72-13-02 GENERAL DYNAMICS: Amdt. 39-1460 as amended by Amendment 39- 1476. Applies to Model 22 and 22M airplanes certificated in all categories which have accumulated 20,000 or more hours' time in service.
Compliance required as indicated.
To prevent failures of the main landing gear beams (P/N 22-16732-5 or -6) as a result of cracks, accomplish the following:
(a) Within the next 25 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 25 hours' time in service until (c), below, is accomplished, visually inspect the exposed surface of the upper and lower beam caps as described in General Dynamics Service Bulletin 880 SB No. 57-23C, paragraph 2.IA(1) or 880M SB No. 57-12C, paragraph 2.IA(1), dated May 12, 1972, or later FAA-approved revisions. If cracks are found during these inspections, comply with (c), below, before further flight.
(b) Within the next 200 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 200 hours' time in service until (c), below, is accomplished, inspect the exposed surface of the upper and lower beam caps as described in SB No. 57-23C, paragraph 2.IA(2) or SB No. 57-12C, paragraph 2.IA(2), or later FAA-approved revisions. If cracks are found during these inspections, comply with (c), below, before further flight.
(c) Within the next 1000 hours' time in service after the effective date of this AD, unless already accomplished, remove the trailing edge panels and rework the trailing edge panel attachment holes per SB No. 57-23C, paragraph 2.IA(3) or SB No. 57-12C, paragraph 2.IA(3), or later FAA-approved revisions. Inspect the screw holes using eddy current or equivalent procedures immediately following this rework and thereafter until (d), below, is accomplished, at not more than 3000 hours' time in service following this rework. Repeat the inspection at or before 4000 and 5000 hours time in service following this rework.If cracks are found during any of these inspections, comply with (d), below, before further flight. If bushings have been installed in accordance with previous issues of SB No. 57-23 or SB No. 57-12, reinspect the bushing fit for tightness and inspect the surface around the bushings for cracks using eddy current or equivalent procedures at intervals not exceeding 3000 hours' time in service following this initial inspection. If loose bushings or cracks are found, repair in accordance with instructions approved by the Chief, Aircraft Engineering Division, FAA Western Region, before further flight. For inspection intervals following repair, see (e) below.
(d) On or before the accumulation of 6,000 hours' time in service following the rework described in (c), above, unless already accomplished, again remove the trailing edge panels and rework holes per SB No. 57-23C, paragraph 2.IA(5) or SB No. 57-12C, paragraph 2.IA(5), or later FAA-approved revisions. Inspect the screw holes usingeddy current or equivalent procedures immediately following this rework and thereafter, until (e), below, is accomplished, at not more than 3000 hours' time in service following this rework. Repeat the inspection at or before 4000 and 5000 hours' time in service following this rework. If cracks are found during any of these inspections, comply with (e), below, before further flight.
(e) On or before the accumulation of 6,000 hours' time in service following the rework described in (d), above, unless already accomplished, again remove the trailing edge panels and rework holes per SB No. 57-23C, paragraph 2.IA(7) or SB No. 57-12C, paragraph 2.IA(7), or later FAA-approved revisions. Inspect the screw holes using eddy current or equivalent procedures immediately following this rework and thereafter at not more than 2000 hours' time in service following this rework. Repeat the inspection at or before 3000, 4000, 5000 and 6000 hours' time in service following this rework. If cracks arefound during any of these inspections, repair in accordance with instructions approved by the Chief, Aircraft Engineering Division, FAA Western Region, before further flight, or replace the beam per (f), below.
After a beam is repaired, the interval inspections of the screw holes (or of the surface around the bushings), following repair and until the beam is replaced, depend upon the repair accomplished, as follows:
(1) Reinforcing straps (steel or aluminum) added to upper or lower cap; 3000 hours' time in service.
(2) Any plugged hole in caps greater than .375 inch diameter but less than .50 inch diameter and then reamed or bushed; 2000 hours' time in service.
(3) Any plugged hole in caps greater than .50 inch diameter and then reamed or bushed; 1000 hours' time in service.
(f) On or before the accumulation of 6,500 hours' time in service following the rework described in (e), above, and at intervals not exceeding 500 hours' time in service thereafter, reinspect the screw holes using eddy current or equivalent procedures until the beam is replaced by a new beam of the same type, or an improved type approved by the Chief, Aircraft Engineering Division, FAA Western Region. If cracks are found during these inspections, replace the beam before further flight.
After the beam is replaced by a new beam of the same type, the inspections and rework specified in this AD are applicable only after the accumulation of 20,000 hours' time in service on the new beam. After the beam is replaced by a new beam of an improved type, this AD is not applicable.
(g) The Chief, Aircraft Engineering Division, FAA Western Region, may approve equivalent inspections, rework procedures, and replacement beams for this AD.
This amendment becomes effective June 15, 1972.
Amendment 39-1460 became effective June 15, 1972.
Amendment 39-1476 becomes effective June 30, 1972.