A line mechanic reported a possible illegal dispatch of a B727-200 aircraft after he misinterpreted ...

Narrative:

Flight engineer (F/east) questioned engine fire bottle weight check date; it was one day expired on tag. General maintenance manual (gmm) section was found that allowed for hydrostatic/acoustic inspection overrun to [go to the] next c-check. F/east accepted that and no logbook entry was created. After aircraft departed; maintenance control called and they had found a maintenance manual (M/M) reference for reweighing the [fire] bottle if it had no pressure gauge. I had remembered the gmm reference from the older; pressure gauge bottles and automatically went to it under the pressure of [being] close to blockout time. I also had read of acoustic testing to determine contents [weight] of bottles and assumed that applied to the bottles with no gauges. Maintenance control stopped the aircraft at the hub to have the bottles reweighed.

Original NASA ASRS Text

Title: A Line Mechanic reported a possible illegal dispatch of a B727-200 aircraft after he misinterpreted a Maintenance Manual (M/M) section for an 'Out of Date' Engine Fire Bottle Weight Check requirement.

Narrative: Flight Engineer (F/E) questioned engine Fire Bottle Weight Check Date; it was one day expired on tag. General Maintenance Manual (GMM) section was found that allowed for Hydrostatic/Acoustic Inspection Overrun to [go to the] next C-Check. F/E accepted that and no Logbook entry was created. After aircraft departed; Maintenance Control called and they had found a Maintenance Manual (M/M) reference for reweighing the [Fire] bottle if it had no pressure gauge. I had remembered the GMM reference from the older; pressure gauge bottles and automatically went to it under the pressure of [being] close to blockout time. I also had read of Acoustic Testing to determine contents [weight] of bottles and assumed that applied to the bottles with no gauges. Maintenance Control stopped the aircraft at the hub to have the bottles reweighed.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	997520
Time
Date	201203
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Night
Aircraft 1
Make Model Name	B727-200
Operating Under FAR Part	Part 91
Flight Phase	Parked
Component
Aircraft Component	Powerplant Fire Extinguishing
Person 1
Function	Technician
Qualification	Maintenance Airframe Maintenance Inspection Authority Maintenance Powerplant
Experience	Maintenance Technician 19
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy

A line mechanic reported a possible illegal dispatch of a B727-200 aircraft after he misinterpreted a maintenance manual (M/M) section for an 'out of date' engine fire bottle weight check requirement.