76-18-09 MESSERSCHMITT-BOLKOW-BLOHM GmbH (MBB): Amendment 39- 2718. Applies to Model BO-105A and BO-105C helicopters, certificated in all categories, incorporating Teledyne Hydra-Power hydraulic actuators, P/N 105-45021, with the following serial numbers: 1012, 1014, 1015, 1016, 1017, 1018, 1019, 1021, 1023, 1027, 1028, 1029, 1030, 1032, 1034, 1035, 1037, 1038, 1040, 1041, 1043, 1044, 1045, 1046, 1049, 1056, 1057, 1062, 1064, 1065, 1066, 1069, 1071, 1075, 1091, 1093, 1101, 1104, 1109, 1113, 1119, 1121, 1123, 1126, 1127, 1156, 1160, and 1161 which have piston rods, P/N D133-750.08E, with S/N's 101 through 440.
Compliance is required as indicated, unless already accomplished.
To prevent possible failure of the main rotor hydraulic actuator and loss of control of the helicopter, accomplish the following:
(a) Before the accumulation of 600 hours total helicopter time in service or within the next 25 hours time in service after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 600 hours time in service from the last inspection until modified in accordance with paragraph (e) of this AD, comply with paragraph (b) of this AD.
(b) Inspect the piston rods, P/N D133-750.08E, in the hydraulic actuators, P/N 105- 45021, for cracks, using a dye penetrant method in accordance with Paragraph 2.B. of the "Accomplishment General" section of MBB Service Bulletin No. 40-19, dated June 2, 1975, or an FAA-approved equivalent.
(c) If a crack is found in a piston rod during an inspection specified in paragraph (b) of this AD, before further flight, replace the cracked piston rod with a serviceable part of same part number and continue to inspect in accordance with paragraph (b) of this AD at intervals not to exceed 600 hours time in service until the modification specified in paragraph (e) of this AD is accomplished.
(d) Comply with paragraph (e) of this AD as follows:
(1) For helicopters with less than 1800 hours totaltime in service on the effective date of this AD and for which it has been less than 4 years since the original issuance of its airworthiness certificate, comply with paragraph (e) of this AD in accordance with paragraph (i) or (ii), whichever occurs later.
(i) Before the accumulation of 1800 hours total time in service or within four years of the date of original issuance of its airworthiness certificate, whichever occurs sooner.
(ii) Within the next 25 hours time in service after the effective date of this AD.
(2) For helicopters with 1800 hours or more total time in service on the effective date of this AD or helicopters for which the effective date of this AD is four years or more after the date of original issuance of its airworthiness certificate, comply with paragraph (e) of this AD within the next 25 hours time in service after the effective date of this AD.
(e) Disassemble the Teledyne Hydra-Power actuator, P/N 105-45021, and replace the piston rods, P/N D133-750.08E, which have S/N's 101 through 440 with serviceable parts of the same part number which have serial numbers other than 101 through 440.
This amendment becomes effective on October 1, 1976.