A line avionics mechanic reports he realized he had forgotten to perform a CAT-3 test for weather mi...

Attributes
ACN	924558
Time
Date	201012
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Night
Aircraft 1
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Flight Phase	Parked
Component
Aircraft Component	INS / IRS / IRU
Person 1
Function	Technician
Qualification	Maintenance Airframe Maintenance Avionics Maintenance Powerplant
Experience	Maintenance Technician 34
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural FAR Deviation - Procedural Published Material / Policy

Narrative:

ZZZ line maintenance; a B737-400 came in with a number 2 IRU (inertial reference unit) fault. Attempted realignment of IRU failed. IRU display showed (status) sts fault 02. Replaced number 2 IRU per maintenance manual (MM) 34-28-41. IRU aligned normally. Signed off installation of IRU. The flight was loaded and ready to go and we were into a delay. As I was typing the log page into our maintenance tracking system; I realized I had forgotten to do the CAT-3 testing for weather minimums for the IRU; nor had I downgraded the aircraft CAT status. The plane had already departed. As soon as I realized what I had done I advised the lead mechanic. I then called ZZZ1 maintenance control and spoke to controller X and advised him of the situation. By that time the aircraft had been gone 10 to 20 minutes. I was in a hurry and I just forgot. We were into a delay and I was anxious to get the flight on its way. No maintenance supervisors on shift.

Original NASA ASRS Text

Title: A Line Avionics Mechanic reports he realized he had forgotten to perform a CAT-3 test for weather minimums and did not downgrade their B737-400 to CAT-1 status; after replacing the number 2 IRU.

Narrative: ZZZ Line Maintenance; a B737-400 came in with a number 2 IRU (Inertial Reference Unit) fault. Attempted realignment of IRU failed. IRU display showed (Status) STS Fault 02. Replaced number 2 IRU per Maintenance Manual (MM) 34-28-41. IRU aligned normally. Signed off installation of IRU. The flight was loaded and ready to go and we were into a delay. As I was typing the log page into our Maintenance Tracking System; I realized I had forgotten to do the CAT-3 testing for weather minimums for the IRU; nor had I downgraded the aircraft CAT status. The plane had already departed. As soon as I realized what I had done I advised the Lead Mechanic. I then called ZZZ1 Maintenance Control and spoke to Controller X and advised him of the situation. By that time the aircraft had been gone 10 to 20 minutes. I was in a hurry and I just forgot. We were into a delay and I was anxious to get the flight on its way. No Maintenance supervisors on shift.

Data retrieved from NASA's ASRS site as of April 2012 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.

A line avionics mechanic reports he realized he had forgotten to perform a CAT-3 test for weather minimums and did not downgrade their B737-400 to CAT-1 status; after replacing the number 2 IRU.