AD 2012-11-13

You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.

(1) Within 50 hours time-in-service (TIS) establish a life limit of 20,000 takeoffs and landings for each aft crosstube P/N 412-321-304. For the purposes of this AD, a takeoff and landing is defined as the cycle from when the helicopter gets light on the skids (takeoff) unloading the aft crosstube and then settles on the skids again (landing) reloading the aft crosstubes. Either the number of landings or takeoffs may be counted.

(i) Create a component history card or equivalent record.

(ii) Determine and record on the history card or equivalent record the total number of takeoffs and landings for each aft crosstube. If the takeoff and landing information is unavailable, estimate the number by multiplying the airframe hours by 10.

(2) Within the next 450 takeoffs and landings, if an aft crosstube has reached 20,000 or more takeoffs and landings, replace it with an airworthy aft crosstube.

(3) Before reaching 2,500 takeoffs and landings or for an aft crosstube with 2,500 or more takeoffs and landings, within 50 hours TIS or within the next 250 takeoffs and landings, whichever occurs first, prepare the aft crosstube inspection areas as depicted in Figure 1 of Aeronautical Accessories, Inc. (AAI), Alert Service Bulletin No. AA-07109, dated April 3, 2008 (ASB), by following the Accomplishment Instructions, Part B, paragraphs 1 through 4, of the ASB. Using a 10X or higher magnifying glass, inspect the prepared areas of each aft crosstube for a crack. If there is a crack, before further flight, replace the cracked aft crosstube with an airworthy aft crosstube. If there are no cracks, after completing the aft crosstube inspection, prime and paint the inspection area by following the Accomplishment Instructions, Part B, paragraphs 6 and 7, of the ASB.

(4) Thereafter, at intervals not to exceed 450 takeoffs and landings, clean the inspection area. Using a 10X or higher magnifying glass, inspect the clear-coated area of the aft crosstube for a crack.

(5) If there is a crack, before further flight, replace the cracked aft crosstube with an airworthy aft crosstube.

(6) Within 30 days or before reaching 2,500 takeoffs and landings, whichever occurs later, and thereafter at intervals not to exceed 2,500 takeoffs and landings or 12 months, whichever occurs first, determine the horizontal deflection of each aft crosstube from the centerline of the helicopter (BL 0.0) to the outside of the skid tubes by following the Accomplishment Instructions, Part D, paragraphs 1 through 3, of the ASB. If the measured aft crosstube horizontal deflection depicted in Figure 2 of the ASB is less than 57 inches (1,448 mm) or greater than 59 inches (1,499 mm), replace the aft crosstube with an airworthy aft crosstube.

(7) Within 3 months or on or before reaching 7,500 takeoffs and landings, whichever occurs later, and thereafter at intervals not to exceed 5,000 takeoffs and landings:

(i) Remove the aft crosstube assembly by removing the aft crosstube support beam assembly, P/N 604-030-001, and both aft crosstube clamp assemblies, P/N 604-027-002.

(ii) Remove paint and sealant from the aft crosstube outboard of the upper center support to top of saddles, both sides, as depicted in Figure 3 of the ASB.

(iii) Fluorescent penetrant inspect each aft crosstube outboard of the upper center support as depicted in Figure 3 of the ASB for a crack.

(iv) If there is a crack, before further flight, replace the cracked aft crosstube with an airworthy aft crosstube.

(8) Revise the helicopter Airworthiness Limitations section of the applicable maintenance manuals or the Instructions for Continued Airworthiness (ICA) by establishing a new retirement life of 20,000 takeoff and landings for aft crosstube P/N 412-321-304 by making pen and ink changes or inserting a copy of this AD into the maintenance manual or the ICAs.