An official website of the United States government
Here's how you know
A .mil website belongs to an official U.S. Department of Defense organization in the United States.
A lock (lock ) or https:// means you’ve safely connected to the .mil website. Share sensitive information only on official, secure websites.

Home : PS Mag Archive : Articles
Would you stake your life, right now, on the condition of your equipment?
Articles
NEWS | July 6, 2023

Apache: Color of Grease Not Cause for Gearbox Replacement

BLUF: Grease discoloration in the Apache tail rotor gearbox and intermediate gearbox is not sufficient cause for replacing them. 

Sgt. Nathan Nolen is reassembling a tail rotor gearbox for an AH-64E Apache Helicopter.
Photo by Capt. Erick Turley
 
Mechanics, Aviation Maintenance Information Message (MIM) is making an update to the recently released TM 1-1520-Longbow/Apace (16 Mar 23). Several task steps in the TM required mechanics to replace the gearboxes in the table below if there was grease discoloration.

Table: Affected gear boxes
Nomenclature NSN Part Number
Tail rotor gearbox 1615-01-254-7793 7-311340001-7
Tail rotor gearbox 1615-01-507-5294 7-311340001-9
Intermediate gearbox 1680-01-530-1625 7-311330001-9
Intermediate gearbox 1680-01-478-7102 7-311330001-7
Intermediate gearbox 1680-01-232-0038 7-311330001-5
 
This guidance is no longer applicable. Analysis has revealed that grease discoloration is not a reliable indication of contamination (other indicators such as vibration and temperature are deemed more reliable). As a result, the requirement to replace gearboxes due to grease discoloration in TM 1-1520-LONGBOW/APACHE (16 Mar 23) is discontinued. The TM will be updated at the next change cycle.
 
To view the MIM, click HERE. Click on Consolidated Listings, select Aviation as the Record Type, H-64 as System Type and MIM as Message Type. Then click Search. Results are listed in chronological order.
Want to get better search results faster? 
Click the link below to access our "how to" guide
.
After entering a keyword, you must hit or click the Search bar/box below for the function to work.
Simply hitting Return won't yield results.
LOGSA Links/URLs
Note about links to archive articles

If you come across a link to a pre-2014 PS Magazine issue or article that uses LOGSA in the web address (URL), use this link instead:
 
For issues/articles from 2014 and after, click on the Archive/Index tab in the top menu of this website.