Black Hawk: Bifilar Weight Nut Guidance

BLUF:  Use passivated bifilar weight nuts (PN SS5086C10) due to a shortage of the silver-plated nuts (PN SS5086C10S) until the UHPO decides which nut to use across all aircraft; also update WP 2717 in IADS.


Photo by Staff Sgt. Austin Berner
 

Mechanics, there’s a change to Fig 05-5 of WP 2717, BIFILAR ASSEMBLY, MAIN ROTOR, in the following three IETMs:
 

• TM 1-1520-280-23&P (Apr 23)
• TM 1-1520-237-23&P (Apr 23)
• TM 1-1520-246-23&P (Apr 23)

Currently, the -280-23&P IETM specifies using SS5086C10S bifilar weight nuts, while the -237 and -246 IETMs specify using SS5086C10 nuts. However, there’s a shortage in the supply system of the SS5806C10S nuts.
 
The difference between the hardware is that the C10S nut is silver-plated, while the C10 nut is passivated. Based on engineering reviews by the Utility Helicopter Product Office (UHPO), the SS5086C10 and SS5086C10S nuts can be used across all Black Hawk aircraft (H-60A/L/M/V) until engineering decides which nut will be provisioned across the fleet.
 
Make a note to update WP 2717 of TM 1-1520-280-23&P (Apr 23) in IADS per the instructions in Aviation Maintenance Action Message (AMAM) GEN-20-AMAM-04.
 
You can view and download the AMAM HERE, with your CAC in hand. Click on Consolidated Listings, select Aviation as the Record Type, GEN as System Type and AMAM as Message Type. Then click Search. Results are listed in chronological order.
 
 You can also visit the IADS website HERE.
 
Also, check out IADS: Export and Import Function Enables Sharing of Notes.