Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number HS5603-5A4 found under Pin Rivet by Mcdonnell Douglas Helicopter. The National Stock Number assigned to this part is 5320014994304, and the Federal Supply Class is 5320 Rivets. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like HS5603-5A4.