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Old 6th Feb 2014, 07:04   #75 (permalink)
TSIO540
 
Join Date: Sep 2008
Location: In the land of smog
Posts: 182
Chaffed Wire

A320

Dispatched with Engine 2 Igniter System A inop under MEL - requiring manual start. The flight was normal until landing.

Symptoms:

During landing with full reverse, an ECAM ENG 2 REV FAULT occurred but the reverser operated normally with no asymmetry.

After landing the APU failed to start and gave an ECAM APU FAULT - APU AUTO SHUTDOWN

On stand, ground power was supplied but tripped off after shutdown and was restored a few seconds later. As the power came on a long series of cautions and warnings appeared on the ECAM, most of which we attributed to the power transfer.

Maintenance action:

APU igniter box fault was deferred and ENG 2 Reverser was locked out.

Departure Attempt 1:

An external air manual start was conducted to a stable idle condition, then a bunch of things happened.

Symptoms:

Then an ECAM ELAC 1 PITCH FAULT occurred, followed by ENG 2 REV FAULT and Engine two Oil pressure indication was lost from the System Display.

Maintenance Action Two:

Engine 2 No4 bearing oil pressure sensor found to be U/S with C/B popped, it was deferred in the tech log.

All flight control power supplies were reset.

Departure Attempt 2:

Engine two started the same way to a stable idle condition then a series of ECAM warnings occurred,

ELAC 1 PITCH FAULT - pilot reset; then

MASTER WARNING ELEV L + R FAULT, ENG 2 REV FAULT, SDAC FAULT and a few others I can't remember - engineer guided resets carried out to no avail.

Maintenance action three:

ELAC 1 suspected to be faulty, deactivated and all other computers reset.

The engineers advised there would be a bunch of faults but they would be spurious and can be reset.

Departure attempt 3:

After start: MASTER WARNING ELEV L + R FAULT occurred but cleared after ELAC 2 and SEC 1, 2 & 3 resets carried out.

The flight control check was normal and the flight proceeded normally albeit 4 hours late with very angry pax.

Solution (finally found a few days later):

ELAC 1 was suspected and after deactivation stopped all of the warnings but after all flight control computers were replaced the problem reoccurred! Further investigation found a chaffed wire (IIRC between ENG 2 and ELAC 1) was shorting out the computers.
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