Hi,

A couple of weeks ago I had an interesting flight experience and would like to hear your thoughts.

I was going from Amsterdam to Newark with Delta on a Boeing 767-300. The plane was delayed two times and I was later told by a flight attendant that there had been a technical problem with the plane which had caused the flight the day before to be canceled.

When we had boarded and the plane started to taxi out on the runway there was a very high, random, metallic, clonking sound coming from underneath the airplane. I sat next to a flight attendant who used a phone to make the captain aware of the situation. The plane stopped and after a while the captain told us that they had found out that the sound was due to a problem with the fuel. "The fuel have been filled in the wrong tank" or something in that line.

We went back to the gate to "move the fuel to the right tank". There were several technicians on the plane who asked about the nature of the clonking sound. After about an hour the fuel problem that caused the sound was fixed and we went back out on the runway. The same clonking sound was still present.

After a few minutes the captain made an announcement and I expected him to say that we were going back to the gate again. But instead he said that we should not worry about the sound – and we took off.

This incident raises several questions:
1. Why wasn't the problem with the misplace fuel noticed before our first take off attempt?
2. Since the clonking sound didn't have anything to do with the misplaced fuel – what would have happened if we would have taken of without moving the fuel?
3. And off course; How come the plane took off with a known, but unsolved, problem?