AD/AE 3007/5 Engine Oil Tank Ventilation System (Cth)
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 39.001(1) of CASR 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.
Rolls Royce (Allison) Turbine Engines - AE 3007 Series
| AD/AE 3007/5 | Engine Oil Tank Ventilation System | 9/2008 |
Applicability: | ALLISON AE3007A engines, serial numbers CAE 310001 thru 310105 installed in EMB-145 aircraft. |
Requirement: | Unless previously accomplished, rework the accessory drive gearbox in accordance with ALLISON Service Bulletin AE3007A-72-045 and install new oil vent system tubes in accordance with ALLISON Service Bulletin AE3007A-79-010. The detailed instructions and procedures to accomplish this AD are included in ALLISON Service Bulletins Nr. AE3007A-72-045, AE3007A-79-009 and Note: DEPARTAMENTO DE AVIAÇÃO CIVIL AD 98-01-05 refers. |
Compliance: | Within 100 flight hours from the effective date of this AD. |
| This Airworthiness Directive becomes effective on 28 August 2008. | |
Background: | There has been an occurrence of engine oil pressure exceeding, in operation, the maximum allowable limit of 90 psig. Investigations revealed that the carbon seals in the centre sump were allowing excess buffer air into the centre sump due to a loss of sealing effectiveness, causing an increase in the overall oil system pressure. To accommodate this situation, the maximum oil pressure limit was increased from 90 psig to 95 psig. The operation up to this new limit, however, causes the scavenge system pressure to increase leading to a life degradation of the engine oil tank. |
James Coyne
Delegate of the Civil Aviation Safety Authority
17 July 2008
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