A B737-700 aircraft two each nose tire replacement were found to be a mismatch.

Attributes
ACN	740288
Time
Date	200705
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
Qualification	technician : airframe technician : powerplant
ASRS Report	740288
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance non adherence : far non adherence : published procedure
Independent Detector	aircraft equipment other aircraft equipment : nose tires mismatched
Resolutory Action	none taken : detected after the fact
Consequence	other
Factors
Maintenance	performance deficiency : non compliance with legal requirements performance deficiency : installation
Supplementary
Problem Areas	Aircraft Maintenance Human Performance
Primary Problem	Maintenance Human Performance

Narrative:

I was informed that I had installed a mismatched pair of nosewheel tires on aircraft X. The date that I had changed the tires was 6 days prior. I do remember changing the tires but do not remember if they were mismatched tires or not. I grabbed the tires from our B-700 tire chart and did verify that they were B-700 type wheel assembly. When it was brought to my attention that they were mismatched; I was a bit surprised. I'm a thorough mechanic and I do pay attention to details. On that night I did change 3 main tires and assisted on another. I was in a tire changing rhythm. I remember reading the maintenance notice awhile back and was in the back of my mind. The mismatched tires were found on a walkaround by a pilot; who then wrote them up in the logbook. They called a mechanic out and they changed them. As this occurrence happen it has made me well aware. And I'm going to make it my duty to inform my coworkers on the proper tires confign on the B-700 aircraft. I have one idea to maybe help to prevent this from happening to other mechanics. I suggest having mechanics sign off after reading a maintenance notice. Or some recurring safety refresher bulletins.

Original NASA ASRS Text

Title: A B737-700 ACFT TWO EACH NOSE TIRE REPLACEMENT WERE FOUND TO BE A MISMATCH.

Narrative: I WAS INFORMED THAT I HAD INSTALLED A MISMATCHED PAIR OF NOSEWHEEL TIRES ON ACFT X. THE DATE THAT I HAD CHANGED THE TIRES WAS 6 DAYS PRIOR. I DO REMEMBER CHANGING THE TIRES BUT DO NOT REMEMBER IF THEY WERE MISMATCHED TIRES OR NOT. I GRABBED THE TIRES FROM OUR B-700 TIRE CHART AND DID VERIFY THAT THEY WERE B-700 TYPE WHEEL ASSEMBLY. WHEN IT WAS BROUGHT TO MY ATTN THAT THEY WERE MISMATCHED; I WAS A BIT SURPRISED. I'M A THOROUGH MECH AND I DO PAY ATTN TO DETAILS. ON THAT NIGHT I DID CHANGE 3 MAIN TIRES AND ASSISTED ON ANOTHER. I WAS IN A TIRE CHANGING RHYTHM. I REMEMBER READING THE MAINT NOTICE AWHILE BACK AND WAS IN THE BACK OF MY MIND. THE MISMATCHED TIRES WERE FOUND ON A WALKAROUND BY A PLT; WHO THEN WROTE THEM UP IN THE LOGBOOK. THEY CALLED A MECH OUT AND THEY CHANGED THEM. AS THIS OCCURRENCE HAPPEN IT HAS MADE ME WELL AWARE. AND I'M GOING TO MAKE IT MY DUTY TO INFORM MY COWORKERS ON THE PROPER TIRES CONFIGN ON THE B-700 ACFT. I HAVE ONE IDEA TO MAYBE HELP TO PREVENT THIS FROM HAPPENING TO OTHER MECHS. I SUGGEST HAVING MECHS SIGN OFF AFTER READING A MAINT NOTICE. OR SOME RECURRING SAFETY REFRESHER BULLETINS.

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.