AD 89-22-16 ACTIVE

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.