What is the wrench size for a -4 flare nut? Want to make sure that I am properly identifying the fitting and using the wrench size of the nut as a back up. Ex the -4 flare nut connecting to a AN823-4D
If you're planning to do much work with aircraft plumbing, consider picking up a set of flare nut wrenches, which are less likely to round off the soft aluminum nuts used with aluminum tubing:
They come in crowfoot form too, which also have their uses: