Narrative:

I was one of the relief first officers. We arrived at the aircraft approximately 1 hour before departure; and after setting up the appropriate cockpit switches; began the preflight. The walkaround was normal until I came to the left wing of the aircraft. I noticed a mechanic on a stand under the left wing; just inboard of the left engine. He was holding a makeshift mop and was wiping what looked like fuel from the wing. However; when he would take his mop away; the fuel would return; running out of a hole which we later found out to be the dry bay drain. After returning to the cockpit; I informed captain about the leak and finished the remainder of my cockpit checks and set-up. Wanting to make sure that the leak was fixed; I returned outside and saw no more fuel running out of the dry bay drain but; upon closer inspection; noticed that someone had stuffed the drain hole with what appeared to be 'saran' plastic wrap. I saw a mechanic approaching and asked him 'are you planning on fixing the leak by stuffing the hole with plastic wrap?' and he shook his head no. He told me what the drain was and that they would be removing an inspection panel in order to see what was going on in the dry bay. I returned to the cockpit and updated captain. He followed me back outside. By this time; the dry bay inspection panel had been removed. The mechanics had sopped up a pool of fuel that had accumulated inside the bay and pronounced the leak fixed. One of the mechanics showed captain a troubleshooting guide they were using. They were classifying the liquid we saw as a stain; which would allow dispatch of the aircraft. We saw on this guide that anything other than a stain must be fixed before departure. Captain and I both agreed it was not a stain but more like a seep or possibly even a heavy seep -- 2 of the other categories on the guide. In either case; the guide used by the mechanics said the leak must be found and fixed. I climbed the ladder stand at the invitation of an inspector to look inside the dry bay. When I looked inside the dry bay; I could see a wet liquid very slowly seeping in from the outboard rib; from what looked like a seam. When I placed my hand on the area; it was wet with a liquid I determined to be jet fuel -- mainly by its smell. After I told captain of this; as well as the lead mechanic; the local mechanics who; though difficult to tell because of language differences; finally acknowledged that it was a fuel leak and not a stain. The flight was canceled and we returned to the hotel. Callback conversation with reporter revealed the following information: reporter stated there were some language problems with the mechanics regarding the fuel coming from the dry bay. Reporter stated that he and the captain were shown a large plastic bag of rags soaked with fuel that were used to remove the seeping fuel from the dry bay. The mechanics seemed to indicate that by removing the fuel; even though the wing was still leaking; everything was ok to go. Although the captain refused the B777; he noticed the same aircraft was released later with a signoff stating the fuel leak was within limits.

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Original NASA ASRS Text

Title: During a walkaround of a B777-200 at an international station; a relief First Officer noticed a Mechanic wiping fuel from the bottom of the wing just inboard of the left engine. Contract Maintenance wanted to classify the fuel leak as a stain; which would allow dispatch of the aircraft; Captain refused.

Narrative: I was one of the relief First Officers. We arrived at the aircraft approximately 1 hour before departure; and after setting up the appropriate cockpit switches; began the preflight. The walkaround was normal until I came to the left wing of the aircraft. I noticed a Mechanic on a stand under the left wing; just inboard of the left engine. He was holding a makeshift mop and was wiping what looked like fuel from the wing. However; when he would take his mop away; the fuel would return; running out of a hole which we later found out to be the dry bay drain. After returning to the cockpit; I informed Captain about the leak and finished the remainder of my cockpit checks and set-up. Wanting to make sure that the leak was fixed; I returned outside and saw no more fuel running out of the dry bay drain but; upon closer inspection; noticed that someone had stuffed the drain hole with what appeared to be 'saran' plastic wrap. I saw a Mechanic approaching and asked him 'Are you planning on fixing the leak by stuffing the hole with plastic wrap?' and he shook his head no. He told me what the drain was and that they would be removing an inspection panel in order to see what was going on in the dry bay. I returned to the cockpit and updated Captain. He followed me back outside. By this time; the dry bay inspection panel had been removed. The Mechanics had sopped up a pool of fuel that had accumulated inside the bay and pronounced the leak fixed. One of the mechanics showed Captain a troubleshooting guide they were using. They were classifying the liquid we saw as a stain; which would allow dispatch of the aircraft. We saw on this guide that anything other than a stain must be fixed before departure. Captain and I both agreed it was not a stain but more like a seep or possibly even a heavy seep -- 2 of the other categories on the guide. In either case; the guide used by the Mechanics said the leak must be found and fixed. I climbed the ladder stand at the invitation of an inspector to look inside the dry bay. When I looked inside the dry bay; I could see a wet liquid very slowly seeping in from the outboard rib; from what looked like a seam. When I placed my hand on the area; it was wet with a liquid I determined to be jet fuel -- mainly by its smell. After I told Captain of this; as well as the Lead Mechanic; the local mechanics who; though difficult to tell because of language differences; finally acknowledged that it was a fuel leak and not a stain. The flight was canceled and we returned to the hotel. Callback conversation with Reporter revealed the following information: Reporter stated there were some language problems with the mechanics regarding the fuel coming from the dry bay. Reporter stated that he and the Captain were shown a large plastic bag of rags soaked with fuel that were used to remove the seeping fuel from the dry bay. The mechanics seemed to indicate that by removing the fuel; even though the wing was still leaking; everything was OK to go. Although the Captain refused the B777; he noticed the same aircraft was released later with a signoff stating the fuel leak was within limits.

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.