During the annual we will be removing over 7000 cubic meters of helium from the ship to these bags, supporting the ship with a bracing system, performing an airframe inspection from inside the envelope (filled with air at that time) and then returning the helium back to the ship.
Wouldn't it be easier to do the inspection with inspectors on SCBA units?
ReplyDeleteIt is (in theory) possible to do the airframe inspection using "Helium Diving" equipment, but the inspection requires multiple people, over multiple days, crawling all over the inside of the envelope, working on catwalks suspended from the frame, etc. The helium dive equipment is bulky, requires training/certification, safety spotters, etc. So it can be done, but at additional risk compared to the "traditional" method.
ReplyDeleteTo date, all NT inspections have been done via helium removal/replacement.
This is certainly an area to research for potential future improvement/optimization -- having the ship inoperable for a month isn't a big deal in Germany where they don't fly the winter months, but it certainly is for climates (such as ours) that support year-round operations.