AD/A320/230 High Pressure Compressor Deterioration (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.
Airbus Industrie A319, A320 and A321 Series Aeroplanes
| AD/A320/230 | High Pressure Compressor Deterioration | 4/2009 TX |
Applicability: | A318-111, A318-112, A319-111, A319-112, A319-115, A320-214, A320 215, |
Requirement: | 1. Determine the EGT margin deterioration of both engines and, depending on the results, carry out the applicable corrective actions in accordance with Requirements 3 and 4 of this AD. 2. Repeat the determination of EGT margin deterioration of both engines, and depending on the results, carry out the applicable corrective actions in accordance with Requirements 3 and 4 of this AD. 3. Maintenance requirements a. For aircraft with both engines indicating more than 80°C EGT margin deterioration, remove one engine and replace it with an engine indicating less than 80°C EGT margin deterioration, in accordance with the instructions of CFM International Service Bulletin CFM56-5B S/B 72-0722. i. Prior to engine removal, perform an HPC borescope inspection (BSI) of both engines per the current applicable A318/A319/A320/A321 AMM instructions for the HPC stages 1, 3, 6, and 9, adhering to the applicable A318/A319/A320/A321 AMM limits to determine which engine should be removed. b. For aircraft with both engines indicating between 75°C of EGT margin deterioration and 80°C of EGT margin deterioration, and for aircraft with one engine indicating between 75°C and 80°C of EGT margin deterioration and the other engine indicating more than 80°C EGT margin deterioration, perform a Compressor Stall Margin Test on both engines, in accordance with AMM Task 71-00-00-710-040. If the test is successful for both engines: i. Follow the operational requirements detailed in Requirement 4 of this AD for every subsequent flight until the engine indicating the highest EGT margin deterioration is replaced by an engine indicating less than 75°C EGT margin deterioration. |
| ii. Within 500 Flight Hours from the determination of EGT margin deterioration, remove the engine indicating the highest EGT margin deterioration and replace it with an engine indicating less than 75°C EGT margin deterioration. If the test is not successful for one or both engines: Replace the engine(s) that failed the test by an engine indicating less than 75°C of EGT margin deterioration. 4. Operational requirements: For aircraft with both engines indicating an EGT margin deterioration above 75°C, allowed for continued operation under the requirements of Requirement 3b of this AD, apply the following procedure for every subsequent flight, for the whole flight duration, except that ENG ANTI ICE…ON is not required during cruise: ENG 1 and 2 BLEEDS ON PACK 1 and 2 ON ENG 1 and 2 ANTI ICE ON The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD. Note 1: This procedure must be taken into account for performance calculation. Note 2: EASA Emergency AD 2008-0228-E dated 26 December 2008 refers. | |
Compliance: | For Requirement 1 - Within 7 days after the effective date of this AD, unless previously accomplished. For Requirement 2 - At intervals not exceeding 800 Flight Cycles. For Requirement 3 and 4 - Before further flight. |
| This Airworthiness Directive becomes effective on 20 February 2009. | |
Background: | Several in service occurrences of High Pressure Compressor (HPC) stalls have been reported by operators of Airbus aircraft fitted with CFM 56-5B engines since January 2007. The root cause is highly deteriorated HPCs. To improve operability and maintainability CFM released ECU software 5BQ in January 2007 which features 2 degrees additional Variable Stator Vanes closure in the low power region to increase the stall margin. This 5BQ software introduction has reduced the frequency of stalls, however since April 2008, 6 different engines with 5BQ software have experienced stalls at 3 different operators. |
| On 15 December a CFM56-5B powered A321 experienced stalls on both engines during the same flight. This event was caused by a high level of HPC deterioration. Stalls on both engines during flight can cause a dual IFSD. Further to additional investigations done by Airbus, it has been determined necessary to mandate additional aircraft level requirements for aircraft with both engines indicating an EGT margin deterioration above 75°C. |
James Coyne
Delegate of the Civil Aviation Safety Authority
16 February 2009
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