Narrative:

[This aircraft] had just pulled into [the] gate. As parts of the meet and greet requiring line technician; I came to the flight deck to meet and greet the inbound flight crew a few minutes after that. As I made my presence known to the inbound flight crew; the captain immediately told me about his observation during aircraft taxi into the gate that the #2 engine anti-ice light on bright blue while switch in off position. Realizing that there is a clear discrepancy between the # 2 engine anti-ice valve and the associated switch in the off position; I then told the captain that I will need to do some research on this. Back to our maintenance office with the aircraft log book; I began my research by looking up aircraft maintenance history and discovered that on the previous day; the #2 engine anti-ice valve has been replaced with a new engine anti-ice valve at another line maintenance station. Due to a repeated write up in two days; my next step was to pull up the MEL manual and to determine which MEL that would apply to the #2 engine anti-ice valve. As got the MEL manual open up; I called maintenance controller to notify him about the inbound pilot report and my research regarding the reported defect and wanted to apply an MEL 30-3C to the effected valve. The MEL 30-3C refers to aircraft maintenance manual (amm) for maintenance procedures on how to prepare the aircraft for flight with the engine anti-ice valve inoperative. As per amm task 30-00-00-040-803 the engine anti-ice valve can be deactivated by locking them closed or open. I chose option 1 that is to manually position the #2 engine anti-ice valve inoperative closed; because it is shorter procedures to perform comparing to the option 2 engine anti-ice valve inoperative open.having [maintenance controller's] concurrence with the applicable MEL 30-3C; I went back to the aircraft along with another mechanic; who would help me with opening the #2 engine right/H cowl for access to the anti-ice valve. With the #2 engine right/H cowl open and using a 6 feet ladder positioned adjacent to the #2 engine; I was in a position to manually put the #2 engine valve in a closed position. Before attempting to turn the valve to a close position; I needed to find out how to determine which direction to manually turn the affected valve to a close position. From a top view looking at the override knob; I could only see an arrow pointing aft of the #2 engine on the manual lock assembly. Further examination; I noted that on the valve body assembly; there is also an arrow pointing forward; which indicates the direction of the air flow. Based on my experience of working with similar pneumatic valves on a different systems; when a valve is in an open position; the arrow on the manual knob indicator would normally pointing parallel to the valve body assembly; and when a valve is in a closed position; the arrow on the manual knob indicator would be perpendicular to the valve body assembly.based on these two arrows' orientations being parallel to one another and the bright blue light observed in the flight deck; indicating that #2 engine anti-ice valve partially open. It is reasonably to say that I should turn the manual clock so that the arrow on the manual clock assembly would be perpendicular to the arrow on the valve body to set the #2 engine anti-ice valve closed.the amm task does not include a view of the engine anti-ice valve manual override indicator. Also the arrows orientations on the engine anti-ice valve are not in conformity as normally accepted standard. [I suggest] amm task should include a view of a manual override/position indicator for the engine anti-ice valve and the arrows' orientations engine anti-ice valve should apply the same standard concept - parallel arrows means open position and perpendicular arrows means closed position.

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Original NASA ASRS Text

Title: A B737NG Mechanic reported he was unable to determine the position of a nose cowl anti-ice valve in order to defer the valve in the closed position.

Narrative: [This aircraft] had just pulled into [the] Gate. As parts of the meet and greet requiring Line Technician; I came to the flight deck to meet and greet the inbound flight crew a few minutes after that. As I made my presence known to the inbound flight crew; the captain immediately told me about his observation during aircraft taxi into the gate that the #2 engine Anti-Ice Light on bright blue while switch in off position. Realizing that there is a clear discrepancy between the # 2 Engine Anti-Ice Valve and the associated switch in the off position; I then told the captain that I will need to do some research on this. Back to our maintenance office with the aircraft log book; I began my research by looking up aircraft maintenance history and discovered that on the previous day; the #2 engine anti-ice valve has been replaced with a new engine anti-ice valve at another line maintenance station. Due to a repeated write up in two days; my next step was to pull up the MEL manual and to determine which MEL that would apply to the #2 engine anti-ice valve. As got the MEL manual open up; I called Maintenance Controller to notify him about the inbound pilot report and my research regarding the reported defect and wanted to apply an MEL 30-3C to the effected valve. The MEL 30-3C refers to Aircraft Maintenance Manual (AMM) for maintenance procedures on how to prepare the aircraft for flight with the engine anti-ice valve inoperative. As per AMM Task 30-00-00-040-803 the engine anti-ice valve can be deactivated by locking them closed or open. I chose option 1 that is to manually position the #2 engine anti-ice valve Inoperative Closed; because it is shorter procedures to perform comparing to the Option 2 Engine Anti-Ice Valve Inoperative Open.Having [Maintenance Controller's] concurrence with the applicable MEL 30-3C; I went back to the aircraft along with another mechanic; who would help me with opening the #2 engine R/H cowl for access to the anti-ice valve. With the #2 engine R/H cowl open and using a 6 feet ladder positioned adjacent to the #2 engine; I was in a position to manually put the #2 engine valve in a closed position. Before attempting to turn the valve to a close position; I needed to find out how to determine which direction to manually turn the affected valve to a close position. From a top view looking at the override knob; I could only see an arrow pointing aft of the #2 engine on the manual lock assembly. Further examination; I noted that on the valve body assembly; there is also an arrow pointing forward; which indicates the direction of the air flow. Based on my experience of working with similar pneumatic valves on a different systems; when a valve is in an open position; the arrow on the manual knob indicator would normally pointing parallel to the valve body assembly; and when a valve is in a closed position; the arrow on the manual knob indicator would be perpendicular to the valve body assembly.Based on these two arrows' orientations being parallel to one another and the Bright Blue Light observed in the flight deck; indicating that #2 engine anti-ice valve partially open. It is reasonably to say that I should turn the manual clock so that the arrow on the manual clock assembly would be perpendicular to the arrow on the valve body to set the #2 engine anti-ice valve closed.The AMM Task does not include a view of the engine anti-ice valve manual override indicator. Also the arrows orientations on the engine anti-ice valve are not in conformity as normally accepted standard. [I suggest] AMM Task should include a view of a manual override/position indicator for the Engine Anti-Ice Valve and the arrows' orientations Engine Anti-Ice Valve should apply the same standard concept - parallel arrows means open position and perpendicular arrows means closed position.

Data retrieved from NASA's ASRS site 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.