89-22-16: Engine Acceleration or Deceleration

89-22-16 GARRETT ENGINE DIVISION: Priority Letter AD issued on October 26, 1989. Applicability: Garrett Turbofan Engine Models TFE731-2, -5, -5AR, and -5R, certificated in any category, installed on, but not limited to, the following aircraft: Lear Jet M31, CASA 101, Falcon 900, Falcon 20-5, and BAe 125-800. Compliance: Required as indicated, unless already accomplished. To prevent an uncommanded engine acceleration or deceleration, accomplish the following: (a) Review the engine log book or maintenance records on the previously listed engine models to determine if DEEC Part Number 2118002-6, 2118002-8, 2118002-9, or 2118002-201 with one of the following serial numbers is installed. Spare DEEC's must also be checked for applicable part number and serial number. DEEC SERIAL NUMBERS PN 2118002-6 PN 2118002-9 PN 2118002-20 68-1094 108-1159 48-1049 78-1128 58-138 68-1095 108-1160 48-1059 78-1129 58-139 69-1096 108-1161 48-1060 78-1130 58-140 68-1097 108-1162 48-1061 78-1131 58-145 68-1106 108-1163 48-1063 78-1133 58-147 68-1108 108-1164 48-1071 78-1134 58-148 68-1109 108-1166 48-1072 78-1135 58-150 68-1110 108-1167 78-1113 78-1136 108-151 68-1111 108-1168 78-1114 78-1137 108-152 68-1112 108-1169 78-1115 78-1138 108-153 108-1152 108-1170 78-1116 78-1139 108-154 108-1154 108-1171 78-1117 78-1140 108-155 108-1155 108-1172 78-1118 78-1141 108-157 108-1156 108-1173 78-1119 78-1142 108-159 108-1157 108-1174 78-1120 78-1145 108-160 108-1158 78-1121 78-1146 108-162 78-1122 78-1147 108-164 PN 2118002-8 78-1123 78-1148 108-165 47-778 78-1124 78-1149 108-166 77-861 78-1125 78-1150 108-167 77-862 78-1126 78-1151 108-168 77-873 78-1127 108-169 108-170 108-172 (b) Remove from service, if necessary, suspect serial numbered DEEC's listed in paragraph (a) with less than 50engine hours time since new within the next 25 engine operating hours after receipt of this priority letter AD, and DEEC's with 50 or more engine hours time since new within the next 100 engine operating hours after receipt of this priority letter AD, and replace with a serviceable DEEC. NOTE: Refer to Garrett Service Bulletin (SB) TFE731-76-3049, dated October 6, 1989, to determine previous accomplishment with this AD, and for removal, installation, repair, and re-identification information for these suspect DEEC's. (c) Repair and re-identify, before further flight, in accordance with the Garrett SB TFE731-76-3049, dated October 6, 1989, suspect serial numbered DEEC's listed in paragraph (a) installed on a spare engine or located as a spare part. (d) Revise the applicable FAA Approved Airplane Flight Manual (AFM) to provide interim emergency procedures to flight crews on airplanes affected by paragraphs (a) and (b), within 10 calendar days after receipt of this priority letter AD, by adding the following: EMERGENCY PROCEDURES In the event that uncommanded engine acceleration or deceleration is experienced: (1) Place power lever for the affected engine in an intermediate position (slightly aft of cruise). (2) Select computer OFF on affected engine (remove electrical power to DEEC). (3) Re-adjust power lever as necessary. (4) Continue with affected computer OFF for the remainder of the flight. NOTE: It is also possible that the DEEC malfunction may affect the reserve power function on engines so equipped; therefore, it is important to conduct the normal reserve power pre-flight check prior to flights during which reserve power may be used. (e) A copy of this AD inserted in the FAA Approved AFM may be considered an acceptable means of compliance with the required AFM revision. (f) Aircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished. (g) Upon submission of substantiating data by an owner or operator through an FAA Airworthiness Inspector, an alternate method of compliance with the requirements of this priority letter AD or adjustments to the compliance schedule specified in this priority letter AD may be approved by the Manager, Los Angeles Aircraft Certification Office, Transport Airplane Directorate, Aircraft Certification Service, Federal Aviation Administration, 3229 East Spring Street, Long Beach, California 90806-2425. (h) Documents pertinent to this priority letter AD may be obtained, upon request, from Garrett General Aviation Services Division, Distribution Center, 2340 East University, Phoenix, Arizona 85037; telephone (602) 255-2548, or may be examined at the office of the Assistant Chief Counsel, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, Rules Docket No. 89-ANE-42. Priority Letter AD 89-22-16, issued on October 26, 1989,becomes effective immediately upon receipt.