AD 72-06-04

72-06-04 HAWKER SIDDELEY: Amdt. 39-1405. Applies to Hawker Siddeley Model DH-114, Series 2, "Heron" airplanes which do not incorporate Heron Modification 1592, Part A.

Compliance is required as indicated.

To prevent failure of the main undercarriage down lock operating lever assembly, accomplish the following:

(a) For airplanes with main undercarriage down lock operating lever assembly, P/N 14-2U.181A (pre Modification 608), within the next 150 hours' time in service after the effective date of this AD unless accomplished within the last 150 hours' time in service, remove the lever assembly from the airplane, remove the protective coating and paint from the assembly and inspect for cracks, using a dye penetrant method, in accordance with Hawker Siddeley Technical News Sheet Series: Heron (114) No. U.12, Issue 1, dated April 13, 1970, or later ARB-approved issue or FAA-approved equivalent. If no cracks are found visually inspect the lever assembly for corrosion.

(b) If cracks, or corrosion that cannot be removed by cleaning are found during the inspection required by paragraph (a), before further flight replace the affected part with a serviceable part of the same part number or replace the lever assembly with a new lever assembly, P/N 14-2U.181A/2, in accordance with Hawker Siddeley "Heron" Modification 1592.

(c) For airplanes with main undercarriage down lock operating lever assembly, P/N 14-2U.181A/1 (post Modification 608), within the next 150 hours' time in service after the effective date of this AD, or within 300 hours' time in service from the last inspection, whichever occurs later, and thereafter at intervals not to exceed 300 hours' time in service from the last inspection, remove the lever assembly from the airplane, remove the protective coating and paint from the assembly and inspect for cracks, using a dye penetrant method, in accordance with Hawker Siddeley Technical News Sheet Series: Heron (114) No. U.12, Issue 1, dated April 13, 1970, or later ARB-approved issue or FAA-approved equivalent.

(d) If cracks are found during an inspection required by paragraph (c), before further flight replace the lever assembly with a new lever assembly, P/N 14-2U.181A/2 in accordance with Hawker Siddeley "Heron" Modification 1592.

(e) The repetitive inspections required by paragraph (c) may be discontinued after lever assembly, P/N 14-2U.181A/2, has been installed in accordance with Hawker Siddeley "Heron" Modification 1592.

(f) Replacement parts and serviceable parts that are reinstalled must be protected with a coat of lanolin, or FAA-approved equivalent prior to their installation in the airplane.

This amendment becomes effective April 6, 1972.