not to exceed 1,200 hours' time in service from the last inspection, visually inspect the attachment flanges of the forward fork joint fitting, (P/N 14WF.1) and forward eye joint fitting, (P/N 14WF.3), located between the inner and center flap sections, for cracks near the fitting-to-flap attachment bolt holes (two per fitting) using a glass of at least 10-power magnification in accordance with Section 4 of Hawker Siddeley Technical News Sheet Series: Heron (114), No. W.16, Issue 1, dated May 4, 1970, or an FAA-approved equivalent. If cracks are found, before further flight replace the cracked parts in accordance with Hawker Siddeley Repair Drawing RD.14WF.109, dated January 23, 1970, or an FAA-approved equivalent.
(c) Within the next 2,400 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 2,400 hours' time in service from the last inspection, visually inspect the corner radius of the small angle brackets on the forward face of the rear vertical flange of Rib No. 01 for cracks using a glass of at least 10-power magnification in accordance with Section 5 of Hawker Siddeley Technical News Sheet Series: Heron (114), No. W.16, Issue 1, dated May 4, 1970, or an FAA-approved equivalent. If cracks are found, before further flight replace the cracked parts with new parts, P/N 14W.5621, or 14W.5623, as applicable.
This amendment becomes effective September 13, 1973.