When I was techrep at Sikorsky a French Army operated H-34 suffered fuel starvation over a mountainous area and in the process of autorotation they severely damaged the lower fuselage. When they opened the forward fuel tank they found a fuel soaked piece of cardboard about ten inches square draped over the fuel pickup blocking off all flow to the engine. One side of the cardboard was blank and the other was red with white lettering. The lettering said “ remove this lock before installing the valve”.
My boss gave me the piece of cardboard and I recognized it. I went down to the fuel tank installation area in the shop and borrowed a float valve. This valve operated much like the float in an SU carburetor or in a toilet. I brought the valve back to my boss and removed it from its container. In order to prevent damage to the metering valve the manufacturer placed a lock in the mechanism to prevent the movement of the float. I removed the lock and unrolled it and on it said remove this lock before installing the valve. Sikorsky ended up footing the repair bill.
Along with the floating cardboard the French Army also sent along several women’s hair pins, twenty or thirty human hairs and several chewing gum wrappers.
Needless to say, Sikorsky tightened up their quality control and the women had to wear hair nets and caps.