A320 wing dry bay
•The dry bay is located in the outer wing between the ribs 5 and 6B (or 6) in the forward third of the tank.
The aim of the dry bay is to ensure that the fuel tank is not breached in case of an engine rotor burst.
–Previously, the wing boxes of all A318, A319 and A320 aircraft included a dry bay, to ensure that in the case of an uncontrolled engine rotor failure, the fuel drip line from the wing did not come closer than 10 inches to the nearest hot surface of the engine.
–The installation of a dry bay remains mandatory for aircraft with IAE engines. However, a dry bay is not necessary for aircraft with CFM56-5 or PW 6000 engines. Therefore, Modification in 2007 introduces a wing box without a dry bay for all A318, A319, A320 and A321 aircraft that have CFM56-5 or PW 6000 engines.
–On single-aisle aircraft with this modification, the inner tank usable fuel capacity is increased by 175 Liters (46 US Gallons) per inner tank.
•All Neo aircraft will require the modified Dry Bay protection to be implemented.
Two holes in the front spar give access to the dry bays. They are closed with closing plates.
•There are closing panels in the fuel tank, at the rear of the dry bays. The closing panels are made of carbon fiber with a honeycomb core
•The most likely cause of a fuel leak reported in the dry bay area is the sealant deterioration.
•Fuel leaks at Dry Bay are detected through 3 drain holes in the bottom skin
•Dry bay is considered as closed area and leak is a No Go because Fuel drips out from the dry bay drain holes are next to the engine
•Once a Fuel leak is noted it is therefore necessary to perform either a temporary or a permanent repair before the next flight.
•Temporary repair in the dry bay is difficult and time consuming due to limited access from outside the tank (through front spare access holes)
•Permanent repair requires tank entry