AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
AlliedSignal (Lycoming) Turbine Engines - T53 Series
AD/T53/21 Tachometer Drive Spur Gear 9/2002
Applicability: T5311A, T5311B, T5313B, T5317A, T5317B, T53-L-11, T53-L-11A, T53-L-11B, T53-L-11C, T53-L-11D, T53- L-11A S/SA, T53-L-13B, T53-L-13B S/SA, T53-L-
13B S/SB and T53-L-703 engines.
Requirement: 1. Test: Perform initial and repetitive special vibration tests of the engine in accordance with the applicable service bulletin listed in Table 1.
Engine Model | Service Bulletin |
T5311A and T5311B | T5311A/B-0100 |
T5313B, T5317A, and T5317B | T5313B/17-0100 |
T53-L-11, -11A, -11B, -11C, -11D, and 11A S/SA | T53-L-11-0100 Revision 2 |
T53-L-13B, -13B S/SA, and –13B S/SB | T53-L-13B-0100 Revision 2 |
T53-L-703 | T53-L-703-0100 Revision 2 |
2. Replacement: For engines that fail the special vibration test either replace the reduction gearbox assembly with a serviceable item or replace the engine, followed by the special vibration test of requirement 1.
Note: FAA AD 2002-03-01 refers.
Compliance: 1. Test:
Initial inspection:
To be carried out within 100 hours aircraft time in service from the effective date of this Directive.
Repetitive:
For Engines with tachometer drive spur gear part number 1-070-062-04, at 500 flight hour intervals since the last special vibration test.
For engines with tachometer drive spur gear part number 1-070-062-06, at 1000 flight hour intervals since the last special vibration test.
AlliedSignal (Lycoming) Turbine Engines - T53 Series
AD/T53/21 (continued)
2. Replacement:
Prior to further flight.
This Airworthiness Directive becomes effective on 5 September 2002.
Background: Vibrations within the reduction gearbox can cause failure of the tachometer drive spur gear. Failure of the gear can lead to potential overspeed of the engine, and loss of power turbine speed indication. Special vibration tests will allow detection of problems and timely replacement of the reduction gearbox.
Eugene Paul Holzapfel
Delegate of the Civil Aviation Safety Authority 26 July 2002
The above AD is notified in the Commonwealth of Australia Gazette on 14 August 2002.