An EMB145 had 4 deferred items: EICAS 115 vac warning; TCASII; egpws and ACARS printer all inoperati...

Attributes
ACN	647480
Time
Date	200502
Place
Locale Reference	airport : zzz.airport
State Reference	US
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	EMB ERJ 145 ER&LR
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
ASRS Report	647480
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance maintenance problem : non compliance with mel maintenance problem : improper documentation non adherence : far non adherence : published procedure
Independent Detector	other other : 1
Resolutory Action	none taken : detected after the fact
Consequence	other other
Factors
Maintenance	contributing factor : manuals contributing factor : schedule pressure performance deficiency : non compliance with legal requirements performance deficiency : repair performance deficiency : fault isolation performance deficiency : logbook entry
Supplementary
Problem Areas	Aircraft Chart Or Publication Maintenance Human Performance
Primary Problem	Maintenance Human Performance

Narrative:

On aircraft X; flew into XXX for overnight maintenance. There were 4 MEL's against the aircraft -- all relocated to the 115 vac system: 1) MEL #24-03115 vac bus off message on EICAS. 2) MEL #34-33 TCASII inoperative due to MEL #24-03. 3) MEL #34-20 egpws inoperative due to MEL #24-03. 4) #23-06 ACARS printer inoperative due to MEL #24-03. During troubleshooting; I found that the 115 vac inverter worked pwring all these system for 10-15 mins and then 115 vac bus off message would appear on the EICAS; all items MEL'ed would fail and an electrical burn smell would be emitted from the ACARS printer. I found that if I disconnected the ACARS printer connector; the 115 vac bus would stay on-line and the TCASII and egpws/windshear system remained operation; but when the ACARS printer was reconnected; it would fail again. MEL's #24-03 and #24-20 were both CAT 'a' MEL's grounding on XXX; MEL #34-33 is a CAT 'B' and grounded on YYY; MEL #23-06 grounded on ZZZ. I replaced the 115 vac inverter not knowing if the ACARS printer might have damaged it. Did not have a printer in stock. I disconnected the ACARS printer connector; covered it with a plastic bag and secured it out of the way in the pedestal. This would allow the aircraft to fly until a printer was available. It was already MEL'ed and could operate for another 7 days without causing problems with the 115 vac bus; TCASII; and egpws/windshear system.

Original NASA ASRS Text

Title: AN EMB145 HAD 4 DEFERRED ITEMS: EICAS 115 VAC WARNING; TCASII; EGPWS AND ACARS PRINTER ALL INOP. FOUND ACARS PRINTER SHORTED CAUSING ALL FAULTS.

Narrative: ON ACFT X; FLEW INTO XXX FOR OVERNIGHT MAINT. THERE WERE 4 MEL'S AGAINST THE ACFT -- ALL RELOCATED TO THE 115 VAC SYS: 1) MEL #24-03115 VAC BUS OFF MESSAGE ON EICAS. 2) MEL #34-33 TCASII INOP DUE TO MEL #24-03. 3) MEL #34-20 EGPWS INOP DUE TO MEL #24-03. 4) #23-06 ACARS PRINTER INOP DUE TO MEL #24-03. DURING TROUBLESHOOTING; I FOUND THAT THE 115 VAC INVERTER WORKED PWRING ALL THESE SYS FOR 10-15 MINS AND THEN 115 VAC BUS OFF MESSAGE WOULD APPEAR ON THE EICAS; ALL ITEMS MEL'ED WOULD FAIL AND AN ELECTRICAL BURN SMELL WOULD BE EMITTED FROM THE ACARS PRINTER. I FOUND THAT IF I DISCONNECTED THE ACARS PRINTER CONNECTOR; THE 115 VAC BUS WOULD STAY ON-LINE AND THE TCASII AND EGPWS/WINDSHEAR SYS REMAINED OP; BUT WHEN THE ACARS PRINTER WAS RECONNECTED; IT WOULD FAIL AGAIN. MEL'S #24-03 AND #24-20 WERE BOTH CAT 'A' MEL'S GNDING ON XXX; MEL #34-33 IS A CAT 'B' AND GNDED ON YYY; MEL #23-06 GNDED ON ZZZ. I REPLACED THE 115 VAC INVERTER NOT KNOWING IF THE ACARS PRINTER MIGHT HAVE DAMAGED IT. DID NOT HAVE A PRINTER IN STOCK. I DISCONNECTED THE ACARS PRINTER CONNECTOR; COVERED IT WITH A PLASTIC BAG AND SECURED IT OUT OF THE WAY IN THE PEDESTAL. THIS WOULD ALLOW THE ACFT TO FLY UNTIL A PRINTER WAS AVAILABLE. IT WAS ALREADY MEL'ED AND COULD OPERATE FOR ANOTHER 7 DAYS WITHOUT CAUSING PROBS WITH THE 115 VAC BUS; TCASII; AND EGPWS/WINDSHEAR SYS.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

An EMB145 had 4 deferred items: EICAS 115 vac warning; TCASII; egpws and ACARS printer all inoperative. Found ACARS printer shorted causing all faults.