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Elevator Boost System-why is it 'upside down'

Stygian USN

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when you speak of hydraulic systems, I know that the left is utility and right is booster. when you're looking back and see a loss of fluid from your left hand, I know I have to cut is the utility. that's why it is reversed. That is to avoid confusion in the emergency procedure.
This would be correct if the booster was designed and installed on B model and on, but the A model has a different hydraulic system. The A model uses engines 1 and 3 for booster and 2 and 4 for utility. As the A was the first model, the left to left and right to right idea doesn't seem to be sensible. On the A model each filter is supplied by one pump on each wing. Logic being that if you shut both outboard engines down, you still have one pump for each system. Both reservoirs are on the right side and interconnected so hydraulic fluid returning from flight controls and flaps can return to the relevant reservoir then overflow back into the emergency reservoir when the booster and utility reservoirs are full.

The A model only looks like a Herc, the similarity just about ends there...........

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  • 1 month later...

Urban legend has it that they took the pack from another plane and had to turn it upside down to fit. As far as the reason why the Booster is on the left and the utility is on the right is commonality (I hate that word). The other two packs have internal crossovers so the booster system pressure actually works on the left side of the aileron and rudder boost pack and the utility works on the right side (viewed from the rear). To make it common, the elevator has external lines that crossover and connect to the opposite side. Now when I look at my booster shut offs they are labeled Elevator Rudder Aileron with Booster on the left and Utility on the right just below the switches. To put it in practice, you're in the back of the airplane and notice a leak on the left side of the boost pack (pick one) if you isolate the left switch it should take care of your problem.

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