58-10-09 VICKERS: Applies to all Viscount 700 Series Aircraft Equipped With 14-Inch Stroke Landing Gear Oleos.
Compliance required as indicated.
On aircraft equipped with 14-inch stroke oleos, cases of circumferential cracks have occurred in the main oleo cylinder, P/N 74450-3. The cracks were at the radius, where the cylinder intersects with the 30-degree taper and 2-3/8 inches above the torsion link lugs, either side of the fore and aft center line. Vickers-Armstrongs has issued the following corrective measures which the British Air Registration Board considers mandatory:
1. On aircraft which have reached a total of 1,000 flying hours and each subsequent 200 landings, the oleos should be visually inspected for cracks around the cylinder circumference. If cracks are suspected, the area should be checked with dye penetrant or approved equivalent.
2. Where cracks are confirmed, the part is considered serviceable subject to a daily visual inspection, providing the combined total length of cracks does not exceed 3 inches and individual cracks do not exceed 1-1/2 inches each in length.
3. Where combined total length of cracks exceeds 3 inches but is not greater than 5 inches, and length of individual cracks not greater than 2-1/2 inches, cracks must be blended out before next flight and area reprotected with seaplane varnish or approved equivalent. Maximum depth of blending or crack must not exceed 0.050 inch. The part is then considered serviceable subject to a check by dye penetrant or approved equivalent every 135 hours.
4. If the length of depth of the cracks exceed the limits quoted in item 3, the part is no longer considered serviceable and must be replaced with new cylinder, in accordance with Vickers Mod. No. D.2694.
5. After embodiment of the new cylinders to either Part (a) or (c) of Mod. D.2694, the above inspections may be discontinued.
6. If no cracks are found during the initial inspection and the cylinderis shotpeened in accordance with PTL 191, Issue 3, the cylinder may be reinspected using dye penetrant or approved equivalent every 1,000 landings.
7. Cylinders having a total length of cracks exceeding 3 inches but not greater than 5 inches, with the length of individual cracks not greater than 2-1/2 inches and the depth of cracks not exceeding 0.050 inch, which have been reworked as follows may be reinspected using dye penetrant or FAA approved equivalent every 500 landings. Rework consists of:
(a) Blend out the crack using a radius of blending not less than 0.5 inch with the maximum depth of blending not to exceed 0.050 inch.
(b) Shotpeen the cylinder in accordance with PTL 191, Issue 3.
(c) Reprotect the reworked area with seaplane varnish or FAA approved equivalent.
The FAA concurs with this action and considers compliance therewith mandatory.
(Vickers-Armstrongs PTL No. 191, Issues 2 and 3, and Modification D.2694 cover this subject.)
This supersedes AD 58-07-05.