This document summarizes an FAA seminar on MD Helicopters aircraft maintenance. It provides information on accessing online manuals, service letters, bulletins, airworthiness directives, and part number cross-references. It also discusses topics like calculating retirement indices, technical issues seen in the field, and supplemental type certificates.
92. Droop Stop Ring - yielding of plating causing cyclic stick grab
93. Droop Stop Ring - yielding of plating causing cyclic stick grab
94. 500N5310-19 Fan Blade Bulge Any bulges or blisters over 0.10 inch (2.54 mm) long in area of pin near outboard end of blade are reason for blade rejection
100. Measure distance between bearings in fork. Measure distance each bearing protrudes from inner surface of fork. Determine shim thickness as required to make each bearing protrude equally (temporarily mark the side requiring the shim with an “ S ”) Measure Hub outside Dimension. Subtract dimension B from A . Subtract 1.123 inch from B Take the difference between 1.123 and Dimension E equals shim thickness to make hub mounting face equal distance from centerline of hub. If D is larger than 1.123 inch temporarily mark bushed side of hub with a U . If 1.123 inch is larger than D temporarily mark unbushed side of hub with a U . If H is greater than E then subtract E from H If E is greater than H then subtract H from E Enter I or J in Shim table. Subtract I or J from C Dimension F = total clearance thickness after centering hub and bearings for preload. Determine shim thickness required to ensure preload: F minus .098 inch divided by 2 = G Orient hub in fork so that S and U are together on the same side. Add up columns in Table and install shims as required. B A C H D E F G S = Small Step Side U = Widest HUB Side Shim Thickness Required G J G I Total = “ S” & “U” marked Unmarked = Actual Dim. Formula Dim. Shim Dim. I J
101. Measure distance between bearings in fork. Measure distance each bearing protrudes from inner surface of fork. Determine shim thickness as required to make each bearing protrude equally (temporarily mark the side requiring the shim with an “ S ”) Measure Hub outside Dimension. Subtract dimension B from A . Subtract 1.123 inch from B Take the difference between 1.123 and D Dimension E equals shim thickness to make hub mounting face equal distance from centerline of hub. If D is larger than 1.123 inch temporarily mark bushed side of hub with a U . If 1.123 inch is larger than D temporarily mark unbushed side of hub with a U . If H is greater than E then subtract E from H If E is greater than H then subtract H from E Enter I or J in Shim table. Subtract I or J from C Dimension F = total clearance thickness after centering hub and bearings for preload. Determine shim thickness required to ensure preload: F minus .098 inch divided by 2 = G Orient hub in fork so that S and U are together on the same side. Add up columns in Table and install shims as required. B A C H D 2.4055 2.2195 .1860 1.0965 .0265 .0100 .0165 .1695 .03575 E F G S = Small Step Side U = Widest HUB Side Actual Dim. Formula Dim. Shim Dim. I J Shim Thickness Required G J G I Total = “ S” & “U” marked Unmarked .03575 .03575 .01650 = .05225 .03575
102. A .018 .008 Difference H Protrusion 2.4055 Inner Fork H H G S U G J C C C Total Clearance E 1.1230 2.2460 perfect hub 2.2195 actual B 1.0965 D Total Shims HUB FORK
103. 3.646 Bolt Before Torque (REF) G S G J C C 369A1602-3 BOLT 3.654 Bolt Stretched (REF) Bolt must stretch .008 to .011 MS21206C4 BEVEL WASHER 369A1605-5 .015 369A1605-7 .062 NAS620C416L .033 MS24665-153 COTTER PIN VCU0001 or SPS79325–428 NUT 2 HOLES 90 DEGREES OUT
105. B A C H D E F G A .018 .008 Difference H Protrusion 2.4055 Inner Fork H H G S U G J C C C Total Clearance E 1.1230 2.2460 perfect hub 2.2195 actual B 1.0965 D Total Shims G I J