2 B757-200 aircraft were dispatched with unmodified thrust management computers caused by inspection...

Attributes
ACN	413442
Time
Date	199805
Day	Sun
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : zzz
State Reference	US
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Light	Night
Aircraft 1
Controlling Facilities	tower : las
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	other : unknown
Navigation In Use	Other Other
Flight Phase	other
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
ASRS Report	413442
Person 2
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure non adherence : far
Independent Detector	other other : unspecified
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

On may/xa/98 and may/xb/98 I had to verify that air carrier aircraft xyz and zxy had a modified thrust management computer installed. I had to check the data plates on the units and install new computers if the part numbers on them weren't correct. I believed the aircraft were in compliance with my inspection and signed the logbooks to reflect this and that no computer replacement was required. During a company sponsored follow-up inspection, it was determined that both of these thrust management computers were unmodified and needed to be replaced according to their part numbers. These unmodified part numbers were yyzzxx-G2. The modified part numbers are yyzzxx-G3 and yyzzyx-G2, which are very similar to the old number. I must have been confused on the nights in question and misinterped the bad number for a good one. I had performed this inspection many times prior to these incidents without complication. I believe these incidents occurred because I was comfortable with the procedure and perhaps a little complacent. Furthermore, I work shift XA00-XI00 and have trouble staying focused all the time.

Original NASA ASRS Text

Title: 2 B757-200 ACFT WERE DISPATCHED WITH UNMODIFIED THRUST MGMNT COMPUTERS CAUSED BY INSPECTION OVERSIGHT.

Narrative: ON MAY/XA/98 AND MAY/XB/98 I HAD TO VERIFY THAT ACR ACFT XYZ AND ZXY HAD A MODIFIED THRUST MGMNT COMPUTER INSTALLED. I HAD TO CHK THE DATA PLATES ON THE UNITS AND INSTALL NEW COMPUTERS IF THE PART NUMBERS ON THEM WEREN'T CORRECT. I BELIEVED THE ACFT WERE IN COMPLIANCE WITH MY INSPECTION AND SIGNED THE LOGBOOKS TO REFLECT THIS AND THAT NO COMPUTER REPLACEMENT WAS REQUIRED. DURING A COMPANY SPONSORED FOLLOW-UP INSPECTION, IT WAS DETERMINED THAT BOTH OF THESE THRUST MGMNT COMPUTERS WERE UNMODIFIED AND NEEDED TO BE REPLACED ACCORDING TO THEIR PART NUMBERS. THESE UNMODIFIED PART NUMBERS WERE YYZZXX-G2. THE MODIFIED PART NUMBERS ARE YYZZXX-G3 AND YYZZYX-G2, WHICH ARE VERY SIMILAR TO THE OLD NUMBER. I MUST HAVE BEEN CONFUSED ON THE NIGHTS IN QUESTION AND MISINTERPED THE BAD NUMBER FOR A GOOD ONE. I HAD PERFORMED THIS INSPECTION MANY TIMES PRIOR TO THESE INCIDENTS WITHOUT COMPLICATION. I BELIEVE THESE INCIDENTS OCCURRED BECAUSE I WAS COMFORTABLE WITH THE PROC AND PERHAPS A LITTLE COMPLACENT. FURTHERMORE, I WORK SHIFT XA00-XI00 AND HAVE TROUBLE STAYING FOCUSED ALL THE TIME.

Data retrieved from NASA's ASRS site as of July 2007 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.

2 B757-200 aircraft were dispatched with unmodified thrust management computers caused by inspection oversight.