90-17-01 ROBINSON HELICOPTER COMPANY (RHC): Amendment 39-6687. Docket No. 89-ASW-58.\n\n\tApplicability: All Model R22 series helicopters, certified in any category, equipped with carburetor air box latches. \n\n\tCompliance: Required within the next 25 hours' time in service after the effective date of this AD, unless already accomplished. \n\n\tTo prevent carburetor air box latches from coming loose in flight, which could result in power loss in critical maneuvers close to the ground, accomplish the following: \n\n\t(a)\tRemove the three carburetor air box latches and replace with four bolts in accordance with the following: \n\n\t\t(1)\tOpen the air box and remove the filter element. \n\n\t\t(2)\tRemove the air box from the helicopter. \n\n\t\t(3)\tDrill out the four rivets in the cover holding 0.25 inch diameter spacers and enlarge the holes to 0.191 inch diameter. Discard the spacers. \n\n\t\t(4)\tClose the cover, and using the holes in the cover as guides, drill four matching holes through the upper box in line with the holes in the cover. \n\n\t\t(5)\tOpen the air box and drill out all the rivets holding the latches to the cover. Discard the latches and angles. Clean the drilling chips from the box. \n\n\t\t(6)\tReinstall the air box to the helicopter. \n\n\t\t(7)\tInstall the filter element and secure the cover using four AN3-35A bolts, AN960-10L washers, AN970-3 washers, and NAS679A3 nuts. \n\n\tNOTE: Refer to Figure 1 for accomplishing the instructions required by paragraph (a). \n\n\t(b)\tAn alternate method of compliance or adjustment of the compliance time, which provides an equivalent level of safety, may be used if approved by the Manager, Los Angeles Aircraft Certification Office, ANM-100L, FAA, Northwest Mountain Region, 3229 E. Spring Street, Long Beach, California 90806-2425. \n\n\tNOTE: Robinson Helicopter Company Service Bulletin Number 61, dated July 28, 1989, pertains to this AD. \n\n\tThis amendment (39-6687, AD 90-17-01) becomes effective on September 10, 1990. \n\nSB 61