A line mechanic reports about the lack of a uniform marking system for aircraft static grounds at th...

Narrative:

I had to replace the crew oxygen (O2) bottle on a B757-200 aircraft. Maintenance manual (MM) 12-15-08 requires the airplane to be 'grounded correctly' per MM 20-41-00. MM 20-41-00 states 'the airplane must be statically grounded to a common; approved; identified ground.' the [static] grounds at the ZZZ maintenance hangar are clearly marked and dated. However; the grounds at company terminal are devoid of markings. This leads one to question the validity of these grounds for aircraft maintenance. Facility maintenance tested a sole ground on gate X (where the B757 resided); using the values found in the servicing manual. After it was determined this ground was indeed 'approved;' the O2 bottle was replaced. There isn't a uniform marking system for the aircraft grounds at ZZZ hangar and terminal areas. [Recommend] the terminal grounding points on all gates be inspected for [static] resistance then marked as 'approved' grounds.

Original NASA ASRS Text

Title: A Line Mechanic reports about the lack of a uniform marking system for aircraft static grounds at their company terminal gates. The Aircraft Maintenance Manual (AMM) required the static 'grounding' of a B757-200 aircraft prior to removing and replacing the Crew Oxygen (O2) bottle.

Narrative: I had to replace the Crew Oxygen (O2) bottle on a B757-200 aircraft. Maintenance Manual (MM) 12-15-08 requires the airplane to be 'grounded correctly' per MM 20-41-00. MM 20-41-00 states 'the airplane must be statically grounded to a common; approved; identified ground.' The [static] grounds at the ZZZ Maintenance Hangar are clearly marked and dated. However; the grounds at company terminal are devoid of markings. This leads one to question the validity of these grounds for aircraft maintenance. Facility Maintenance tested a sole ground on Gate X (where the B757 resided); using the values found in the Servicing Manual. After it was determined this ground was indeed 'approved;' the O2 bottle was replaced. There isn't a uniform marking system for the aircraft grounds at ZZZ Hangar and terminal areas. [Recommend] the Terminal grounding points on all gates be inspected for [static] resistance then marked as 'approved' grounds.

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	1080634
Time
Date	201304
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Dusk
Aircraft 1
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	Parked
Component
Aircraft Component	Oxygen System/Crew
Person 1
Function	Technician
Qualification	Maintenance Airframe Maintenance Powerplant
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

A line mechanic reports about the lack of a uniform marking system for aircraft static grounds at their company terminal gates. The aircraft maintenance manual (amm) required the static 'grounding' of a B757-200 aircraft prior to removing and replacing the crew oxygen (O2) bottle.