Narrative:

Installed the aft moisture barrier in aircraft and had signed off the step on the work card for completion of the job. At this time; an FAA inspector advised me that I had not completed the step on the work card about the height of the moisture barrier on the sidewall structure it was supposed to be 3 inches high and in one section I had let it drop to 2.5 inches. At this time; he had my supervisor call me to the office and lectured me on how important it was to go by what the paperwork says. Confusion regarding engineering change request configuration drawing for bathtub build-up. Conflict between required height of bathtub liner on work card and engineering change request. Inability to install dado panels and lavatories with one type of configuration stated on engineering change request. Callback conversation with reporter revealed the following information: reporter stated the moisture barrier (liner); is actually a mylar type material; approximately 24-inches wide; lay over the floorboards in all exposed wet areas; and is very durable. The liner is not a requirement by the FAA; but an addition by his carrier's engineering to prevent moisture; such as water; coffee or lavatory fluids leaking down in between the cabin floorboard seams in the galleys; lavatories and entry doorways. Any leaking fluid can drop into the lower compartments; including the electronics equipment bay (east/east) area. Reporter stated the B737-800's use a vacuum type lavatory flush system and a minimal amount of potable water for toilet operation.

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Original NASA ASRS Text

Title: A Mechanic reports an FAA Inspector advised him he had not completed a step on a work card that requires a 3-inch height of a moisture barrier; on the sidewall structure in their B737-800.

Narrative: Installed the aft moisture barrier in aircraft and had signed off the step on the work card for completion of the job. At this time; an FAA Inspector advised me that I had not completed the step on the work card about the HGT of the moisture barrier on the sidewall structure it was supposed to be 3 inches high and in one section I had let it drop to 2.5 inches. At this time; he had my Supervisor call me to the office and lectured me on how important it was to go by what the paperwork says. Confusion regarding engineering change request configuration drawing for bathtub build-up. Conflict between required HGT of bathtub liner on work card and engineering change request. Inability to install dado panels and lavatories with one type of configuration stated on engineering change request. Callback conversation with reporter revealed the following information: Reporter stated the moisture barrier (liner); is actually a Mylar type material; approximately 24-inches wide; lay over the floorboards in all exposed wet areas; and is very durable. The liner is not a requirement by the FAA; but an addition by his carrier's engineering to prevent moisture; such as water; coffee or lavatory fluids leaking down in between the cabin floorboard seams in the galleys; lavatories and entry doorways. Any leaking fluid can drop into the lower compartments; including the Electronics Equipment Bay (E/E) area. Reporter stated the B737-800's use a vacuum type lavatory flush system and a minimal amount of potable water for toilet operation.

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.