AD 82-24-05 ACTIVE

82-24-05 DETROIT DIESEL ALLISON: Amendment 39-4498. Applies to all Detroit Diesel Allison (DDA) Model 250 series engines equipped with Bendix fuel control assemblies and power turbine governor assemblies containing or suspected of containing P/N 2526146 bushing assemblies with a nylon ball bearing separator.
NOTE: Assemblies listed in the appendix to this AD have steel ball bearing separators.
Compliance required, as indicated, unless already accomplished.
To prevent possible engine power loss, autoacceleration, overspeeding, or power turbine governor instability/malfunctioning caused by failure of P/N 2526146 bushing assemblies with a nylon ball bearing separator installed in Bendix fuel control assemblies and power turbine governor assemblies, accomplish the following:
(a) Before further flight, remove from service affected Bendix fuel control assembly and power turbine governor assembly that exhibit one or more of the following symptoms that cannot be corrected by following the maintenance procedures in the appropriate DDA Operations and Maintenance Manual and, where applicable, install assemblies that have steel ball bearing separators:

Fuel Control Assembly Symptoms
N1 fluctuation
Autoacceleration or overspeed
Inability to obtain maximum power or N1 limiting
Inability to adjust/set idle speed or excessive flight idle

Power Turbine Governor Symptoms
Governor instability
Excessive droop which cannot be cured by correct control system rigging

NOTE: Above symptoms manifested by fuel control assemblies or power turbine governor assemblies which incorporate steel ball bearing separators should be corrected using appropriate DDA Operations and Maintenance Manual procedures.
(b) Inspect in accordance with Paragraph (c) affected Bendix fuel control assemblies and power turbine governor assemblies within the hours time in service specified in the following schedule or before October 16, 1983, whichever occurs first:

Time in Service (Hours) of Fuel Control or Power Turbine Governor Since New or Last Overhaul
Inspect Within The Following Time (Hours) In Service
Less than 300
100
300 or more and less than 600
50
600 or more and less than 900
150
900 or more and less than 1200
200
More than 1200
250

(c) Inspect in accordance with the applicable DDA Commercial Engine Alert Bulletin, or later FAA- approved revision, listed below to determine whether the P/N 2526146 bushing assembly with a nylon ball bearing separator is installed:

Engine Model
Bulletin No., dated October 15, 1982
250-C18
CEB-A-229
250-C20, -C20B, -C20F, -C20J
CEB-A-1206
250-B15G
CEB-A-99
250-B17, -B17B, -B17C
CEB-A-1166
250-C28B, -28C
CEB-A-73-2026
250-C30, -C30P, -C30S
CEB-A-73-3021

(d) If a bushing assembly containing a nylon ball bearing separator is identified during inspection required by Paragraph (c), replace the bushing assembly with a serviceable assembly having a steel ball bearing separator. Reidentify serviceable fuel control assemblies or power turbine governor assemblies, after inspection, in accordance with the applicable DDA service bulletin.
(e) Special flight permits may be issued in accordance with FARs 21.197 and 21.199 to operate aircraft to a base where compliance with this AD can be accomplished.
(f) Upon request of an operator, the Manager, Chicago Aircraft Certification Office, FAA, Central Region, may adjust the compliance time specified in this AD provided such requests are made through an FAA maintenance inspector, and the request contains substantiating data to justify the request for that operator.
(g) Upon request of the operator, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, Chicago Aircraft Certification Office, FAA, Central Region.
This amendment becomes effective November 26, 1982.

AD 82-24-05 APPENDIX

All Bendix fuel control assemblies andpower turbine governor assemblies installed in DDA Model 250 series engines are suspected of containing nylon ball bearing separators, except the following assemblies all of which have steel ball bearing separators:
1. Units identified by the letter "K" marked on the fuel control assemblies or power turbine governor assemblies identification plate in the "less issues" (LI) block.
2. The following fuel control assemblies and power turbine governor assemblies which have acceptable New Hampshire Ball Bearing (NHBB) bushing assemblies and are NOT marked with letter "K."

Model
Bendix Part No.
DDA Part No.
DDA Model
Unit Serial No.
Fuel Control Assemblies:

DP-N2
2524644-18
23001794
250-C20B/F/J
336103 and subsequent
DP-P2
2524654-15
23001796
250-B17B/C
336036 and subsequent
DP-T3
2524738-20
23001797
250-C28B/C
334078 and subsequent
DP-V1
2524854-1
23004537
250-C30P
336051 and subsequent
DP-V1
2524745-17
23001798
250-C30/S
334132 and subsequent
Power Turbine Governor Assemblies:

AL-AA1
2524667-8
23005492
250-C20/B/F
29288 and subsequent
AL-AA1
2524769-7
23005493
250-C20B/J
29367 and subsequent
AL-AC1
2524677-6
23005494
250-C28B/C
27511 and subsequent
AL-AD1
2524692-5
23006268
250-C30/P/S
28914 and subsequent

3. Fuel control assemblies and power turbine governor assemblies manufactured prior to November 7, 1979, provided that they have NOT been overhauled or have NOT had P/N 2526146 bushing assembly replaced since that date. The following listed fuel control assemblies and power turbine governor assemblies were manufactured prior to November 7, 1979:

Model
Bendix Part No.
Engine Model
All Serial Numbers Including and Prior To
Fuel Control Assemblies:

DP-D3
2524463
250-C18
323884
DP-D3
2524527
250-C18
326174
DP-M1
2524384
250-B15G
319258
DP-N1
2524552
250-C20
320894
DP-N2
2524644
250-C20B, C20F, C20J
327936
DP-P1
2524558
250-B17
319575
DP-P2
2524654
250-B17B
327892
DP-P2
2524661
250-B17B, B17C
317461
DP-T3
2524738
250-C28B, C28C
328100
DP-V1
2524745
250-C30, C30S
326387
Power Turbine Governor Assemblies:

AL-AA1
2524553
250-C20/B/F
18010
AL-AA1
2524667
250-C20/B/F
22797
AL-AA1
2524706
250-C20/B/J
20218
AL-AA1
2524769
250-C20/B/J
22921
AL-AC1
2524677
250-C28B, C28C
23097
AL-AD1
2524692
250-C30, C30P, C30S
21897