Narrative:

When I arrived at the airport; it was night and snowing hard and was forecast to continue. The aircraft had a left wing illumination light inoperative. I refused the aircraft due to inability to see the wings to do a wing check if needed and therefore adversely affecting safety of flight.when I got to the airplane the old; [maintenance document] was there; it states; 'the wing scan (illumination) light does not illuminate the top surface of the wing and is not required/effective for wing visual inspections.' I find it unfathomable that the MEL would have this language considering there is no other aircraft lighting; which will illuminate any part of the wing. The MEL language is concerning in light of the following statements from the flight operation manual:'wings: concentrate on the leading and trailing edges of each wing; as the slats; spoilers and ailerons usually provide an early indication of imminent fluid failure.' this is exactly the area; which these lights illuminate.'…check both wings as a strong wind can cause one side of the aircraft to fail first.' 'reason for not deferring lights on one side.''…at night use all available external lighting.' 'fluids are considered to have failed...when this occurs; the fluid begins to appear opaque rather than transparent and glossy...'I submit that there is no way to discern these details without illumination.my recommendation is that the language in the MEL be changed requiring the lights be operative if there is an expectation that deicing will take place at night and at the very least to remove what I consider to be an incorrect statement about the lights not being effective.

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Original NASA ASRS Text

Title: A319 Captain reported refusing an aircraft in night snowy conditions because the wing illumination light was deferred inoperative; and could not inspect the wing for snow contamination.

Narrative: When I arrived at the airport; it was night and snowing hard and was forecast to continue. The aircraft had a left wing illumination light inoperative. I refused the aircraft due to inability to see the wings to do a wing check if needed and therefore adversely affecting safety of flight.When I got to the airplane the old; [maintenance document] was there; it states; 'the wing scan (illumination) light does not illuminate the top surface of the wing and is not required/effective for wing visual inspections.' I find it unfathomable that the MEL would have this language considering there is no other aircraft lighting; which will illuminate any part of the wing. The MEL language is concerning in light of the following statements from the Flight Operation Manual:'Wings: Concentrate on the leading and trailing edges of each wing; as the slats; spoilers and ailerons usually provide an early indication of imminent fluid failure.' This is exactly the area; which these lights illuminate.'…Check both wings as a strong wind can cause one side of the aircraft to fail first.' 'Reason for not deferring lights on one side.''…At night use all available external lighting.' 'Fluids are considered to have failed...When this occurs; the fluid begins to appear opaque rather than transparent and glossy...'I submit that there is no way to discern these details without illumination.My recommendation is that the language in the MEL be changed requiring the lights be operative if there is an expectation that deicing will take place at night and at the very least to remove what I consider to be an incorrect statement about the lights not being effective.

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.