Chinook: Use the Right O-Rings and Packings to Prevent Engine Fires

BLUF: Don’t use the current O-rings and packings NSN listed in the IETM on the Chinook engine fuel manifolds.

Photo by Spc. Oscar Toscano
 

Mechanics, you’ve probably heard about the grounding of Chinook helicopters because of engine fires resulting from use of incorrect O-rings and packings. 
 
The problem arose because the DLA supply system lumped together the correct packing O-rings and packings for the engines in the same package with other O-rings and packings of the same size that were incorrect. The incorrect O-rings and packings aren't of the proper material to sustain fuel and heat exposure and when ordered from the supply system, maintainers installed the incorrect O-rings and packings, which eventually caused engine fires. The correct O-rings and packings for the Chinook engines are designed for fuel and heat exposure.
 
DLA is working on a fix by separating the correct part number (PN 2-300-228-01 with CAGE code 07060) from other associated NSNs for O-ring and packings.
 
The only authorized O-rings and packings to be used on the Chinook engine fuel manifolds come with NSN 5331-01-703-3320, and you can identify the correct O-rings and packings by their gray color. Do not use any other O-ring and packings NSNs.
  
Make a note that the authorized NSN is new and the current supply chain stock is depleted. It’s not available through regular supply channels, but the original equipment manufacturer (OEM) is working on replenishing the stock ASAP.
 
IETMs 1-1520-271-23&P (Apr 21) and 1-2840-265-23&P (Apr 21) will be updated with the new NSN in future IETM changes.
 
In WP 0488 of IETM 1-2840-265-23&P (Apr 21), the torque for tightening the hardware and bolts associated with the O-rings and packings isn’t specified. Using the standard torque chart doesn't adequately torque the bolts. The correct torque is 42 inch-pounds, which will be added to the work packages in the next IETM updates. For more information, check out Aviation Safety Action Message (ASAM) H-47-22-ASAM-06.
 
To view and download ASAM H-47-22-ASAM-06, click HERE. Click on Consolidated Listings, select Aviation as the Record Type, GEN as System Type and ASAM as Message Type. Then click Search. Results are listed in chronological order.